Sample records for dihydrate-catalyzed efficient synthesis

  1. Efficient Synthesis of Optically Active Alcohols

    J.S. Chen; Z.R. Dong; Y.Y. Li; B.Z. Li; Y. Xing; W.Y. Shen; G. Chen; X.Q. Zhang; J. X. Gao


    @@ 1Introduction Optically active secondary alcohols are versatile building blocks for synthesis of unnatural biological active compounds and functional materials. Therefore, study on efficient synthesis of optically active alcohols is becoming an important subject in synthetic organic chemistry. Catalytic asymmetric reduction of carbonyl compounds is a practical method to create chiral alcohols. For the past decades, a large number of catalytic methods have been developed to achieve this goal.

  2. Efficient and Facile Synthesis of ( ± )-Salvirecognine

    PENG Xuan-Jia; SHE Xue-Gong; BIE Ping-Yan; PAN Xin-Fu


    @@ Salvirecognine (7) is a diterpene isolated from Salvia recognita[1] which has been the subject of continued and growing interest, due to the range of biological activities shown by many members of this family. [2] In order to study further relationships between the structure and biological activity of the diterpene compounds and as an extension of diterpenoid synthesis in our laboratory, [3,4] the first total synthesis of the title compound was achieved by an efficient and facile route (Scheme 1).

  3. Tactical Synthesis Of Efficient Global Search Algorithms

    Nedunuri, Srinivas; Smith, Douglas R.; Cook, William R.


    Algorithm synthesis transforms a formal specification into an efficient algorithm to solve a problem. Algorithm synthesis in Specware combines the formal specification of a problem with a high-level algorithm strategy. To derive an efficient algorithm, a developer must define operators that refine the algorithm by combining the generic operators in the algorithm with the details of the problem specification. This derivation requires skill and a deep understanding of the problem and the algorithmic strategy. In this paper we introduce two tactics to ease this process. The tactics serve a similar purpose to tactics used for determining indefinite integrals in calculus, that is suggesting possible ways to attack the problem.

  4. efficient and convenient synthesis of symmetrical carboxylic ...

    Preferred Customer

    An efficient and convenient procedure for the synthesis of symmetrical .... solution was stirred for 16 h at 35 °C followed by filtration and washing with ... obtained hydrous zirconia sample was ground to fine powder and immersed in 1 M H2SO4 ..... Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH: Weinheim; 2002.

  5. An efficient asymmetric synthesis of (-)-wodeshiol

    Soon Ho Lee; Jae-Chul Jung; Oee Sook Park


    An efficient synthesis of (-)-wodeshiol 1 is described. The key reactions include highly stereoselective aldol condensation of piperonal with the dianion of chiral oxazolidinone, subsequent intramolecular ring cyclization of the aldol product 8 and a diastereocontrolled oxygenation of dilactone 7 in good yield.


    Zhu Yutian; Ichiro Hagiwara


    Based on the improved mode superposition method proposed by Z.D.Ma and I.Hagiwara, a precisely compensated efficient mode synthesis method is developed.The calculation procedure is discussed in detail and the truncation error is also analyzed.By comparison, it is shown that this method has a higher accuracy and a less calculation time than the general used ones.

  7. Short and efficient synthesis of fluorinated δ-lactams

    Cogswell, Thomas J.; Donald, Craig S.; Long, De-Liang; Marquez, Rodolfo


    The diastereoselective synthesis of fluorinated δ-lactams has been achieved through an efficient five step process. The route can tolerate a range of functionalities, and provides a quick route for the generation of new fluorinated medicinal building blocks.

  8. An efficient chemical synthesis of nicotinamide riboside (NAR) and analogues.

    Tanimori, Shinji; Ohta, Takeshi; Kirihata, Mitsunori


    A simple and efficient synthesis of nicotinamide riboside (NAR) 1 and derivatives 4 and 5 via trimethylsilyl trifluoromethanesulfonate (TMSOTf)-mediated N-glycosilation followed by spontaneous deacetylation by treating with methanol is reported.

  9. An Improved, Highly Efficient Method for the Synthesis of Bisphenols

    L. S. Patil


    Full Text Available An efficient synthesis of bisphenols is described by condensation of substituted phenols with corresponding cyclic ketones in presence of cetyltrimethylammonium chloride and 3-mercaptopropionic acid as a catalyst in extremely high purity and yields.

  10. An efficient synthesis of loline alkaloids

    Cakmak, Mesut; Mayer, Peter; Trauner, Dirk


    Loline (1) is a small alkaloid that, in spite of its simple-looking structure, has posed surprising challenges to synthetic chemists. It has been known for more than a century and has been the subject of extensive biological investigations, but only two total syntheses have been achieved to date. Here, we report an asymmetric total synthesis of loline that, with less then ten steps, is remarkably short. Our synthesis incorporates a Sharpless epoxidation, a Grubbs olefin metathesis and an unprecedented transannular aminobromination, which converts an eight-membered cyclic carbamate into a bromopyrrolizidine. The synthesis is marked by a high degree of chemo- and stereoselectivity and gives access to several members of the loline alkaloid family. It delivers sufficient material to support a programme aimed at studying the complex interactions between plants, fungi, insects and bacteria brokered by loline alkaloids.

  11. Cooperative catalysis designing efficient catalysts for synthesis

    Peters, René


    Written by experts in the field, this is a much-needed overview of the rapidly emerging field of cooperative catalysis. The authors focus on the design and development of novel high-performance catalysts for applications in organic synthesis (particularly asymmetric synthesis), covering a broad range of topics, from the latest progress in Lewis acid / Br?nsted base catalysis to e.g. metal-assisted organocatalysis, cooperative metal/enzyme catalysis, and cooperative catalysis in polymerization reactions and on solid surfaces. The chapters are classified according to the type of cooperating acti

  12. Concise and efficient synthesis of calothrixin B.

    Sissouma, Drissa; Maingot, Lucie; Collet, Sylvain; Guingant, André


    A convergent synthesis of the naturally occurring alkaloid Calothrixin B is presented, which used a regioselective hetero-Diels-Alder reaction between a "push-pull" 2-aza-diene and a N-protected 3-bromo-9H-carbazole-1,4-dione to construct the five-ring skeleton of the molecule. Protection of the indole motif with a benzyl group was unattractive for delivery of sufficient target material because the removal of the protecting group had not been high yielding. We therefore elected to temporarily protect the indole motif with a more labile benzyloxycarbonyl group. Accordingly, the synthesis of calothrixin B proceeded in 17% overall yield over 9 steps from the commercially available 1,2,3,9-tetrahydro-4H-carbazol-4-one.

  13. An Efficient Microscale Procedure for the Synthesis of Aspirin

    Pandita, Sangeeta; Goyal, Samta


    The synthesis of aspirin is a part of many undergraduate organic synthesis labs and is frequently used in qualitative organic analysis laboratory for the identification of salicylic acid. We have found that aspirin can be synthesized on microscale by a simple and efficient procedure that eliminates the heating step employed in literature procedures and gives a pure, ferric-negative product (no purple color with alcoholic ferric chloride solution).

  14. Efficient view synthesis from uncalibrated stereo

    Braspenning, Ralph; Op de Beeck, Marc


    For multiview auto-stereoscopic 3D displays, available stereo content needs to be converted to multiview content. In this paper we present a method to efficiently synthesize new views based on the two existing views from the stereo input. This method can be implemented in real-time and is also capable of handling uncalibrated stereo input. Good performance is shown compared to state-of-the-art disparity estimation algorithms and view rendering methods.

  15. Efficient Synthesis of an Aluminum Amidoborane Ammoniate

    Junzhi Yang


    Full Text Available A novel species of metal amidoborane ammoniate, [Al(NH2BH363−][Al(NH363+] has been successfully synthesized in up to 95% via the one-step reaction of AlH3·OEt2 with liquid NH3BH3·nNH3 (n = 1~6 at 0 °C. This solution based reaction method provides an alternative pathway to the traditional mechano-chemical ball milling methods, avoiding possible decomposition. MAS 27Al NMR spectroscopy confirms the formulation of the compound as an Al(NH2BH363− complex anion and an Al(NH363+ cation. Initial dehydrogenation studies of this aluminum based M-N-B-H compound demonstrate that hydrogen is released at temperatures as low as 65 °C, totaling ~8.6 equivalents of H2 (10.3 wt % upon heating to 105 °C. This method of synthesis offers a promising route towards the large scale production of metal amidoborane ammoniate moieties.

  16. Efficient synthesis of benzothiazine and acrylamide compounds

    Souza, Ana Maria Alves; Walfrido, Simone Torres Padua; Leite, Lucia Fernanda Costa; Lima, Maria Carmo Alves; Galdino, Suely Lins; Pitta, Ivan Rocha [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Antibioticos; Barbosa Filho, Jose Maria [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Simone, Carlos Alberto de; Ellena, Javier Alcides, E-mail: [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Fisica


    This article describes the synthesis of the new (2Z)-2-(4-methoxybenzylidene)-6-nitro-4H -benzo[1,4]thiazine-3-one, (2Z)-2-(4-methoxybenzylidene)-4-methyl-6-nitro-4H-benzo[1,4]thiazine-3-one, (2Z)-6-amino-2-(4-methoxybenzylidene)-4H -benzo[1,4]thiazine-3-one, (2Z)-6-butylamino-2-(4-methoxybenzylidene)-4-methyl-4H-benzo[1,4] -thiazine-3-one and (2E)-N-alkyl-N-(2-hydroxy-5-nitrophenyl) -3-phenylacrylamides and the spectroscopic data. The arylidenebenzothiazine compounds were prepared using the Knoevenagel condensation with substituted benzaldehydes in the presence of sodium methoxide in DMF. The presence of a nitro substituent in the 4-position, water and a slightly acid reaction medium in this condensation caused the rupture of the benzothiazine ring and subsequent formation of the phenylacrylamide compounds. A crystallographic data was presented for (2E)-3-(4-bromophenyl)-N-dodecyl-N -(2-hydroxy-5-nitrophenyl) acrylamide. (author)

  17. An efficient synthesis of quinolines under solvent-free conditions

    Mihir K Chaudhuri; Sahid Hussain


    An efficient synthesis of substituted quinolines has been achieved in a one-pot reaction from -nitrobenzaldehyde and enolizable ketones using SnCl2.2H2O as the reductant under microwave irradiation without any solvent or catalyst.

  18. Novel efficient process for methanol synthesis by CO2 hydrogenation

    Kiss, Anton Alexandru; Pragt, J.J.; Vos, H.J.; Bargeman, Gerrald; de Groot, M.T.


    Methanol is an alternative fuel that offers a convenient solution for efficient energy storage. Complementary to carbon capture activities, significant effort is devoted to the development of technologies for methanol synthesis by hydrogenation of carbon dioxide. While CO2 is available from plenty

  19. Novel efficient process for methanol synthesis by CO2 hydrogenation

    Kiss, Anton A.; Pragt, J.J.; Vos, H.J.; Bargeman, G.; Groot, de M.T.


    Methanol is an alternative fuel that offers a convenient solution for efficient energy storage. Complementary to carbon capture activities, significant effort is devoted to the development of technologies for methanol synthesis by hydrogenation of carbon dioxide. While CO2 is available from plenty o

  20. Highly efficient heterogeneous procedure for the synthesis of fructone fragrancy


    A novel heterogeneous strong acid catalyst was synthesized through the copolymerization of p-toluenesulfonic acid and paraformaldehyde and utilized for the synthesis of fructone. The results showed that the catalyst was very efficient for the reaction with the yield over 95%. The advantages of extremely high density of acidity, high thermal and chemical stability, low cost for the simple synthetic procedure, and reusability made the catalyst one of the best choices for the reaction.

  1. Energy efficiency in nanoscale synthesis using nanosecond plasmas

    Pai, David Z.; (Ken) Ostrikov, Kostya; Kumar, Shailesh; Lacoste, Deanna A.; Levchenko, Igor; Laux, Christophe O.


    We report a nanoscale synthesis technique using nanosecond-duration plasma discharges. Voltage pulses 12.5 kV in amplitude and 40 ns in duration were applied repetitively at 30 kHz across molybdenum electrodes in open ambient air, generating a nanosecond spark discharge that synthesized well-defined MoO3 nanoscale architectures (i.e. flakes, dots, walls, porous networks) upon polyamide and copper substrates. No nitrides were formed. The energy cost was as low as 75 eV per atom incorporated into a nanostructure, suggesting a dramatic reduction compared to other techniques using atmospheric pressure plasmas. These findings show that highly efficient synthesis at atmospheric pressure without catalysts or external substrate heating can be achieved in a simple fashion using nanosecond discharges. PMID:23386976

  2. Rapid and Efficient Synthesis of Diaryl Carbazones using Microwave Technology

    SHI Lei; PAN Feng; WANG Yu-lu


    Diaryl carbazone is an important organic analytical reagent normally prepared by the oxidation of diaryl carbazine, but in literatures' methods, the yields were low and the procedures were trouble1,2. Recently, our laboratory reported some new methods for the preparation of diaryl carbazone from diaryl carbazine3,4. Generally, these methods have drawbacks such as tedious operation3, using large amounts of volatile and poisonous solvent which will pollute the environment inevitably3, long reaction time and complicated oxidation system4. In continuation of our studies on the synthesis of azo compounds, we decided to develop a new method to overcome the limitation.As we know, the application of microwave techniques for organic synthesis has attracted considerable interests in recent years5. Using microwave technology can enhance the selectivity and reactivity, increase the chemical yields and shorten the reaction time6. It has been widely used in a variety of organic reactions7,8. However, the synthesis of diaryl carbazones using microwave has not been reported so far.In this paper, a rapid and efficient synthesis of diaryl carbazones with NaBrO3/H2SO4 as oxidation system using microwave technology is reported for the first time. By this method, in short time (0.5 rmin), we have synthesized ten diaryl carbazones in good yields.In the oxidation study, we found that the acidic condition is necessary in these reactions.This method only needs cheap and easily available oxidants, simple instruments and easy work-up.In conclusion, It is a facile and rapid method for the preparation of diaryl carbazones from diaryl carbazines with NaBrO3/H2SO4.

  3. Framework for efficient synthesis of spatially embedded morphologies

    Vanherpe, Liesbeth; Kanari, Lida; Atenekeng, Guy; Palacios, Juan; Shillcock, Julian


    Many problems in science and engineering require the ability to grow tubular or polymeric structures up to large volume fractions within a bounded region of three-dimensional space. Examples range from the construction of fibrous materials and biological cells such as neurons, to the creation of initial configurations for molecular simulations. A common feature of these problems is the need for the growing structures to wind throughout space without intersecting. At any time, the growth of a morphology depends on the current state of all the others, as well as the environment it is growing in, which makes the problem computationally intensive. Neuron synthesis has the additional constraint that the morphologies should reliably resemble biological cells, which possess nonlocal structural correlations, exhibit high packing fractions, and whose growth responds to anatomical boundaries in the synthesis volume. We present a spatial framework for simultaneous growth of an arbitrary number of nonintersecting morphologies that presents the growing structures with information on anisotropic and inhomogeneous properties of the space. The framework is computationally efficient because intersection detection is linear in the mass of growing elements up to high volume fractions and versatile because it provides functionality for environmental growth cues to be accessed by the growing morphologies. We demonstrate the framework by growing morphologies of various complexity.

  4. Efficient Algorithms for Optimal 4-Bit Reversible Logic System Synthesis

    Zhiqiang Li


    Full Text Available Owing to the exponential nature of the memory and run-time complexity, many methods can only synthesize 3-bit reversible circuits and cannot synthesize 4-bit reversible circuits well. We mainly absorb the ideas of our 3-bit synthesis algorithms based on hash table and present the efficient algorithms which can construct almost all optimal 4-bit reversible logic circuits with many types of gates and at mini-length cost based on constructing the shortest coding and the specific topological compression; thus, the lossless compression ratio of the space of n-bit circuits reaches near 2×n!. This paper presents the first work to create all 3120218828 optimal 4-bit reversible circuits with up to 8 gates for the CNT (Controlled-NOT gate, NOT gate, and Toffoli gate library, and it can quickly achieve 16 steps through specific cascading created circuits.

  5. Facile and Efficient Synthesis of Bolaamphiphilic Tetraether Phosphocholines.

    Svenson, Sönke; Thompson, David H.


    A facile synthesis of ether-linked bolaform phospholipids in good yields has been developed. Triflic acid catalyzed oxirane ring opening of benzyl-protected rac-glycidyl with long-chain 1,omega-alkanediols (n = 16, 20) produced 1,1'-diglycerol diethers in 80-90% yield. Double alkylation of the secondary hydroxy groups with 1-bromooctane or 1-bromodecane gave the corresponding benzyl-protected tetraethers in 66% yield. Hydrogenolysis of the benzyl groups in the presence of Pd/C (55-66% yield) followed by phosphorylation with 2 equiv of 2-chloro-2-oxo-1,3,2-dioxaphospholane and amination with excess trimethylamine produced the tetraether bolaform bisphosphocholines as white powders in approximately 75% yield. This approach provides a reliable and efficient method for preparing a wide variety of symmetrical bolaform phospholipids on a multigram scale.

  6. An efficient synthesis of D-galactose-based multivalent neoglycoconjugates

    Andrade, S.F. de; Souza Filho, J.D. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Quimica; Alves, Ricardo J., E-mail: [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Fac. de Farmacia; Figueiredo, Rute C. [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)


    In this work, the synthesis of dimeric, trimeric and tetrameric D-galactose-based neoglycoconjugates is reported. The monosaccharide ligand was prepared in 5 straightforward steps from D-galactose using the Doebner modification of the Knoevenagel reaction for chain elongation. The ligand was coupled to 1,4-butanediamine, tris-(2-ethylamino)amine, pentaerythrityltetramine and PAMAM dendrimers (1,4-butanodiamine core G0 and 1,12-dodecanediamine core G0). The unprotected glycodendrimers were purified by size-exclusion chromatography (SEC). This was the only step in which a chromatographic method was employed throughout the synthetic route. This is a new and efficient strategy for the preparation of neoglycoconjugates. (author)

  7. Enantioselective palladium-catalyzed dearomative cyclization for the efficient synthesis of terpenes and steroids.

    Du, Kang; Guo, Pan; Chen, Yuan; Cao, Zhen; Wang, Zheng; Tang, Wenjun


    A novel enantioselective palladium-catalyzed dearomative cyclization has been developed for the efficient construction of a series of chiral phenanthrenone derivatives bearing an all-carbon quaternary center. The effectiveness of this method in the synthesis of terpenes and steroids was demonstrated by a highly efficient synthesis of a kaurene intermediate, the facile construction of the skeleton of the anabolic steroid boldenone, and the enantioselective total synthesis of the antimicrobial diterpene natural product (-)-totaradiol.

  8. A Rapid and Efficient Synthesis of 2, 4, 6-Triarylpyridines under Microwave Irradiation

    Xian Qiang HUANG; Hong Xia LI; Jin Xian WANG; Xue Feng JIA


    An rapid and efficient synthesis of 2, 4, 6-triarylpyridines is reported using substituted benzaldehydes, substituted acetophenones and ammonia as starting materials under microwave irradiation in the presence of PEG-400.

  9. Highly Efficient Asymmetric Synthesis Usomg Organocatalyst Derived From(S)-proline



    1 Results Much effort has been focused on organocatalytic asymmetric synthesis in these several years. We have already documented highly efficient organocatalytic asymmetric acylation of a wide variety of racemic alcohols and meso-diols catalyzed bya chiral 1,2-diamine derived from (S)-proline[1]. (S)-Homoproline seems to be a potentially interesting organocatalyst, but no examples using (S)-homoproline itself in asymmetric synthesis has been reported. We have accomplished an efficient and practical syn...

  10. Enzymatic biodiesel synthesis. Key factors affecting efficiency of the process

    Szczesna Antczak, Miroslawa; Kubiak, Aneta; Antczak, Tadeusz; Bielecki, Stanislaw [Institute of Technical Biochemistry, Faculty of Biotechnology and Food Sciences, Technical University of Lodz, Stefanowskiego 4/10, 90-924 Lodz (Poland)


    Chemical processes of biodiesel production are energy-consuming and generate undesirable by-products such as soaps and polymeric pigments that retard separation of pure methyl or ethyl esters of fatty acids from glycerol and di- and monoacylglycerols. Enzymatic, lipase-catalyzed biodiesel synthesis has no such drawbacks. Comprehension of the latter process and an appreciable progress in production of robust preparations of lipases may soon result in the replacement of chemical catalysts with enzymes in biodiesel synthesis. Engineering of enzymatic biodiesel synthesis processes requires optimization of such factors as: molar ratio of substrates (triacylglycerols: alcohol), temperature, type of organic solvent (if any) and water activity. All of them are correlated with properties of lipase preparation. This paper reports on the interplay between the crucial parameters of the lipase-catalyzed reactions carried out in non-aqueous systems and the yield of biodiesel synthesis. (author)

  11. Synthesis of Normorphans through an Efficient Intramolecular Carbamoylation of Ketones.

    Diaba, Faïza; Montiel, Juan A; Serban, Georgeta; Bonjoch, Josep


    An unexpected C-C bond cleavage was observed in trichloroacetamide-tethered ketones under amine treatment and exploited to develop a new synthesis of normophans from 4-amidocyclohexanones. The reaction involves an unprecedented intramolecular haloform-type reaction of trichloroacetamides promoted by enamines (generated in situ from ketones) as counter-reagents. The methodology was applied to the synthesis of compounds embodying the 6-azabicyclo[3.2.1]octane framework.

  12. A Novel Implementation of Efficient Algorithms for Quantum Circuit Synthesis

    Zeller, Luke

    In this project, we design and develop a computer program to effectively approximate arbitrary quantum gates using the discrete set of Clifford Gates together with the T gate (π/8 gate). Employing recent results from Mosca et. al. and Giles and Selinger, we implement a decomposition scheme that outputs a sequence of Clifford, T, and Tt gates that approximate the input to within a specified error range ɛ. Specifically, the given gate is first rounded to an element of Z[1/2, i] with a precision determined by ɛ, and then exact synthesis is employed to produce the resulting gate. It is known that this procedure is optimal in approximating an arbitrary single qubit gate. Our program, written in Matlab and Python, can complete both approximate and exact synthesis of qubits. It can be used to assist in the experimental implementation of an arbitrary fault-tolerant single qubit gate, for which direct implementation isn't feasible.

  13. Zinc oxide nanoparticles: A highly efficient and readily recyclable catalyst for the synthesis of xanthenes

    Javad Safaei-Ghomi; Mohammad Ali Ghasemzadeh


    A novel and efficient route for the synthesis of 1,8-dioxooctahydroxanthenes and 14-aryl-14H-dibenzo[a,j]xanthenes is described through one-pot multi-component reaction of dimedone and 2-naphthol with various aryl aldehydes using ZnO nanoparticles under solvent-free conditions.This method provides a novel and improved pathway for the synthesis of xanthenes in the terms of excellent yields,short reaction times,reusability and low catalyst loading.

  14. Efficient enantio- and diastereodivergent synthesis of poison-frog alkaloids 251O and trans-223B.

    Toyooka, Naoki; Zhou, Dejun; Nemoto, Hideo; Tezuka, Yasuhiro; Kadota, Shigetoshi; Andriamaharavo, Nirina R; Garraffo, H Martin; Spande, Thomas F; Daly, John W


    An efficient and flexible synthesis of poison-frog alkaloids 251O and trans-223B has been achieved by using for both alkaloids an enantiodivergent process starting from the common lactam 1. The relative stereochemistry of 251O and trans-223B was determined to be 7 (R = n-C(7)H(15), R' = n-Pr) and 14 by the present enantioselective synthesis.

  15. Solid Superacid Catalyzed Efficient Synthesis of 2-Diethylaminoethyl Aryloxyacetates

    Ming De CHEN; An Qi CHEN; Min LIN; Zhao Ying LI; Jin CHEN


    2-Diethylaminoethyl aryloxyacetates are prepared efficiently in 75~95% yields by condensation of the corresponding aryloxyacetic acids with 2-diethylaminoethanol in the presence of catalytic amount of solid superacid SO4 -/Fe2O3.

  16. An Efficient Synthesis of Pyridoxal Oxime Derivatives under Microwave Irradiation

    Dajana Gašo-Sokač


    Full Text Available Quaternary salts of pyridoxal oxime have been synthesized by the quaternization of pyridoxal oxime with substituted phenacyl bromides using microwave heating. Microwave-assisted rapid synthesis was done both in solvent (acetone and under solvent-free conditions. Good to excellent yields (58%–94% were obtained in acetone in very short reaction times (3–5 min as well as in the solvent-free procedure (42%–78% in very short reaction times (7–10 min too. Effective metodologies for the preparation of pyridoxal oxime quaternary salts, having the advantagies of being eco-friendly, easy to handle, and performed in shorter reactions time are presented. The structure of compound 7, in which a 4-fluorophenacyl moiety is bonded to the pyridinium ring nitrogen atom, was unequivocally confirmed by the single-crystal X-ray diffraction method.

  17. An Efficient and Practical Procedure for Synthesis of Diacetals

    JIN Tong-Shou; YANG Mi-Na; FENG Guo-Liang; LI Tong-Shuang


    @@ Pentaerythritol diacetals are useful in many fields. They can be applied as plasticizers and vulcanizers of various polymeric materials, as raw materials for production of valuable resins and lacquers, as physiologically active substances and as defoamers for washing solution containing anionic surfactants. [ 1 ~ 4] Synthsis of diacetals from 2,2bis(hydroxymethyl)-1, 3-propanediol with aldehydes and ketones in refluxing toluene using ZrO2/S2O2- 8 solid superacid as catalyst in 85% ~ 99% yields has been described. The catalysts are easily regenerated by washing with ethanol followed by drying at 120 ℃ for 4 h and could be reused 5 times for the synthesis pentaerythritol diacetal 3e without significant loss of activity. This method possesses the advantages of the operational simplicity, short reaction time, use of inexpensive materials, non-corrosion, non-polluting, high yields and reusable catalysts.

  18. Efficient synthesis of natural polyphenolic stilbenes: resveratrol, piceatannol and oxyresveratrol.

    Sun, Hong-Yi; Xiao, Chun-Fen; Cai, Yu-Chen; Chen, Yu; Wei, Wen; Liu, Xian-Ke; Lv, Ze-Liang; Zou, Yong


    The practical synthesis of important natural polyphenolic stilbenes, including resveratrol, piceatannol and oxyresveratrol, through Perkin methodology is described. Starting from 3,5-dihydoxyacetophenone (1), the common intermediate 3,5-dimethoxyphenylacetic acid (3) can be obtained via methylation and Willgerodt-Kindler reaction. Perkin condensations between (3) and substituted phenylaldehydes 4 furnished E-2,3-diarylacrylic acids 5, followed by decarboxylation in Cu/quinoline giving stilbene intermediates 6 which bear the Z-configuration. Finally, through a simultaneous demethylation/isomerization process in AlI₃/CH₃CN system, the target compounds 7a-c can be obtained respectively in good to high overall yields. The synthetic method proved to be more concise, trans-specific, mild, economical and commonly applicable.

  19. Efficiency, error and yield in light-directed maskless synthesis of DNA microarrays

    Agbavwe Christy


    Full Text Available Abstract Background Light-directed in situ synthesis of DNA microarrays using computer-controlled projection from a digital micromirror device--maskless array synthesis (MAS--has proved to be successful at both commercial and laboratory scales. The chemical synthetic cycle in MAS is quite similar to that of conventional solid-phase synthesis of oligonucleotides, but the complexity of microarrays and unique synthesis kinetics on the glass substrate require a careful tuning of parameters and unique modifications to the synthesis cycle to obtain optimal deprotection and phosphoramidite coupling. In addition, unintended deprotection due to scattering and diffraction introduce insertion errors that contribute significantly to the overall error rate. Results Stepwise phosphoramidite coupling yields have been greatly improved and are now comparable to those obtained in solid phase synthesis of oligonucleotides. Extended chemical exposure in the synthesis of complex, long oligonucleotide arrays result in lower--but still high--final average yields which approach 99%. The new synthesis chemistry includes elimination of the standard oxidation until the final step, and improved coupling and light deprotection. Coupling Insertions due to stray light are the limiting factor in sequence quality for oligonucleotide synthesis for gene assembly. Diffraction and local flare are by far the largest contributors to loss of optical contrast. Conclusions Maskless array synthesis is an efficient and versatile method for synthesizing high density arrays of long oligonucleotides for hybridization- and other molecular binding-based experiments. For applications requiring high sequence purity, such as gene assembly, diffraction and flare remain significant obstacles, but can be significantly reduced with straightforward experimental strategies.

  20. Efficient synthesis of triarylamine-based dyes for p-type dye-sensitized solar cells

    Wild, Martin; Griebel, Jan; Hajduk, Anna; Friedrich, Dirk; Stark, Annegret; Abel, Bernd; Siefermann, Katrin R.


    The class of triarylamine-based dyes has proven great potential as efficient light absorbers in inverse (p-type) dye sensitized solar cells (DSSCs). However, detailed investigation and further improvement of p-type DSSCs is strongly hindered by the fact that available synthesis routes of triarylamine-based dyes are inefficient and particularly demanding with regard to time and costs. Here, we report on an efficient synthesis strategy for triarylamine-based dyes for p-type DSSCs. A protocol for the synthesis of the dye-precursor (4-(bis(4-bromophenyl)amino)benzoic acid) is presented along with its X-ray crystal structure. The dye precursor is obtained from the commercially available 4(diphenylamino)benzaldehyde in a yield of 87% and serves as a starting point for the synthesis of various triarylamine-based dyes. Starting from the precursor we further describe a synthesis protocol for the dye 4-{bis[4‧-(2,2-dicyanovinyl)-[1,1‧-biphenyl]-4-yl]amino}benzoic acid (also known as dye P4) in a yield of 74%. All synthesis steps are characterized by high yields and high purities without the need for laborious purification steps and thus fulfill essential requirements for scale-up.

  1. An efficient methodology for the synthesis of 3-styryl coumarins

    Martins, Sergio M.A.; Pereira, Antonio M.D.R.L. [Centro de Quimica, Departamento de Quimica, Universidade de Evora, Evora (Portugal); Branco, Paula C.S. [REQUIMTE, Departamento de Quimica, Universidade Nova de Lisboa, Caparica (Portugal)


    Regioselective and highly efficient Heck arylation of 3-vinyl-6,7-dimethoxycoumarin has been developed to afford 3-styryl coumarins in good to very high yields. The increase in conjugation reflects on the absorbance of the synthesized compounds revealing all pronounced bathochromic shifts and hyperchromic effects. (author)

  2. A highly efficient synthesis of itraconazole intermediates and their analogues

    Ahn, Chong Il; Myoung, Young Chan; Choi, Ha Young; Kim, Seung Jin [Agency for Technology and Standards, Gwacheon (Korea, Republic of)


    Itraconazole is an important drug for oral treatment of histoplasmosis and blastomycosis. Itraconazole has been the targets of many synthetic efforts due to their diverse antifungal activities. In this study, an efficient synthetic route for Itraconazole intermediates has been developed using new procedures. Also, Itraconazole analogues introducing 2- and 3-methoxy group instead of Itraconazole intermediates with 4-methoxy group were synthesized.

  3. Efficient Synthesis of 2,6-Diphenyl-4-arylpyrylium Tetrafluoroborate


    Four pyrylium salts, (2,6-diphenyl-4-arylpyrylium tetrafluoroborate, aryl =C6Hs, 4-MeO C6H4, 4-Me2NC6H4, 4-NO2C6H4) were synthesized efficiently and economically from acctophenone and substituted chalcones in the presence of borontrifluoride.

  4. An Operationally Simple and Efficient Synthesis of Orthogonally Protected L-threo-β-Hydroxyasparagine

    Guzmán-Martinez, Aikomari; VanNieuwenhze, Michael S.


    A synthesis of orthogonally protected L-threo-β-hydroxyasparagine from L-aspartic acid is reported. Iodocyclization of 3-benzoylaminoaspartic acid provided an intermediate oxazoline dicarboxylate that was efficiently hydrolyzed to L-threo-β-hydroxyaspartic acid. The synthetic route for conversion of the free β-hydroxy-α-amino acid into the target compound is highly efficient and amenable to preparation various orthogonally protected asparagine derivatives, on a multiple gram scale. PMID:19593390

  5. An Operationally Simple and Efficient Synthesis of Orthogonally Protected L-threo-beta-Hydroxyasparagine.

    Guzmán-Martinez, Aikomari; Vannieuwenhze, Michael S


    A synthesis of orthogonally protected L-threo-beta-hydroxyasparagine from L-aspartic acid is reported. Iodocyclization of 3-benzoylaminoaspartic acid provided an intermediate oxazoline dicarboxylate that was efficiently hydrolyzed to L-threo-beta-hydroxyaspartic acid. The synthetic route for conversion of the free beta-hydroxy-alpha-amino acid into the target compound is highly efficient and amenable to preparation various orthogonally protected asparagine derivatives, on a multiple gram scale.

  6. Efficient short step synthesis of Corey's tamiflu intermediate.

    Kipassa, Nsiama Tienabe; Okamura, Hiroaki; Kina, Kengo; Hamada, Toshiyuki; Iwagawa, Tetsuo


    Corey's tamiflu intermediate was synthesized from a bicyclolactam adduct obtained by base-catalyzed Diels-Alder reaction of N-nosyl-3-hydroxy-2-pyridone with ethyl acrylate. A compound that has the same array of functional groups with the Corey's intermediate was obtained in four steps from the DA adduct in 47% overall yield. The intermediate itself was also prepared efficiently by simply changing the protective group.

  7. Bimetallic Nanoparticles as Efficient Catalysts: Facile and Green Microwave Synthesis

    Magda Blosi


    Full Text Available This work deals with the development of a green and versatile synthesis of stable mono- and bi-metallic colloids by means of microwave heating and exploiting ecofriendly reagents: water as the solvent, glucose as a mild and non-toxic reducer and polyvinylpirrolidone (PVP as the chelating agent. Particle size-control, total reaction yield and long-term stability of colloids were achieved with this method of preparation. All of the materials were tested as effective catalysts in the reduction of p-nitrophenol in the presence of NaBH4 as the probe reaction. A synergistic positive effect of the bimetallic phase was assessed for Au/Cu and Pd/Au alloy nanoparticles, the latter showing the highest catalytic performance. Moreover, monoand bi-metallic colloids were used to prepare TiO2- and CeO2-supported catalysts for the liquid phase oxidation of 5-hydroxymethylfufural (HMF to 2,5-furandicarboxylic acid (FDCA. The use of Au/Cu and Au/Pd bimetallic catalysts led to an increase in FDCA selectivity. Finally, preformed Pd/Cu nanoparticles were incorporated into the structure of MCM-41-silica. The resulting Pd/Cu MCM-41 catalysts were tested in the hydrodechlorination of CF3OCFClCF2Cl to CF3OCF=CF2. The effect of Cu on the hydrogenating properties of Pd was demonstrated.

  8. An Efficient One-Pot Three-Component Synthesis of Novel Sulfanyl Tetrazoles Using Ionic Liquids

    Sankari Kanakaraju


    Full Text Available An efficient, simple, and environmentally benign method for the synthesis of novel sulfanyl tetrazoles has been achieved by one-pot three-component reaction of phenacyl bromides/3-(2-bromoacetylcoumarins with KSCN and NaN3 using [Bmim]BF4 ionic liquid. It could be reused and recycled for four runs without significant loss of product yield.

  9. Asymmetric and efficient synthesis of homophenylalanine derivatives via Friedel-Crafts reaction with trifluoromethanesulfonic acid

    Murashige, Ryo; Hayashi, Yuka; Hashimoto, Makoto; 橋本, 誠


    An efficient Friedel-Crafts reaction of TFA-Asp(Cl)-OMe and stoichiometric amounts of benzene was established by using neat trifluoromethanesulfonic acid (TfOH) as solvent and catalyst under a mild condition. This methodology has been applied to many aromatic compounds and enabled synthesis of several homophenylalanine derivatives.

  10. Silica triflate as an efficient reagent for the solvent-free synthesis of coumarins


    Silica triflate, as a new silica-based reagent, can be used for the efficient synthesis of 4-substituted coumarins via a Pechmann reaction under solvent-free reaction conditions. All reactions were performed at 80 ℃ in good to high yields.

  11. Novel and efficient supramolecular synthesis of pyrroles in the presence of β-cyclodextrin in water

    K. Ramesh; K. Karnakar; G. Satish; Y.V.D. Nageswar


    A simple and efficient synthesis of highly substituted pyrroles was achieved in water medium via multi-component strategy,using amine,DMAD/DEAD as well as phenacyl bromide catalyzed by β-CD.Utilizing this protocol various pyrrole derivatives were synthesized in good to excellent yields.

  12. An Efficient Solid-state Synthesis of 2-Thio-4-imidazolidinone Derivatives

    LI,Jian-Ping; MA,Chun-Ming


    @@ In recent years increasingly intense interest has been directed towards the generation of small organic molecules by solid-state reactions, which has many advantages over conventional solution phase synthesis such as high efficiency and selectivity, easy separation and purification and environmental acceptability.

  13. Efficient Synthesis of 4,7-Diamino Substituted 1,10-Phenanthroline-2,9-dicarboxamides

    Larsen, Anders Foller; Ulven, Trond


    A convenient and high-yielding multigram synthesis of the versatile intermediate 4,7-dichloro-1,10-phenanthroline-2,9-dicarboxylic acid is described. The intermediate is further efficiently derivatized to 4,7-diamino-1,10-phenanthroline-2,9-dicarboxamides with potential G-quadruplex stabilizing e...

  14. A rapid and efficient synthesis of indoloquinolinone and its analogues under microwave irradiation

    Yu Jing Lu; Ning Sun; Zhi Shu Huang; Lian Quan Gu


    A rapid and efficient method was established for the synthesis of indoloquinolinone and its analogues using acid-promotedcyclization in the present of PPA. All the reactions were completed in good yields in 10min under microwave irradiation.? 2008 Zhi Shu Huang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  15. Efficient synthesis of dibenzyl carbonates from benzyl halides and Cs2CO3

    Yuxuan He


    Full Text Available A simple and efficient protocol for the synthesis of dibenzyl carbonates has been developed. The reaction was accomplished using benzyl halides and Cs2CO3 as the starting materials in the presence of atmospheric pressure of CO2, affording a variety of the dibenzyl carbonates in good to excellent yields under rather mild conditions.

  16. Tannic acid Catalyzed an Efficient Synthesis of 2,4,5-Triaryl-1H-Imidazole

    Shitole Nana Vikram


    Full Text Available Tannic acid (C76H52O46 has been found to be an efficient catalyst for one-pot synthesis of 2,4,5-triaryl substituted imidazoles by the reaction of an arylaldehyde, benzyl/benzoin and an ammonium acetate. The short reaction time and excellent yields making this protocol practical and economically attractive.

  17. A practical and efficient synthesis of five-membered azasugar derivatives


    A practical and efficient synthesis of 1,4-dideoxy-1,4-imino-D-arabinol and its partially protected derivatives has been described via the key intermediate with a norbornane-like structure using D-glucose as a starting material.

  18. Efficient synthesis of functionalized butenolides mediated by vinyltriphenylphosphonium salts in aqueous media

    Mohammad A.Khalilzadeh; Adel Hasannia; Mohammad M.Baradarani; Zinatossadat Hossaini


    An efficient synthesis of 5-oxo-2,5-dihydro-3-furancarboxylate derivatives via reaction of dialkyl acetylenedicarboxylate with triphenylphosphine(Ph3P) in the presence of activated carbonyl compounds such as ethyl pyruvate,benzil,benzoylcyanide,biacetyle or N-alkylisatins is described.

  19. An Unexpected and Efficient Synthesis of Open-chain Derivatives of Bistetronic Acid under Microwave Irradiation

    SHI Feng; MA Ning; ZHOU Dianxiang; ZHANG Ge; JIANG Bo; TU Shujiang


    An unexpected and efficient synthesis of novel open-chain derivatives of bistetronic acid has been successfully achieved in glyclol under microwave irradiation (MW).This method has the prominent advantages of short reaction time,high yield,operational simplicity as well as environmental friendliness.

  20. Novel and Efficient Synthesis of the Promising Drug Candidate Discodermolide


    supported in part by this award: Ph.D. SUNY Stony Brook: Zhou Zhou Ph.D. SUNY Stony Brook: Peng Wang Ph.D. SUNY Stony Brook: Qiu- zhe Xie Ph.D. SUNY...Stolarzewicz Ph.D. SUNY Stony Brook: Pei Wang Continuing in the PhD program at SUNY Stony Brook Junyong Lee Hee Nam Lim Daniel C. Elliot Matthew E...IBS) in Waltham, MA. Intelligent Biosystems is a biotech company that is focused on efficient gene sequencing. Peng Wang is employed by Ren

  1. Synthesis of energy-efficient counters implemented in PLD circuits

    Kulisz, Józef; Nawrot, Radosław; Kania, Dariusz


    The paper presents a comparison of four methods of implementing sequential circuits in Programmable Logic Devices in respect of dissipated power. Objective of the research was to investigate influence of different methods of "disabling" the clock signal on the dynamic power consumed by the circuit. The comparison is carried out using simple counter circuits, i. e. circuits the algorithm of which is described by linear graphs. However, the presented considerations are general, and can be applied to any sequential circuit. Results of simulation tests show that the method based on clock gating is the most efficient one, and it leads to significant reduction of the dissipated dynamic power. The authors also propose a simple modification of global clock network structures, to facilitate clock gating.

  2. Efficient chemoenzymatic synthesis of pelitrexol via enzymic differentiation of a remote stereocenter.

    Hu, Shanghui; Kelly, Sean; Lee, Steve; Tao, Junhua; Flahive, Erik


    [structure: see text] An efficient chemoenzymatic process is described for the synthesis of pelitrexol, a novel GARFT inhibitor. The remoteness of this molecule's stereocenter in the tetrahydropterin moiety from the terminal carbonyl group provided a significant challenge in synthesis. The introduction of an oxalamic ester adjacent to the stereocenter dramatically enhanced an enzyme's enantioselectivity for hydrolysis at the terminal ester, producing the desired S-acid with high optical purity and yield. The recycling of the "wrong" enantiomer is achieved via a dehydrogenation/hydrogenation strategy.

  3. Imino Diels-Alder Reaction Catalyzed by Iodine: Efficient Synthesis of Tetrahydroquinolines

    LI, Yun-Cheng; ZHANG, Jun-Min; DONG, Li-Ting; YAN, Ming


    Iodine was found to be an efficient catalyst for the imino Diels-Alder reaction of N-arylimine with enol ethers to provide tetrahydroquinolines in good yields. The influence of the loading of iodine, reaction solvent, the structure of imine and enol ethers was studied. One pot synthesis of tetrahydroquinolines from aldehyde, aniline and enol ethers catalyzed by iodine was also applicable and provided tetrahydroquinolines in comparable yields. Mild reaction conditions, facile experimental procedure, low price of iodine and good yield of products render this new method attractive for practical synthesis of many tetrahydroquinoline derivatives.

  4. A Facile and Efficient Synthesis of (15R)-Latanoprost from Chiral Precursor Corey Lactone Diol

    K Vijendhar; B Srinivas; Sathyanarayana Boodida


    An efficient asymmetric synthetic route for the synthesis of anti-glaucoma agent, (15R)-latanoprost using Corey lactone diol as chiral substrate under Swern oxidation, allylic reduction and Wittig reaction conditions has been developed. In this method, reduction of keto and alkene functional groups has been achieved in a single step using low cost catalyst NiCl2/NaBH4 in methanol. This new synthetic protocol is a good alternative for the synthesis of latanoprost with high stereo selectivity and improved yield.

  5. An efficient synthesis and spectroscopic characterization of Schiff bases containing 9,10-anthracenedione moiety

    Fareed Ghulam


    Full Text Available A new method has been developed for the synthesis of novel Schiff bases containg anthraquinone moiety using dodeca-Tungstosilicic acid/P2O5 under solvent free conditions at room temperature. The reaction was completed in 1-3 minutes with excellent yields. This method was found to be more efficient, easy and hazardous free for the synthesis of azomethines. The development of these type of methadologies in synthetic chemistry may contribute to green chemistry. The structures of synthesized novel Schiff bases was elucidated using 1H-NMR, 13C-NMR, LCMS, FTIR and CHN analysis.

  6. Simple and Efficient Procedure for Synthesis of N'-Arylamidines Using Trimethylaluminum

    Korbad, Balaji L.; Lee, Sanghyeup [Catholic Univ., of Daegu, Daegu (Korea, Republic of)


    In conclusion, we have developed simple and efficient procedure for the synthesis of N'-arylamidines using tri-methylaluminum, nitriles and aryl amines under mild condition. Aliphatic, aromatic nitriles were reacted well with a variety of aromatic amine to afford corresponding amidines in good to high yields. Amidines are an important class of compounds that have wide range of application in the fields of catalyst design, material science, medicinal chemistry and also shown the promising anti-inflammatory and analgesic activity. They are valuable synthons for synthesis of various heterocyclic compounds. In addition, recent studies have demonstrated their capacity to fix carbon dioxide.

  7. Efficient synthesis of α,β-unsaturated alkylimines performed with allyl cations and azides: application to the synthesis of an ant venom alkaloid.

    Hayashi, Kyohei; Tanimoto, Hiroki; Zhang, Huan; Morimoto, Tsumoru; Nishiyama, Yasuhiro; Kakiuchi, Kiyomi


    An efficient synthesis of α,β-unsaturated alkylimines at low temperature using azides has been developed. Carbocations generated from allyl alcohols helped achieve a rapid conversion under mild conditions with azides to afford reactive α,β-unsaturated imines. Hydroxy or alkoxy groups are essential for these transformations, and utilizing readily accessible allyl alcohols gave a wide extension of substrates. The efficiency of this novel method is demonstrated in the total synthesis of an iminium ant venom alkaloid.

  8. Highly Efficient Synthesis of Clean Biofuels from Biomass Using FeCuZnAIK Catalyst

    Song-bai Qiu; Yong Xu; Tong-qi Ye; Fei-yan Gong; Zhi Yang; Mitsuo Yamamoto; Yong Liu; Quan-xin Li


    Highly efficient synthesis of clean biofuels using the bio-syngas obtained from biomass gasification was performed over Fe1.5Cu1Zn1Al1K0.117 catalyst.The maximum biofuel yield from the bio-syngas reaches about 1.59 kg biofuels/(kgcatal·h) with a contribution of 0.57 kg alcohols/(kgcatal·h) and 1.02 kg liquid hydrocarbons/(kgcatal·h).The alcohol products in the resulting biofuels were dominated by the C2+ alcohols (mainly C2-C6 alcohols) with a content of 73.55%-89.98%.The selectivity of the liquid hydrocarbons (C5+) in the hydrocarbon products ranges from 60.37% to 70.94%.The synthesis biofuels also possess a higher heat value of 40.53-41.49 MJ/kg.The effects of the synthesis conditions,including temperature,pressure,and gas hourly space velocity,on the biofuel synthesis were investigated in detail.The catalyst features were characterized by inductively coupled plasma and atomic emission spectroscopy,X-ray diffraction,temperature programmed reduction,and the N2 adsorption-desorption isotherms measurements.The present biofuel synthesis with a higher biofuel yield and a higher selectivity of liquid hydrocarbons and C2+ alcohols may be a potentially useful route to produce clean biofuels and chemicals from biomass.

  9. A coenzyme-independent decarboxylase/oxygenase cascade for the efficient synthesis of vanillin.

    Furuya, Toshiki; Miura, Misa; Kino, Kuniki


    Vanillin is one of the most widely used flavor compounds in the world as well as a promising versatile building block. The biotechnological production of vanillin from plant-derived ferulic acid has attracted much attention as a new alternative to chemical synthesis. One limitation of the known metabolic pathway to vanillin is its requirement for expensive coenzymes. Here, we developed a novel route to vanillin from ferulic acid that does not require any coenzymes. This artificial pathway consists of a coenzyme-independent decarboxylase and a coenzyme-independent oxygenase. When Escherichia coli cells harboring the decarboxylase/oxygenase cascade were incubated with ferulic acid, the cells efficiently synthesized vanillin (8.0 mM, 1.2 g L(-1) ) via 4-vinylguaiacol in one pot, without the generation of any detectable aromatic by-products. The efficient method described here might be applicable to the synthesis of other high-value chemicals from plant-derived aromatics.

  10. An Efficient One-Pot Multicomponent Synthesis of 4-Aza-Podophyllotoxin Derivatives in Ionic Liquid

    Hossein Naeimi


    Full Text Available A simple, green, and efficient procedure for the synthesis of 4-aza-podophyllotoxin derivatives by using a one-pot three-component reaction of benzaldehydes, 1,3-cyclohexanediones, and anilinolactones in the presence of catalytic amount of alum in 1-butyl-3-methylimidazolium triflate as green media is described. This reaction proceeded under mild conditions with the use of an inexpensive and readily available catalyst, high to excellent yields, and simple workup procedure.

  11. Zirconyl chloride promoted highly efficient solid phase synthesis of amide derivatives


    An efficient solid phase route for the synthesis of amide derivatives by the reaction of carboxylic acids with urea in the presence of catalytic amount of zirconyl chloride under microwave irradiation conditions was described. In this way, a range of interesting amide derivatives was obtained in good to excellent yields. The catalyst was recycled with fresh reactants and it gave almost similar results without significant loss of activity up to the third run.

  12. Synthesis of (R-Dihydropyridones as Key Intermediates for an Efficient Access to Piperidine Alkaloids

    Serkos A Haroutounian


    Full Text Available The efficient transformation of D-glucal to (2R-hydroxymethyldihydro-pyridinone 5 in seven steps and 35 % overall yield is reported. Dihydropyridone 5 constitutes a versatile chiral building block for the synthesis of various piperidine alkaloids. In this regard, 5 was converted to piperidinol 13 and piperidinone 15, that may be further elaborated for the syntheses of (+-desoxoprosophylline (1 and deoxymannojirimycin (3 or D-mannolactam (4, respectively.

  13. Efficient and convenient synthesis of indazol-3(2H)-ones and 2-aminobenzonitriles.

    Dou, Guolan; Shi, Daqing


    A mild, efficient, one-pot protocol for the synthesis of indazole-3(2H)-ones via cyclization of nitro-aryl substrates through low-valent titanium reagent has been described. The method used Triethylamine (TEA) to control pH. Particularly, 2-aminobenzonitriles were synthesized by one step easily. The mechanistic course of the reaction suggests the involvement of an anion leading to an intramolecular cyclization via N-N bond formation.

  14. An efficient synthesis of 8-substituted Odoratine derivatives by the Suzuki coupling reaction

    Ravi Kumar P; Balakrishna C; Murali B; Ramakrishna Gudipati; Prasanta K Hota; Avinash B Chaudhary; Jaya Shree A; Satyanarayana Yennam; Manoranjan Behera


    An efficient method for the preparation of 8-substituted odoratine [(3-(3', 4' -methylenedioxyphenyl)-5,6,7-trimethoxyisoflavone] derivatives, structurally similar to glaziovianin A, a known cytotoxic substance, has been described. The key steps in the synthesis are site selective bromination reaction followed by Suzuki coupling reaction in very good yield. The structural assignment of the bromo derivative was determined utilizing 2D-HMBC and NOEs NMR techniques.

  15. A versatile and an efficient synthesis of 5-substituted-1-tetrazoles

    Madhusudana Reddy Muthukur Bhoje Gowd; Mohamed Afzal Pasha


    A simple, efficient and a versatile method for the synthesis of 5-substituted-1-tetrazoles by a [3+2]-cycloaddition reaction of arylnitriles with sodium azide in DMF using ZrOCl2·8 H2O as catalyst has been developed. The reactions work well at 100°C and give the desired products in excellent yield. The examples studied include arylnitriles having electron donating as well as electron releasing groups on the arene nucleus.

  16. Alum:An efficient catalyst for one-pot synthesis of a-aminophosphonates

    Swapnil S.Sonar; Kiran F.Shelke; Gopal K.Kakade; Bapurao B.Shingate; Murlidhar S.Shingare


    Alum(KA1(SO4)2·12H2O)is an inexpensive,efficient,non-toxic and mild catalyst for the one-pot synthesis of a-aminophosphonates.A three component reaction of an aldehyde/ketone,an amine and triethyl phosphite was carried out under solvent-free conditions to afford the corresponding a-aminophosphonates in short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents.

  17. Nano Clinoptilolite: Highly Efficient Catalyst for the Synthesis of Chromene Derivatives Under Solvent-Free Conditions.

    Hallajian, Sara; Khalilzadeh, Mohammad A; Tajbakhsh, Mahgol; Alipour, Eskandar; Safaei, Zahra


    An efficient and selective synthesis of substituted chromene derivatives via three-component reaction of 4-hydroxycoumarin or 1,3-dicarbonyl compounds, activated acetylenic compounds and N-nucleophiles is described. The reaction was conducted under solvent-free conditions at 70°C using potassium fluoride impregnated on natural zeolite as a cheap and available solid base. The procedure has several advantages involving selectivity, excellent yields and a convenient work-up method.

  18. Efficient one-pot four-component synthesis of fused thiazolopyridin-2-ones in ionic liquid

    Prashant Singh; Kamlesh Kumari; Gaurav Kaithwas; Gaurav Kaithwas


    An efficient one-pot synthesis of fused thiazolopyridinone derivatives (5-amino-6,7-diphenyl-4,7-dihydro-3H-thiazolo[4,5-b]pyridin-2-ones) by four-component reaction of aldehyde, benzylcyanide, ammonium acetate and thiazolidine-2,4-dione in ionic liquid is reported. This protocol has the advantages of environmental friendliness, higher yields, less reaction time, and convenient operation. Also, optimization of the synthesized compounds has been done using Hyperchem 8.0.

  19. Directed evolution of leucine dehydrogenase for improved efficiency of L-tert-leucine synthesis.

    Zhu, Lin; Wu, Zhe; Jin, Jian-Ming; Tang, Shuang-Yan


    L-tert-Leucine and its derivatives are used as synthetic building blocks for pharmaceutical active ingredients, chiral auxiliaries, and ligands. Leucine dehydrogenase (LeuDH) is frequently used to prepare L-tert-leucine from the α-keto acid precursor trimethylpyruvate (TMP). In this study, a high-throughput screening method for the L-tert-leucine synthesis reaction based on a spectrophotometric approach was developed. Directed evolution strategy was applied to engineer LeuDH from Lysinibacillus sphaericus for improved efficiency of L-tert-leucine synthesis. After two rounds of random mutagenesis, the specific activity of LeuDH on the substrate TMP was enhanced by more than two-fold, compared with that of the wild-type enzyme, while the activity towards its natural substrate, leucine, decreased. The catalytic efficiencies (k cat/K m) of the best mutant enzyme, H6, on substrates TMP and NADH were all enhanced by more than five-fold as compared with that of the wild-type enzyme. The efficiency of L-tert-leucine synthesis by mutant H6 was significantly improved. A productivity of 1170 g/l/day was achieved for the mutant enzyme H6, compared with 666 g/l/day for the wild-type enzyme.

  20. Highly efficient and eco-friendly gold-catalyzed synthesis of homoallylic ketones

    Gómez-Suárez, Adrián


    We report a new catalytic protocol for the synthesis of γ,δ-unsaturated carbonyl units from simple starting materials, allylic alcohols and alkynes, via a hydroxalkoxylation/Claisen rearrangement sequence. This new process is more efficient (higher TON and TOF) and more eco-friendly (increased mass efficiency) than the previous state-of-the-art technique. In addition, this method tolerates both terminal and internal alkynes. Moreover, computational studies have been carried out in order to shed light on how the Claisen rearrangement is initiated. © 2014 American Chemical Society.

  1. A mild and efficient procedure for the synthesis of ethers from various alkyl halides

    Mosstafa Kazemi


    Full Text Available A simple, mild and practical procedure has been developed for the synthesis of symmetrical and unsymmetrical ethers by using DMSO, TBAI in the presence of K2CO3. We extended the utility of Potassium carbonate as an efficient base for the preparation of ethers. A wide range of alkyl aryl and dialkyl ethers are synthezied from treatment of aliphatic alcohols and phenols with various alkyl halides in the prescence of efficient base Potassium carbonate. Secondary alkyl halides were easily converted to corresponding ethers in releatively good yields . This is a mild, simple and practical procedure for the preparation of ethers in high yields and suitable times under mild condition.

  2. Simplified Application of Material Efficiency Green Metrics to Synthesis Plans: Pedagogical Case Studies Selected from "Organic Syntheses"

    Andraos, John


    This paper presents a simplified approach for the application of material efficiency metrics to linear and convergent synthesis plans encountered in organic synthesis courses. Computations are facilitated and automated using intuitively designed Microsoft Excel spreadsheets without invoking abstract mathematical formulas. The merits of this…

  3. Simplified Application of Material Efficiency Green Metrics to Synthesis Plans: Pedagogical Case Studies Selected from "Organic Syntheses"

    Andraos, John


    This paper presents a simplified approach for the application of material efficiency metrics to linear and convergent synthesis plans encountered in organic synthesis courses. Computations are facilitated and automated using intuitively designed Microsoft Excel spreadsheets without invoking abstract mathematical formulas. The merits of this…

  4. Rapid and Efficient Synthesis of Hydroxytriarylmethanes under Ultra Sonic Irradiation Using Keggin Heteropolyacids and Preyssler Catalysts in Green Conditions

    Hooshang Hamidian


    Full Text Available A new synthesis of hydroxytriarylmethane derived from the reaction of 2-sulfobenzoic anhydride and phenols in the presence of heteropolyacids as green, reusable, and efficient catalyst (using catalytic amount under ultrasonic irradiation is reported in this paper.

  5. High-efficient Synthesis of Graphene Oxide Based on Improved Hummers Method

    Yu, Huitao; Zhang, Bangwen; Bulin, Chaoke; Li, Ruihong; Xing, Ruiguang


    As an important precursor and derivate of graphene, graphene oxide (GO) has received wide attention in recent years. However, the synthesis of GO in an economical and efficient way remains a great challenge. Here we reported an improved NaNO3-free Hummers method by partly replacing KMnO4 with K2FeO4 and controlling the amount of concentrated sulfuric acid. As compared to the existing NaNO3-free Hummers methods, this improved routine greatly reduces the reactant consumption while keeps a high yield. The obtained GO was characterized by various techniques, and its derived graphene aerogel was demonstrated as high-performance supercapacitor electrodes. This improved synthesis shows good prospects for scalable production and applications of GO and its derivatives.

  6. Efficient synthesis of silver nanoparticles from Prosopis juliflora leaf extract and its antimicrobial activity using sewage

    Raja, K.; Saravanakumar, A.; Vijayakumar, R.


    In this paper, aqueous extract of fresh leaves of Prosopis juliflora was used for the synthesis of silver (Ag) nanoparticles. UV-Vis spectroscopy studies were carried out to asses silver nanoparticles formation within 5 min, scanning electron microscopic was used to characterize shape of the Ag nanoparticles, X-ray diffraction analysis confirms the nanoparticles as crystalline silver and facecentered cubic type and Fourier transform infra-red assed that shows biomolecule compounds which are responsible for reduction and capping material of silver nanoparticles. The anti microbial activity of silver nanoparticle was performed using sewage. The approach of plant-mediated synthesis appears to be cost efficient, eco-friendly and easy methods.

  7. Rational design and synthesis of freestanding photoelectric nanodevices as highly efficient photocatalysts.

    Qu, Yongquan; Liao, Lei; Cheng, Rui; Wang, Yue; Lin, Yung-Chen; Huang, Yu; Duan, Xiangfeng


    Photocatalysts are of significant interest in solar energy harvesting and conversion into chemical energy. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here we report the rational design of a new generation of freestanding photoelectric nanodevices as highly efficient and stable photocatalysts by integrating a nanoscale photodiode with two redox catalysts in a single nanowire heterostructure. We show that a platinum-silicon-silver nanowire heterostructure can be synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. We further demonstrated that the Schottky diodes exhibited a pronounced photovoltaic effect with nearly unity internal quantum efficiency and that the integrated nanowire heterostructures could be used as highly efficient photocatalysts for a wide range of thermodynamically downhill and uphill reactions including the photocatalytic degradation of organic dyes and the reduction of metal ions and carbon dioxide using visible light. Our studies for the first time demonstrated the integration of multiple distinct functional components into a single nanostructure to form a standalone active nanosystem and for the first time successfully realized a photoelectric nanodevice that is both highly efficient and highly stable throughout the entire solar spectrum. It thus opens a rational avenue to the design and synthesis of a new generation of photoelectric nanosystems with unprecedented efficiency and stability and will have a broad impact in areas including environmental remediation, artificial photosynthesis and solar fuel production.

  8. Study on Parallel Processing for Efficient Flexible Multibody Analysis based on Subsystem Synthesis Method

    Han, Jong-Boo; Song, Hajun; Kim, Sung-Soo [Chungnam Nat’l Univ., Daejeon (Korea, Republic of)


    Flexible multibody simulations are widely used in the industry to design mechanical systems. In flexible multibody dynamics, deformation coordinates are described either relatively in the body reference frame that is floating in the space or in the inertial reference frame. Moreover, these deformation coordinates are generated based on the discretization of the body according to the finite element approach. Therefore, the formulation of the flexible multibody system always deals with a huge number of degrees of freedom and the numerical solution methods require a substantial amount of computational time. Parallel computational methods are a solution for efficient computation. However, most of the parallel computational methods are focused on the efficient solution of large-sized linear equations. For multibody analysis, we need to develop an efficient formulation that could be suitable for parallel computation. In this paper, we developed a subsystem synthesis method for a flexible multibody system and proposed efficient parallel computational schemes based on the OpenMP API in order to achieve efficient computation. Simulations of a rotating blade system, which consists of three identical blades, were carried out with two different parallel computational schemes. Actual CPU times were measured to investigate the efficiency of the proposed parallel schemes.

  9. A highly efficient green synthesis of 1, 8-dioxo-octahydroxanthenes

    Ilangovan Andivelu


    Full Text Available Abstract SmCl3 (20 mol% has been used as an efficient catalyst for reaction between aromatic aldehydes and 5,5-dimethyl-1,3-cyclohexanedione at 120°C to give 1,8-dioxo-octahydroxanthene derivatives in high yield. The same reaction in water, at room temperature gave only the open chain analogue of 1,8-dioxo-octahydroxanthene. Use of eco-friendly green Lewis acid, readily available catalyst and easy isolation of the product makes this a convenient method for the synthesis of either of the products.

  10. An efficient catalyst-free protocol for the synthesis of quinoxaline derivatives under ultrasound irradiation

    Guo,Wen-Xue; Jin,Hui-Le; Chen,Jiu-Xi; Chen, Fan; Ding,Jin-Chang; Wu,Hua-Yue


    A highly efficient and facile method has been described for the synthesis of quinoxaline derivatives in good to excellent yields (80-99%) by condensation reaction of heterocyclic as well as aliphatic 1,2-diketones (R¹COCOR¹, R¹ = Et, Ph, p-MeC6H5, p-MeOC6H5, Furyl) with 1,2-diamines (1,2-(NH2)2C6H3R², R² = H, Br, NO2, PhCO). A systematic study was carried out to examine the influence of reaction media and electronic factors of the substrates on the reaction results.

  11. An efficient protocol for the solid-phase synthesis of glycopeptides under microwave irradiation.

    Garcia-Martin, Fayna; Hinou, Hiroshi; Matsushita, Takahiko; Hayakawa, Shun; Nishimura, Shin-Ichiro


    A standardized and smooth protocol for solid-phase glycopeptides synthesis under microwave irradiation was developed. Double activation system was proved to allow for highly efficient coupling of Tn-Ser/Thr and bulky core 2-Ser/Thr derivatives. Versatility and robustness of the present strategy was demonstrated by constructing a Mucine-1 (MUC1) fragment and glycosylated fragments of tau protein. The success of this approach relies on the combination of microwave energy, a resin consisting totally of polyethylene glycol, a low excess of sugar amino acid and the "double activation" method.

  12. Rapid and Efficient Synthesis of ω-Alkylenediphosphoric Acids from Phosphorus Oxychloride

    Dalila Meziane


    Full Text Available The aim of this investigation was to develop an efficient, rapid, and selective method for the synthesis of ω-alkylenediphosphoric acids (HO2(OP-O-CH2n-O-P(O(OH2 from reaction of several diols with phosphorus oxychloride. The reaction was investigated using three methodologies: (i presence of a base, (ii classical heating, and (iii use of microwave irradiation. Influence of reaction temperature and molar ratio of reagents, as well as the nature of the solvent, was studied using these three different methods.

  13. A sustainable and efficient synthesis of benzyl phosphonates using PEG/KI catalytic system

    Gawande, Manoj; Disale, Shamrao; Kale, Sandip; Abraham, George; Kahandal, Sandeep; Sawarkar, Ashish


    An efficient and expedient protocol for the synthesis of benzyl phosphonates using KI/K2CO3 as a catalytic system and PEG-400 as benign solvent has been developed. The reaction proceeds smoothly at room temperature achieving excellent selectivity and yield of the corresponding products. The combination of PEG-400, KI and K2CO3 in this reaction avoids the need of volatile/toxic organic solvents and reactive alkali metals or metal nanoparticles/hydrides. We believe that this benign combination (PEG-400 and KI) could be used for other related organic transformations.

  14. A sustainable and efficient synthesis of benzyl phosphonates using PEG/KI catalytic system

    Manoj B. Gawande


    Full Text Available An efficient and expedient protocol for the synthesis of benzyl phosphonates using KI/K2CO3 as a catalytic system and PEG-400 as benign solvent has been developed. The reaction proceeds smoothly at room temperature achieving excellent selectivity and yield of the corresponding products. The combination of PEG-400, KI and K2CO3 in this reaction avoids the need of volatile/toxic organic solvents and reactive alkali metals or metal nanoparticles/hydrides. We believe that this benign combination (PEG-400 and KI could be used for other related organic transformations.

  15. Efficient Synthesis and Biological Evaluation of 5'-GalNAc Conjugated Antisense Oligonucleotides.

    Østergaard, Michael E; Yu, Jinghua; Kinberger, Garth A; Wan, W Brad; Migawa, Michael T; Vasquez, Guillermo; Schmidt, Karsten; Gaus, Hans J; Murray, Heather M; Low, Audrey; Swayze, Eric E; Prakash, Thazha P; Seth, Punit P


    Conjugation of triantennary N-acetyl galactosamine (GalNAc) to oligonucleotide therapeutics results in marked improvement in potency for reducing gene targets expressed in hepatocytes. In this report we describe a robust and efficient solution-phase conjugation strategy to attach triantennary GalNAc clusters (mol. wt. ∼2000) activated as PFP (pentafluorophenyl) esters onto 5'-hexylamino modified antisense oligonucleotides (5'-HA ASOs, mol. wt. ∼8000 Da). The conjugation reaction is efficient and was used to prepare GalNAc conjugated ASOs from milligram to multigram scale. The solution phase method avoids loading of GalNAc clusters onto solid-support for automated synthesis and will facilitate evaluation of GalNAc clusters for structure activity relationship (SAR) studies. Furthermore, we show that transfer of the GalNAc cluster from the 3'-end of an ASO to the 5'-end results in improved potency in cells and animals.

  16. Highly Efficient Synthesis of 2-Aryl-3-methoxyacrylates via Suzuki-Miyaura Coupling Reaction

    Kim, Hyung Ho; Lee, Chun Ho; Song, Young Seob; Park, No Kyun; Kim, Bum Tae; Heo, Jung Nyoung [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of)


    We have developed a highly efficient and convergent synthesis of 2-aryl-3-methoxyacrylates via the Suzuki-Miyaura coupling reaction of α-iodo-β-methoxy-acrylate with arylboronic acids. The biological activities of 2-aryl-3-methoxyacrylate derivatives will be reported in due course. The Suzuki-Miyaura coupling reaction provides a convenient access to the carbon-carbon bond formation with high efficiency. Recently, a number of 2-aryl-3-methoxy-acrylates served as a key scaffold for the development of biologically active pharmaceuticals and agrochemicals. Especially, the discovery of the naturally-occurring fungicides, such as strobilurin A and oudemansin A, possessing a β-methoxyacrylate moiety was immediately seized great attention by industrial research groups to open a new era of the strobilurin family including azoxy-strobin and picoxystrobin.

  17. Synthesis and Evaluation of Tetramethylguanidinium-Polyethylenimine Polymers as Efficient Gene Delivery Vectors

    Manohar Mahato


    Full Text Available Previously, we demonstrated that 6-(N,N,N′,N′-tetramethylguanidinium chloride-hexanoyl-polyethylenimine (THP polymers exhibited significantly enhanced transfection efficiency and cell viability. Here, in the present study, we have synthesized a series of N,N,N′,N′-tetramethylguanidinium-polyethylenimine (TP1-TP5 polymers via a single-step reaction involving peripheral primary amines of bPEI and varying amounts of 2-(1H-benzotriazol-1-yl-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU. These polymers were found to interact efficiently with negatively charged pDNA and formed stable complexes in the size range of ~240–450 nm. Acid-base titration profiles revealed improved buffering capacity of TP polymers as compared to bPEI. Transfection and cytotoxicity assays performed with TP/pDNA complexes on HEK293, CHO, and HeLa cells showed significantly higher transfection efficiency and cell viability with one of the complexes, TP2/pDNA complex, exhibited the highest transfection efficiency (~1.4–2.3-fold outcompeting native bPEI and the commercially available transfection reagent, Lipofectamine 2000. Compared to previously reported THP polymers, the transfection efficiency of TP/pDNA complexes was found to be lower, as examined by flow cytometry. These results highlight the importance of the hydrophobic C-6 linker in THP polymers in forming compact nanostructures with pDNA, which might lead to efficient uptake and internalization of the complexes; however, the projected TP polymers offer an advantage of their rapid and economical one-step synthesis.

  18. Design and Synthesis of Novel Block Copolymers for Efficient Opto-Electronic Applications

    Sun, Sam-Shajing; Fan, Zhen; Wang, Yiqing; Taft, Charles; Haliburton, James; Maaref, Shahin


    It has been predicted that nano-phase separated block copolymer systems containing electron rich donor blocks and electron deficient acceptor blocks may facilitate the charge carrier separation and migration in organic photovoltaic devices due to improved morphology in comparison to polymer blend system. This paper presents preliminary data describing the design and synthesis of a novel Donor-Bridge-Acceptor (D-B-A) block copolymer system for potential high efficient organic optoelectronic applications. Specifically, the donor block contains an electron donating alkyloxy derivatized polyphenylenevinylene (PPV), the acceptor block contains an electron withdrawing alkyl-sulfone derivatized polyphenylenevinylene (PPV), and the bridge block contains an electronically neutral non-conjugated aliphatic hydrocarbon chain. The key synthetic strategy includes the synthesis of each individual block first, then couple the blocks together. While the donor block stabilizes and facilitates the transport of the holes, the acceptor block stabilizes and facilitates the transport of the electrons, the bridge block is designed to hinder the probability of electron-hole recombination. Thus, improved charge separation and stability are expected with this system. In addition, charge migration toward electrodes may also be facilitated due to the potential nano-phase separated and highly ordered block copolymer ultra-structure.

  19. Highly Efficient Synthesis of an Emerging Lipophilic Antioxidant: 2-Ethylhexyl Ferulate

    Kuo-Chuan Huang


    Full Text Available Ferulic acid in ester form has shown a stronger ability in ameliorating certain pathological conditions and inhibiting lipid oxidation. In present study, a solvent-free and reduced pressure evaporation system was developed for lipase-catalyzed synthesis of 2-ethylhexyl ferulate (2-EF from ferulic acid and 2-ethylhexanol. A Box-Behnken design with response surface methodology (RSM and artificial neural network (ANN was selected to model and optimize the process. Based on the yields of 2-EF, reaction temperature was shown to be the most important process factor on the molar conversion among all variables. The residual values and the coefficient of determination (R2 calculated from the design data indicated that ANN was better than RSM in data fitting. Overall, the present lipase-catalyzed approach for 2-EF synthesis at low reaction temperature in a reduced pressure evaporation system shows high 2-EF production efficiency. Notably, this approach can reduce the enzyme denaturation and ferulic acid oxidation that usually occur during long-term biosynthetic operations at high temperature.

  20. Self-templated synthesis of novel carbon nanoarchitectures for efficient electrocatalysis

    Wu, Xi-Lin; Wen, Tao; Guo, Hong-Li; Liu, Shoujie; Wang, Xiangke; Xu, An-Wu; Mezger, Markus


    The cost-efficient large-scale production of novel carbon nanostructure with high performance is still a challenge, restricting their applications in catalysis. Herein, we present a low-cost one-pot and one-step approach for the synthesis of both N-doped graphene (NG) and N-doped carbon nanotubes (NCNTs) from self-templated organic nanoplates. By varying the FeCl3 concentration in the precursor, we can control the formation of graphene or CNTs. To the best of our knowledge, this is the first example for the controllable synthesis of graphene or CNTs by varying the precursors’ compositions. This provides a simple and cost-effective route for the large-scale production of both NG and NCNTs for applications in catalysis. By example, we show how these unique structured nanocarbons can be applied in electrocatalysis for oxygen reduction reaction (ORR). The obtained NG and NCNTs show excellent ORR activities with long-term stability under alkaline conditions. The unique porous nanostructure, abundant defects, homogeneous N-doping and high N-content in the NG and NCNTs can provide abundant active sites, leading to the excellent ORR performance. This research not only displayed a simple and cost-effective approach for the large-scale production of novel carbon nanoarchitectures, but also revealed the exceptional application potential of these nanocarbons for electrocatalysis.

  1. Direct synthesis of strong grating couplers for efficient integrated optical beam forming

    Urošević, Stevan


    We describe a computational method for the direct synthesis of non-uniform optical grating coupler geometries on a photonic chip to form beams of arbitrary field distribution. The method is applied to grating couplers using high index contrast, typically encountered in silicon photonics for fiber-to-chip coupling and chip-based optical beam forming. We use a numerical synthesis approach to synthesize a non-uniform structure that emits a particular desired beam pattern, and explicitly take into account chirp generated by non-uniform gratings. Even for strong, short gratings, and for designs within the constraints of existing standard 45nm SOI-CMOS foundry process, mode overlaps exceeding 90% can be obtained. We discuss strengths and shortcomings of the approach and particular implementation. We demonstrate the method by synthesizing non-uniform grating coupler designs for efficient mode matching to optical fiber modes or single free-space beam modes with Gaussian magnitude and flat phase front and show that go...

  2. Bioreaction Engineering Leading to Efficient Synthesis of L-Glyceraldehyd-3-Phosphate.

    Molla, Getachew S; Kinfu, Birhanu M; Chow, Jennifer; Streit, Wolfgang; Wohlgemuth, Roland; Liese, Andreas


    Enantiopure L-glyceraldehyde-3-phosphate (L-GAP) is a useful building block in natural biological and synthetic processes. A biocatalytic process using glycerol kinase from Cellulomonas sp. (EC catalyzed phosphorylation of L-glyceraldehyde (L-GA) by ATP is used for the synthesis of L-GAP. L-GAP has a half-life of 6.86 h under reaction conditions. The activity of this enzyme depends on the Mg(2+) to ATP molar ratio showing maximum activity at the optimum molar ratio of 0.7. A kinetic model is developed and validated showing a 2D correlation of 99.9% between experimental and numerical data matrices. The enzyme exhibits inhibition by ADP, AMP, methylglyoxal and Ca(2+) , but not by L-GAP and inorganic orthophosphate. Moreover, equal amount of Ca(2+) exerts a different degree of inhibition relative to the activity without the addition of Ca(2+) depending on the Mg(2+) to ATP molar ratio. If the Mg(2+) to ATP molar ratio is set to be at the optimum value or less, inorganic hexametaphosphate (PPi6) suppresses the enzyme activity; otherwise PPi6 enhances the enzyme activity. Based on reaction engineering parameters such as conversion, selectivity and specific productivity, evaluation of different reactor types reveals that batchwise operation via stirred-tank reactor is the most efficient process for the synthesis of L-GAP.

  3. Highly efficient isocyanate-free microwave-assisted synthesis of [6]-oligourea

    Qaroush, Abdussalam K.


    A new eco-friendly, isocyanate-free, energy-saving method for the production of [6]-oligourea, utilizing a green carbonylating agent, viz. propylene carbonate, is reported. It comprises an organocatalyzed, microwave-assisted, solvent-free synthesis. Two modes of microwave-assisted synthesis, viz. dynamic and fixed energy modes, were applied. Upon optimization, the dynamic mode gave 79% yields of [6]-oligourea. On the other hand, almost quantitative yields were obtained using the fixed mode, within 20 min, at 10 W and with the same catalyst loading. Combination of both organocatalysis and microwave energy input appears to be a key issue for the efficiency of the reaction, with the fixed energy mode being best suited. It should be noted that all data reported are reproducible (due to the homogeneous microwave technology used by CEM Discover S-Class of microwave reactors). To the best of our knowledge, this is the best eco-friendly synthetic approach for the preparation of the title oligomers. It paves the way for using more of the biorenewable and sustainable chemicals as a feedstock for the production of polyureas. The oligomer produced was analyzed by EA, ATR-FTIR, XRD, 1H and 13CNMR. Furthermore, thermal properties of the resulting [6]-oligourea were analyzed using TGA and DSC. © The Royal Society of Chemistry 2013.

  4. Improving the time efficiency of the Fourier synthesis method for slice selection in magnetic resonance imaging.

    Tahayori, B; Khaneja, N; Johnston, L A; Farrell, P M; Mareels, I M Y


    The design of slice selective pulses for magnetic resonance imaging can be cast as an optimal control problem. The Fourier synthesis method is an existing approach to solve these optimal control problems. In this method the gradient field as well as the excitation field are switched rapidly and their amplitudes are calculated based on a Fourier series expansion. Here, we provide a novel insight into the Fourier synthesis method via representing the Bloch equation in spherical coordinates. Based on the spherical Bloch equation, we propose an alternative sequence of pulses that can be used for slice selection which is more time efficient compared to the original method. Simulation results demonstrate that while the performance of both methods is approximately the same, the required time for the proposed sequence of pulses is half of the original sequence of pulses. Furthermore, the slice selectivity of both sequences of pulses changes with radio frequency field inhomogeneities in a similar way. We also introduce a measure, referred to as gradient complexity, to compare the performance of both sequences of pulses. This measure indicates that for a desired level of uniformity in the excited slice, the gradient complexity for the proposed sequence of pulses is less than the original sequence.

  5. Synthesis and Characterization of Highly Efficient Nickel Nanocatalysts and Their Use in Degradation of Organic Dyes

    Nazar Hussain Kalwar


    Full Text Available The present study describes the synthesis of highly active and ordered structures of nickel nanocatalysts by a facile, green, and economically viable approach. The study reveals efficient catalytic activity for the degradation of a number of toxic organic dyes, such as eosin-B (EB, rose bengal (RB, eriochrome black-T (ECBT, and methylene blue (MB. The stable ordered nickel nanostructure (Ni NSs arrays were prepared via a modified hydrazine reduction route with unique and controlled morphologies in a lyotropic liquid crystalline medium using a nonionic surfactant (Triton X-100. Characterization and optimization studies for the fabricated Ni NSs involving their surface binding interactions, size, and morphologies were carried out using UV-Vis spectroscopy, Fourier transform infrared (FTIR spectroscopy, X-ray diffraction (XRD, and scanning electron microscopy (SEM.

  6. One-Step Facile Synthesis of a Simple Hole Transport Material for Efficient Perovskite Solar Cells

    Chen, Hu


    A hole transporting material was designed for use in perovskite solar cells, with a facile one-step synthesis from inexpensive, com-mercially available reagents. The molecule comprises a central fluorinated phenyl core with pendant aryl amines, namely, 3,6-difluoro-N1,N1,N2,N2,N4,N4,N5,N5-octakis(4-methoxyphenyl)benzene-1,2,4,5-tetraamine (DFTAB). A power conversion efficiency of up to 10.4% was achieved in a mesoporous perovskite device architecture. The merits of a simple and potentially low cost syn-thetic route as well as promising performance in perovskite devices, encourages further development of this materials class as new low-cost hole transporting materials for the scale up of perovskite solar cells.

  7. High efficiency photoluminescence from silicon nanocrystals prepared by plasma synthesis and organic surface passivation

    Mangolini, L.; Kortshagen, U. [Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Jurbergs, D.; Rogojina, E. [Innovalight Inc., 3303 Octavius Drive Suite 104, Santa Clara, CA 95054 (United States)


    An efficient synthesis route for highly luminescent silicon quantum dots is presented. Silicon nanocrystals were synthesized in the gas phase using an argon-silane non-thermal plasma in a continuous flow reactor. Liquid phase surface passivation was used to improve the optical properties and avoid surface oxidation of the silicon quantum dots. Various alkenes, such as octadecene, dodecene and styrene, were covalently bonded to the plasma-produced particles, while strictly avoiding exposure of the raw powder to oxidizing agents. Stable colloidal solutions of silicon quantum dots with ensemble quantum yields between 60% and 70% were achieved. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. A Novel Process for High-efficient Synthesis of One-dimensional Carbon Nanoraaterials from Flames

    Xiang QI; Jun ZHANG; Chunxu PAN


    The substrate pre-treatment plays a key role in obtaining hollow-cored carbon nanotubes (CNTs) and solidcored carbon nanofibers (CNFs) from flames. This paper introduces a simply and high-efficient process by coating a NiSO4 or FeSO4 layer on the substrate as catalyst precursors. Comparing with the regular pretreatment methods, the present experiments showed that the coating pre-treatment provided the following advantages: 1) greatly shortening the synthesis time; 2) available variant substrates and carbon sources; 3) narrowing the diameters distribution. The sulfate is considered to be a crucial factor at the growth of CNTs and CNFs, because it increases the surface energy of catalyst particles and the surface specificity of sulfurs action in metallic grains. This novel process provides a possibility for high quality and mass production of CNTs and CNFs from flames.

  9. An efficient catalyst-free protocol for the synthesis of quinoxaline derivatives under ultrasound irradiation

    Guo, Wen-Xue; Jin, Hui-Le; Chen, Jiu-Xi; Chen, Fan; Wu, Hua-Yue [Wenzhou University, Wenzhou (China). Coll. of Chemistry and Materials Engineering; Ding, Jin-Chang [Wenzhou Vocational and Technical College, Wenzhou (China)


    A highly efficient and facile method has been described for the synthesis of quinoxaline derivatives in good to excellent yields (80-99%) by condensation reaction of heterocyclic as well as aliphatic 1,2-diketones (R{sup 1}COCOR{sup 1}, R{sup 1} = Et, Ph, p-MeC{sub 6}H{sub 5}, p-MeOC{sub 6}H{sub 5}, Furyl) with 1,2-diamines (1,2-(NH{sub 2}){sub 2}C{sub 6}H{sub 3}R{sup 2}, R{sup 2} = H, Br, NO{sub 2}, PhCO). A systematic study was carried out to examine the influence of reaction media and electronic factors of the substrates on the reaction results. (author)

  10. A Novel, Simple and Efficient Synthesis of Ferrocenyl Enones and Alkynols

    SUN,Moran; HUANG,Guo-Sheng; WANG,Peng; SHI,Qing-Hui; LIANG,Yong-Min; MA,Yong-Xiang


    @@ Propargylic alcohols are versatile precursors to many organic molecules including natural products and pharmaceutical compounds.[1] In our continuing interest in the development of practical methods for synthesis of ferrocene derivatives, we decided to investigate the efficiencies of ferrocenylacetylene addition to aromatic aldehydes under t-BuOKcatalyzed condition.[2] Interestingly, we found that the usually reliable coupling reaction between terminal alkyne of type 1 and aromatic aldehydes of type 2 does not furnish the expected propargylic alcohols, but that the isomeric aryl enones 3are found in high yield and very short reaction time (10~20 min). This provided a promising protocol for preparation of ferrocenyl chalcones in a practical, economical and mild sense compared with the traditional method. To the best of our knowledge, this unusual reaction was first observed for the addition of ferrocenylacetylene to aldehyde in a base-catalyzed manner (Eq. 1).

  11. An efficient one-pot synthesis, characterization and antibacterial activity of novel chromeno-pyrimidine derivatives

    Suresh, Lingala; Kumar, P. Sagar Vijay; Chandramouli, G. V. P.


    A simple and efficient one-pot three component, green protocol was established for the synthesis of chromenopyrano[2,3-d]pyrimidine derivatives starting from 3-amino-pyrano[2,3-c]chromene-2-carbonitrile, N,N-dimethylformamide dimethylacetal and aromatic amines in the presence of 1-butyl-3-methylimidazolium hydrogen sulphate[Bmim]HSO4 ionic liquid. The present procedure offers a domino reaction strategy, cleaner conversion, short reaction times and high yields. Among the screened derivatives, the compounds 4g and 4h were identified as lead molecules which established promising antimicrobial towards Gram-positive bacterial strains such as Staphylococcus aureus MTCC 96, Staphylococcus aureus MLS16 MTCC 2940 and Bacillus subtilis MTCC 121.

  12. Nonlinear inverse synthesis for high spectral efficiency transmission in optical fibers

    Le, Son Thai; Turitsyn, Sergei K


    In linear communication channels, spectral components (modes) defined by the Fourier transform of the signal propagate without interactions with each other. In certain nonlinear channels, such as the one modelled by the classical nonlinear Schr\\"odinger equation, there are nonlinear modes (nonlinear signal spectrum) that also propagate without interacting with each other and without corresponding nonlinear cross talk; effectively, in a linear manner. Here, we describe in a constructive way how to introduce such nonlinear modes for a given input signal. We investigate the performance of the nonlinear inverse synthesis (NIS) method, in which the information is encoded directly onto the continuous part of the nonlinear signal spectrum. This transmission technique, combined with the appropriate distributed Raman amplification, can provide an effective eigenvalue division multiplexing with high spectral efficiency, thanks to highly suppressed channel cross talk. The proposed NIS approach can be integrated with any...

  13. Efficient Synthesis of Single-Chain Polymer Nanoparticles via Amide Formation

    Ana Sanchez-Sanchez


    Full Text Available Single-chain technology (SCT allows the transformation of individual polymer chains to folded/collapsed unimolecular soft nanoparticles. In this work we contribute to the enlargement of the SCT toolbox by demonstrating the efficient synthesis of single-chain polymer nanoparticles (SCNPs via intrachain amide formation. In particular, we exploit cross-linking between active methylene groups and isocyanate moieties as powerful “click” chemistry driving force for SCNP construction. By employing poly(methyl methacrylate- (PMMA- based copolymers bearing β-ketoester units distributed randomly along the copolymer chains and bifunctional isocyanate cross-linkers, SCNPs were successfully synthesized at r.t. under appropriate reaction conditions. Characterization of the resulting SCNPs was carried out by means of a combination of techniques including size exclusion chromatography (SEC, infrared (IR spectroscopy, proton nuclear magnetic resonance (1H NMR spectroscopy, dynamic light scattering (DLS, and elemental analysis (EA.

  14. Efficient Synthesis of Functionalized Benzimidazoles and Perimidines: Ytterbium Chloride Catalyzed CmC Bond Cleavage%Efficient Synthesis of Functionalized Benzimidazoles and Perimidines: Ytterbium Chloride Catalyzed CmC Bond Cleavage

    Cai, Lijian; Ji, Xiaofeng; Yao, Zhigang; Xu, Fan; Shen, Qi


    An efficient method is developed for the synthesis of functionalized benzimidazoles and perimidines by the condensation of aryl diamines with β-carbonyl compounds catalyzed by ytterbium chloride. The reactions give good yields under mild conditions. A mechanism involving a lanthanide activated C--C bond cleavage is proposed.

  15. A general and efficient palladium-catalyzed carbonylative synthesis of 2-aryloxazolines and 2-aryloxazines from aryl bromides.

    Wu, Xiao-Feng; Neumann, Helfried; Neumann, Stephan; Beller, Matthias


    Oxazoline is OK! A general and efficient method for the synthesis of oxazolines has been developed. This allowed the preparation of 27 five-membered-ring heterocycles and 11 six-membered-ring heterocycles in moderate to good yields. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Poly(4-vinylpyridine efficiently catalyzed one-pot four-component synthesis of pyrano[2,3-c]pyrazoles

    Jalal Albadi


    Full Text Available An efficient one-pot synthesis of pyrano[2,3-c]pyrazoles via four-component reaction of phenyl hydrazine, ethyl acetoacetate, malononitrile and aromatic aldehydes, catalyzed by poly(4-vinylpyridine is reported. This method provides many advantages such as, atom-economy, easy work up, clean procedure, short reaction times and high yields of products.

  17. PEG-400 as an efficient and recyclable reaction medium for the synthesis of polyhydroquinolines via Hantzsch reaction

    Shitole Nana Vikram


    Full Text Available Polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using PEG-400 as reaction medium. The present method does not involve any hazardous organic solvents or toxic catalysts. The present methodology offers several advantages such as simple procedure, excellent yields with shorter reaction times and purification of products by non-chromatographic methods.

  18. Silver iodide nanoparticle as an efficient and reusable catalyst for the one-pot synthesis of benzofurans under aqueous conditions

    Javad Safaei-Ghomi; Mohammad Ali Ghasemzadeh


    Recyclable heterogeneous AgI nanoparticles were efficiently catalysed one-pot three-component reaction of aldehydes, secondary amines and alkyne in aqueous media. This method provides a novel and improved approach for the synthesis of 2,3-disubstituted benzo[b]furan derivatives to obtain excellent yields, short reaction times and low catalyst loading.

  19. An Efficient Method for Synthesis of N-tert-Butyl Amides Using Oxalic Acid Dihydrate in Solvent-Free Condition

    Masoud Mokhtary


    Full Text Available An efficient method for the synthesis of N-tert-butyl amides by reaction of nitriles with tert-butyl acetate or tert-butanol is described using oxalic acid dihydrate in solvent-free condition. The result showed that tert-butyl acetate served as a relatively better source of tert-butyl carbocation than tert-butanol.

  20. Efficient Nazarov cyclization/Wagner-Meerwein rearrangement terminated by a Cu(II)-promoted oxidation: synthesis of 4-alkylidene cyclopentenones.

    Lebœuf, David; Theiste, Eric; Gandon, Vincent; Daifuku, Stephanie L; Neidig, Michael L; Frontier, Alison J


    The discovery and elucidation of a new Nazarov cyclization/Wagner-Meerwein rearrangement/oxidation sequence is described that constitutes an efficient strategy for the synthesis of 4-alkylidene cyclopentenones. DFT computations and EPR experiments were conducted to gain further mechanistic insight into the reaction pathways. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. ZnO Nanoparticles: An Efficient Reagent, Simple and One-Pot Procedure for Synthesis of Highly Functionalized Dihydropyridine Derivatives

    Marziyeh Khazaei


    Full Text Available A new and efficient one-pot synthesis of dihydropyridones derivatives by four-component reaction between cyanoacetamide, aryl aldehydes, and ethyl acetoacetate with ammonium acetate using nano ZnO is described. The reaction was performed in ethanol under reflux conditions and afforded good yields of products.

  2. An efficient partial synthesis of 4′-O-methylquercetin via regioselective protection and alkylation of quercetin

    Nian-Guang Li


    Full Text Available An efficient partial 5-step synthesis of 4′-O-methylquercetin from quercetin in 63% yield is reported. This strategy relies on the selective protection of the catechol group with dichlorodiphenylmethane in diphenyl ether as solvent and on the selective protection of the hydroxyl groups at positions 3 and 7 with chloromethyl ether.

  3. Rapid and efficient synthesis of new chiral aromatic amide molecular tweezers under solvent-free conditions using microwave

    Xiao Xiang Zhao; Zhi Gang Zhao; Xing Li Liu; Xiu Ming Wu


    An efficient and simple method for the synthesis of new chiral aromatic amide molecular tweezers by irradiation with microwave under solvent-free conditions has been developed.Its main advantages are short reaction times.good conversions and the environmentally friendly nature of the process.

  4. Microwave-assisted Green and Efficient Synthesis of N6-(2-Hydroxyethyl)adenosine and its Analogues

    Gui Rong QU; Ming Wei GENG; Su Hui HAN; Zhi Guang ZHANG; Feng XUE


    An efficient protocol for the synthesis of N6-(2-Hydroxyethyl)adenosine and its analogues through nucleophilic substitution was developed. All the reactions were completed in 10 min under microwave irradiation. Using water as solvent makes our method eco-friendly and easy to handle with.

  5. Ruthenium(Ⅲ) chloride as an efficient catalyst for the synthesis of perimidine derivatives under mild conditions

    Jing Zhang; Song Lin Zhang; Jun Min Zhang


    Various biologically important perimidine derivatives have been synthesized efficiently from various ketones and naphthalene1,8-diamine by using a catalytic amount of RuC13 (1 mol%). This method is a very simple and high yielding reaction for the synthesis of perimidine derivatives.

  6. An efficient method for synthesis of phenacyl derivatives under homogeneous phase transfer catalyst condition in aqueous media

    Soheil Sayyahi; Jafar Saghanezhad


    In this letter, a mild and efficient procedure for synthesis of phenacyl derivatives under homogenous catalysis in the presence of tetrabutylammonium bromide in aqueous media is described. The nucleophilic substitution reactions were performed under ecofriendly conditions and gave the corresponding products in high yields and short reaction times.

  7. Efficient Synthesis of Peptide and Protein Functionalized Pyrrole-Imidazole Polyamides Using Native Chemical Ligation

    Brian M. G. Janssen


    Full Text Available The advancement of DNA-based bionanotechnology requires efficient strategies to functionalize DNA nanostructures in a specific manner with other biomolecules, most importantly peptides and proteins. Common DNA-functionalization methods rely on laborious and covalent conjugation between DNA and proteins or peptides. Pyrrole-imidazole (Py–Im polyamides, based on natural minor groove DNA-binding small molecules, can bind to DNA in a sequence specific fashion. In this study, we explore the use of Py–Im polyamides for addressing proteins and peptides to DNA in a sequence specific and non-covalent manner. A generic synthetic approach based on native chemical ligation was established that allows efficient conjugation of both peptides and recombinant proteins to Py–Im polyamides. The effect of Py–Im polyamide conjugation on DNA binding was investigated by Surface Plasmon Resonance (SPR. Although the synthesis of different protein-Py–Im-polyamide conjugates was successful, attenuation of DNA affinity was observed, in particular for the protein-Py–Im-polyamide conjugates. The practical use of protein-Py–Im-polyamide conjugates for addressing DNA structures in an orthogonal but non-covalent manner, therefore, remains to be established.

  8. Efficient synthesis and evaluation of bis-pyridinium/bis-quinolinium metallosalophens as antibiotic and antitumor candidates

    Elshaarawy, Reda F. M.; Eldeen, Ibrahim M.; Hassan, Eman M.


    Inspired with the pharmacological diversity of salophens and in our endeavor to explore a new strategy which may conflict the invasion of drug resistance, we report herein efficient synthetic routes for the synthesis of new RO-salophen(Cl), pyridinium/quinolinium-based salophens (3a-e) and metallosalophens (4a-j). These new architectures have been structurally characterized by elemental and spectral analysis as well pharmacologically evaluated for their in vitro antimicrobial, against a common panel of pathogenic bacterial and fungal strains, and anticancer activities against human colon carcinoma (HCT-116) cell lines. Antimicrobial assay results revealed that all tested compounds exhibited moderate to superb broad-spectrum efficacy in comparison to the standard antibiotic with a preferential ability to perform as a fungicides than to act as bactericides. Noteworthy, VO(II)-salophens are more effective in reduction HCT-116 cell viability than Cu(II)-salophens. For example, VO(II)-salophen3 (4f) (IC50 = 2.13 μg/mL) was ca. 10-fold more efficient than Cu(II)-salophen3 (4e) (IC50 = 20.30 μg/mL).

  9. Efficient Synthesis of Peptide and Protein Functionalized Pyrrole-Imidazole Polyamides Using Native Chemical Ligation.

    Janssen, Brian M G; van Ommeren, Sven P F I; Merkx, Maarten


    The advancement of DNA-based bionanotechnology requires efficient strategies to functionalize DNA nanostructures in a specific manner with other biomolecules, most importantly peptides and proteins. Common DNA-functionalization methods rely on laborious and covalent conjugation between DNA and proteins or peptides. Pyrrole-imidazole (Py-Im) polyamides, based on natural minor groove DNA-binding small molecules, can bind to DNA in a sequence specific fashion. In this study, we explore the use of Py-Im polyamides for addressing proteins and peptides to DNA in a sequence specific and non-covalent manner. A generic synthetic approach based on native chemical ligation was established that allows efficient conjugation of both peptides and recombinant proteins to Py-Im polyamides. The effect of Py-Im polyamide conjugation on DNA binding was investigated by Surface Plasmon Resonance (SPR). Although the synthesis of different protein-Py-Im-polyamide conjugates was successful, attenuation of DNA affinity was observed, in particular for the protein-Py-Im-polyamide conjugates. The practical use of protein-Py-Im-polyamide conjugates for addressing DNA structures in an orthogonal but non-covalent manner, therefore, remains to be established.

  10. A Facile Synthesis of Nitrogen-Doped Highly Porous Carbon Nanoplatelets: Efficient Catalysts for Oxygen Electroreduction

    Zhang, Yaqing; Zhang, Xianlei; Ma, Xiuxiu; Guo, Wenhui; Wang, Chunchi; Asefa, Tewodros; He, Xingquan


    The oxygen reduction reaction (ORR) is of great importance for various renewable energy conversion technologies such as fuel cells and metal-air batteries. Heteroatom-doped carbon nanomaterials have proven to be robust metal-free electrocatalysts for ORR in the above-mentioned energy devices. Herein, we demonstrate the synthesis of novel highly porous N-doped carbon nanoplatelets (N-HPCNPs) derived from oatmeal (or a biological material) and we show the materials’ high-efficiency as electrocatalyst for ORR. The obtained N-HPCNPs hybrid materials exhibit superior electrocatalytic activities towards ORR, besides excellent stability and good methanol tolerance in both basic and acidic electrolytes. The unique nanoarchitectures with rich micropores and mesopores, as well as the high surface area-to-volume ratios, present in the materials significantly increase the density of accessible catalytically active sites in them and facilitate the transport of electrons and electrolyte within the materials. Consequently, the N-HPCNPs catalysts hold a great potential to serve as low-cost and highly efficient cathode materials in direct methanol fuel cells (DMFCs). PMID:28240234

  11. A Facile Synthesis of Nitrogen-Doped Highly Porous Carbon Nanoplatelets: Efficient Catalysts for Oxygen Electroreduction.

    Zhang, Yaqing; Zhang, Xianlei; Ma, Xiuxiu; Guo, Wenhui; Wang, Chunchi; Asefa, Tewodros; He, Xingquan


    The oxygen reduction reaction (ORR) is of great importance for various renewable energy conversion technologies such as fuel cells and metal-air batteries. Heteroatom-doped carbon nanomaterials have proven to be robust metal-free electrocatalysts for ORR in the above-mentioned energy devices. Herein, we demonstrate the synthesis of novel highly porous N-doped carbon nanoplatelets (N-HPCNPs) derived from oatmeal (or a biological material) and we show the materials' high-efficiency as electrocatalyst for ORR. The obtained N-HPCNPs hybrid materials exhibit superior electrocatalytic activities towards ORR, besides excellent stability and good methanol tolerance in both basic and acidic electrolytes. The unique nanoarchitectures with rich micropores and mesopores, as well as the high surface area-to-volume ratios, present in the materials significantly increase the density of accessible catalytically active sites in them and facilitate the transport of electrons and electrolyte within the materials. Consequently, the N-HPCNPs catalysts hold a great potential to serve as low-cost and highly efficient cathode materials in direct methanol fuel cells (DMFCs).

  12. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B. Peter; Motkuri, Radha Kishan


    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method.

  13. An Efficient Synthesis Strategy for Metal-Organic Frameworks: Dry-Gel Synthesis of MOF-74 Framework with High Yield and Improved Performance.

    Das, Atanu Kumar; Vemuri, Rama Sesha; Kutnyakov, Igor; McGrail, B Peter; Motkuri, Radha Kishan


    Vapor-assisted dry-gel synthesis of the metal-organic framework-74 (MOF-74) structure, specifically Ni-MOF-74 produced from synthetic precursors using an organic-water hybrid solvent system, showed a very high yield (>90% with respect to 2,5-dihydroxyterepthalic acid) and enhanced performance. The Ni-MOF-74 obtained showed improved sorption characteristics towards CO2 and the refrigerant fluorocarbon dichlorodifluoromethane. Unlike conventional synthesis, which takes 72 hours using the tetrahydrofuran-water system, this kinetic study showed that Ni-MOF-74 forms within 12 hours under dry-gel conditions with similar performance characteristics, and exhibits its best performance characteristics even after 24 hours of heating. In the dry-gel conversion method, the physical separation of the solvent and precursor mixture allows for recycling of the solvent. We demonstrated efficient solvent recycling (up to three times) that resulted in significant cost benefits. The scaled-up manufacturing cost of Ni-MOF-74 synthesized via our dry-gel method is 45% of conventional synthesis cost. Thus, for bulk production of the MOFs, the proposed vapor-assisted, dry-gel method is efficient, simple, and inexpensive when compared to the conventional synthesis method.

  14. Tuning the Synthesis of Manganese Oxides Nanoparticles for Efficient Oxidation of Benzyl Alcohol.

    Fei, Jingyuan; Sun, Lixian; Zhou, Cuifeng; Ling, Huajuan; Yan, Feng; Zhong, Xia; Lu, Yuxiang; Shi, Jeffrey; Huang, Jun; Liu, Zongwen


    The liquid phase oxidation of benzyl alcohol is an important reaction for generating benzaldehyde and benzoic acid that are largely required in the perfumery and pharmaceutical industries. The current production systems suffer from either low conversion or over oxidation. From the viewpoint of economy efficiency and environmental demand, we are aiming to develop new high-performance and cost-effective catalysts based on manganese oxides that can allow the green aerobic oxidation of benzyl alcohol under mild conditions. It was found that the composition of the precursors has significant influence on the structure formation and surface property of the manganese oxide nanoparticles. In addition, the crystallinity of the resulting manganese nanoparticles was gradually improved upon increasing the calcination temperature; however, the specific surface area decreased obviously due to pore structure damage at higher calcination temperature. The sample calcined at the optimal temperature of 600 °C from the precursors without porogen was a Mn3O4-rich material with a small amount of Mn2O3, which could generate a significant amount of [Formula: see text] species on the surface that contributed to the high catalytic activity in the oxidation. Adding porogen with precursors during the synthesis, the obtained catalysts were mainly Mn2O3 crystalline, which showed relatively low activity in the oxidation. All prepared samples showed high selectivity for benzaldehyde and benzoic acid. The obtained catalysts are comparable to the commercial OMS-2 catalyst. The synthesis-structure-catalysis interaction has been addressed, which will help for the design of new high-performance selective oxidation catalysts.

  15. Tuning the Synthesis of Manganese Oxides Nanoparticles for Efficient Oxidation of Benzyl Alcohol

    Fei, Jingyuan; Sun, Lixian; Zhou, Cuifeng; Ling, Huajuan; Yan, Feng; Zhong, Xia; Lu, Yuxiang; Shi, Jeffrey; Huang, Jun; Liu, Zongwen


    The liquid phase oxidation of benzyl alcohol is an important reaction for generating benzaldehyde and benzoic acid that are largely required in the perfumery and pharmaceutical industries. The current production systems suffer from either low conversion or over oxidation. From the viewpoint of economy efficiency and environmental demand, we are aiming to develop new high-performance and cost-effective catalysts based on manganese oxides that can allow the green aerobic oxidation of benzyl alcohol under mild conditions. It was found that the composition of the precursors has significant influence on the structure formation and surface property of the manganese oxide nanoparticles. In addition, the crystallinity of the resulting manganese nanoparticles was gradually improved upon increasing the calcination temperature; however, the specific surface area decreased obviously due to pore structure damage at higher calcination temperature. The sample calcined at the optimal temperature of 600 °C from the precursors without porogen was a Mn3O4-rich material with a small amount of Mn2O3, which could generate a significant amount of {O}_2- species on the surface that contributed to the high catalytic activity in the oxidation. Adding porogen with precursors during the synthesis, the obtained catalysts were mainly Mn2O3 crystalline, which showed relatively low activity in the oxidation. All prepared samples showed high selectivity for benzaldehyde and benzoic acid. The obtained catalysts are comparable to the commercial OMS-2 catalyst. The synthesis-structure-catalysis interaction has been addressed, which will help for the design of new high-performance selective oxidation catalysts.

  16. An efficient PEG-400 mediated catalyst free green synthesis of 2-amino-thiazoles from α-diazoketones and thiourea



    A simple and efficient method has been developed for the synthesis of 2-aminothiazoles from α-diazoketones using PEG-400 solvent system. This novel synthetic approach involves the reaction between thiourea and α-diazoketones in PEG-400 at 100 ◦C to yield the corresponding 2-aminothiazoles in good yields.The method is simple, rapid and generates thiazole derivatives in excellent yields without the use of any catalysts. This green protocol can be utilized for fast synthesis of various 2-aminothiazoles in good yields.

  17. Synthesis and simulation of efficient divided wall column sequences for bioethanol recovery and purification from an actual lignocellulosic fermentation broth

    Torres-Ortega, Carlo Edgar; Rong, Ben-Guang


    of column sections as novel synthesis approaches to formulate hybrid units and divided wall columns. Rigorous simulation in Aspen Plus V8.0 was used to simulate the intensified separation systems. The new intensified alternatives achieved relevant savings, ranging from 17 to 23% in TAC (total annual costs......, the intensified system with lowest TAC, and a multieffect distillation column scheme. The intensified system obtained cost savings of 15–20% higher than the multieffect scheme. We concluded that the novel synthesis procedure generated systems that efficiently reduced the energy and capital costs...

  18. An efficient synthesis of iminoquinones by a chemoselective domino ortho-hydroxylation/oxidation/imidation sequence of 2-aminoaryl ketones.

    Chandrasekar, Selvaraj; Sekar, Govidasamy


    An efficient chemoselective domino oxidative homocoupling of 2-aminoaryl ketones in the presence of 2-iodoxybenzoic acid (IBX) for the synthesis of iminoquinone has been developed. The domino reaction proceeds via three consecutive steps, such as domino ortho-hydroxylation of 2-aminoaryl ketones, oxidation of a phenol derivative to benzoquinone and dimerization through imine formation to yield iminoquinone. Importantly, this reaction allows the recycling of the oxidant IBX by recovering the by-product iodosobenzoic acid (IBA) and oxidizing it back to IBX. A four step domino strategy for the synthesis of iminoquinone through in situ generation of 2-amino benzophenone from (2-amino phenyl)(phenyl)methanol was also developed.

  19. Efficient one-pot synthesis of monodisperse alkyl-terminated colloidal germanium nanocrystals

    Carolan, Darragh, E-mail:; Doyle, Hugh, E-mail: [University College Cork, Tyndall National Institute (Ireland)


    An efficient one-pot method for fabricating alkyl-capped germanium nanocrystals (Ge NCs) is reported. Ge NCs with a size of 3.9 ± 0.5 nm, are formed by co-reduction of germanium tetrachloride in the presence of n-butyltrichlorogermane, producing NCs with butyl-terminated surfaces. The advantage of this method is that it allows rapid synthesis and functionalisation of NCs with minimal post-synthetic purification requirements. TEM imaging showed that the Ge NCs are monodisperse and highly crystalline, while EDX and SAED confirmed the chemical identity and crystal phase of the NCs. FTIR and XPS confirmed that the Ge NCs were well passivated, with some oxidation of the nanocrystal surface. Optical spectroscopy of the NCs showed a strong absorbance in the UV region and an excitation wavelength dependent photoluminescence in the UV/violet. Time resolved photoluminescence measurements showed the presence of two nanosecond lifetime components, consistent with recombination of photogenerated excitons at low lying energy states present at the nanocrystal surface. Photoluminescence quantum yields were determined to be 37 %, one of the highest values reported for organically terminated Ge NCs.

  20. Green synthesis of copper nanoparticles for the efficient removal (degradation) of dye from aqueous phase.

    Sinha, Tanur; Ahmaruzzaman, M


    The present work reports the utilization of a common household waste material (fish scales of Labeo rohita) for the synthesis of copper nanoparticles. The method so developed was found to be green, environment-friendly, and economic. The fish scale extracts were acting as a stabilizing and reducing agents. This method avoids the use of external reducing and stabilizing agents, templates, and solvents. The compositional abundance of gelatin may be envisaged for the effective reductive as well as stabilizing potency. The mechanisms for the formation of nanoparticles have also been presented. The synthesized copper nanoparticles formed were predominantly spherical in nature with an average size of nanoparticles in the range of 25-37 nm. The copper nanoparticles showed characteristic Bragg's reflection planes of fcc which was supported by both selected area electron diffraction and X-ray diffraction pattern and showed surface plasmon resonance at 580 nm. Moreover, the energy dispersive spectroscopy pattern also revealed the presence of only elemental copper in the copper nanoparticles. The prepared nanoparticles were used for the remediation of a carcinogenic and noxious textile dye, Methylene blue, from aqueous solution. Approximately, 96 % degradation of Methylene blue dye was observed within 135 min using copper nanoparticles. The probable mechanism for the degradation of the dye has been presented, and the degraded intermediates have been identified using the liquid chromatography-mass spectroscopy technique. The high efficiency of nanoparticles as photocatalysts has opened a promising application for the removal of hazardous dye from industrial effluents contributing indirectly to environmental cleanup process.

  1. Biochemical characterization of a first fungal esterase from Rhizomucor miehei showing high efficiency of ester synthesis.

    Yu Liu

    Full Text Available BACKGROUND: Esterases with excellent merits suitable for commercial use in ester production field are still insufficient. The aim of this research is to advance our understanding by seeking for more unusual esterases and revealing their characterizations for ester synthesis. METHODOLOGY/PRINCIPAL FINDINGS: A novel esterase-encoding gene from Rhizomucor miehei (RmEstA was cloned and expressed in Escherichia coli. Sequence analysis revealed a 975-bp ORF encoding a 324-amino-acid polypeptide belonging to the hormone-sensitive lipase (HSL family IV and showing highest similarity (44% to the Paenibacillus mucilaginosus esterase/lipase. Recombinant RmEstA was purified to homogeneity: it was 34 kDa by SDS-PAGE and showed optimal pH and temperature of 6.5 and 45°C, respectively. The enzyme was stable to 50°C, under a broad pH range (5.0-10.6. RmEstA exhibited broad substrate specificity toward p-nitrophenol esters and short-acyl-chain triglycerols, with highest activities (1,480 U mg(-1 and 228 U mg(-1 for p-nitrophenyl hexanoate and tributyrin, respectively. RmEstA efficiently synthesized butyl butyrate (92% conversion yield when immobilized on AOT-based organogel. CONCLUSION: RmEstA has great potential for industrial applications. RmEstA is the first reported esterase from Rhizomucor miehei.

  2. Efficient synthesis of tension modulation in strings and membranes based on energy estimation.

    Avanzini, Federico; Marogna, Riccardo; Bank, Balázs


    String and membrane vibrations cannot be considered as linear above a certain amplitude due to the variation in string or membrane tension. A relevant special case is when the tension is spatially constant and varies in time only in dependence of the overall string length or membrane surface. The most apparent perceptual effect of this tension modulation phenomenon is the exponential decay of pitch in time. Pitch glides due to tension modulation are an important timbral characteristic of several musical instruments, including the electric guitar and tom-tom drum, and many ethnic instruments. This paper presents a unified formulation to the tension modulation problem for one-dimensional (1-D) (string) and two-dimensional (2-D) (membrane) cases. In addition, it shows that the short-time average of the tension variation, which is responsible for pitch glides, is approximately proportional to the system energy. This proportionality allows the efficient physics-based sound synthesis of pitch glides. The proposed models require only slightly more computational resources than linear models as opposed to earlier tension-modulated models of higher complexity.

  3. Facile and Efficient Synthesis of Carbosiloxane Dendrimers via Orthogonal Click Chemistry Between Thiol and Ene.

    Zhang, Zhida; Feng, Shengyu; Zhang, Jie


    A combination of a thiol-Michael addition reaction and a free radical mediated thiol-ene reaction is employed as a facile and efficient approach to carbosiloxane dendrimer synthesis. For the first time, carbosiloxane dendrimers are constructed rapidly by an orthogonal click strategy without protection/deprotection procedures. The chemoselectivity of these two thiol-ene click reactions leads to a design of a new monomer containing both electron-deficient carbon-carbon double bonds and unconjugated carbon-carbon double bonds. Siloxane bonds are introduced as the linker between these two kinds of carbon-carbon double bonds. Starting from a bifunctional thiol core, the dendrimers are constructed by iterative thiol-ene click reactions under different but both mild reaction conditions. After simple purification steps the fifth dendrimer with 54 peripheral functional groups is obtained with an excellent overall yield in a single day. Furthermore, a strong blue glow is observed when the dendrimer is excited by a UV lamp.

  4. Efficient, chemoselective synthesis of immunomicelles using single-domain antibodies with a C-terminal thioester

    Raats Jos MH


    Full Text Available Abstract Background Classical bioconjugation strategies for generating antibody-functionalized nanoparticles are non-specific and typically result in heterogeneous compounds that can be compromised in activity. Expression systems based on self-cleavable intein domains allow the generation of recombinant proteins with a C-terminal thioester, providing a unique handle for site-specific conjugation using native chemical ligation (NCL. However, current methods to generate antibody fragments with C-terminal thioesters require cumbersome refolding procedures, effectively preventing application of NCL for antibody-mediated targeting and molecular imaging. Results Targeting to the periplasm of E. coli allowed efficient production of correctly-folded single-domain antibody (sdAb-intein fusions proteins. On column purification and 2-mercapthoethanesulfonic acid (MESNA-induced cleavage yielded single-domain antibodies with a reactive C-terminal MESNA thioester in good yields. These thioester-functionalized single-domain antibodies allowed synthesis of immunomicelles via native chemical ligation in a single step. Conclusion A novel procedure was developed to obtain soluble, well-folded single-domain antibodies with reactive C-terminal thioesters in good yields. These proteins are promising building blocks for the chemoselective functionalization via NCL of a broad range of nanoparticle scaffolds, including micelles, liposomes and dendrimers.

  5. Expeditious and Efficient Synthesis of Benzoxazoles, Benzothiazoles, Benzimidazoles Catalyzed by Ga(OTf)3 under Solvent-Free Conditions%Expeditious and Efficient Synthesis of Benzoxazoles, Benzothiazoles, Benzimidazoles Catalyzed by Ga(OTf)3 under Solvent-Free Conditions

    刘巨艳; 刘倩; 徐玮; 王玮璐


    A new and efficient method for the synthesis of benzoxazoles, benzothiazoles, benzimidazoles from reactions of o-substituted aminoaromatics with orthoesters in the presence of catalytic amounts of Ga(OTf)3 under solvent-free conditions is presented. The remarkable features of this new protocol are high conversion, very short reaction times, cleaner reaction profiles under solvent-free conditions, straight forward procedure, and use of relatively non-toxic catalysts.

  6. An Efficient Synthesis of Nitriles from Aldoximes Using Diethyl Phosphorocyanidate under Mild Conditions

    Lee, Kieseung; An, Hyeonseong; Hwang, Chanyeon [Woosuk Univ.,Wanju (Korea, Republic of)


    Nitriles are valuable intermediates in organic synthesis not only because they serve as the appropriate precursors to various functional groups, but also because they are widely used as the key intermediates for pharmaceuticals, agrochemicals and various N-heterocyclic compounds. The cyano group itself is also frequently found in many biologically important molecules. Therefore, a variety of synthetic routes to nitriles from diverse chemical precursors have been developed. Among these routes, nitrile synthesis from aldoximes using an appropriate dehydrating agent has been a general and clean method. For this purpose, numerous reagents such as chlorosulfonyl isocyanate, di-2-pyridyl sulfite, Burgess reagent, [RuCl{sub 2}(p-cymene)]{sub 2}/MS, 4A, BOP, Pd(OAc){sub 2}/PPh{sub 3}, Cu(OAc){sub 2}/ultrasound have been developed. These reagents, however, may have limitations in some respects such as harsh reaction conditions, use of expensive or less readily available reagents, low yields, and lack of generality. Therefore, there is still a need to develop mild and general method for this conversion. Diethyl phosphorocyanidate (DEPC) was initially introduced as an efficient peptide coupling reagent, and has been utilized for useful organic reactions. Previously, we reported that 2-chloro-1-methylpyridinium iodide is an efficient and mild reagent for the dehydration of aldoximes to nitriles under mild conditions. In continuation of our interest in developing mild method for the conversion of aldoximes to nitriles, we herein wish to report the first application of DEPC to the efficient synthesis of nitriles from aldoximes under mild conditions (Scheme 1). In order to obtain the information regarding the optimum reaction conditions, 4-pyridine aldoxime (1a) was reacted with DEPC without base, and in presence of various base in CH{sub 2}Cl{sub 2} at rt for a prolonged reaction time (20 h) (Table 1). CH{sub 2}CI{sub 2} was chosen as reaction medium in this reaction due to the

  7. Time- and energy-efficient solution combustion synthesis of binary metal tungstate nanoparticles with enhanced photocatalytic activity.

    Thomas, Abegayl; Janáky, Csaba; Samu, Gergely F; Huda, Muhammad N; Sarker, Pranab; Liu, J Ping; van Nguyen, Vuong; Wang, Evelyn H; Schug, Kevin A; Rajeshwar, Krishnan


    In the search for stable and efficient photocatalysts beyond TiO2 , the tungsten-based oxide semiconductors silver tungstate (Ag2 WO4 ), copper tungstate (CuWO4 ), and zinc tungstate (ZnWO4 ) were prepared using solution combustion synthesis (SCS). The tungsten precursor's influence on the product was of particular relevance to this study, and the most significant effects are highlighted. Each sample's photocatalytic activity towards methyl orange degradation was studied and benchmarked against their respective commercial oxide sample obtained by solid-state ceramic synthesis. Based on the results herein, we conclude that SCS is a time- and energy-efficient method to synthesize crystalline binary tungstate nanomaterials even without additional excessive heat treatment. As many of these photocatalysts possess excellent photocatalytic activity, the discussed synthetic strategy may open sustainable materials chemistry avenues to solar energy conversion and environmental remediation.

  8. Solvent-Free Green and Efficient One-Pot Synthesis of Dihydropyrano[3,2-c]chromene Derivatives

    Jain, Shubha; Rajguru, Deepika; Keshwal, Balwant S.; Acharya, Aman D.


    A rapid, clean, and highly efficient method for synthesis of dihydropyrano[3,2-c]chromene derivatives by one-pot, three-component condensation of aromatic aldehydes, malononitrile, and 4-hydroxycoumarin using DABCO as catalyst in solvent-free neat conditions is described. The present method has the advantages of mild reaction conditions, short reaction times, easy isolation of products, and excellent yields. PMID:24282643

  9. Ytterbium(Ⅲ) Triflate as an Efficient Catalyst for the Synthesis of Perimidine Derivatives under Mild Conditions

    ZHANG,Song-Lin; ZHANG,Jun-Min


    Various biologically important perimidine derivatives have been efficiently synthesized in excellent yields using naphthalene-1,8-diamine with various ketones in the presence of a catalytic amount of Yb(OTf)3. The influence of the loading of Yb(OTf)3, reaction solvent, the structure of ketones was studied. This method is a very easy, simple and high yielding reaction for the synthesis of perimidine derivatives.

  10. Efficient PPA-SiO2-catalyzed Synthesis of β-enaminones Under Solvent-Free Conditions

    Muhammad Nisar


    Full Text Available An efficient method has been developed for the synthesis of β-enaminones under solvent-free reaction conditions using PPA-SiO2 as catalyst. The reaction yields were good to excellent (up to 90%. This methodology affords high selectivity and good tolerance of a variety of different functional groups present on both aromatic and aliphatic amines. In addition, the methodology is environmentally benign and cost-effective due to absence of solvent and easy work-up.

  11. Efficient sonochemical synthesis of alkyl 4-aryl-6-chloro-5-formyl-2-methyl-1,4-dihydropyridine-3-carboxylate derivatives.

    Ruiz, Enrique; Rodríguez, Hortensia; Coro, Julieta; Niebla, Vladimir; Rodríguez, Alfredo; Martínez-Alvarez, Roberto; de Armas, Hector Novoa; Suárez, Margarita; Martín, Nazario


    A facile, efficient and environment-friendly protocol for the synthesis of 6-chloro-5-formyl-1,4-dihydropyridine derivatives has been developed by the convenient ultrasound-mediated reaction of 2(1H)pyridone derivatives with the Vilsmeier-Haack reagent. This method provides several advantages over current reaction methodologies including a simpler work-up procedure, shorter reaction times and higher yields.

  12. One-pot efficient green synthesis of 1,4-dihydro-quinoxaline-2,3-dione derivatives

    Harjyoti Thakuria; Gopal Das


    An efficient synthesis of the potential pharmacophore 1,4-dihydro-quinoxaline-2,3-dione (1) has been achieved in a one-pot reaction at room temperature from substituted -phenylene diamine and oxalic acid under solvent-free conditions by a simple grinding method with unsurpassed atom economy. Thermal and powder X-ray diffraction analysis was carried out for some hydrated crystals.

  13. Synthesis of substituted 1,4-diazepines and 1,5-benzodiazepines using an efficient heteropolyacid-catalyzed procedure.

    Kaoua, Rachedine; Bennamane, Norah; Bakhta, Saliha; Benadji, Sihame; Rabia, Cherifa; Nedjar-Kolli, Bellara


    An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs) was developed. High yields and short reaction times were obtained for both electron-releasing and electron-withdrawing substituted 1,4-diazepine  and 1,5-benzodiazepines derivatives.

  14. An efficient, microwave-assisted, one-pot synthesis of novel 5,6,7,8-tetrahydroquinoline-3-carbonitriles



    Full Text Available An efficient, microwave-assisted synthesis of novel 2-alkoxy-5,6,7,8--tetrahydroquinoline-3-carbonitriles, which have not hitherto been reported, via reactions of cyclohexanone and arylidene malononitriles in the corresponding alcohols in presence of sodium is described. All the newly synthesized compounds were characterized by the IR, 1H-NMR, 13C-NMR and mass spectrescopic techniques and by elemental analyses. The newly synthesized compounds were evaluated for their antibacterial and antifungal activities.

  15. Fe-Al/clay as an efficient heterogeneous catalyst for solvent-free synthesis of 3, 4-dihydropyrimidones

    Bashir A Dar; Praveen Patidar; Sunil Kumar; Mohammad Arif Wagay; Akshay K Sahoo; Parduman R Sharma; Sanjay Pandey; Meena Sharma; Baldev Singh


    A practical, efficient, environmentally benign condensation of an aldehyde, ethylacetoacetate and urea/thiourea for the synthesis of 3, 4-dihydropyrimidinones, employing Fe-Al/clay composite catalyst is described. The process has been carried out under solvent-free conditions in the presence of very small amount of catalyst. The catalyst used for this process is easy to prepare, easy to handle, cost effective, easy to separate and recyclable at least up to 5 cycles with good to excellent yield.

  16. Efficient Synthesis of the C1- C7 Fragment of Didemnaketal A

    Xue Qiang LI; Xue Zhi ZHAO; Pei Nian LIU; Yong Qiang TU


    The stereoselective synthesis of the C1-C7 fragment (3R,4S,6R)-3,4-di[(tert-butyl- dimethylsilyl)oxy]-7-hydroxy-6-methylheptan-2-one, which is the crucial intermediate for synthesis of the HIV-1 protease inhibitive didemnaketals, was developed via 12 steps from the natural (+)-pulegone.

  17. New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

    Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus


    Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

  18. Efficient continuous synthesis of high purity deep eutectic solvents by twin screw extrusion.

    Crawford, D E; Wright, L A; James, S L; Abbott, A P


    Mechanochemical synthesis has been applied to the rapid synthesis of Deep Eutectic Solvents (DESs), including Reline 200 (choline chloride : urea, 1 : 2), in a continuous flow methodology by Twin Screw Extrusion (TSE). This gave products in higher purity and with Space Time Yields (STYs), four orders of magnitude greater than for batch methods.

  19. Synthesis of Colloidal Nanocrystal Heterostructures for High-Efficiency Light Emission

    Lu, Yifei

    Group II-VI semiconductor nanocrystals, particularly those based on ZnCdS(Se), can be synthesized using well established chemical colloidal processes, and have been a subject of extensive research over the past decade. Their optical properties can be easily tuned through size and composition variations, making them very attractive for many optoelectronic applications including light-emitting diodes (LEDs) and solar cells. Incorporation of diverse internal heterostructures provides an additional means for tuning the optical and electronic properties of conventional ZnCdS(Se) nanocrystals. Extensive bandgap and strain engineering may be applied to the resultant nanocrystal heterostructures to achieve desirable properties and enhanced performance. Despite the high scientific and practical interests of this unique class of nanomaterials, limited efforts have been made to explore their synthesis and potential device applications. This thesis focuses on the synthesis, engineering, characterization, and device demonstration of two types of CdSe-based nanocrystal heterostructures: core/multishell quantum dots (QDs) and QD quantum wells (QDQWs). Their optical properties have been tuned by bandgap and strain engineering to achieve efficient photoluminescence (PL) and electroluminescence (EL).Firstly, yellow light-emitting CdSe QDs with a strain-compensated ZnS/ZnCdS bilayer shell were synthesized using the successive ion layer adsorption and reaction technique and the effects of the shell on the luminescent properties were investigated. The core/shell/shell QDs enjoyed the benefits of excellent exciton confinement by the ZnS intermediate shell and strain compensation by the ZnCdS outer shell, and exhibited 40% stronger PL and a smaller peak redshift upon shell growth compared to conventional CdSe/ZnCdS/ZnS core/shell/shell QDs with an intermediate lattice adaptor. CdSe/ZnS/ZnCdS QD-LEDs had a luminance of 558 cd/m2 at 20 mA/cm 2, 28% higher than that of CdSe/ZnCdS/ZnS QD

  20. Direct formation of small Cu2O nanocubes, octahedra, and octapods for efficient synthesis of triazoles

    Tsai, Ya-Huei; Chanda, Kaushik; Chu, Yi-Ting; Chiu, Chun-Ya; Huang, Michael H.


    In most studies describing the preparation of Cu2O crystals of various morphologies, the particle sizes are normally hundreds of nanometers to micrometers due to rapid particle growth, so they are not exactly nanocrystals. Here we report surfactant-free formation of sub-100 nm Cu2O nanocrystals with systematic shape evolution from cubic to octahedral structures by preparing an aqueous mixture of Cu(OAc)2, NaOH, and N2H4 solution. Adjustment of the hydrazine volume enables the particle shape control. Uniform nanocubes and octahedra were synthesized with edge lengths of 37 and 67 nm, respectively. Novel Cu2O octapods with an edge length of 135 nm were also produced by mixing CuCl2 solution, SDS surfactant, NaOH solution, and NH2OH.HCl reductant solution. All of them are nearly the smallest Cu2O nanocrystals of the same shapes ever reported. These small cubes, octahedra, and octapods were employed as catalysts in the direct synthesis of 1,2,3-triazoles from the reaction of alkynes, organic halides, and NaN3 at 55 °C. All of them displayed high product yields in short reaction times. The octahedra enclosed by the {111} facets are the best catalysts, and can catalyze this cycloaddition reaction with high yields in just 2 h when different alkynes were used to make diverse triazole products. Hence, the small Cu2O particles provide time-saving, energy-efficient, and high product yield benefits to organocatalysis.In most studies describing the preparation of Cu2O crystals of various morphologies, the particle sizes are normally hundreds of nanometers to micrometers due to rapid particle growth, so they are not exactly nanocrystals. Here we report surfactant-free formation of sub-100 nm Cu2O nanocrystals with systematic shape evolution from cubic to octahedral structures by preparing an aqueous mixture of Cu(OAc)2, NaOH, and N2H4 solution. Adjustment of the hydrazine volume enables the particle shape control. Uniform nanocubes and octahedra were synthesized with edge

  1. Facile and controlled synthesis of aligned WO3 nanorods and nanosheets as an efficient photocatalyst material

    Ahmed, Bilal; Kumar, Sumeet; Ojha, Animesh K.; Donfack, P.; Materny, A.


    In this work, we have performed a facile and controlled synthesis of WO3 nanorods and sheets in different crystal phases (triclinic, orthorhombic and monoclinic) of WO3 using the sol-gel method. The detailed structures of the synthesized materials were examined by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy measurements. The shapes and crystal phases of the WO3 nanostructures were found to be highly dependent on the calcination temperature. The variation in crystalline phases and shapes is modified the electronic structure of the samples, which causes a variation in the value of optical band gap. The value of the Raman line intensity ratio I264/I320 has been successfully used to identify the structural transition from the triclinic to the orthorhombic phase of WO3. The PL spectra of the synthesized products excited at wavelengths 380, 400, and 420 nm exhibit intense emission peaks that cover the complete visible range (blue-green-red). The emission peaks at 460 and 486 nm were caused by the near band-edge and band to band transition, respectively. The peaks in spectral range 500-600 nm might be originated from the presence of oxygen vacancies lying within the energy band gap. The synthesized WO3 nanostructures showed improved photocatalytic activity for the photodegradation of MB dye. The enhanced photocatalytic activity of WO3 nanosheets compared to WO3 nanorods for photodegradation of methylene blue (MB) dye could be due to the shape of the nanostructured WO3. The sheet type of structure provides more active surface for the interaction of dye molecules compared to the rods, which results in a more efficient degradation of the dye molecules.

  2. Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

    Wafa Gati


    Full Text Available We have developed a general synthesis of polysubstituted 1,4-dihydropyridines and pyridines based on a highly regioselective lithiation/6-endo-dig intramolecular carbolithiation from readily available N-allyl-ynamides. This reaction, which has been successfully applied to the formal synthesis of the anti-dyskinesia agent sarizotan, further extends the use of ynamides in organic synthesis and further demonstrates the synthetic efficiency of carbometallation reactions.

  3. Combining the [2,3] Sigmatropic Rearrangement and Ring-Closing Metathesis Strategies for the Synthesis of Spirocyclic Alkaloids. A Short and Efficient Route to (+/-)-Perhydrohistrionicotoxin

    Tanner, David Ackland; Hagberg, Lars; Poulsen, Anders


    and efficient formal total synthesis of the alkaloid (+/-)-perhydrohistrionicotoxin (2). Thus, (+/-)-depentylperhydrohistrionicotoxin, 1, a known key intermediate for the synthesis of 2, was synthesised from 2,3-epoxycyclohexan-1-one in 10 laboratory operations and ca. 20% overall yield. The synthetic route...

  4. Partially reduced iridium oxide clusters dispersed on titania as efficient catalysts for facile synthesis of dimethylformamide from CO2, H2 and dimethylamine.

    Bi, Qing-Yuan; Lin, Jian-Dong; Liu, Yong-Mei; Xie, Song-Hai; He, He-Yong; Cao, Yong


    A novel bifunctional catalyst based on partially reduced iridium oxide supported on TiO2 was found to be exceedingly efficient for the organic-solvent-free synthesis of dimethylformamide from CO2, H2 and dimethylamine.

  5. An Efficient Method for the Synthesis of Acyl-diazenes Using NaNO2/NaHSO4·H2O


    An efficient and convenient method for the synthesis of acyl-diazenes is reported. Ten acyl-diazenes have been synthesized from acylhydrazines in excellent yields under mild conditions. There are eight new substances among these compounds.

  6. Rapid (∼10 min) synthesis of single-crystalline, nanorice TiO2 mesoparticles with a high photovoltaic efficiency of above 8%.

    Parmar, K P S; Ramasamy, Easwaramoorthi; Lee, Jinwoo; Lee, Jae Sung


    A novel rapid (∼10 min) microwave-hydrothermal synthesis is demonstrated for nanorice TiO(2) mesoparticles as an anode of a dye-sensitized solar cell with an excellent photovoltaic efficiency of above 8%.

  7. Tribromomelamine: A Novel and Efficient Catalyst for the Synthesis 2-Arylthiazolines under Solvent-free Conditions

    Liqiang Wu


    Full Text Available A novel procedure for the synthesis of 2-arylthiazolines through one-pot condensation of of nitriles with 2-aminoethanethiol in the presence of tribromomelamine as catalyst under solvent-free conditions is described.

  8. Nano-Ticl .SiO : a Versatile and Efficient Catalyst for Synthesis of ...


    important biological and pharmacological effects. In many cases ... For example, costs of synthesis, unrecoverable catalysts, strong ... A Bruker (DRX-400 Avance) NMR was used to record ..... d Using microwave oven, Kenwood, 1300 W.

  9. Efficiency

    I.P. van Staveren (Irene)


    textabstractThe dominant economic theory, neoclassical economics, employs a single economic evaluative criterion: efficiency. Moreover, it assigns this criterion a very specific meaning. Other – heterodox – schools of thought in economics tend to use more open concepts of efficiency, related to comm

  10. A novel tandem Betti/Ullmann oxidation reaction as an efficient route for synthesis of new oxazepine derivatives



    A novel tandem Betti/Ullmann/oxidation reaction was used for synthesis of new oxazepine derivatives containing kojic acid. This protocol includes a three-component Betti reaction of 2-naphthol, 2- haloanilines and kojic aldehyde followed by copper-mediated intramolecular Ullmann C-O coupling reactionand subsequently aerobic oxidation. This method provides a new and useful strategy for the construction of heterocycles. Also novel Betti bases based on kojic acid derivatives have been synthesized. In this regard, boric acid functionalized silica supported Fe₃O₄ nanoparticle have been designed, synthesized and used as a highly efficient, environmentally benign and recyclable heterogeneous magnetic nanocatalyst for the direct synthesis of desired Betti bases under solvent free conditions.

  11. Synthesis of Ultrathin PdCu Alloy Nanosheets Used as a Highly Efficient Electrocatalyst for Formic Acid Oxidation.

    Yang, Nailiang; Zhang, Zhicheng; Chen, Bo; Huang, Ying; Chen, Junze; Lai, Zhuangchai; Chen, Ye; Sindoro, Melinda; Wang, An-Liang; Cheng, Hongfei; Fan, Zhanxi; Liu, Xiaozhi; Li, Bing; Zong, Yun; Gu, Lin; Zhang, Hua


    Inspired by the unique properties of ultrathin 2D nanomaterials and excellent catalytic activities of noble metal nanostructures for renewable fuel cells, a facile method is reported for the high-yield synthesis of ultrathin 2D PdCu alloy nanosheets under mild conditions. Impressively, the obtained PdCu alloy nanosheet after being treated with ethylenediamine can be used as a highly efficient electrocatalyst for formic acid oxidation. The study implicates that the rational design and controlled synthesis of an ultrathin 2D noble metal alloy may open up new opportunities for enhancing catalytic activities of noble metal nanostructures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Synthesis of a Sulfonated Two-Dimensional Covalent Organic Framework as an Efficient Solid Acid Catalyst for Biobased Chemical Conversion.

    Peng, Yongwu; Hu, Zhigang; Gao, Yongjun; Yuan, Daqiang; Kang, Zixi; Qian, Yuhong; Yan, Ning; Zhao, Dan


    Because of limited framework stability tolerance, de novo synthesis of sulfonated covalent organic frameworks (COFs) remains challenging and unexplored. Herein, a sulfonated two-dimensional crystalline COF, termed TFP-DABA, was synthesized directly from 1,3,5-triformylphloroglucinol and 2,5-diaminobenzenesulfonic acid through a previously reported Schiff base condensation reaction, followed by irreversible enol-to-keto tautomerization, which strengthened its structural stability. TFP-DABA is a highly efficient solid acid catalyst for fructose conversion with remarkable yields (97 % for 5-hydroxymethylfurfural and 65 % for 2,5-diformylfuran), good chemoselectivity, and good recyclability. The present study sheds light on the de novo synthesis of sulfonated COFs as novel solid acid catalysts for biobased chemical conversion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A green and efficient protocol for the synthesis of quinoxaline, benzoxazole and benzimidazole derivatives using heteropolyanion-based ionic liquids: as a recyclable solid catalyst.

    Vahdat, Seyed Mohammad; Baghery, Saeed


    In this paper, we introduce two nonconventional ionic liquid compounds which are composed of propane sulfonate functionalized organic cations and heteropolyanions as green solid acid catalysts for the highly efficient and green synthesis of 2,3-disubstitutedquinoxaline derivatives. These ionic liquids are in the solid state at room temperature and the synthesis is carried out via the one-pot condensation reaction of various o-phenylenediamine with 1,2-diketone derivatives. Benzoxazole and benzimidazole derivatives were also synthesized by these novel catalysts via the one-pot condensation from reaction orthoester with o-aminophenol (synthesis of benzoxazole derivatives) and ophenylenediamine (synthesis of benzimidazole derivatives). All experiments successfully resulted in the desired products. The described novel synthesis method has several advantages of safety, mild condition, high yields, short reaction times, simplicity and easy workup compared to the traditional method of synthesis.

  14. Microorganisms as efficient biosystem for the synthesis of metal nanoparticles: current scenario and future possibilities.

    Salunke, Bipinchandra K; Sawant, Shailesh S; Lee, Sang-Ill; Kim, Beom Soo


    Nanoparticles, the elementary structures of nanotechnology, are important materials for fundamental studies and variety of applications. The different sizes and shapes of these materials exhibit unique physical and chemical properties than their bulk materials. There is a great interest in obtaining well-dispersed, ultrafine, and uniform nanoparticles to delineate and utilize their distinct properties. Nanoparticle synthesis can be achieved through a wide range of materials utilizing a number of methods including physical, chemical, and biological processes with various precursors from liquids and solids. There is a growing need to prepare environmentally friendly nanoparticles that do not produce toxic wastes in their process synthesis protocol. This kind of synthesis can be achieved by green environment benign processes, which happen to be mostly of a biological nature. Microorganisms are one of the most attractive and simple sources for the synthesis of different types of nanoparticles. This review is an attempt to provide the up-to-date information on current status of nanoparticle synthesis by different types of microorganisms such as fungi, yeast, bacteria, cyanobacteria, actinomycete, and algae. The probable biosynthesis mechanism and conditions for size/shape control are described. Various applications of microbially synthesized nanoparticles are summarized. They include antibacterial, antifungal, anticancer, larvicidal, medical imaging, biosensor, and catalytic applications. Finally, limitations and future prospects for specific research are discussed.

  15. EGDMA-cross-linked polystyrene resin: An efficient support for gel phase peptide synthesis

    P K Ajikumar; K S Devaky


    This article illustrates the application of a 2% ethyleneglycol dimethacrylate-cross-linked polystyrene support (EGDMA-PS) in manual solid phase peptide synthesis. This copolymer has been characterised and optimised for peptide synthesis by performing the synthesis of a few model peptides and two biologically important peptides. EGDMA-cross-linked polystyrene support was prepared by the suspension polymerisation of the monomers EGDMA and styrene. EGDMA-PS resin undergoes facile swelling in a variety of solvents, both polar and nonpolar, used in peptide synthesis. The polymer was functionalised by Friedel-Crafts chloromethylation reaction. Peptides were assembled on a 2% cross-linked chloromethyl polymer support of capacity 1.63 mmol Cl/g. The biological peptides synthesised are an 11-residue peptide ATP binding site of the CDC2 kinase and a difficult sequence-a nineresidue peptide 34-42 corresponding to a portion of the hydrophobic terminus of the-amyloid protein 1-42. After synthesis, the peptides were cleaved from the support by treating with neat TFA. Purity of the peptides obtained in good yield was checked by TLC and HPLC methods and found to be fairly high.

  16. Hydrothermal Synthesis of VO2 Polymorphs: Advantages, Challenges and Prospects for the Application of Energy Efficient Smart Windows.

    Li, Ming; Magdassi, Shlomo; Gao, Yanfeng; Long, Yi


    Vanadium dioxide (VO2 ) is a widely studied inorganic phase change material, which has a reversible phase transition from semiconducting monoclinic to metallic rutile phase at a critical temperature of τc ≈ 68 °C. The abrupt decrease of infrared transmittance in the metallic phase makes VO2 a potential candidate for thermochromic energy efficient windows to cut down building energy consumption. However, there are three long-standing issues that hindered its application in energy efficient windows: high τc , low luminous transmittance (Tlum ), and undesirable solar modulation ability (ΔTsol ). Many approaches, including nano-thermochromism, porous films, biomimetic surface reconstruction, gridded structures, antireflective overcoatings, etc, have been proposed to tackle these issues. The first approach-nano-thermochromism-which is to integrate VO2 nanoparticles in a transparent matrix, outperforms the rest; while the thermochromic performance is determined by particle size, stoichiometry, and crystallinity. A hydrothermal method is the most common method to fabricate high-quality VO2 nanoparticles, and has its own advantages of large-scale synthesis and precise phase control of VO2 . This Review focuses on hydrothermal synthesis, physical properties of VO2 polymorphs, and their transformation to thermochromic VO2 (M), and discusses the advantages, challenges, and prospects of VO2 (M) in energy-efficient smart windows application. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Atomically thin Pt shells on Au nanoparticle cores: facile synthesis and efficient synergetic catalysis

    Engelbrekt, Christian; Seselj, Nedjeljko; Poreddy, Raju


    We present a facile synthesis protocol for atomically thin platinum (Pt) shells on top of gold (Au) nanoparticles (NPs) (Au@PtNPs) in one pot under mild conditions. The Au@PtNPs exhibited remarkable stability (> 2 years) at room temperature. The synthesis, bimetallic nanostructures and catalytic...... clearly show that the active surface is dominated by Pt with a specific surface area above 45 m2 per gram of Pt. Interactions with the Au core increase the activity of the Pt shell by up to 55% and improve catalytic selectivity compared to pure Pt. The Au@Pt NPs show exciting catalytic activity...

  18. A Facile and Efficient Synthesis of Arylsulfonates and Arylsulfonyl Hydrazides under Solvent Free Conditions

    ZHAO,Na; WANG,Yu-Lu; WANG,Jin-Ye


    @@ Organosulfur compounds are useful materials and most of them have pharmacological properties. The sulfonic esters are important intermediates in organic synthesis and used as acaricides and thermal recording materials. The sulfonyl hydrazides are valuable as inhibitors, agrochemical fungicides, insecticides and photographic images. Some methods have been reported for preparing these compounds to date. Usually, these reactions were carried out in organic solvent[1,2]such as pyridine and DMF. Even up-to date solid-phase synthesis requires solvent. What's more, they have other drawbacks including long reaction time, producing much wastes and by-products, tedious experimental procedure.

  19. Unusual pyrimidine participation: efficient stereoselective synthesis of potent dual orexin receptor antagonist MK-6096.

    Chung, John Y L; Zhong, Yong-Li; Maloney, Kevin M; Reamer, Robert A; Moore, Jeffrey C; Strotman, Hallena; Kalinin, Alexei; Feng, Ronnie; Strotman, Neil A; Xiang, Bangping; Yasuda, Nobuyoshi


    An asymmetric synthesis of dual orexin receptor antagonist MK-6096 (1) is described. Key steps for the trans-2,5-disubstituted piperidinyl ether fragment include a biocatalytic transamination, a trans-selective Mukaiyama aldol, and a regioselective pyridyl SNAr process. The pyrimidyl benzoic acid was synthesized via a Negishi coupling and a nitrile hydrolysis. Coupling of the two fragments via a catalytic T3P-mediated amidation completed the synthesis. Unusual behaviors in the hydrolysis of pyrimidyl benzonitrile and the amide coupling of the pyrimidyl benzoic acid are also described.

  20. Efficient synthesis of sulfonamide derivatives on solid supports catalyzed using solvent-free and microwave-assisted methods

    Argelia Camargo-Ordoñez


    Full Text Available In this work we report the synthesis of sulfonamide derivatives using a conventional procedure and with solid supports, such as silica gel, florisil, alumina, 4Å molecular sieves, montmorillonite KSF, and montmorillonite K10 using solvent-free and microwave-assisted methods. Our results show that solid supports have a catalytic activity in the formation of sulfonamide derivatives. We found that florisil, montmorillonite KSF, and K10 could be used as inexpensive alternative catalysts that are easily separated from the reaction media. Additionally, solvent-free and microwave-assisted methods were more efficient in reducing reaction time and in increasing yield.

  1. Efficient synthesis of sulfonamide derivatives on solid supports catalyzed using solvent-free and microwave-assisted methods

    Camargo-Ordonez, Argelia; Moreno-Reyes, Christian; Olazaran-Santibanez, Fabian; Martinez-Hernandez, Sheila; Bocanegra-Garcia, Virgilio; Rivera, Gildardo [Universidad Autonoma de Tamaulipas, Reynosa (Mexico). Dep. de Farmacia y Quimica Medicinal


    In this work we report the synthesis of sulfonamide derivatives using a conventional procedure and with solid supports, such as silica gel, florisil, alumina, 4A molecular sieves, montmorillonite KSF, and montmorillonite K10 using solvent-free and microwave-assisted methods. Our results show that solid supports have a catalytic activity in the formation of sulfonamide derivatives. We found that florisil, montmorillonite KSF, and K10 could be used as inexpensive alternative catalysts that are easily separated from the reaction media. Additionally, solvent-free and microwave-assisted methods were more efficient in reducing reaction time and in increasing yield. (author)

  2. An Efficient Solvent Free Synthesis of 1,8-Dioxo-octahydroxanthene Using p-Toluene Sulfonic Acid

    BAYAT, Mohammad; IMANIEH, Hossien; HOSSIENI, Seyydeh Hajar


    A simple and efficient method for the synthesis of 1,8-dioxo-octahydroxanthene by using p-toluenesulfonic acid as a catalyst under solvent free conditions is described, which involves cyclizafion of 2,2-arylmethylenebis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) that was obtained firstly by the reaction of dimedone with aromatic aldehydes in water as solvent and catalyst at room temperature. The experimental procedures in the two steps are very simple and the products are formed in excellent yields.

  3. Facile and efficient one-pot synthesis of 2-arylbenzoxazoles using hydrogen tetrachloroaurate as catalyst under oxygen atmosphere

    Yun-kui LIU; Da-jie MAO; Shao-jie LOU; Jian-qiang QIAN; Zhen-yuan XU


    In this paper, we presented a novel method for the facile and efficient one-pot synthesis of 2-arylbenzoxazoles, which oxygen atmosphere with anhydrous tetrahydrofuran (THF) as solvent or in solvent-free condition. The results show that this method could bring excellent yields as high as 96%. THF was proven to be the best choice among several solvents screened and the reaction was tolerated with a variety of aromatic aldehydes possessing electron-donating or withdrawing groups. The advantages of the present method lie in catalytic process using economic and environmentally benign dioxygen as oxidant.

  4. Efficient and high yield one-pot synthesis of cyclometalated platinum(II) β-diketonates at ambient temperature.

    Hudson, Zachary M; Blight, Barry A; Wang, Suning


    Cyclometalated Pt(II) β-diketonates are widely used as efficient luminescent materials but are typically prepared at high temperatures in low yields using excess reagents. A one-pot synthesis of these complexes is described employing stoichiometric reagents and short reaction times at ambient temperature, giving yields of up to 94%. The method is applicable to a broad range of substrates including N^C, P^C, and C^C chelate Pt(II) complexes and different β-diketonate ligands.

  5. Sequential Infiltration Synthesis of Doped Polymer Films with Tunable Electrical Properties for Efficient Triboelectric Nanogenerator Development.

    Yu, Yanhao; Li, Zhaodong; Wang, Yunming; Gong, Shaoqin; Wang, Xudong


    Doping polymer with AlOx via sequential infiltration synthesis enables bulk modification of triboelectric polymers with tunable electric or dielectric properties, which broadens the material selection and achieves a durable performance gain of triboelectric nanogenerators. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Efficient synthesis of large-scale thinned arrays using a density-taper initialised genetic algorithm

    Du Plessis, WP


    Full Text Available The use of the density-taper approach to initialise a genetic algorithm is shown to give excellent results in the synthesis of thinned arrays. This approach is shown to give better SLL values more consistently than using random values and difference...

  7. An efficient and green synthesis of novel benzoxazole under ultrasound irradiation.

    Nikpassand, Mohammad; Fekri, Leila Zare; Farokhian, Pegah


    Ultrasound as green process and an alternative energy source was investigated for the environmentally benign synthesis of novel benzoxazoles from different azo-linked salicylic acid derivatives and 2-amino-4-chlorophenol in short reaction time and high yield. These benzoxazole compounds have been characterized by elemental analysis, FT-IR, (1)H NMR and (13)C NMR spectroscopy.

  8. An Efficient Green Synthesis of 3-Amino-1H-chromenes Catalyzed ...


    disorder.18. Traditional methods have been reported for the synthesis of ... vantages and potentially explore industrial applications.38 ... sol-gel, hydrothermal, thermal evaporation, oxidation and anodization.39–45 Although the use of ZnO nanoparticles (NPs) ... 1aryl-1H-benzo[f]chromene-2-carbonitriles (4) via a three-.

  9. Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction

    An, Qi; Hassan, Youssef; Yan, Xiaotong; Krolla-Sidenstein, Peter; Mohammed, Tawheed; Lang, Mathias; Bräse, Stefan


    Conjugated microporous polymers (CMPs) are materials of low density and high intrinsic porosity. This is due to the use of rigid building blocks consisting only of lightweight elements. These materials are usually stable up to temperatures of 400 °C and are chemically inert, since the networks are highly crosslinked via strong covalent bonds, making them ideal candidates for demanding applications in hostile environments. However, the high stability and chemical inertness pose problems in the processing of the CMP materials and their integration in functional devices. Especially the application of these materials for membrane separation has been limited due to their insoluble nature when synthesized as bulk material. To make full use of the beneficial properties of CMPs for membrane applications, their synthesis and functionalization on surfaces become increasingly important. In this respect, we recently introduced the solid liquid interfacial layer-by-layer (LbL) synthesis of CMP-nanomembranes via Cu catalyzed azide–alkyne cycloaddition (CuAAC). However, this process featured very long reaction times and limited scalability. Herein we present the synthesis of surface grown CMP thin films and nanomembranes via light induced thiol–yne click reaction. Using this reaction, we could greatly enhance the CMP nanomembrane synthesis and further broaden the variability of the LbL approach.

  10. An Efficient Protocol for the Liquid-Phase Synthesis of Furano- and Pyranoquinolines

    LIN,Xu-Feng; WANG,Yan-Guang; CUI,Sun-Liang; YANG,Wei-Qiang


    @@ In recent years, the liquid-phase synthesis of small heterocyclic molecules has been a subject of intense research activity, since it represents one of the most promising ways to generate small molecular libraries in the field of combinatorial chemistry. Substituted quinolines offer a high degree of structure diversity and have proven to be very important in medicinal chemistry.

  11. An efficient synthesis of isocoumarins via a CuI catalyzed cascade reaction process


    3-Alkyl isocoumarins are provided by CuI/amino acid-catalyzed Sonogashira coupling reaction of o-bromo benzoic acids and terminal alkynes and the subsequent additive cyclization. This cascade process allows synthesis of diverse isocoumarins by varying both coupling partners bearing a wide range of functional groups.

  12. Fast and efficient synthesis of microporous polymer nanomembranes via light-induced click reaction.

    An, Qi; Hassan, Youssef; Yan, Xiaotong; Krolla-Sidenstein, Peter; Mohammed, Tawheed; Lang, Mathias; Bräse, Stefan; Tsotsalas, Manuel


    Conjugated microporous polymers (CMPs) are materials of low density and high intrinsic porosity. This is due to the use of rigid building blocks consisting only of lightweight elements. These materials are usually stable up to temperatures of 400 °C and are chemically inert, since the networks are highly crosslinked via strong covalent bonds, making them ideal candidates for demanding applications in hostile environments. However, the high stability and chemical inertness pose problems in the processing of the CMP materials and their integration in functional devices. Especially the application of these materials for membrane separation has been limited due to their insoluble nature when synthesized as bulk material. To make full use of the beneficial properties of CMPs for membrane applications, their synthesis and functionalization on surfaces become increasingly important. In this respect, we recently introduced the solid liquid interfacial layer-by-layer (LbL) synthesis of CMP-nanomembranes via Cu catalyzed azide-alkyne cycloaddition (CuAAC). However, this process featured very long reaction times and limited scalability. Herein we present the synthesis of surface grown CMP thin films and nanomembranes via light induced thiol-yne click reaction. Using this reaction, we could greatly enhance the CMP nanomembrane synthesis and further broaden the variability of the LbL approach.

  13. Copper iodide nanoparticles on poly(4-vinylpyridine): A new and efficient catalyst for the synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions

    Jalal Albadi; Mosadegh Keshavarz; Masoumeh Abedini; Moloud Khoshakhlagh


    Poly(4-vinylpyridine)-supported nanoparticles of copper(I) iodide is reported as a new, efficient and recyclable catalyst for the synthesis of 1,8-dioxooctahydroxanthenes under solvent-free conditions. This catalyst can be recovered by simple filtration and recycled up to 10 consecutive runs without losing of its efficiency.

  14. Highly efficient synthesis of endomorphin-2 under thermodynamic control catalyzed by organic solvent stable proteases with in situ product removal.

    Xu, Jiaxing; Sun, Honglin; He, Xuejun; Bai, Zhongzhong; He, Bingfang


    An efficient enzymatic synthesis of endomorphin-2 (EM-2) was achieved using organic solvent stable proteases in nonaqeous media, based on thermodynamic control and an in situ product removal methodology. The high stability of biocatalysts in organic solvents enabled the aleatoric modulation of the nonaqueous reaction media to shift thermodynamic equilibrium toward synthesis. Peptide Boc-Phe-Phe-NH2 was synthesized with a high yield of 96% by the solvent stable protease WQ9-2 in monophase medium with an economical molar ratio of the substrate of 1:1. The tetrapeptide Boc-Tyr-Pro-Phe-Phe-NH2 was synthesized with a yield of 88% by another organic solvent tolerant protease PT121 from Boc-Tyr-Pro-OH and Phe-Phe-NH2 in an organic-aqueous biphasic system. The reaction-separation coupling in both enzymatic processes provides "driving forces" for the synthetic reactions and gives a high yield and high productivity without purification of the intermediate, thereby making the synthesis more amenable to scale-up. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Controlled synthesis, growth mechanism and highly efficient solar photocatalysis of nitrogen-doped bismuth subcarbonate hierarchical nanosheets architectures.

    Dong, Fan; Sun, Yanjuan; Ho, Wing-Kei; Wu, Zhongbiao


    The synthesis and self-assembly of hierarchical architectures from nanoscale building blocks with unique morphology, orientation and dimension have opened up new opportunities to enhance their functional performances and remain a great challenge. This work represents tunable synthesis of various types of 3D monodisperse in situ N-doped (BiO)(2)CO(3) hierarchical architectures composed of 2D single-crystal nanosheets with dominant (001) facets by a one-pot template-free hydrothermal method from bismuth citrate and ammonia solution. Depending on the concentration of ammonia solution, the morphology of N-doped (BiO)(2)CO(3), including dandelion-like, hydrangea-like and peony flower-like microspheres, can be selectively constructed due to different self-assembly patterns of nanosheets. It was revealed that the ammonia played dual roles in the formation of N-doped (BiO)(2)CO(3) architectures. One is to hydrolyze bismuth citrate, and the other is to behave as a nitrogen doping source. The in situ doped nitrogen substituted for oxygen in (BiO)(2)CO(3) and subsequently narrowed the band gap, making N-doped (BiO)(2)CO(3) visible light active. Due to the special nanosheets architectures, the prepared various N-doped (BiO)(2)CO(3) materials exhibited especially efficient photocatalytic activity and high durability for the removal of NO in air under both visible and UV light irradiation. Based on the direct observation of the growth process with respect to phase structure, chemical composition and morphological structure, a novel growth mechanism is revealed, which involves a unique multistep pathway, including reaction-nucleation, aggregation, crystallization, dissolution-recrystallization, and Ostwald ripening. The facile synthesis approach and the proposed growth mechanism could provide new insights into the design and controlled synthesis of inorganic hierarchical materials with new or enhanced properties.

  16. Retention of OsNMD3 in the cytoplasm disturbs protein synthesis efficiency and affects plant development in rice.

    Shi, Yanyun; Liu, Xiangling; Li, Rui; Gao, Yaping; Xu, Zuopeng; Zhang, Baocai; Zhou, Yihua


    The ribosome is the basic machinery for translation, and biogenesis of ribosomes involves many coordinated events. However, knowledge about ribosomal dynamics in higher plants is very limited. This study chose a highly conserved trans-factor, the 60S ribosomal subunit nuclear export adaptor NMD3, to characterize the mechanism of ribosome biogenesis in the monocot plant Oryza sativa (rice). O. sativa NMD3 (OsNMD3) shares all the common motifs and shuttles between the nucleus and cytoplasm via CRM1/XPO1. A dominant negative form of OsNMD3 with a truncated nuclear localization sequence (OsNMD3(ΔNLS)) was retained in the cytoplasm, consequently interfering with the release of OsNMD3 from pre-60S particles and disturbing the assembly of ribosome subunits. Analyses of the transactivation activity and cellulose biosynthesis level revealed low protein synthesis efficiency in the transgenic plants compared with the wild-type plants. Pharmaceutical treatments demonstrated structural alterations in ribosomes in the transgenic plants. Moreover, global expression profiles of the wild-type and transgenic plants were investigated using the Illumina RNA sequencing approach. These expression profiles suggested that overexpression of OsNMD3(ΔNLS) affected ribosome biogenesis and certain basic pathways, leading to pleiotropic abnormalities in plant growth. Taken together, these results strongly suggest that OsNMD3 is important for ribosome assembly and the maintenance of normal protein synthesis efficiency.

  17. Biocompatible PEGylated MoS2 nanosheets: controllable bottom-up synthesis and highly efficient photothermal regression of tumor.

    Wang, Shige; Li, Kai; Chen, Yu; Chen, Hangrong; Ma, Ming; Feng, Jingwei; Zhao, Qinghua; Shi, Jianlin


    Two-dimensional transition metal dichalcogenides, particularly MoS2 nanosheets, have been deemed as a novel category of NIR photothermal transducing agent. Herein, an efficient and versatile one-pot solvothermal synthesis based on "bottom-up" strategy has been, for the first time, proposed for the controlled synthesis of PEGylated MoS2 nanosheets by using a novel "integrated" precursor containing both Mo and S elements. This facile but unique PEG-mediated solvothermal procedure endowed MoS2 nanosheets with controlled size, increased crystallinity and excellent colloidal stability. The photothermal performance of nanosheets was optimized via modulating the particulate size and surface PEGylation. PEGylated MoS2 nanosheets with desired photothermal conversion performance and excellent colloidal and photothermal stability were further utilized for highly efficient photothermal therapy of cancer in a tumor-bearing mouse xenograft. Without showing observable in vitro and in vivo hemolysis, coagulation and toxicity, the optimized MoS2-PEG nanosheets showed promising in vitro and in vivo anti-cancer efficacy.

  18. Applied reaction dynamics: Efficient synthesis gas production via single collision partial oxidation of methane to CO on Rh(111)

    Gibson, K. D.; Viste, M.; Sibener, S. J.


    Supersonic molecular beams have been used to determine the yield of CO from the partial oxidation of CH4 on a Rh(111) catalytic substrate, CH4+(1/2)O2→CO +2H2, as a function of beam kinetic energy. These experiments were done under ultrahigh vacuum conditions with concurrent molecular beams of O2 and CH4, ensuring that there was only a single collision for the CH4 to react with the surface. The fraction of CH4 converted is strongly dependent on the normal component of the incident beam's translational energy, and approaches unity for energies greater than ˜1.3eV. Comparison with a simplified model of the methane-Rh(111) reactive potential gives insight into the barrier for methane dissociation. These results demonstrate the efficient conversion of methane to synthesis gas, CO +2H2, are of interest in hydrogen generation, and have the optimal stoichiometry for subsequent utilization in synthetic fuel production (Fischer-Tropsch or methanol synthesis). Moreover, under the reaction conditions explored, no CO2 was detected, i.e., the reaction proceeded with the production of very little, if any, unwanted greenhouse gas by-products. These findings demonstrate the efficacy of overcoming the limitations of purely thermal reaction mechanisms by coupling nonthermal mechanistic steps, leading to efficient C-H bond activation with subsequent thermal heterogeneous reactions.

  19. Low intensity-ultrasonic irradiation for highly efficient, eco-friendly and fast synthesis of graphene oxide.

    Soltani, Tayyebeh; Lee, Byeong-Kyu


    High quality graphene oxide (GO) with low layer number (less than five layers) and large inter-layer space was produced via a new and efficient method using environmentally friendly, fast and economic ultrasonic radiation. The ultrasonic method neither generated any toxic gas nor required any NaNO3, which have been the main drawbacks of the Hummers methods. The major obstacles of the recently reported improved Hummers method for GO synthesis, such as high reaction temperature (50°C) and long reaction time (12h), were successfully solved using a low intensity-ultrasonic bath for 45min at 30°C, which significantly reduced the reaction time and energy consumption for GO synthesis. Furthermore, ultrasonic GO exhibited higher surface area, higher crystallinity and higher oxidation efficiency with many hydrophilic groups, fewer sheets with higher spaces between them, a higher sp(3)/sp(2) ratio, and more uniform size distribution than classically prepared GO. Therefore, the new ultrasonic method could be applicable for the sustainable and large-scale production of GO. The production yield of the ultrasonic-assisted GO was 1.25-fold greater than the GO synthesized with the improved Hummers method. Furthermore, the required production cost based on total energy consumption for ultrasonic GO was only 6.5% of that for classical GO.

  20. Efficient One-Pot Synthesis of Colloidal Zirconium Oxide Nanoparticles for High-Refractive-Index Nanocomposites.

    Liu, Chao; Hajagos, Tibor Jacob; Chen, Dustin; Chen, Yi; Kishpaugh, David; Pei, Qibing


    Zirconium oxide nanoparticles are promising candidates for optical engineering, photocatalysis, and high-κ dielectrics. However, reported synthetic methods for the colloidal zirconium oxide nanoparticles use unstable alkoxide precursors and have various other drawbacks, limiting their wide application. Here, we report a facile one-pot method for the synthesis of colloidally stable zirconium oxide nanoparticles. Using a simple solution of zirconium trifluoroacetate in oleylamine, highly stable zirconium oxide nanoparticles have been synthesized with high yield, following a proposed amidization-assisted sol-gel mechanism. The nanoparticles can be readily dispersed in nonpolar solvents, forming a long-term stable transparent solution, which can be further used to fabricate high-refractive-index nanocomposites in both monolith and thin-film forms. In addition, the same method has also been extended to the synthesis of titanium oxide nanoparticles, demonstrating its general applicability to all group IVB metal oxide nanoparticles.

  1. Green synthesis of polysaccharide/gold nanoparticle nanocomposite: an efficient ammonia sensor.

    Pandey, Sadanand; Goswami, Gopal K; Nanda, Karuna K


    A low cost eco-friendly method for the synthesis of gold nanoparticles (AuNPs) using guar gum (GG) as a reducing agent is reported. The nanoparticles obtained are characterized by UV-vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Based on these results, a potential mechanism for this method of AuNPs synthesis is discussed. GG/AuNPs nanocomposite (GG/AuNPs NC) was exploited for optical sensor for detection of aqueous ammonia based on surface plasmon resonance (SPR). It was found to have good reproducibility, response times of ∼10 s and excellent sensitivity with a detection limit of 1ppb (parts-per-billion). This system allows the rapid production of an ultra-low-cost GG/AuNPs NC-based aqueous ammonia sensor.

  2. Efficient Synthesis of Primary Nitrocarbamates of Sugar Alcohols: From Food to Energetic Materials.

    Axthammer, Quirin J; Klapötke, Thomas M; Krumm, Burkhard


    The synthesis of various new polyvalent nitrocarbamates derived from sugar alcohols was accomplished by an economically benign two-step synthesis. The precursor carbamates were synthesized with the reagent chlorosulfonyl isocyanate (CSI) and further nitrated using mixed acid. The starting materials, sugar alcohols, are renewable biomass, mainly used in food and cosmetic industry. The structures of one carbamate and one nitrocarbamate were exemplary described by single-crystal X-ray-analysis. The heat of formation is calculated by the use of isodesmic reactions and the energetic performance data were estimated. All compounds were fully characterized by elemental analysis, vibrational spectroscopy, (1)H, (13)C, and (14/15)N NMR spectroscopy and thermal analysis (DSC). The nitrocarbamates exhibit good detonation performance and have significantly lower sensitivities compared to the commonly used nitrate ester explosive PETN.

  3. Computationally efficient beampattern synthesis for dual-function radar-communications

    Hassanien, Aboulnasr; Amin, Moeness G.; Zhang, Yimin D.


    The essence of amplitude-modulation based dual-function radar-communications is to modulate the sidelobe of the transmit beampattern while keeping the main beam, where the radar function takes place, unchanged during the entire processing interval. The number of distinct sidelobe levels (SLL) required for information embedding grows exponentially with the number of bits being embedded. We propose a simple and computationally cheap method for transmit beampattern synthesis which requires designing and storing only two beamforming weight vectors. The proposed method first designs a principal transmit beamforming weight vector based on the requirements dictated by the radar function of the DFRC system. Then, a second weight vectors is obtained by enforcing a deep null towards the intended communication directions. Additional SLLs can be realized by simply taking weighted linear combinations of the two available weight vectors. The effectiveness of the proposed method for beampattern synthesis is verified using simulations examples.

  4. Efficient Fixation of Carbon Dioxide by Electrolysis - Facile Synthesis of Useful Carboxylic Acids -

    Masao Tokuda


    Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide (scCO2) has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.

  5. The Challenge of Efficient Synthesis of Biofuels from Lignocellulose for Future Renewable Transportation Fuels

    Päivi Mäki-Arvela


    Full Text Available Dehydration of sugars to 5-hydroxymethylfurfural (HMF has recently been under intensive study by a multitude of research groups. On the other hand, when lignocellulosic biomass is applied as the starting material, very few studies can be found in the open literature. The direct synthesis of HMF, in line with the idea of “one-pot” synthesis strategy from lignocellulose, is demanding since the overall process should encompass dissolution, hydrolysis, and dehydration steps in a single processing unit. Ionic liquid-assisted methods to produce hydroxymethyl-furfural directly from lignocellulosic biomass are reported here together with a short overview of the most important biofuels. In reality, HMF is not suitable to be used as a single-component fuel as such, and, consequently, methods to produce HMF derivatives suitable as liquid fuels are reported.

  6. An Efficient One-pot Three-component Process for Synthesis of Perfluoroalkylated Quinolizines

    Dandan Shen; Yanjie Xu; Dong He; Jing Han; Jie Chen; Hongmei Deng; Min Shao


    A facile multi-component process for the synthesis of perfluoroalkylated quinolizine derivatives was achieved using various arylidenemalononitriles,pyridine,and methyl perfluoroalk-2-ynoates as starting materials.Moderate yields were obtained under mild condition.The structures of perfluoroalkylated quinolizine derivatives were characterized by means of 1H NMR,13C NMR,19F NMR,IR,LRMS and HRMS.Furthermore,the reaction mechanism was proposed.

  7. Nickel nanoparticles: A highly efficient catalyst for one pot synthesis of tetraketones and biscoumarins

    Jitender M Khurana; Kanika Vij


    A novel and practically useful protocol has been designed wherein, polyvinyl pyrrolidone (PVP) stabilized nickel nanoparticles have been used as a catalyst for promoting the synthesis of 2,2'-aryl-methylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one), 2,2'-aryl-methylene bis(3-hydroxy-2-cyclohexene-1-one), also known as tetraketones, and biscoumarins via Knoevenagel condensation followed by rapid Michael addition.

  8. Efficient MW-Assisted Synthesis, Spectroscopic Characterization, X-ray and Antioxidant Properties of Indazole Derivatives

    Efrain Polo; Jorge Trilleras; Juan Ramos; Antonio Galdámez; Jairo Quiroga; Margarita Gutierrez


    A small series of tetrahydroindazoles was prepared, starting from 2-acetylcyclohexanone and different hydrazines using reflux and a focused microwave reactor. Microwave irradiation (MW) favored the formation of the desired products with improved yields and shortened reaction times. This is a simple and green method for the synthesis of substituted tetrahydroindazole derivatives. The in vitro antioxidant activity was evaluated using the DPPH and ABTS methods. In these assays, 2-(4-fluorophenyl...

  9. Biochemical Characterization of a First Fungal Esterase from Rhizomucor miehei Showing High Efficiency of Ester Synthesis

    Yu Liu; Haibo Xu; Qiaojuan Yan; Shaoqing Yang; Xiaojie Duan; Zhengqiang Jiang


    BACKGROUND: Esterases with excellent merits suitable for commercial use in ester production field are still insufficient. The aim of this research is to advance our understanding by seeking for more unusual esterases and revealing their characterizations for ester synthesis. METHODOLOGY/PRINCIPAL FINDINGS: A novel esterase-encoding gene from Rhizomucor miehei (RmEstA) was cloned and expressed in Escherichia coli. Sequence analysis revealed a 975-bp ORF encoding a 324-amino-acid polypeptide be...

  10. Clean and Efficient Synthesis Using Mechanochemistry: Coordination Polymers, Metal-Organic Frameworks and Metallodrugs

    Friščić, Tomislav; Halasz, Ivan; Štrukil, Vjekoslav; Maksić, Mirjana; Dinnebier, Robert E


    This review briefly discusses recent advances and future prospects in the mechanochemical synthesis of coordination compounds by ball milling and grinding, and highlights our contributions to the mechanosynthesis of porous metal-organic frameworks (MOFs) and zeolitic imidazolate frameworks (ZIFs), metal-organic pharmaceutical derivatives and metallodrugs using the recently developed mechanochemical methods of liquid-assisted grinding (LAG) and ion- and liquid-assisted grinding (ILAG). The...

  11. High-efficiency synthesis of nanoparticles in a repetitive multigap spark discharge generator

    Ivanov, V. V.; Efimov, A. A.; Mylnikov, D. A.; Lizunova, A. A.; Bagazeev, A. V.; Beketov, I. V.; Shcherbinin, S. V.


    We describe a method of obtaining aerosol nanoparticles in a repetitive spark discharge generator with 12 interelectrode gaps between tin electrodes, which operates at a pulse repetition frequency of 2.5 kHz. During synthesis of tin oxide nanoparticles in air, the mass productivity of the gas discharge generator reaches up to 9 g/h for primary particles with characteristic sizes within 5-10 nm and agglomerate size on the order of 50 nm.

  12. Efficient Direct Synthesis of Indole over Novel Ag/SiO2 Catalyst


    @@Indole is an important heterocycle substance which could be used to produce indigo dye, perfume, forage additive and tryptophan[1~3]. Although there are some methods to produce indole[4], one of the most promising routes, from an industrial point of view, seems to be the direct synthesis from aniline and ethylene glycol[5]. This is a one step reaction from reactants to indole and the starting materials are inexpensive.

  13. An efficient method for synthesis of organophosphorus compounds in aqueous media

    Reza Heydari; Malek Taher Maghsoodlou; Razieh Nejat Yami


    A convenient and facile one-pot synthesis of stable phosphorus ylides and 1,4-diionic organophosphorus compounds is reported by the reaction of triphenyiphosphine, dialkylacetylenedicarboxylates and N-H, C-H or S-H acids in the presence of poly-ethyleneglycol (PEG), β-cyclodextrin (β-CD), glycerine (Gly) or ethyleneglycol (EG) in water. This methodology is of interest due to the use of water as a solvent, thus minimizing the cost operational hazards, and environmental pollution.

  14. An efficient and facile synthesis of highly substituted 2,6-dicyanoanilines.

    Yi, Chenyi; Blum, Carmen; Liu, Shi-Xia; Frei, Gabriela; Neels, Antonia; Renaud, Philippe; Leutwyler, Samuel; Decurtins, Silvio


    A one-pot procedure for the synthesis of substituted 2,6-dicyanoanilines starting from readily available ynones and malononitrile has been developed. For instance, penta-1,4-diyn-3-one is converted into the acetylene-substituted aniline derivative 1 in good yield. Upon photoexcitation, this chromophore shows a strong blue emission with a high quantum yield. The ground- and the excited-state geometries, charge distributions, and excitation energies of 1 have been evaluated by ab initio calculations.

  15. Triton-B catalyzed, efficient and solvent-free approach for the synthesis of dithiocarbamates

    Sadaf Zaidi


    Full Text Available A novel one-pot, solvent-free method for the synthesis of dithiocarbamates was developed through the reaction of corresponding alkyl halides, amines and carbon disulfide employing catalytic amount of benzyl trimethyl ammonium hydroxide (Triton-B. The reaction conditions are milder with extremely simple work-up procedures than the reported methods, afforded high yields (82-98% of the desired products.

  16. An efficient synthesis of pyrazole chalcones under solvent free conditions at room temperature

    Parvin Kumar; Sunil Kumar; Khalid Husain; Ashwani Kumar


    An easy,safe,solvent free and effective method for the synthesis of pyrazole-substituted chalcones has been achieved by grinding pyrazole aldehydes and acetophenones in the presence of activated barium hydroxide(C-200) in high yield within short span of time.All reactions were carried out just by grinding the two reactants in the presence of activated barium hydroxide(C-200).Results are also compared with sodium hydroxide and potassium hydroxide.

  17. Trifluoromethanesulfonic acid promoted Dakin-West reaction: An efficient and convenient synthesis of -acetamido ketones

    Ravindra M Kumbhare; Madabhushi Sridhar


    Trifluoromethanesulfonic acid promoted efficient condensation of an aromatic aldehyde with an acetophenone and acetonitrile in the presence of acetylchloride as an activator producing -acetamido carbonyl compounds is described.

  18. (+)-Dinapsoline: an efficient synthesis and pharmacological profile of a novel dopamine agonist.

    Sit, Sing-Yuen; Xie, Kai; Jacutin-Porte, Swanee; Taber, Matthew T; Gulwadi, Amit G; Korpinen, Carolyn D; Burris, Kevin D; Molski, Thaddeus F; Ryan, Elaine; Xu, Cen; Wong, Henry; Zhu, Juliang; Krishnananthan, Subramaniam; Gao, Qi; Verdoorn, Todd; Johnson, Graham


    A highly convergent synthesis was developed for the novel dopamine agonist dinapsoline (12) (Ghosh, D.; Snyder, S. E.; Watts, V. J.; Mailman, R. B.; Nichols, D. E. 8,9-Dihydroxy-2,3,7, 11b-tetrahydro-1H-naph[1,2,3-de]isoquinoline: A Potent Full Dopamine D(1) Agonist Containing a Rigid beta-Phenyldopamine Pharmacophore. J. Med. Chem. 1996, 39 (2), 549-555). The crucial step in the new synthesis was a free radical-initiated cyclization to give the complete dinapsoline framework. The improved synthesis required half as many steps as the original procedure (Nichols, D. E.; Mailman, R.; Ghosh, D. Preparation of novel naphtho[1,2,3-de]isoquinolines as dopamine receptor ligands. PCT Int. Appl. WO 9706799 A1, Feb 27, 1997). One of the late-stage intermediates (11) was resolved into a pair of enantiomers. From there, the (R)-(+)-12 (absolute configuration by X-ray) of dinapsoline was identified as the active enantiomer. In unilateral 6-hydroxydopamine (6-OHDA)-lesioned rats, (+)-dinapsoline showed robust rotational behavior comparable to that of an external benchmark, trans-4,5,5a,6,7,11b-hexahydro-2-propyl-benzo[f]thieno[2,3-c]quinoline-9,10-diol, hydrochloride 18 (Michaelides, M. R.; Hong, Y. Preparation of heterotetracyclic compounds as dopamine agonists. PCT Int. Appl. WO 9422858 A1, Oct 13, 1994).

  19. Optimization for the Synthesis Efficiency of the 11C-Raclopride

    LI Hai-feng


    Full Text Available The synthesis conditions of the 11C-Raclopride with domestic PET-CM-3H-IT-I synthesis module and 11C-Triflate-CH-3I as methylation agent were studied, which included the alkali equivalent, solvents, temperature, the amount of precursor and elution conditions for the product. The optimum condition was 1.5-3.0 g/L of precursor in acetone (0.2 mL, alkali equivalent (0.30-1.25 eq and at room temperature (25 ℃ for synthesis of 11C-Raclopride. It could be got with radiochemical yield of (64.82±4.74% (n=46, EOB of 11C-Triflate-CH3. The radiochemical purity was over 97% and the specific activity was at (423.61±13.43 GBq/g. It took 23 minutes from 11C-CO2 to 11C-Raclopride, and the production radioactivity was (6.9±0.87 GBq (n=46. The synthetic process was reliable and reproducible, and the product synthesized by this process was suitable for clinical use.

  20. Templated synthesis of nickel nanoparticles: Toward heterostructured nanocomposites for efficient hydrogen storage

    Nelson, Nicholas Cole [Iowa State Univ., Ames, IA (United States)


    The world is currently facing an energy and environmental crisis for which new technologies are needed. Development of cost-competitive materials for catalysis and hydrogen storage on-board motor vehicles is crucial to lead subsequent generations into a more sustainable and energy independent future. This thesis presents work toward the scalable synthesis of bimetallic heterostructures that can enable hydrogen to compete with carbonaceous fuels by meeting the necessary gravimetric and volumetric energy densities and by enhancing hydrogen sorption/desorption kinetics near ambient temperatures and pressures. Utilizing the well-known phenomenon of hydrogen spillover, these bimetallic heterostructures could work by lowering the activation energy for hydrogenation and dehydrogenation of metals. Herein, we report a novel method for the scalable synthesis of silica templated zero-valent nickel particles (Ni⊂SiO2) that hold promise for the synthesis of nickel nanorods for use in bimetallic heterostructures for hydrogen storage. Our synthesis proceeds by chemical reduction of a nickel-hydrazine complex with sodium borohydride followed by calcination under hydrogen gas to yield silica encapsulated nickel particles. Transmission electron microscopy and powder X-ray diffraction were used to characterize the general morphology of the resultant nanocapsules as well as the crystalline phases of the incorporated Ni0 nanocrystals. The structures display strong magnetic behavior at room temperature and preliminary data suggests nickel particle size can be controlled by varying the amount of nickel precursor used in the synthesis. Calcination under different environments and TEM analysis provides evidence for an atomic migration mechanism of particle formation. Ni⊂SiO2 nanocapsules were used as seeds to induce heterogeneous nucleation and subsequent growth within the nanocapsule via electroless nickel plating. Nickel nanoparticle growth occurs

  1. One-pot synthesis of well-defined polyether/polyester block copolymers and terpolymers by a highly efficient catalyst switch approach

    Alamri, Haleema


    A highly efficient methodology, based on a novel catalyst switch approach with rapid crossover characteristics, was developed for the one-pot synthesis of block co/terpolymers of cyclic ethers and esters. This new approach, which takes advantage of one of the best catalysts for epoxide (t-BuP4) and cyclic ester (t-BuP2) polymerization, opens new horizons toward the synthesis of cyclic ether/ester complex macromolecular architectures. © The Royal Society of Chemistry 2016.

  2. A Rapid and Efficient Synthesis of Diaryl Thioureas via Solvent-Free Reaction Using Microwave


    A rapid and efficient method for the preparation of diaryl thiourea compounds was reported for the first time.Twelve diaryl thiourea compounds that possessing biological activity have been synthesized in excellent yields (91-97%).The reaction proved to be extremely simple and highly efficient (in 1.5-4.5 min).

  3. Simple, mild, and highly efficient synthesis of 2-substituted benzimidazoles and bis-benzimidazoles

    Eren, Bilge, E-mail: [Faculty of Science and Arts, Department of Chemistry, Bilecik Seyh Edebali University, (Turkey); Bekdemir, Yunus [Faculty of Science and Arts, Canik Basari University, Samsun (Turkey)


    A new convenient method for preparation of 2-substituted benzimidazoles and bis-benzimidazoles is presented. In this method, o-phenylenediamines were condensed with bisulfite adducts of various aldehydes and di-aldehydes under neat conditions by microwave heating. The results were also compared with results of synthesis by conventional heating under reflux. Structures of the products were confirmed by infrared, {sup 1}H- and {sup 13}C-NMR spectroscopy. Short reaction times, good yields, easy purification of products, and mild reaction conditions are the main advantages of this method. (author)

  4. An efficient domino one-pot synthesis of novel spirofuran-indenoquinoxalines by vinyltriphenylphosphonium salts



    A simple and convenient multi-component domino reaction has been described for the synthesis of novel spirofuran-indenoquinoxaline derivatives. Products were obtained by a three-component condensation reaction between ninhydrin, aromatic 1,2-diamines and dialkyl ethynedicarboxylates in the presence of a catalytic amount of triphenylphosphine in CH2Cl2 at ambient temperature in excellent yields. This one-pot process produces biologically and pharmacologically significant heterocycles with the formation of five new bonds (one C–C, two C=N and two C–O) and two new rings in a single operation.

  5. An Efficient, Clean, and Catalyst-Free Synthesis of Fused Pyrimidines Using Sonochemistry

    M. Mamaghani


    Full Text Available In this report, synthesis of indenopyrido[2,3-d]pyrimidine and pyrimido[4,5-b]quinoline derivatives was investigated via one-pot three-component reaction between 6-amino-2-(alkylthio-pyrimidin-4(3Hone, 1,3-indanedione, or 1,3-cyclohexadione and arylaldehyde under ultrasonic irradiation in ethylene glycol as solvent at 65°C. In these reactions fused pyrimidine derivatives were synthesized with high to excellent yields (82–97% and short reaction times (10–33 min.

  6. An Efficient, Clean, and Catalyst-Free Synthesis of Fused Pyrimidines Using Sonochemistry


    In this report, synthesis of indenopyrido[2,3-d]pyrimidine and pyrimido[4,5-b]quinoline derivatives was investigated via one-pot three-component reaction between 6-amino-2-(alkylthio)-pyrimidin-4(3H)one, 1,3-indanedione, or 1,3-cyclohexadione and arylaldehyde under ultrasonic irradiation in ethylene glycol as solvent at 65°C. In these reactions fused pyrimidine derivatives were synthesized with high to excellent yields (82–97%) and short reaction times (10–33 min).

  7. Facile and efficient synthesis of quinoline-4-carboxylic acids under microwave irradiation


    A facile and efficient method for the preparation of 2-non-substituted quinoline-4-carboxylic acids is described via the Pfitzinger reaction of isatins with sodium pyruvate following consequent decarboxylation under microwave irradiation.

  8. Polyethylene glycol in water: A simple, efficient and green protocol for the synthesis of quinoxalines

    Hemant V Chavan; Laxman K Adsul; Babasaheb P Bandgar


    A variety of biologically important quinoxaline derivatives has been efficiently synthesized in excellent yields under extremely mild conditions using PEG-600 and water. This inexpensive, non-toxic, ecofriendly and readily available system efficiently condensed several aromatic as well as aliphatic 1,2-diketones with aromatic and aliphatic 1,2-diamines to afford the products in excellent yield. Polyethylene glycol (PEG) can be recovered and recycled.

  9. KF/Clinoptilolite: an efficient promoter for the synthesis of thioethers.

    Salmanpour, Sadegh; Khalilzadeh, Mohammad A; Hosseini, Abolfazl


    Potassium fluoride impregnated on natural zeolite as a new solid base system effectively catalyzes the coupling of thiophenols with electron-deficient fluoro-, chloro- and bromo-arenes in DMSO. This versatile and efficient solid base has been demonstrated to afford the corresponding desired products in good to excellent yields. This procedure provides a convenient, efficient and practical method for the preparation of diaryl thioethers.

  10. Synthesis of amino-rich silica-coated magnetic nanoparticles for the efficient capture of DNA for PCR.

    Bai, Yalong; Cui, Yan; Paoli, George C; Shi, Chunlei; Wang, Dapeng; Zhou, Min; Zhang, Lida; Shi, Xianming


    Magnetic separation has great advantages over traditional bio-separation methods and has become popular in the development of methods for the detection of bacterial pathogens, viruses, and transgenic crops. Functionalization of magnetic nanoparticles is a key factor for efficient capture of the target analytes. In this paper, we report the synthesis of amino-rich silica-coated magnetic nanoparticles using a one-pot method. This type of magnetic nanoparticle has a rough surface and a higher density of amino groups than the nanoparticles prepared by a post-modification method. Furthermore, the results of hydrochloric acid treatment indicated that the magnetic nanoparticles were stably coated. The developed amino-rich silica-coated magnetic nanoparticles were used to directly adsorb DNA. After magnetic separation and blocking, the magnetic nanoparticles and DNA complexes were used directly for the polymerase chain reaction (PCR), without onerous and time-consuming purification and elution steps. The results of real-time quantitative PCR showed that the nanoparticles with higher amino group density resulted in improved DNA capture efficiency. The results suggest that amino-rich silica-coated magnetic nanoparticles are of great potential for efficient bio-separation of DNA prior to detection by PCR. Copyright © 2016. Published by Elsevier B.V.

  11. Efficient synthesis of chloro-derivatives of sialosyllactosylceramide, and their enhanced inhibitory effect on epidermal growth factor receptor activation.

    Kawashima, Nagako; Qu, Huanhuan; Lobaton, Marlin; Zhu, Zhenyuan; Sollogoub, Matthieu; Cavenee, Webster K; Handa, Kazuko; Hakomori, Sen-Itiroh; Zhang, Yongmin


    Glycosphingolipids are components of essentially all mammalian cell membranes and are involved in a variety of significant cellular functions, including proliferation, adhesion, motility and differentiation. Sialosyllactosylceramide (GM3) is known to inhibit the activation of epidermal growth factor receptor (EGFR). In the present study, an efficient method for the total chemical synthesis of monochloro- and dichloro-derivatives of the sialosyl residue of GM3 was developed. The structures of the synthesized compounds were fully characterized by high-resolution mass spectrometry and nuclear magnetic resonance. In analyses of EGFR autophosphorylation and cell proliferation ([(3)H]-thymidine incorporation) in human epidermoid carcinoma A431 cells, two chloro-derivatives exhibited stronger inhibitory effects than GM3 on EGFR activity. Monochloro-GM3, but not GM3 or dichloro-GM3, showed a significant inhibitory effect on ΔEGFR, a splicing variant of EGFR that lacks exons 2-7 and is often found in human glioblastomas. The chemical synthesis of other GM3 derivatives using approaches similar to those described in the present study, has the potential to create more potent EGFR inhibitors to block cell growth or motility of a variety of types of cancer that express either wild-type EGFR or ΔEGFR.

  12. Efficient synthesis of the intermediate of abacavir and carbovir using a novel (+)-γ-lactamase as a catalyst.

    Gao, Shuaihua; Zhu, Shaozhou; Huang, Rong; Lu, Yingxiu; Zheng, Guojun


    The enantiomers of 2-azabicyclo[2.2.1]hept-5-en-3-one (γ-lactam) are key chiral synthons in the synthesis of antiviral drugs such as carbovir and abacavir. (+)-γ-Lactamase can be used as a catalyst in the enzymatic preparation of optically pure (-)-γ-lactam. Here, a (+)-γ-lactamase discovered from Bradyrhizobium japonicum USDA 6 by sequence-structure guided genome mining was cloned, purified and characterized. The enzyme possesses a significant catalytic activity towards γ-lactam. The active site of the (+)-γ-lactamase was studied by homologous modeling and molecular docking, and the accuracy of the prediction was confirmed by site-specific mutagenesis. The (+)-γ-lactamase reveals the great practical potential as an enzymatic method for the efficient production of carbocyclic nucleosides of pharmaceutical interest.

  13. Emeraldine Base Form of Polyaniline Nanofibers as New, Economical, Green, and Efficient Catalyst for Synthesis of Z-Aldoximes

    Rajender Boddula


    Full Text Available A facile, clean, economical, efficient, and green process was developed for the preparation of Z-aldoximes at room temperature under solvent-free condition using emeraldine base form of polyaniline as novel catalyst. In this methodology, PANI base absorbed the by-product of HCl (polluting chemical from hydroxylamine hydrochloride and converted to polyaniline-hydrochloride salt (PANI-HCl salt. This PANI-HCl salt could be easily recovered and used in new attempts without any purification in many areas such as catalyst, electrical and electronics applications meant for conducting polymers. As far as our knowledge is concerned, emeraldine base as catalyst in organic synthesis for the first time.

  14. Efficient synthesis of trisubstituted pyrazoles and isoxazoles using a traceless "catch and release" solid-phase strategy.

    Ma, Wenli; Peterson, Brian; Kelson, Andrew; Laborde, Edgardo


    An efficient three-component, two-step "catch and release" solid-phase synthesis of 3,4,5-trisubstituted pyrazoles and isoxazoles has been developed. The first step involves a base-promoted condensation of a 2-sulfonyl- or a 2-carbonyl-acetonitrile derivative (1 or 7) with an isothiocyanate 2 and in situ immobilization of the resulting thiolate anion on Merrifield resin. Reaction of the resin-bound sulfonyl intermediate 4 with hydrazine or hydroxylamine, followed by release from the resin and intramolecular cyclization, affords 3,5-diamino-4-(arylsulfonyl)-1H-pyrazoles 5 or isoxazoles 6, respectively. Reaction of the resin-bound carbonyl intermediate 9 with hydrazine, on the other hand, leads to 3-(arylamino)-5-aryl-1H-pyrazole-4-carbonitriles 10.

  15. Hierarchically macroporous silver monoliths using Pluronic F127: Facile synthesis, characterization and its application as an efficient biomaterial for pathogens

    Gowhar Ahmad Naikoo


    Full Text Available Herein we report the facile synthesis of three dimensional macroporous (MP silver monoliths serving as intelligent biomaterials against Gram negative (Escherichia coli, Salmonella typhimurium and Gram positive (Bacillus subtilis bacteria with more efficacy against Gram negative bacteria. The macroporous silver monoliths were examined by Fourier transform infra red (FTIR spectroscopy, thermogravimetric analysis (TGA, X-ray diffraction (XRD study, field emission scanning electron microscopy (FESEM, energy dispersion X-ray spectroscopy analysis (EDX and Brunauer–Emmet–Teller (BET adsorption technique. From the antibacterial activity results, it was concluded that macroporous silver monoliths can serve as efficient disinfection agents. The enhanced antibacterial properties of macroporous silver monoliths was possibly due to high surface free energy of the surface Ag+ atoms leading to cell membrane damage followed by cell death.

  16. Efficient utilization of greenhouse gases in a gas-to-liquids process combined with CO2/steam-mixed reforming and Fe-based Fischer-Tropsch synthesis.

    Zhang, Chundong; Jun, Ki-Won; Ha, Kyoung-Su; Lee, Yun-Jo; Kang, Seok Chang


    Two process models for carbon dioxide utilized gas-to-liquids (GTL) process (CUGP) mainly producing light olefins and Fischer-Tropsch (F-T) synthetic oils were developed by Aspen Plus software. Both models are mainly composed of a reforming unit, an F-T synthesis unit and a recycle unit, while the main difference is the feeding point of fresh CO2. In the reforming unit, CO2 reforming and steam reforming of methane are combined together to produce syngas in flexible composition. Meanwhile, CO2 hydrogenation is conducted via reverse water gas shift on the Fe-based catalysts in the F-T synthesis unit to produce hydrocarbons. After F-T synthesis, the unreacted syngas is recycled to F-T synthesis and reforming units to enhance process efficiency. From the simulation results, it was found that the carbon efficiencies of both CUGP options were successfully improved, and total CO2 emissions were significantly reduced, compared with the conventional GTL processes. The process efficiency was sensitive to recycle ratio and more recycle seemed to be beneficial for improving process efficiency and reducing CO2 emission. However, the process efficiency was rather insensitive to split ratio (recycle to reforming unit/total recycle), and the optimum split ratio was determined to be zero.

  17. Synthesis of dye-sensitized solar cells. Efficiency cells as a thickness of titanium dioxide

    Szura, Dominika


    Defying the influence of the thickness of TiO2 efficiency of dye-sensitized solar cell. It was confirmed that the compatibility of printed layers with the parameters closely related with the DSSC. It was found that the increase in thickness of the titanium dioxide layer, increases the distance between the electrodes, determined by the thickness of the Surlyn foil. With the rise of thickness of dyed layer of TiO2 established decrease in the value of its transmittance. Greatest transparency and aesthetic value obtained for photovoltaic modules with a single layer of titanium dioxide. The improved performance efficiency and preferred yields maximum power were noticed and exhibited by the cells covered with three layers of TiO2. It was established that the behaviour of economic efficiency in the production process, provides a range of cells with two layers of oxide, showing a similar performance and greater transparency.

  18. Synthesis of dye-sensitized solar cells. Efficiency cells as a thickness of titanium dioxide

    Szura Dominika


    Full Text Available Defying the influence of the thickness of TiO2 efficiency of dye-sensitized solar cell. It was confirmed that the compatibility of printed layers with the parameters closely related with the DSSC. It was found that the increase in thickness of the titanium dioxide layer, increases the distance between the electrodes, determined by the thickness of the Surlyn foil. With the rise of thickness of dyed layer of TiO2 established decrease in the value of its transmittance. Greatest transparency and aesthetic value obtained for photovoltaic modules with a single layer of titanium dioxide. The improved performance efficiency and preferred yields maximum power were noticed and exhibited by the cells covered with three layers of TiO2. It was established that the behaviour of economic efficiency in the production process, provides a range of cells with two layers of oxide, showing a similar performance and greater transparency.

  19. Efficient branch-and-bound algorithms for the synthesis of minimum-unit heat exchanger networks

    Mocsny, D.; Govind, R. (Dept. of Chemical Engineering, Univ. of Cincinnati, Cincinnati, OH (US))


    Several recent schemes have been advanced in the literature for formulating the synthesis of minimum-unit heat exchanger networks as mixed-integer linear programming problems. Until now, no special-purpose algorithms have been proposed for solving the resulting models. In this work, a branch-and-bound algorithm is described, which uses Balinski's relaxation to generate a succession of linear programs, along with the transportation simplex algorithm to solve each subproblem. Careful attention is given to the structuring of constraints to take maximum advantage of the information represented by the process pinch and the problem table residuals. Computational examples are presented which show a substantial performance improvement over currently available general-purpose branch-and-bound codes. The effects of varying the branch selection rules are described.

  20. An Efficient Amide-Aldehyde-Alkene Condensation: Synthesis for the N-Allyl Amides.

    Quan, Zheng-Jun; Wang, Xi-Cun


    The allylamine skeleton represents a significant class of biologically active nitrogen compounds that are found in various natural products and drugs with well-recognized pharmacological properties. In this personal account, we will briefly discuss the synthesis of allylamine skeletons. We will focus on showing a general protocol for Lewis acid-catalyzed N-allylation of electron-poor N-heterocyclic amides and sulfonamide via an amide-aldehyde-alkene condensation reaction. The substrate scope with respect to N-heterocyclic amides, aldehydes, and alkenes will be discussed. This method is also capable of preparing the Naftifine motif from N-methyl-1-naphthamide or methyl (naphthalene-1-ylmethyl)carbamate, with paraformaldehyde and styrene in a one-pot manner.

  1. Stannous oxalate: An efficient catalyst for poly(trimethylene terephthalate) synthesis


    A complete study on the catalytic activity of stannous oxalate for poly(trimethylene terephthalate) (PTT) synthesis via esterification method is carried out by comparison to the well known catalysts (tetrabutyl titanate (TBT), dibutyltin oxide (Bu2SnO), and stannous octoate (SOC)). Their catalytic activity in the esterification process is monitored by measuring the amount of water generated, while intrinsic viscosity (IV) and content of terminal carboxyl groups (CTCG) are used as the index in the polycondensation process. Stannous oxalate shows higher activity than the other catalysts. Decrease in reaction time and improvements in PTT property are observed. The higher catalytic activity of stannous oxalate is attributed to its chelate molecular structure.

  2. Caesium carbonate as a highly efficient catalyst for the synthesis of macrocyclicdiamides

    Esmael Rostami


    Full Text Available In this research work, we report the synthesis of macrocyclicdiamides from the reaction of diesters and aliphatic diamines in the presence of caesium carbonate. It has been demonstrated that among the carbonate of alkali metals (Li2CO3, Na2CO3, K2CO3 and CS2CO3, CS2CO3 appears to be the best catalyst for macrocyclization. Diesters with different substitution patterns on the aromatic ring reacted smoothly with diamines under optimal conditions, affording the corresponding macrocycles in high yields. Introducing a rigid group (e.g., sulfone on the substrate led to somewhat decreased yield. Various substrates proved to be suitable for this macrocyclization reaction, especially, the flexible ones.

  3. Efficient Synthesis of Dimethyl Ether from Methanol in a Bifunctional Zeolite Membrane Reactor.

    Zhou, Chen; Wang, Nanyi; Qian, Yanan; Liu, Xiaoxing; Caro, Jürgen; Huang, Aisheng


    A sandwich FAU-LTA zeolite dual-layer membrane has been developed and used as a catalytic membrane reactor for the synthesis of dimethyl ether (DME). In the top H-FAU layer with mild acidity, methanol is dehydrated to DME. The other reaction product, water, is removed in situ through a hydrophilic Na-LTA layer, which is located between the porous alumina support and the H-FAU top layer. The combination of mild acidity with the continuous removal of water results in high methanol conversion (90.9 % at 310 °C) and essentially 100 % DME selectivity. Furthermore, owing to the selective and continuous removal of water through the Na-LTA membrane, catalyst deactivation can be effectively suppressed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Selective and efficient synthesis of ethanol from dimethyl ether and syngas

    Rasmussen, Dominik Bjørn

    an important role as a gasoline additive or substitute and a catalytic process has been demonstrated, in which dimethyl ether (DME) produced from synthesis gas is converted to methyl acetate (MA), which is subsequently converted to EtOH and methanol (MeOH). MeOH can afterwards be easily converted to DME, using...... of Mordenite and that the reaction of CO with methyl groups is the rate limiting reaction step. Thus, in contrast to the previous DFT studies, the DFT model developed here is fully consistent the experimental results. An experimental study of the reaction kinetics has shown that MA inhibits the reaction....... A kinetic model, taking this effect into account, was developed and it could accurately describe the dependence of the reaction rates on the amount of catalyst and the partial pressures of the reactants. The product inhibition of the reaction rate makes it difficult to scale the process up, as 2 it sets...

  5. Efficient Synthesis of Cyclic Block Copolymers by Rotaxane Protocol by Linear/Cyclic Topology Transformation.

    Valentina, Stephanie; Ogawa, Takahiro; Nakazono, Kazuko; Aoki, Daisuke; Takata, Toshikazu


    High-yielding synthesis of cyclic block copolymer (CBC) using the rotaxane protocol by linear-cyclic polymer topology transformation was first demonstrated. Initial complexation of OH-terminated sec-ammonium salt and a crown ether was followed by the successive living ring-opening polymerizations of two lactones to a linear block copolymer having a rotaxane structure by the final capping of the propagation end. CBC was obtained in a high yield by an exploitation of the mechanical linkage through the translational movement of the rotaxane component to transform polymer structure from linear to cyclic. Furthermore, the change of the polymer topology was translated into a macroscopic change in crystallinity of the block copolymer.

  6. Synthesis of taurine–fluorescein conjugate and evaluation of its retina-targeted efficiency in vitro

    Meihong Huang


    Full Text Available In this work, retinal penetration of fluorescein was achieved in vitro by covalent attachment of taurine to fluorescein, yielding the F–Tau conjugate. Nuclear magnetic resonance (NMR and high resolution mass spectrometry (HRMS were used to confirm the successful synthesis of F–Tau. The cellular uptake of F–Tau in adult retinal pigment epithelial cells (ARPE-19 and human retinal microvascular endothelial cells (hRMECs was visualized via confocal scanning microscopy. The results indicated an improvement of solubility and a reduction of logP of F–Tau compared with fluorescein. As compared with fluorescein, F–Tau showed little toxicity, and was retained longer by cells in uptake experiments. F–Tau also displayed higher transepithelial permeabilities than fluorescein in ARPE-19 and hRMECs monolayer cells (P<0.05. These results showed that taurine may be a useful ligand for targeting small-molecule hydrophobic pharmaceuticals into the retina.

  7. Synthesis of mesoporous hollow carbon hemispheres as highly efficient Pd electrocatalyst support for ethanol oxidation

    Yan, Zaoxue; Meng, Hui; Li, Zihui; Shen, Pei Kang [The Key Laboratory of Low-carbon Chemistry and Energy Conservation of Guangdong Province, The State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-Sen University, Guangzhou, 510275 (China); Shi, Lei [Changling Catalyst Division, Sinopec Group, Yueyang 414012 (China)


    The synthesis procedure of the highly mesoporous hollow carbon hemispheres (HCHs) using glucose as carbon source and solid core mesoporous shell silica (SCMSS) as template and the formation mechanism of the HCHs have been presented. The HCHs show an ultrahigh surface area of 1095.59 m{sup 2} g{sup -1} and an average mesopore size of 9.38 nm. The hemispherical structure with large mesopores also results in the improvement in the mass transfer and therefore more concentrated ethanol solution can be used to increase the energy density. The additional advantage of the HCHs compared to the hollow carbon spheres is that they can provide the similar surface area at reduced volume. The current densities of ethanol oxidation on Pd nanoparticles supported on HCH (Pd/HCH) electrocatalyst are three times as many as on Pd/C at the same Pd loadings. (author)

  8. Growth rate hypothesis and efficiency of protein synthesis under different sulphate concentrations in two green algae.

    Giordano, Mario; Palmucci, Matteo; Raven, John A


    The growth rate hypothesis (GRH) predicts a positive correlation between growth rate and RNA content because growth depends upon the protein synthesis machinery. The application of this hypothesis to photoautotrophic organisms has been questioned. We tested the GRH on one prasinophycean, Tetraselmis suecica, and one chlorophycean, Dunaliella salina, grown at three sulphate concentrations. Sulphate was chosen because its concentration in the oceans increased through geological time and apparently had a role in the evolutionary trajectories of phytoplankton. Cell protein content and P quota were positively related to the RNA content (r = 0.62 and r = 0.74, respectively). The correlation of the RNA content with growth rates (r = 0.95) indicates that the GRH was valid for these species when growth rates were below 0.82 d(-1) .

  9. A straightforward and efficient synthesis of 3-(pyrimidinyl)propanoates from levulinic acid

    Flores, Alex F.C.; Malavolta, Juliana L.; Souto, Alynne A.; Goularte, Rayane B.; Flores, Darlene C., E-mail: [Universidade Federal de Santa Maria (UFSM/NUQUIMHE), RS (Brazil). Departamento de Quimica. Nucleo de Quimica de Heterociclos


    The cyclocondensation of methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate and methyl 7,7,7-trichloro-4-methoxy-6-oxo-4-heptenoate, derived from levulinic acid with amidines [NH{sub 2}CONH{sub 2}, NH{sub 2}CR(NH) (R = H, Me, Ph, NH{sub 2}, SMe and 1H-pyrazol-1-yl), 5-amino-3-methyl-1H-pyrazol and 2-aminothiazole] into pyrimidine and pyrimidine-like derivatives as a new type of glutamate-like 3-(trihalomethylatedpyrimidinyl)propanoate is reported. Preparation of 3-(trihalomethylatedpyrimidinyl) propanohydrazides is also described. The synthetic potential of this straightforward protocol was established by the synthesis of fourteen new 3-(pyrimidinyl) propanoates in regular to good yields (38-92%). The structural assignments were based on the analysis of their {sup 1}H and {sup 13}C nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS) data. (author)

  10. Highly Efficient Synthesis of Novel Poly-aza Bis-histidines

    ZHOU Cheng-He; Juan F. Miravet; LIU Qiang; M. Isabel Burguete; Santiago V. Luis


    @@ A series of novel poly-aza bis-histidines with much potential in medicinal, bioinorganic, bioorganic, biomimetic and supramolecular chemistry were synthesized conveniently, efficiently and readily in excellent yields from commercial histidine. The low temperature in the reaction of the protected histidine with poly-aza diamine 5 is key condition for the selective preparation of target compounds with high yields.

  11. Highly efficient synthesis of phenols by copper-catalyzed hydroxylation of aryl iodides, bromides, and chlorides.

    Yang, Kai; Li, Zheng; Wang, Zhaoyang; Yao, Zhiyi; Jiang, Sheng


    8-Hydroxyquinolin-N-oxide was found to be a very efficient ligand for the copper-catalyzed hydroxylation of aryl iodides, aryl bromides, or aryl chlorides under mild reaction conditions. This methodology provides a direct transformation of aryl halides to phenols and to alkyl aryl ethers. The inexpensive catalytic system showed great functional group tolerance and excellent selectivity. © 2011 American Chemical Society

  12. Efficient utilization of crude glycerol as fermentation substrate in the synthesis of poly(3-hydroxybutyrate) biopolymers

    One refined and 2 crude glycerol samples were utilized to produce poly(3-hydroxybutyrate) (PHB) by Pseudomonas oleovorans NRRL B-14682. Fermentation conditions were determined to efficiently utilize glycerol while maintaining PHB yields. A batch culture protocol including 1% glycerol and an aerati...

  13. An Efficient Solid-State Synthesis of N-Aryl-2-phenyldiazenecarboxamides


    A new and efficient solid-state reaction using K3Fe(CN)6/KOH to oxidize diaryl semicarbazides for preparing azo compounds has been reported. Nine N-aryl-2-phenyl-diazenecarboxamides have been synthesized in excellent yields with simple instrument.

  14. Rapid and efficient synthesis of fused heterocyclic pyrimidines under ultrasonic irradiation.

    Mosslemin, Mohammad Hossein; Nateghi, Mohammad Reza


    Some fused heterocyclic pyrimidines have been synthesized in high yields using ultrasound irradiation in a one-pot, three-component and efficient process by condensation reaction of barbituric acids, aldehydes and a series of enamines in water. Prominent among the advantages of this new method are operational simplicity, good yields in short reaction times and easy work-up procedures employed.

  15. Synthesis of Soluble Host Materials for Highly Efficient Red Phosphorescent Organic Light-Emitting Diodes.

    Suh, Min Chul; Park, So-Ra; Cho, Ye Ram; Shin, Dong Heon; Kang, Pil-Gu; Ahn, Dong A; Kim, Hyung Suk; Kim, Chul-Bae


    New soluble host materials with benzocarbazole and triphenyltriazine moieties, 11-[3-(4,6-diphenyl-[1,3,5]triazin-2-yl)-phenyl]-11H-benzo[a]carbazole and 11-[3'-(4,6-diphenyl-[1,3,5]triazin-2-yl)-biphenyl-4-yl]-11H-benzo[a]carbazole, were synthesized for highly efficient red phosphorescent organic light-emitting diodes (PHOLED). Hole-transporting benzocarbazole moiety and electron transporting triphenyltriazine moiety, which are severely twisted each other enhance the solubility of those materials in common organic solvent. The improved solubility from this molecular design could be due to a reduced π-π stacking interaction, which gives a very uniform film morphology after spin coating of those materials. As a result, we obtained highly efficient soluble PHOLEDs combined with an evaporated blue common layer structure. The resultant red PHOLED exhibited the maximum current efficiency as well as external quantum efficiency values up to 23.7 cd/A and 19.0%.

  16. N-heterocyclic carbene-catalyzed internal redox reaction of alkynals: an efficient synthesis of allenoates.

    Zhao, Yu-Ming; Tam, Yik; Wang, Yu-Jie; Li, Zigang; Sun, Jianwei


    An efficient N-heterocyclic carbene (NHC)-catalyzed internal redox reaction of alkynals that bear a γ leaving group has been developed. This process provides a new access to a range of allenoates in good yields. Preliminary results demonstrate that the enantioselective variant can also be achieved.

  17. Efficient Synthesis of 2,6—Diphenyl—4—arylpyrylium Tetrafluoroborate

    ShrongShiLIN; ChengYongLI; 等


    Four pyrylium salts,(2,6-diphenyl-4-arylpyrylium tetrafluoroborate,aryl=C6H5,4-MeO C6H4,4-Me2NC6H4,4-NO2C6H4) were synthesized efficiently and economically from acetophenone and substituted chalcones in the presence of borontrifluoride.

  18. PbO as an efficient and reusable catalyst for one-pot synthesis of tetrahydro benzo pyrans and benzylidene malonitriles

    Ashok V Borhade; Bhagwat K Uphade; Dipak R Tope


    PbO nanoparticles have been employed as an efficient catalyst for the solvent-free synthesis of tetrahydrobenzo pyrans (yields 81-91%) and benzylidene malonitriles (yields 90-96%) at room temperature using green chemistry approach. PbO nanoparticles were found to be highly efficient, eco-friendly and recyclable heterogeneous catalyst. PbO nanoparticles were prepared by hydrothermal method and characterized by IR, XRD, BET Surface area, SEM, EDAX and TEM with SAED techniques.

  19. Rapid and Efficient Synthesis of Silver Nanofluid Using Electrical Discharge Machining

    Kuo-Hsiung Tseng; Heng-Lin Lee; Chih-Yu Liao; Kuan-Chih Chen; Hong-Shiou Lin


    The electrical discharge machining (EDM) system has been proven feasible as a rapid and efficient method for silver nanofluid preparation. This study prepared the silver nano-fluid via EDM and investigated the relationship between its process parameters and product characteristics. The prior study had found that the silver nano-fluid prepared by EDM contained both silver nanoparticles and silver ions. Silver ions had revealed the cause of the high suspension of the silver nanoparticles. To ex...

  20. Synthesis of Schiff Bases via Environmentally Benign and Energy-Efficient Greener Methodologies

    Arshi Naqvi


    Full Text Available Non classical methods (water based reaction, microwave and grindstone chemistry were used for the preparation of Schiff bases from 3-chloro-4-fluoro aniline and several benzaldehydes. The key raw materials were allowed to react in water, under microwave irradiation and grindstone. These methodologies constitute an energy-efficient and environmentally benign greener chemistry version of the classical condensation reactions for Schiff bases formation.

  1. Efficient synthesis of 4(3H)-quinazolinones using a soluble polymeric support

    Chang Xie; Hong Xia Li; Ming Guo Liu; Ming Wu Ding


    4(3H)-Quinazolinones have been synthesized from poly(ethylene glycol) (PEG) supported aza-Wittig reaction. 2-Dialkylamino-4(3H)-quinazolinones 6 were synthesized efficiently by reaction of secondary amine with PEG-supported carbodiimides 4, whichwere obtained from aza-Wittig reaction of PEG-supported iminophosphoranes 3 with isocyanates.?2008 Ming Wu Ding. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  2. Copper-catalysed intramolecular O-arylation: a simple and efficient method for benzoxazole synthesis.

    Wu, Fengtian; Zhang, Jie; Wei, Qianbing; Liu, Ping; Xie, Jianwei; Jiang, Haojie; Dai, Bin


    A wide range of 2-substituted benzoxazoles can be efficiently synthesized from N-(2-iodo-/bromo-phenyl)benzamides, and even the less reactive N-(2-chlorophenyl)benzamides, via Cu-catalysed intramolecular coupling cyclization reactions using methyl 2-methoxybenzoate as the ligand under mild reaction conditions. In addition, the benzoxazoles can be easily prepared from the primary amides coupling with o-dihalobenzenes in a single step.

  3. The Synthesis of Organic Molecules of Intrinsic Microporosity Designed to Frustrate Efficient Molecular Packing.

    Taylor, Rupert G D; Bezzu, C Grazia; Carta, Mariolino; Msayib, Kadhum J; Walker, Jonathan; Short, Rhys; Kariuki, Benson M; McKeown, Neil B


    Efficient reactions between fluorine-functionalised biphenyl and terphenyl derivatives with catechol-functionalised terminal groups provide a route to large, discrete organic molecules of intrinsic microporosity (OMIMs) that provide porous solids solely by their inefficient packing. By altering the size and substituent bulk of the terminal groups, a number of soluble compounds with apparent BET surface areas in excess of 600 m(2)  g(-1) are produced. The efficiency of OMIM structural units for generating microporosity is in the order: propellane>triptycene>hexaphenylbenzene>spirobifluorene>naphthyl=phenyl. The introduction of bulky hydrocarbon substituents significantly enhances microporosity by further reducing packing efficiency. These results are consistent with findings from previously reported packing simulation studies. The introduction of methyl groups at the bridgehead position of triptycene units reduces intrinsic microporosity. This is presumably due to their internal position within the OMIM structure so that they occupy space, but unlike peripheral substituents they do not contribute to the generation of free volume by inefficient packing.

  4. The Synthesis of Organic Molecules of Intrinsic Microporosity Designed to Frustrate Efficient Molecular Packing

    Taylor, Rupert G. D.; Bezzu, C. Grazia; Carta, Mariolino; Msayib, Kadhum J.; Walker, Jonathan; Short, Rhys; Kariuki, Benson M.


    Abstract Efficient reactions between fluorine‐functionalised biphenyl and terphenyl derivatives with catechol‐functionalised terminal groups provide a route to large, discrete organic molecules of intrinsic microporosity (OMIMs) that provide porous solids solely by their inefficient packing. By altering the size and substituent bulk of the terminal groups, a number of soluble compounds with apparent BET surface areas in excess of 600 m2 g−1 are produced. The efficiency of OMIM structural units for generating microporosity is in the order: propellane>triptycene>hexaphenylbenzene>spirobifluorene>naphthyl=phenyl. The introduction of bulky hydrocarbon substituents significantly enhances microporosity by further reducing packing efficiency. These results are consistent with findings from previously reported packing simulation studies. The introduction of methyl groups at the bridgehead position of triptycene units reduces intrinsic microporosity. This is presumably due to their internal position within the OMIM structure so that they occupy space, but unlike peripheral substituents they do not contribute to the generation of free volume by inefficient packing. PMID:26751824

  5. Microwave: An Important and Efficient Tool for the Synthesis of Biological potent Organic Compounds.

    Kumari, Kamlesh; Vishvakarma, Vijay K; Singh, Prashant; Patel, Rajan; Chandra, Ramesh


    Green Chemistry is an interdisciplinary science or can also be explained as a branch of chemistry. It is generally described as the chemistry to aim to synthesize chemical compounds to trim down the utilization of harmful chemicals proposed by the Environmental Protection Agency (EPA). Recently, the plan of academicians, researchers, industrialists is to generate greener and more efficient methodologies to carry out various organic syntheses. In the present scenario, green chemistry utilizes the raw materials economically, minimizes the waste and prevents the uses of harmful or hazardous chemicals to make the organic reactions simple and efficient. Microwave technique is a new simple and efficient technology which opens new prospects to the chemist to carry out various reactions, which are difficult using conventional methodology. It is used to decrease the duration of time to carry various organic transformation along with maximum yield, minimum by-products, minimum energy utilization, less manpower etc. e.g. various famous organic reactions have been carried out by various research groups like Aldol condensation, Knoevenagel condensation, Beckmann rearrangement, Vilsmeier reaction, Perkin reaction, Benzil-Benzilic acid rearrangement, Fischer cyclization, Mannich reaction, Claisen-Schmidt condensation, etc. Further, reduction, oxidation, coupling, condensation reaction were also performed using microwave technology. Copyright© Bentham Science Publishers; For any queries, please email at

  6. Efficient MW-Assisted Synthesis, Spectroscopic Characterization, X-ray and Antioxidant Properties of Indazole Derivatives

    Efrain Polo


    Full Text Available A small series of tetrahydroindazoles was prepared, starting from 2-acetylcyclohexanone and different hydrazines using reflux and a focused microwave reactor. Microwave irradiation (MW favored the formation of the desired products with improved yields and shortened reaction times. This is a simple and green method for the synthesis of substituted tetrahydroindazole derivatives. The in vitro antioxidant activity was evaluated using the DPPH and ABTS methods. In these assays, 2-(4-fluorophenyl-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f showed moderate DPPH decoloring activity, while 3-methyl-4,5,6,7-tetrahydro-1H-indazole (3a, 3-methyl-2-phenyl-4,5,6,7-tetrahydro-2H-indazole (3b and 2-(4-fluorophenyl-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f were the most active in the ABTS assay. All compounds were well characterized by IR, 1H-, 13C-NMR and GC-MS spectroscopy and physical data, while the structure of 4-(3-methyl-4,5,6,7-tetrahydro-2H-indazol-2-ylbenzoic acid (3e was also determined by single crystal X-ray analysis.

  7. Efficient MW-Assisted Synthesis, Spectroscopic Characterization, X-ray and Antioxidant Properties of Indazole Derivatives.

    Polo, Efrain; Trilleras, Jorge; Ramos, Juan; Galdámez, Antonio; Quiroga, Jairo; Gutierrez, Margarita


    A small series of tetrahydroindazoles was prepared, starting from 2-acetylcyclohexanone and different hydrazines using reflux and a focused microwave reactor. Microwave irradiation (MW) favored the formation of the desired products with improved yields and shortened reaction times. This is a simple and green method for the synthesis of substituted tetrahydroindazole derivatives. The in vitro antioxidant activity was evaluated using the DPPH and ABTS methods. In these assays, 2-(4-fluorophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f) showed moderate DPPH decoloring activity, while 3-methyl-4,5,6,7-tetrahydro-1H-indazole (3a), 3-methyl-2-phenyl-4,5,6,7-tetrahydro-2H-indazole (3b) and 2-(4-fluorophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f) were the most active in the ABTS assay. All compounds were well characterized by IR, ¹H-, (13)C-NMR and GC-MS spectroscopy and physical data, while the structure of 4-(3-methyl-4,5,6,7-tetrahydro-2H-indazol-2-yl)benzoic acid (3e) was also determined by single crystal X-ray analysis.

  8. An Efficient and Versatile Synthesis of Isoflavones from 2-Methoxybenzoic Acids

    Lee, Jae In [Duksung Women' s University, Seoul (Korea, Republic of)


    Isoflavones (3-aryl-4H-1-benzopyran-4-ones) are found naturally in soybeans and many plants of the Leguminosae family. They have attracted much attention due to their biological activities, such as their anti-cancer, anti-inflammatory, and antifungal properties. Isoflavones intake through foods is important to human health, because they potentially regulate fatty acid metabolism and methoxy-substituted isoflavones in particular increase cell permeability. Isoflavones have also been synthesized by the coupling of 3-iodochromones with arylboronic acids. The condensation of 2'-hydroxyacetophenones with DMF dimethyl acetal formed 3-(dimethylamino)-2'-hydroxyphenylpropenones, which were cyclized using iodine to form 3-iodochromones. This process was followed by Suzuki coupling with arylboronic acids or aryl boronates to obtain isoflavones. The synthesis of isoflavones (6) from 5 was based on the formylation of the methylene group of 5 using DMF-POCl{sub 3}. Previously, the reaction of the DMF-POCl{sub 3} complex on benzyl 2-hydroxyphenyl ketones led to isoflavones, for which DMF was used as the reagent and solvent for 18 h at gentle reflux.

  9. Boric acid as a mild and efficient catalyst for one-pot synthesis of 1-amidoalkyl-2-naphthols under solvent-free conditions

    Aziz Shahrisa; Somayeh Esmati; Mahdi Gholamhosseini Nazari


    An efficient green chemistry method has been developed for the synthesis of 1-amidoalkyl-2-naphthol derivatives via a one-pot three-component condensation of 2-naphthol, aldehydes and amide in the presence of boric acid as a mild catalyst.

  10. I2/K2CO3: An efficient catalyst for the synthesis of 5-aryl-2,6-dicyano-3-methylanilines

    Bandita Datta; Mohamed Afzal Pasha


    Molecular iodine in the presence of potassium carbonate has been found to be an efficient and ecofriendly catalyst for the synthesis of polysubstituted dicyanoanilines from aldehydes, acetone and malononitrile under solvent-free thermal condition. The experimental procedure is simple, includes shorter reaction times (less than 10 min) and results in excellent yield of the products.

  11. Efficient traceless solid-phase synthesis of 3,4-dihydropyrazino[1,2-b]indazoles and their 6-oxides.

    Pudelová, Nadezda; Krchnák, Viktor


    A highly efficient novel traceless solid-phase synthesis of 3,4-dihydropyrazino[1,2-b]indazoles and their 6-oxides was developed by using commercially available building blocks, diamines, 2-nitrobenzenesulfonyl chlorides, and bromoketones/bromoacetates. Mild reaction conditions, diversely substituted building blocks, and high purity of crude products enabled effective combinatorial syntheses of libraries.

  12. Ceric ammonium nitrate catalysed three component one-pot efficient synthesis of 2,4,5-triaryl-1H-imidazoles

    Jaiprakash N Sangshetti; Nagnnath D Kokare; Sandeep A Kotharkara; Devanand B Shinde


    Ceric ammonium nitrate (CAN) is used as an efficient catalyst for the synthesis of 2,4,5-triaryl-1H-imidazoles via condensation of benzoin/benzil, ammonium acetate, and aromatic aldehydes. The easy work-up, higher yields and shorter reaction time are the advantages of the method presented here.

  13. Trichloroisocyanuric acid as an efficient homogeneous catalyst for the chemoselective synthesis of 2-substituted oxazolines, imidazolines and thiazolines under solvent-free condition

    Hojati Fatemeh Seyedeh


    Full Text Available Trichloroisocyanuric acid as a commercially available and inexpensive catalyst has been used in a new, facile and efficient procedure for the synthesis of 2-oxazolines, 2-imidazolines and 2-thiazolines through the reaction of nitriles with 2-aminoethanol, ethylenediamine or 2-aminoethanthiol under solvent -free conditions.

  14. Caesium fluoride-promoted Stille coupling reaction: an efficient synthesis of 9Z-retinoic acid and its analogues using a practical building block.

    Okitsu, Takashi; Iwatsuka, Kinya; Wada, Akimori


    A highly efficient and rapid total synthesis of 9Z-retinoic acid was accomplished by caesium fluoride-promoted Stille coupling reaction; using a common building block, 9Z-retinoic acid analogues were also prepared by the same method without isomerisation of the Z-double bond.

  15. Nano -propylsulphonated -Fe2O3: A novel magnetically recyclable heterogeneous catalyst for the efficient synthesis of bis(pyrazolyl)methanes in water

    Sara Sobhani; Zahra Pakdin-Parizi; Razieh Nasseri


    Nano -propylsulphonated -Fe2O3 (NPS--Fe2O3) was applied as a new magnetically recyclable heterogeneous catalyst for the efficient one-pot synthesis of bis(pyrazolyl)methanes in water. The catalyst was easily isolated from the reaction mixture by a magnetic bar and reused at least five times without significant degradation in activity.

  16. Zr(HSO44: An Efficient Catalyst for the Synthesis of 3-(2'- Benzothiazolyl-2,3-dihydroquinazolin- 4(1H-ones

    Liqiang Wu


    Full Text Available A simple and efficient synthesis of 3-(2'-benzothiazolyl-2,3-dihydro quinazolin-4(1H- ones has been accomplished by the one-pot condensation of isatoic anhydride, aldehyde and 2-aminobenzothiazole under solvent-free conditions in the presence of Zr(HSO44.

  17. An Efficient Synthesis of Functionalized 3-(α-amidobenzyl-4-hydroxycoumarin Derivatives by ZnO Nanoparticles Promoted Condensation Reaction Between Aromatic Aldehyde, 4-hydroxycoumarin, and Amides

    Hossein Anaraki-Ardakani


    Full Text Available An efficient and green protocol for the synthesis of 3-(α-amidobenzyl-4-hydroxycoumarin derivatives by one pot, three component coupling reaction of aromatic aldehyde, 4-hydroxycoumarin, and amides has been developed using ZnO nanoparticles (NPs as the catalyst. The procedure is formed in high yields, short reaction time and an environmentally friendly specificity.

  18. H-Y-zeolites induced heterocyclization: Highly efficient synthesis of substituted-quinazolin-4(3H)ones under microwave irradiation

    M. Bakavoli; O. Sabzevari; M. Rahimizadeh


    A highly efficient synthesis of 2-amino-N-substituted-benzamides was performed by the condensation of isatoic anhydride with several amines in solvent-free conditions under microwave irradiation. H-Y-zeolites induced heterocyclization of these products with ortho-esters under similar conditions afforded the relevant substituted-quinazolin-4(3H)ones in high yields.

  19. An efficient multi-component synthesis of 14-aryl-14H-dibenzo[a,j]xanthene derivatives by AgI nanoparticles

    Javad Safaei-Ghomi


    Full Text Available Recoverable heterogeneous AgI nanoparticles efficiently catalyzed the one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes via multi-component reaction of aldehydes and 2-naphthol under solvent-free conditions. The present approach offers several advantages such as short reaction times, high yields, easy purification, reusability of the catalyst and low catalyst loading.

  20. Easy synthesis approach of Pt-nanoparticles on polyaniline surface: an efficient electro-catalyst for methanol oxidation reaction

    Mondal, Sanjoy; Malik, Sudip


    A facile room temperature and surfactant free synthesis of platinum nanoparticles (Pt-NPs) on benzene tetra-carboxylic acid doped polyaniline (BDP) tube has been successfully demonstrated by solution dipping method. Preparation of Pt-NPs has been done through a red-ox reaction between BDP tubes and Pt-salt, as BDP itself acts as nontoxic reducing agent as well as template cum stabilizer for Pt-NPs. In BDP@Pt composites, ∼2.5 ± 0.5 nm spherical shaped Pt-NPs as observed from TEM studies are nicely decorated on the surface of BDP. The population or the loading density of Pt-NPs on BDP tube is greatly controlled by changing the w/w ratio of BDP to H2PtCl6. Synthesized BDP@Pt composites are subsequently employed as an efficient electro-catalyst for methanol oxidation reaction (MOR) in acidic medium. Furthermore, the observed catalytic activity is consequently ∼12 times higher than that of commercially available Pt/C catalyst. Depending on the loading density of Pt-NPs on BDP tubes, the efficiency and carbon monoxide (CO) tolerance ability of composites have been explored.

  1. Green synthesis of highly efficient CdSe quantum dots for quantum-dots-sensitized solar cells

    Gao, Bing; Shen, Chao; Zhang, Mengya; Yuan, Shuanglong; Yang, Yunxia, E-mail:, E-mail:; Chen, Guorong, E-mail:, E-mail: [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhang, Bo [Department of Physics, East China University of Science and Technology, Shanghai 200237 (China)


    Green synthesis of CdSe quantum dots for application in the quantum-dots-sensitized solar cells (QDSCs) is investigated in this work. The CdSe QDs were prepared with glycerol as the solvent, with sharp emission peak, full width at half maximum around 30 nm, and absorption peak from 475 nm to 510 nm. The reaction is environmental friendly and energy saving. What's more, the green synthesized CdSe QDs are coherence to the maximum remittance region of the solar spectrum and suitable as sensitizers to assemble onto TiO{sub 2} electrodes for cell devices application. What's more, the dynamic procedure of the carriers' excitation, transportation, and recombination in the QDSCs are discussed. Because the recombination of the electrons from the conduction band of TiO{sub 2}'s to the electrolyte affects the efficiency of the solar cells greatly, 3-Mercaptopropionic acid capped water-dispersible QDs were used to cover the surface of TiO{sub 2}. The resulting green synthesized CdSe QDSCs with Cu{sub 2}S as the electrode show a photovoltaic performance with a conversion efficiency of 3.39%.

  2. Controllable synthesis of α-sulfur spheres with hierarchical nanostructures for efficient visible-light-driven photocatalytic ability

    Dang, Xueming; Zhang, Xiufang, E-mail:; Zhang, Weiqiang; Dong, Xiaoli; Wang, Guowen; Ma, Hongchao


    Highlights: • α-Sulfur spheres with hierarchical nanostructures are controllably produced. • Addition quantity of PVP affects photocatalytic ability of α-sulfur. • The enhanced photocatalytic ability of α-sulfur hierarchical sphere is found. - Abstract: Visible-light-active α-sulfur spheres with hierarchical nanostructures were fabricated by simple solution-phase synthesis with PVP as the template for enhanced photocatalytic ability. The α-sulfur hierarchical spheres with an ultrahigh specific surface area can controllable synthesized by changing the addition quantity of PVP. The obtained products are systematically studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis absorption spectroscopy (DRS), Fluorescence (FL) and Brunauer-Emmett-Teller (BET). The photocatalytic activity of the as-prepared samples is evaluated by photocatalytic degradation of Rhodamine B (RhB) aqueous solution under visible light illumination. The results indicate that the morphology, specific surface area, photo absorbance ability, the separation efficiency of photogenerated carriers and the reactant adsorption performance can be controlled by varying the addition quantity of PVP. When 200 mg PVP is added, α-sulfur hierarchical spheres with uniform particle size about 1 μm and ultrahigh specific surface area of 67.1 m{sup 2}/g is obtained, and its photocatalytic activity reaches a maximum value, which can be attributed to the combined effects of photo absorbance ability, the separation efficiency of photogenerated carriers and the reactant adsorption performance.

  3. Gene cloning and molecular characterization of the Talaromyces thermophilus lipase catalyzed efficient hydrolysis and synthesis of esters.

    Romdhane, Ines Belhaj-Ben; Frikha, Fakher; Maalej-Achouri, Inès; Gargouri, Ali; Belghith, Hafedh


    A genomic bank from Talaromyces thermophilus fungus was constructed and screened using a previously isolated fragment lipase gene as probe. From several clones isolated, the nucleotide sequence of the lipase gene (TTL gene) was completed and sequenced. The TTL coding gene consists of an open reading frame (ORF) of 1083bp encoding a protein of 269 Aa with an estimated molecular mass of 30kDa. The TTL belongs to the same gene family as Thermomyces lanuginosus lipase (TLL, Lipolase®), a well known lipase with multiple applications. The promoter sequence of the TTL gene showed the conservation of known consensus sequences PacC, CreA, Hap2-3-4 and the existence of a particular sequence like the binding sites of Oleate Response Element (ORE) and Fatty acids Responsis Element (FARE) which are similar to that already found to be specific of lipolytic genes in Candida and Fusarium, respectively. Northern blot analysis showed that the TTL expression was much higher on wheat bran than on olive oil as sole carbon source. Compared to the Lipolase®, this enzyme was found to be more efficient for the hydrolysis and the synthesis of esters; and its synthetic efficiency even reached 91.6% from Waste Cooking Oil triglycerides.

  4. Shape-Controlled Synthesis of High-Quality Cu7 S4 Nanocrystals for Efficient Light-Induced Water Evaporation.

    Zhang, Changbo; Yan, Cong; Xue, Zhenjie; Yu, Wei; Xie, Yinde; Wang, Tie


    Copper sulfides (Cu2-x S), are a novel kind of photothermal material exhibiting significant photothermal conversion efficiency, making them very attractive in various energy conversion related devices. Preparing high quality uniform Cu2-x S nanocrystals (NCs) is a top priority for further energy-and sustainability relevant nanodevices. Here, a shape-controlled high quality Cu7 S4 NCs synthesis strategy is reported using sulfur in 1-octadecene as precursor by varying the heating temperature, as well as its forming mechanism. The performance of the Cu7 S4 NCs is further explored for light-driven water evaporation without the need of heating the bulk liquid to the boiling point, and the results suggest that as-synthesized highly monodisperse NCs perform higher evaporation rate than polydisperse NCs under the identical morphology. Furthermore, disk-like NCs exhibit higher water evaporation rate than spherical NCs. The water evaporation rate can be further enhanced by assembling the organic phase Cu7 S4 NCs into a dense film on the aqueous solution surface. The maximum photothermal conversion efficiency is as high as 77.1%.

  5. Synthesis of Bismuth-Nanoparticle-Enriched Nanoporous Carbon on Graphene for Efficient Electrochemical Analysis of Heavy-Metal Ions.

    Cui, Lin; Wu, Jie; Ju, Huangxian


    A BiNPs@NPCGS nanocomposite was designed for highly efficient detection of multiple heavy-metal ions by in situ synthesis of bismuth-nanoparticle (BiNP)-enriched nanoporous carbon (NPS) on graphene sheet (GS). The NPCGS was prepared by pyrolysis of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals deposited on graphene oxide and displayed a high surface area of 1251 m(2)  g(-1) and a pore size of 3.4 nm. BiNPs were deposited on NPCGS in situ by chemical reduction of Bi(3+) with NaBH4 . Due to the restrictive effect of the pore/surface structure of NPCGS, the BiNPs were uniform and well dispersed on the NPCGS. The BiNPs@NPCGS showed good conductivity and high effective area, and the presence of BiNPs allowed it to act as an efficient material for anodic-stripping voltammetric detection of heavy-metal ions. Under optimized conditions, the BiNPs@NPCGS-based sensor could simultaneously determine Pb(2+) and Cd(2+) with detection limits of 3.2 and 4.1 nM, respectively. Moreover, the proposed sensor could also differentiate Tl(+) from Pb(2+) and Cd(2+). Owing to its advantages of simple preparation, environmental friendliness, high surface area, and fast electron-transfer ability, BiNPs@NPCGS showed promise for practical application in sensing heavy-metal ions.

  6. Plasma-Assisted Synthesis of NiCoP for Efficient Overall Water Splitting

    Liang, Hanfeng


    Efficient water splitting requires highly active, earth-abundant, and robust catalysts. Monometallic phosphides such as NiP have been shown to be active toward water splitting. Our theoretical analysis has suggested that their performance can be further enhanced by substitution with extrinsic metals, though very little work has been conducted in this area. Here we present for the first time a novel PH plasma-assisted approach to convert NiCo hydroxides into ternary NiCoP. The obtained NiCoP nanostructure supported on Ni foam shows superior catalytic activity toward the hydrogen evolution reaction (HER) with a low overpotential of 32 mV at 10 mA cm in alkaline media. Moreover, it is also capable of catalyzing the oxygen evolution reaction (OER) with high efficiency though the real active sites are surface oxides in situ formed during the catalysis. Specifically, a current density of 10 mA cm is achieved at overpotential of 280 mV. These overpotentials are among the best reported values for non-noble metal catalysts. Most importantly, when used as both the cathode and anode for overall water splitting, a current density of 10 mA cm is achieved at a cell voltage as low as 1.58 V, making NiCoP among the most efficient earth-abundant catalysts for water splitting. Moreover, our new synthetic approach can serve as a versatile route to synthesize various bimetallic or even more complex phosphides for various applications.

  7. Efficient synthesis of graphene oxide and the mechanisms of oxidation and exfoliation

    Yuan, Rui; Yuan, Jing; Wu, Yanping; Chen, Lei; Zhou, Huidi; Chen, Jianmin


    An efficient method for the preparation of graphene oxide (GO) was descried through inducing the ultrasonic in the rate-determining step of oxidation processes. Both the transformation procedures and the detailed molecular behavior of parent graphene (PG), partially oxidized graphene (PGO) and GO in H2SO4 and aqueous solution were investigated by molecular dynamic simulation (MD) combining with experiments. The results obtained from MD simulation show that the addition of KMnO4 truly marked the beginning of the reaction which carried out from the border of PG flakes to the centre. This oxidation procedure was the rate-determining step and mainly contained three steps: the boundary carbon atoms oxidized, the distance of the corresponding interlayer enlarged and the oxidizing agent diffused into the unoxidized region, the processes was repeated until oxidized completely. So, the introducing ultrasonic in this section can accelerate not only the exfoliation of layers but also the diffusion of oxidizer and finally raises the oxidation efficiency dramatically. To further clarify these simulation results, the GO was prepared by the method mentioned above. The analyses results for the X-ray diffraction (XRD), Raman spectra and X-ray photoelectron spectroscopy (XPS) of the resulting GO show that the ultrasonic method could perfectly shortens the oxidation time from 12 h to 3 h and forms the higher degree of oxidation products with more carboxylic acid groups on its edges. Thus, this study provides a better understanding of the transformation procedures of graphite and proposes an efficient way to produce GOs suitable for various chemical modifications.

  8. Functionalization of mesoporous carbon with superbasic MgO nanoparticles for the efficient synthesis of sulfinamides.

    Chakravarti, Rajashree; Mano, Ajayan; Iwai, Hideo; Aldeyab, Salem S; Kumar, R Pradeep; Kantam, M Lakshmi; Vinu, Ajayan


    Highly basic MgO nanoparticles with different sizes have been successfully immobilized over mesoporous carbon with different pore diameters by a simple wet-impregnation method. The prepared catalysts have been characterized by various sophisticated techniques, such as XRD, nitrogen adsorption, electron energy loss spectroscopy, high-resolution TEM, X-ray photoelectron spectroscopy, and the temperature-programmed desorption of CO(2). XRD results reveal that the mesostructure of the support is retained even after the huge loading of MgO nanoparticles inside the mesochannels of the support. It is also demonstrated that the particle size and dispersion of the MgO nanoparticles on the support can be finely controlled by the simple adjustment of the textural parameters of the supports. Among the support materials studied, mesoporous carbon with the largest pore diameter and large pore volume offered highly crystalline small-size cubic-phase MgO nanoparticles with a high dispersion. The basicity of the MgO-supported mesoporous carbons can also be controlled by simply changing the loading of the MgO and the pore diameter of the support. These materials have been employed as heterogeneous catalysts for the first time in the selective synthesis of sulfinamides. Among the catalysts investigated, the support with the large pore diameter and high loading of MgO showed the highest activity with an excellent yield of sulfinamides. The catalyst also showed much higher activity than the pristine MgO nanoparticles. The effects of the reaction parameters, including the solvents and reaction temperature, and textural parameters of the supports in the activity of the catalyst have also been demonstrated. Most importantly, the catalyst was found to be highly stable, showing excellent activity even after the third cycle of reaction.

  9. An Efficient and Short Route for the Synthesis of Reverse Pyrrole Ribonucleosides

    Pereira Letícia O. R.


    Full Text Available The synthesis of reverse pyrrole ribonucleosides methyl 5-C-(4-acetyl-5-methyl-pyrrol-1-yl-2,3-O-isopropylidene-5-deoxy- beta-D-ribofuranoside (10, methyl 5-C-(4-ethoxycarbonyl-5-methyl-pyrrol-1-yl-2,3-O-isopropylidene-5-deoxy- beta-D-ribofuranoside (11, methyl 5-C-(4-acetyl-5-methyl-pyrrol-1-yl-5-deoxy-beta-D-ribofuranoside (12, methyl 5-C-(4-ethoxycarbonyl-5-methyl-pyrrol-1-yl-5-deoxy- beta-D-ribofuranoside (13, methyl 5-deoxy-5-C-(3'-formyl-4'-hydroxypropyl-pyrrol-1'-yl-2,3-O-isopropylidene- beta-D-ribofuranoside (16 and methyl 5-deoxy-5-C-(3'-formyl-pyrrol-1'-yl-2,3-O-isopropylidene- beta-D-ribofuranoside (18 are described starting from readily available methyl 5-amino-5-deoxy-2,3-O-isopropylidene-beta-D-ribofuranoside (9. The synthetic strategy for the construction of the heterocyclic ring was based on the nucleophilic attack of (9 to 4-acetyl-2-n-butoxy-5-methyl-4,5-dihydrofuran (4, 4-carbetoxy-2-n-butoxy-5-methyl-4,5-dihydrofuran (5, 4-formyl-2-n-butoxy-4,5-dihydrofuran (6 and 4-formyl-1-methyl dioxabyciclo[3.3.0]oct-3-en (8, in situ. The later compounds were obtained from reaction between 3-diazo-2,4-pentadione (1, ethyl 2-diazoacetoacetate (2 or diazomalonaldehyde (3 and enol ethers using dirhodium tetraacetate as a catalyst.

  10. Design and synthesis of molecular donors for solution-processed high-efficiency organic solar cells.

    Coughlin, Jessica E; Henson, Zachary B; Welch, Gregory C; Bazan, Guillermo C


    Organic semiconductors incorporated into solar cells using a bulk heterojunction (BHJ) construction show promise as a cleaner answer to increasing energy needs throughout the world. Organic solar cells based on the BHJ architecture have steadily increased in their device performance over the past two decades, with power conversion efficiencies reaching 10%. Much of this success has come with conjugated polymer/fullerene combinations, where optimized polymer design strategies, synthetic protocols, device fabrication procedures, and characterization methods have provided significant advancements in the technology. More recently, chemists have been paying particular attention to well-defined molecular donor systems due to their ease of functionalization, amenability to standard organic purification and characterization methods, and reduced batch-to-batch variability compared to polymer counterparts. There are several critical properties for efficient small molecule donors. First, broad optical absorption needs to extend towards the near-IR region to achieve spectral overlap with the solar spectrum. Second, the low lying highest occupied molecular orbital (HOMO) energy levels need to be between -5.2 and -5.5 eV to ensure acceptable device open circuit voltages. Third, the structures need to be relatively planar to ensure close intermolecular contacts and high charge carrier mobilities. And last, the small molecule donors need to be sufficiently soluble in organic solvents (≥10 mg/mL) to facilitate solution deposition of thin films of appropriate uniformity and thickness. Ideally, these molecules should be constructed from cost-effective, sustainable building blocks using established, high yielding reactions in as few steps as possible. The structures should also be easy to functionalize to maximize tunability for desired properties. In this Account, we present a chronological description of our thought process and design strategies used in the development of highly

  11. Simple, Efficient and Controllable Synthesis of Iodo/Di-iodoarenes via Ipsoiododecarboxylation/Consecutive Iodination Strategy

    Yang, Yun; Zhang, Lijuan; Deng, Guo-Jun; Gong, Hang


    A practical, efficient, and operationally simple strategy for the ipsoiododecarboxylation and di-iodination of aromatic carboxylic acids using the low-cost commercial reagent succinimide (NIS) as iodine source is reported. This iodination or di-iodination process can be easily controlled through reaction conditions, thereby providing corresponding iodination or di-iodination products with high yields. Furthermore, these two reactions can be easily scaled up to gram-scale by using palladium catalyst (0.66 mol%), which provides high isolated yield.

  12. An efficient synthesis of spiro--lactams having sulfenyl, sulfinyl and sulfonyl moiety

    Reshma; Renu Arora; Geeta Hundal; Aman Bhalla; S S Bari


    An efficient and a facile route to spiro--lactams is described. 3-allyl-3-methylthio--lactams, which are synthesized through a Lewis acid mediated C-3 alkylation of the trans-3-chloro-3-methylthio--lactams, undergo a facile intrasulfenyl cyclization reaction in the presence of halogens like bromine and iodine to give spiro -lactams in good yield. These halospiro--lactams are then subjected to dehalogenation reaction using Raney-nickel. The resulting spiro--lactams are further transformed into their sulfinyl and sulfonyl derivatives by using -chloroperbenzoic acid as an oxidant.

  13. A concise, efficient synthesis of sugar-based benzothiazoles through chemoselective intramolecular C-S coupling

    Shen, Chao


    Sugar-based benzothiazoles are a new class of molecules promising for many biological applications. Here, we have synthesized a wide range of sugar-based benzothiazoles from readily accessible glycosyl thioureas by chemoselective, palladium-catalyzed C-S coupling reactions. Corroborated by theoretical calculations, a mechanistic investigation indicates that the coordination to the palladium by a pivaloyl carbonyl group and the presence of intramolecular hydrogen bonding play important roles in the efficiency and chemoselectivity of reaction. These fluorescent glycoconjugates can be observed to readily enter mammalian tumor cells and exhibit potential in vitro antitumor activity. This journal is © The Royal Society of Chemistry 2012.

  14. Development of efficient, small particle size luminescent oxides using combustion synthesis

    Shea, Lauren Elizabeth

    Luminescent materials (phosphors) find application in cathode-ray tubes (CRTs), medical and industrial equipment monitors, fluorescent lamps, xerography, and many types of flat panel displays. Many commercially available phosphors were optimized in the 1960s for high voltage (>10 kV) CRT applications. Recently, a great deal of emphasis has been placed on the development and improvement of phosphors for flat panel displays that operate at low voltages (displays demand high resolution phosphor screens which can only be realized using phosphors with smaller particle size (displays. This technique exploits the exothermic redox reaction of metal nitrates (oxidizers) with an organic fuel (reducing agent). Typical fuels include urea (CHsb4Nsb2O), carbohydrazide (CHsb6Nsb4O), or glycine (Csb2Hsb5NOsb2). Resulting powders were well-crystallized, with a large surface area and small particle size. Phosphor powders were exposed to photoluminescence excitation by high energy (254 nm, E = 4.88 eV) and low energy photons (365 nm, E = 3.4 eV and 435 nm, E = 2.85 eV) and cathodoluminescence excitation by a low-voltage (100-1000 V) electron beam. Photoluminescence (PL) techniques resulted in the measurement of spectral energy distribution and relative intensities. Phosphor efficiencies in lumens per watt (lm/W) were obtained by low-voltage cathodoluminescence measurements. The effects of processing parameters such as type of fuel, fuel to oxidizer ratio, and heating rate were studied. The combustion process was optimized based on these processing parameters in order to maximize the luminescence of the phosphor powders in the as-synthesized condition. An increase in PL intensity with increasing flame temperature of reaction was observed. Post-reaction annealing (1000-1600sp°C) increased the PL intensity and CL efficiency of the as-synthesized powders. Diffusion of the activator ions, particle growth, reduction of residual carbon impurities, disorder surrounding the activator ions

  15. Solvothermal Synthesis of Well-Disperse ZnS Nanorods with Efficient Photocatalytic Properties

    Yun Chen


    Full Text Available Well-disperse short-range-ordered ZnS nanorods with efficient photocatalytic property for photodegradation of Rhodamin B have been successfully synthesized through a solvothermal method. Solvent used can be recovered and reused, which makes the route environment-friendly. Dodecylamine was found effective in organizing nanorods to ordered monolayer. Characterization showed that these nanorods were uniform with the diameter of about 3 nm and length of nearly 30 nm. And it is expected that these monodisperse ZnS nanorods have potential applications in electroluminescence materials.

  16. Simple, Efficient and Controllable Synthesis of Iodo/Di-iodoarenes via Ipsoiododecarboxylation/Consecutive Iodination Strategy

    Yang, Yun; Zhang, Lijuan; Deng, Guo-Jun; Gong, Hang


    A practical, efficient, and operationally simple strategy for the ipsoiododecarboxylation and di-iodination of aromatic carboxylic acids using the low-cost commercial reagent succinimide (NIS) as iodine source is reported. This iodination or di-iodination process can be easily controlled through reaction conditions, thereby providing corresponding iodination or di-iodination products with high yields. Furthermore, these two reactions can be easily scaled up to gram-scale by using palladium catalyst (0.66 mol%), which provides high isolated yield. PMID:28091536

  17. Simple synthesis of cobalt sulfide nanorods for efficient electrocatalytic oxidation of vanillin in food samples.

    Sivakumar, Mani; Sakthivel, Mani; Chen, Shen-Ming


    Well-defined CoS nanorods (NR) were synthesized using a simple hydrothermal method, and were tested as an electrode material for electro-oxidation of vanillin. The NR material was characterized with regard to morphology, crystallinity, and electro-activity by use of appropriate analytical techniques. The resulting CoS NR@Nafion modified glassy carbon electrode (GCE) exhibited efficient electro-oxidation of vanillin with a considerable linear range of current-vs-concentration (0.5-56μM vanillin) and a detection limit of 0.07μM. Also, food samples containing vanillin were studied to test suitability for commercial applications.

  18. An efficient algorithm for antenna synthesis updating following null-constraint changes

    Magdy, M. A.; Paoloni, F. J.; Cheah, J. Y. C.


    The procedure to maximize the array signal to noise ratio with null constraints involves an optimization problem that can be solved efficiently using a modified Cholesky decomposition (UD) technique. Following changes in the main lobe and/or null positions, the optimal element weight vector can be updated without the need for a new complete matrix inversion. Some properties of the UD technique can be utilized such that the updating algorithm reprocesses only a part of the unit triangular matrix U. Proper ordering of matrix entries can minimize the dimension of the updated part.

  19. Synthesis, characterization and corrosion inhibition efficiency of N-(4-(Morpholinomethyl Carbamoyl Phenyl Furan-2-Carboxamide

    N. Zulfareen


    Full Text Available A mannich base namely N-(4-(Morpholinomethyl Carbamoyl Phenyl Furan-2-Carboxamide (MFC was synthesized and characterized by FT-IR, 1H NMR, and 13C NMR. The molecular weight of MFC was confirmed by LC-MS. The inhibition effect of MFC on brass in 1 M HCl medium has been investigated by weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS and cyclic voltametry (CV. Thermodynamic parameters such as free energy, entropy and enthalpy were calculated to describe the mechanism of corrosion inhibitor. The inhibition efficiency of MFC increases with increase in concentration and temperature ranges from 30 °C to 60 °C. Polarization measurements indicated that MFC acts as a mixed type corrosion inhibitor. AC impedance indicates that Rct value increases with increase in the concentration of inhibitor. CV reveals that the oxidation of the copper is controlled by the addition of inhibitor on the brass metal. Surface analysis using scanning electron microscope (SEM shows a significant morphological improvement on the brass surface with the addition of the inhibitor. The adsorption of MFC on brass obeys Langmuir adsorption isotherm. The molecular structure of MFC was distorted to quantum chemical indices using density functional theory (DFT which indicates that the inhibition efficiency of MFC is closely related to quantum parameters.

  20. 1,3,5-Trimethylpyrazolium chloride based ionogel as an efficient and reusable heterogeneous catalyst for the synthesis of benzimidazoles

    Pankaj Sharma; Monika Gupta


    A new approach for the synthesis of benzimidazoles using ionogel under solvent-free conditions is reported. Catalytic activity of ionogel was compared with silica coated with ionic liquid (silica-IL) and it was found that ionogel is highly active compared to silica-IL for the synthesis of benzimidazoles. Moreover, ionogel was recyclable for the synthesis of benzimidazoles.

  1. Efficient chemoenzymatic oligosaccharide synthesis by reverse phosphorolysis using cellobiose phosphorylase and cellodextrin phosphorylase from Clostridium thermocellum.

    Nakai, Hiroyuki; Hachem, Maher Abou; Petersen, Bent O; Westphal, Yvonne; Mannerstedt, Karin; Baumann, Martin J; Dilokpimol, Adiphol; Schols, Henk A; Duus, Jens Ø; Svensson, Birte


    acceptors at subsite +1. High yields in chemoenzymatic synthesis, a novel regioselectivity, and novel oligosaccharides including products of CtCDP catalysed oligosaccharide oligomerisation using α-d-glucosyl 1-fluoride, all together contribute to the formation of an excellent basis for rational engineering of CBP and CDP to produce desired oligosaccharides.

  2. Electrodeposited synthesis of self-supported Ni-P cathode for efficient electrocatalytic hydrogen generation

    Ruixian Wu


    Full Text Available One of the key challenges for electrochemical water splitting is the development of low-cost and efficient hydrogen evolution cathode. In this work, a self-supported Ni-P cathode was synthesized by a facile electrodeposition method. The composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The Ni-P cathode performed low onset over-potential, good catalytic activity and long-term stability under neutral and alkaline conditions. The mechanism of Ni-P electrode for hydrogen production was discussed by electrochemical impedance spectroscopy. The excellent performance of Ni-P cathode was mainly attributed to the synergistic effect of phosphate anions and the self-supported feature.

  3. Efficient Synthesis of Boron-Containing α-Acyloxyamide Analogs via Microwave Irradiation

    Po-Shen Pan


    Full Text Available In this report, a Passerini three-component reaction utilizing boron-containing carboxylic acids or aldehydes is discussed. The reaction was carried out in water and facilitated by the use of microwave irradiation. This methodology allowed for the efficient formation of a broad range of boron-containing α-acyloxyamides under mild conditions within a short time. Two series of boron-containing α-acyloxyamides were synthesized and subsequently screened for cytotoxicity using the MTT cell viability assay. Two potential lead compounds were found to have potent activity against the HepG2 cancer cell line, demonstrating the potential of this methodology for use in the development of novel pharmaceuticals.

  4. Renewable rigid diamines: efficient, stereospecific synthesis of high purity isohexide diamines.

    Thiyagarajan, Shanmugam; Gootjes, Linda; Vogelzang, Willem; van Haveren, Jacco; Lutz, Martin; van Es, Daan S


    We report an efficient three-step strategy for synthesizing rigid, chiral isohexide diamines derived from 1,4:3,6-dianhydrohexitols. These biobased chiral building blocks are presently the subject of several investigations (in our and several other groups) because of their application in high-performance biobased polymers, such as polyamides and polyurethanes. Among the three possible stereo-isomers, dideoxy-diamino isoidide and dideoxy-diamino isosorbide can be synthesized from isomannide and isosorbide respectively in high yield with absolute stereo control. Furthermore, by using this methodology dideoxy-amino isomannide-a tricyclic adduct-was obtained starting from isoidide in high yield. Our improved synthetic route is a valuable advance towards meeting scale and purity demands for evaluating the properties of new biobased performance materials, which will benefit the development of these plastics.

  5. Synthesis of mesoporous NH2-SBA-15 by a simple and efficient strategy

    You, Long; Yuan, Fang; Ma, Feng


    Amine modified SBA-15 (NH2-SBA-15) was synthesized by a simple and efficient strategy, that is, activation at first and followed by amination. The samples were characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), environmental scanning electron microscopy (ESEM), thermo gravimetric (TG) analysis, and nitrogen adsorption. Results show that the as-prepared NH2-SBA-15 possessed a large surface area, stable skeleton structure, and high amino contents. Moreover, the CO2 temperature programmed desorption (CO2-TPD) experiments of the as-prepared NH2-SBA-15 were studied, and the results show that the introduction of amino groups results in the increase of the basic sites of SBA-15, which is beneficial to the adsorption of CO2.

  6. Synthesis of highly efficient Ag@AgCl plasmonic photocatalysts with various structures.

    Wang, Peng; Huang, Baibiao; Lou, Zaizhu; Zhang, Xiaoyang; Qin, Xiaoyan; Dai, Ying; Zheng, Zhaoke; Wang, Xiaoning


    By means of a simple ion-exchange process (using different precursors) and a light-induced chemical reduction reaction, highly efficient Ag@AgCl plasmonic photocatalysts with various self-assembled structures-including microrods, irregular balls, and hollow spheres-have been fabricated. All the obtained Ag@AgCl catalysts were characterized by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and UV-visible diffuse reflectance spectroscopy. The effect of the different morphologies on the properties of the photocatalysts was studied. The average content of elemental Ag in Ag@AgCl was found to be about 3.2 mol %. All the catalysts show strong absorption in the visible-light region. The obtained Ag@AgCl samples exhibit enhanced photocatalytic activity for the degradation of organic contaminants under visible-light irradiation. The stability of the plasmonic photocatalysts was also investigated in detail.

  7. Electrodeposited synthesis of self-supported Ni-P cathode for efficient electrocatalytic hydrogen generation

    Ruixian Wu; Yuming Dong n; Pingping Jiang; Guangli Wang; Yanmei Chen; Xiuming Wu


    One of the key challenges for electrochemical water splitting is the development of low-cost and efficient hydrogen evolution cathode. In this work, a self-supported Ni-P cathode was synthesized by a facile electrodeposition method. The composition and morphology were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The Ni-P cathode performed low onset over-potential, good catalytic activity and long-term stability under neutral and alkaline conditions. The mechanism of Ni-P electrode for hydrogen production was discussed by electrochemical impedance spectroscopy. The excellent performance of Ni-P cathode was mainly attributed to the synergistic effect of phosphate anions and the self-supported feature.

  8. Efficient cyanoaromatic photosensitizers for singlet oxygen production: synthesis and characterization of the transient reactive species.

    Ronzani, Filippo; Arzoumanian, Emmanuel; Blanc, Sylvie; Bordat, Patrice; Pigot, Thierry; Cugnet, Cyril; Oliveros, Esther; Sarakha, Mohamed; Richard, Claire; Lacombe, Sylvie


    In order to graft cyanoaromatic molecules onto various inert supports, we designed two new cyanoanthracene derivatives of benzo[b]triphenylene-9,14-dicarbonitrile (DBTP, 1), which already demonstrated good photosensitizing properties. We synthesized 3-(N-hydroxypropyl)carboxamido-9,14-dicyanobenzo[b]triphenylene, 3 and 3-(N-N0-Boc-aminohexyl)carboxamido-9,14-dicyanobenzo[b]triphenylene, 4 and compared their photophysical properties in acetonitrile relative to those of the parent compound 1 and its carboxylic derivative 9,14-dicyanobenzo[b]triphenylene-3-carboxylic acid, 2. The transient species were analysed and the quantum yields of singlet oxygen production (ΦΔ) determined in acetonitrile. The effect of chemical functionalization can be considered negligible, since absorption spectra, fluorescence emission spectra and fluorescence lifetimes do not significantly change with the substituent. The triplet-triplet absorption spectra and the triplet excited state lifetimes are similar for the whole series. For compounds 1-4 high values of ΦΔ, close to that of the standard sensitizer 1H-phenalen-1-one (PN, ΦΔ ≈ 1), and higher than that of the well-known photosensitizer 9,10-dicyanoanthracene (DCA), are due to very efficient intersystem crossing from the singlet to the triplet excited state and subsequent energy transfer to ground state oxygen ((3)O2). They belong to a class of very efficient photosensitizers, absorbing visible light and stable under irradiation, they may be functionalized without significant changes to their photophysical behaviour, and grafted onto various supports.

  9. Synthesis and photoactivity of the highly efficient Ag species/TiO{sub 2} nanoflakes photocatalysts

    Liu Yong [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, Wuhan 430074 (China); Hu Juncheng, E-mail: [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, Wuhan 430074 (China); Li Jinlin [Key Laboratory of Catalysis and Materials Science of the State Ethnic Affairs Commission and Ministry of Education, South-Central University for Nationalities, Wuhan 430074 (China)


    Research highlights: > Highly efficient Ag species-TiO{sub 2} nanoflakes catalyst was prepared. > The variety and relative amount of Ag species in TiO{sub 2} can be well tuned. > The enhanced photocatalytic activity can be attributed to the Ag species. - Abstract: Ag species/TiO{sub 2} nanoflakes photocatalysts with different relative contents (Ag{sup +}, Ag{sup 2+}, Ag{sup 0}) have been successfully synthesized by a simple template-free synthetic strategy. X-ray photoelectron spectroscopy, X-ray diffraction, and UV-vis diffuse reflectance spectra indicated that the dopant ions (Ag{sup +} or Ag{sup 2+}) were partly incorporated into the titanium dioxide nanoflakes. Meanwhile, part of the silver ions migrated to the surface after the subsequent calcination and aggregated into ultra-small metallic Ag nanoclusters (NCs) (1-2 nm), which are well dispersed on the surface of TiO{sub 2} nanoflakes. The photocatalytic activities of the Ag species/TiO{sub 2} materials obtained were evaluated by testing the photodegradation of the azo dye reactive brilliant X-3B (X-3B) under near UV irradiation. Interestingly, it was found that the maximum photocatalytic efficiency was observed when Ag species coexisted in three valence states (Ag{sup +}, Ag{sup 2+}, Ag{sup 0} NCs), which was higher than that of Degussa P25. The high photocatalytic activity of the Ag species/TiO{sub 2} can be attributed to the synergy effect of the three Ag species.

  10. "In-gel" purified ditags direct synthesis of highly efficient SAGE Libraries

    Sloan Andrew E


    Full Text Available Abstract Background SAGE (serial analysis of gene expression is a recently developed technique for systematic analysis of eukaryotic transcriptomes. The most critical step in the SAGE method is large scale amplification of ditags which are then are concatemerized for the construction of representative SAGE libraries. Here, we report a protocol for purifying these ditags via an 'in situ' PAGE purification method. This generates ditags free of linker contaminations, making library construction simpler and more efficient. Results Ditags used to generate SAGE libraries were demarcated 'in situ' on preparative polyacrylamide gels using XC and BPB dyes, which precisely straddle the ditag band when a 16% PAGE gel (19:1 acrylamide:bis, 5% cross linker is used to resolve the DNA bands. Here, the ditag DNA was directly excised from gel without visualization via EtBr or fluorescent dye staining, resulting in highly purified ditag DNA free of contaminating linkers. These ditags could be rapidly self ligated even at 4°C to generate concatemers in a controlled manner, which in turn enabled us to generate highly efficient SAGE libraries. This reduced the labor and time necessary, as well as the cost. Conclusions This approach greatly simplified the ditag purification procedure for constructing SAGE libraries. Since the traditional post-run staining with EtBr or fluorescent dyes routinely results in cross contamination of a DNA band of interest by other DNA in the gel, the dry gel DNA excision method described here may also be amenable to other molecular biology techniques in which DNA purity is critically important.

  11. Common Distribution of gad Operon in Lactobacillus brevis and its GadA Contributes to Efficient GABA Synthesis toward Cytosolic Near-Neutral pH

    Wu, Qinglong; Tun, Hein Min; Law, Yee-Song; Khafipour, Ehsan; Shah, Nagendra P.


    Many strains of lactic acid bacteria (LAB) and bifidobacteria have exhibited strain-specific capacity to produce γ-aminobutyric acid (GABA) via their glutamic acid decarboxylase (GAD) system, which is one of amino acid-dependent acid resistance (AR) systems in bacteria. However, the linkage between bacterial AR and GABA production capacity has not been well established. Meanwhile, limited evidence has been provided to the global diversity of GABA-producing LAB and bifidobacteria, and their mechanisms of efficient GABA synthesis. In this study, genomic survey identified common distribution of gad operon-encoded GAD system in Lactobacillus brevis for its GABA production among varying species of LAB and bifidobacteria. Importantly, among four commonly distributed amino acid-dependent AR systems in Lb. brevis, its GAD system was a major contributor to maintain cytosolic pH homeostasis by consuming protons via GABA synthesis. This highlights that Lb. brevis applies GAD system as the main strategy against extracellular and intracellular acidification demonstrating its high capacity of GABA production. In addition, the abundant GadA retained its activity toward near-neutral pH (pH 5.5–6.5) of cytosolic acidity thus contributing to efficient GABA synthesis in Lb. brevis. This is the first global report illustrating species-specific characteristic and mechanism of efficient GABA synthesis in Lb. brevis. PMID:28261168

  12. Nano-TiCl4/SiO2: An efficient heterogeneous solid acid catalyst for the one pot cascade five-component synthesis of densely functionalized tetrahydropyridines

    Abdolhamid Bamoniri; Bi Bi Fatemeh Mirjalili; Reza Tarazian


    Nano-TiCl4/SiO2 was found to be an inexpensive and efficient heterogeneous solid acid catalyst for the synthesis of one-pot cascade synthesis of highly functionalized asymmetric tetrahydropyridines from the five-component condensation reaction of the para-substituted anilines and aromatic aldehydes with ethyl acetoacetate under thermal conditions. Novel methodology, environmentally benign conditions, clean protocol, easy work-up and high yields are the important advantages of this protocol. The products were characterized using physical and spectroscopic data such as FT-IR, 1H-NMR and in some cases 13C-NMR and CHN analysis.

  13. An efficient and facile synthesis of divergent C-3/C-5 bis-functionalized 2-oxindoles from 5-formyl-Morita-Baylis-Hillman adducts of oxindole

    Kodirajan Selvakumar; Kandapalam Arun Prasath Lingam; Rama Varma Luxmi Varma; Poovan Shanmugavelan


    An efficient and facile synthesis of divergent C-3/C-5 bis-functionalized 2-oxindole derivatives has been achieved from 3,5-bis-Morita-Baylis-Hillman (MBH) adducts of oxindole via nucleophilic substitution reaction for the first time. Wider scope of substrate and rate acceleration has been observed in second MBH reaction under typical reaction condition. The synthetic usefulness of bi-functionalized bis-allyl derivative has been demonstrated by the synthesis of potent bis-pyrazole via [3+2]-annulation strategy.

  14. An efficient one-pot three-component synthesis of α-amino nitriles via Strecker reaction catalysed by bismuth(III nitrate

    S. Sheik Mansoor


    Full Text Available A convenient and efficient one-pot method for the synthesis of a variety of α-amino nitriles from aldehydes, amines and trimethylsilyl cyanide (TMSCN in the presence of a catalytic amount of Bi(NO33 at room temperature in acetonitrile (MeCN is described. The significant features of this method are simple work-up procedure, inexpensive and non-toxic catalyst, shorter reaction times and excellent product yields. The catalyst Bi(NO33 can be reused. The reusability of the catalyst has been studied for the synthesis of various amino nitriles.

  15. Practical and Efficient Synthesis of α-Aminophosphonic Acids Containing 1,2,3,4-Tetrahydroquinoline or 1,2,3,4-Tetrahydroisoquinoline Heterocycles.

    Ordóñez, Mario; Arizpe, Alicia; Sayago, Fracisco J; Jiménez, Ana I; Cativiela, Carlos


    We report here a practical and efficient synthesis of α-aminophosphonic acid incorporated into 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroisoquinoline heterocycles, which could be considered to be conformationally constrained analogues of pipecolic acid. The principal contribution of this synthesis is the introduction of the phosphonate group in the N-acyliminium ion intermediates, obtained from activation of the quinoline and isoquinoline heterocycles or from the appropriate δ-lactam with benzyl chloroformate. Finally, the hydrolysis of phosphonate moiety with simultaneous cleavage of the carbamate afforded the target compounds.

  16. Efficient Synthesis of β-Aryl-γ-lactams and Their Resolution with (S-Naproxen: Preparation of (R- and (S-Baclofen

    Iris J. Montoya-Balbás


    Full Text Available An efficient synthesis of enantiomerically-pure β-aryl-γ-lactams is described. The principal feature of this synthesis is the practical resolution of β-aryl-γ-lactams with (S-Naproxen. The procedure is based on the Michael addition of nitromethane to benzylidenemalonates, which was easily obtained, followed by the reduction of the γ-nitroester in the presence of Raney nickel and the subsequent saponification/decarboxylation reaction. The utility of this methodology was highlighted by the preparation of enantiomerically-pure (R- and (S-Baclofen hydrochloride.

  17. Synthesis of copper hydroxide and oxide nanostructures via anodization technique for efficient photocatalytic application.

    Hyam, Rajeshkumar Shankar; Lee, Jongseok; Cho, Eunju; Khim, Jeehyeong; Lee, Haigun


    We have demonstrated a facile protocol for synthesizing CuO and Cu2O mixed-phase nanostructures by anodization of copper hydroxide (Cu(OH)2) nanoneedles and their heat treatment in different atmospheres, which affect photocatalytic degradation efficiency. The oxygen annealed sample had relatively small (100 nm) lamellar, spherical nanoparticulate structures on the substrate surface, which showed better photocatalytic degradation of reactive black 5 dye resulting from the appropriate morphology and phase formation, compared to the samples annealed in different atmospheres and vacuum. The pseudo first-order rate constant (k) of the oxygen annealed sample was 0.0054/min, which was relatively high due to the formation of a CuO-Cu2O heterojunction with matching band potentials. Air, nitrogen, argon and vacuum annealing resulted in bigger particles and different morphologies, which led to pseudo first-order rate constants (k) of 0.0032/min (air-annealed); 0.0021/min (N2-annealed); 0.0033/min (Ar-annealed); and 0.0027/min (vacuum-annealed), which resulted in poor photocatalytic degradation of the reactive black 5 dye.

  18. Synthesis of magnetic biocomposite for efficient adsorption of azo dye from aqueous solution.

    Sivashankar, R; Sathya, A B; Krishnakumar, Uma; Sivasubramanian, V


    A novel magnetic biocomposite was synthesized using metal chlorides and aquatic macrophytes by co-precipitation method. The resulting product, magnetic biocomposite was characterized by Fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). The adsorption performance of the magnetic biocomposite was tested with removal of Metanil Yellow dye from aqueous solution. The effect of influencing parameters such as initial dye concentration, solution pH and agitation were investigated. The equilibrium isotherm was well described by the Langmuir model with the with maximum adsorption capacity of 90.91mg/g. Adsorption kinetics experiments were carried out and the data were well fitted by a pseudo-second-order equation. The results revealed that the magnetic biocomposite could efficiently adsorb the azo dyes from aqueous solution, and the spent adsorbents could be recovered completely by magnetic separation process. Therefore, the prepared magnetic biocomposite could thus be used as promising adsorbent for the removal of azo dyes from polluted water.

  19. A convenient and highly efficient synthesis of one kind of peptide nucleic acid monomer

    Xuemei Tang


    Full Text Available S-Thyminyl-L-cysteine methyl ester hydrochloride (compound 1, a non-classical peptide nucleic acid monomer, was synthesized through the key intermediate, N-tert- butoxycarbonyl-S-thyminyl-L-cysteine (compound 3, which afforded from the reaction of S-thyminyl-L-cysteine hydrochloride (compound 2 with di-tert-butyl dicarbonate (Boc2O. This was followed by the esterification and deprotection of compound 3 at an overall yield of 82%. The mixture of thionyl chloride and methanol was found as an efficient reagent for simultaneous deprotection of tert-butoxycarbonyl (Boc group and esterification of carboxy group of compound 3. This high-yield two-step method was also applied to other analogues of compound 1 successfully. The chemical structures of four new compounds (5a-5d were confirmed by 1H NMR and 13C NMR.DOI:

  20. Synthesis of Efficiently Green Luminescent CdSe/ZnS Nanocrystals Via Microfluidic Reaction

    Luan Weiling


    Full Text Available AbstractQuantum dots with emission in the spectral region from 525 to 535 nm are of special interest for their application in green LEDs and white-light generation, where CdSe/ZnS core-shell structured nanocrystals (NCs are among promising candidates. In this study, triple-ligand system (trioctylphosphine oxide–oleic acid–oleylamine was designed to improve the stability of CdSe NCs during the early reaction stage. With the precisely controlled reaction temperature (285 °C and residence time (10 s by the recently introduced microfluidic reaction technology, green luminescent CdSe NCs (λ = 522 nm exhibiting narrow FWHM of PL (30 nm was reproducibly obtained. After that, CdSe/ZnS core-shell NCs were achieved with efficient luminescence in the pure green spectral region, which demonstrated high PL QY up to 70% and narrow PL FWHM as 30 nm. The strengthened mass and heat transfer in the microchannel allowed the formation of highly luminescent CdSe/ZnS NCs under low reaction temperature and short residence time (T = 120 °C,t = 10 s. The successful formation of ZnS layer was evidence of the substantial improvement of PL intensity, being further confirmed by XRD, HRTEM, and EDS study.

  1. Synthesis of magnetic metal-organic framework (MOF) for efficient removal of organic dyes from water

    Zhao, Xiaoli; Liu, Shuangliu; Tang, Zhi; Niu, Hongyun; Cai, Yaqi; Meng, Wei; Wu, Fengchang; Giesy, John P.


    A novel, simple and efficient strategy for fabricating a magnetic metal-organic framework (MOF) as sorbent to remove organic compounds from simulated water samples is presented and tested for removal of methylene blue (MB) as an example. The novel adsorbents combine advantages of MOFs and magnetic nanoparticles and possess large capacity, low cost, rapid removal and easy separation of the solid phase, which makes it an excellent sorbent for treatment of wastewaters. The resulting magnetic MOFs composites (also known as MFCs) have large surface areas (79.52 m2 g-1), excellent magnetic response (14.89 emu g-1), and large mesopore volume (0.09 cm3 g-1), as well as good chemical inertness and mechanical stability. Adsorption was not drastically affected by pH, suggesting π-π stacking interaction and/or hydrophobic interactions between MB and MFCs. Kinetic parameters followed pseudo-second-order kinetics and adsorption was described by the Freundlich isotherm. Adsorption capacity was 84 mg MB g-1 at an initial MB concentration of 30 mg L-1, which increased to 245 mg g-1 when the initial MB concentration was 300 mg L-1. This capacity was much greater than most other adsorbents reported in the literature. In addition, MFC adsorbents possess excellent reusability, being effective after at least five consecutive cycles.


    A. Khodabakhshi


    Full Text Available In this study the efficiency of magnetic nanoparticles for removal of trivalent arsenic from synthetic industrial wastewater was evaluated. The nanoparticles was prepared by sol-gel method and characterized by X-ray methods including XRD, XRF, and SEM, and vibrating sample magnetometer (VSM. The results showed that synthesized nanoparticles were in the size range of 40-300 nm, purity of about 90%, and magnetization of nanoparticles was 36.5emu/g. In initial conditions including: pH=7, As(III concentration of 10 mg/L, nanomagnetite concentration of 1g/L, shaking speed of 250 rpm and 20 minute retention time, 82% of As (III was removed. Competition from common coexisting ions such as Na+, Ni2+, Cu2+, SO42-, and Cl- was ignorable but for NO3- was significant. The adsorption data of magnetite nanoparticles fit well with Freundlich isotherm equations. The adsorption capacity of the Fe3O4 for As (III at pH=7 was obtained as 23.8 mg/g. It was concluded that magnetite nanoparticles have considerable potential in removal of As(III from synthetic industrial wastewaters.

  3. Efficient synthesis and characterization of ergosterol laurate in a solvent-free system.

    He, Wen-Sen; Yin, Ji; Xu, Han-Shan; Qian, Qiu-Ying; Jia, Cheng-Sheng; Ma, Hai-Le; Feng, Biao


    Ergosterol and its derivatives have attracted much attention for a variety of health benefits, such as anti-inflammatory and antioxidant activities. However, ergosterol esters are advantageous because this compound has better solubility than the free ergosterol. In this work, ergosterol laurate was efficiently synthesized for the first time by direct esterification in a solvent-free system. The desired product was purified, characterized by Fourier transform infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance, and finally confirmed to be ergosterol laurate. Meanwhile, the effect of various catalysts, catalyst dose, reaction temperature, substrate molar ratio, and reaction time were studied. Both the conversion of ergosterol and the selectivity of the desired product can reach above 89% under the selected conditions: sodium dodecyl sulfate + hydrochloric acid as the catalyst, 2:1 molar ratio of lauric acid/ergosterol, catalyst dose of 4% (w/w), 120 °C, and 2 h. The oil solubility of ergosterol and its laurate was also compared. The results showed that the solubility of ergosterol in oil was significantly improved by direct esterification with lauric acid, thus greatly facilitating the incorporation into a variety of oil-based systems.

  4. Synthesis, spectral, SHG efficiency and computational studies of some newly synthesized unsymmetrical azines of 4-biphenylcarboxaldehyde

    Arulmani, R.; Sankaran, K. R.


    A series of novel unsymmetrical azines 2-8 are prepared and characterized by FT-IR, 1H, 13C NMR, Mass and UV spectral studies. The Gaussian-03 B3LYP/6-311+G(d,p) calculations on these azines are used to evaluate the heat of formation of the different conformers, identify the stable conformation, to determine dipole moment (μ), polarizability (α0), first hyperpolarizability (βtot), selected geometrical parameters, MEP surface, frontier molecular orbital energies (HOMO-LUMO) and their energy gap. The μ, α0, βtot values clearly depict that the unsymmetrical azine 8 is found to have a good NLO property compared to other azines 1-7. The SHG measurement of unsymmetrical azine 8 was performed by Kurtz and Perry powder method and the results indicated that the azine 8 is having comparable efficiency as that of potassium dihydrogen phosphate (KDP) crystal. The natural bond orbital (NBO) analysis of the unsymmetrical azines 2-8 are also made using B3LYP/6-31G(d,p) basis set.

  5. Synthesis and characterization of chitosan tripolyphosphate nanoparticles and its encapsulation efficiency containing Russell's viper snake venom.

    Venkatesan, C; Vimal, S; Hameed, A S Sahul


    Chitosan Tripolyphosphate (CS/TPP) nanoparticle is a biodegradable and nontoxic polysaccharide, used as a carrier for drug delivery. The morphology and particle-size measurements of the nanoparticles were studied by field emission scanning electron microscopy and Fourier Transform Infrared Spectroscopy (FTIR). This study aims to evaluate the impact of Russell's viper venom encapsulation on various factors and loading capacity, in addition to explore the physicochemical structure of nanoparticles. FTIR confirmed that tripolyphosphoric groups of TPP linked with ammonium groups of CS in the nanoparticles. Our results showed that CS can react with TPP to form stable cationic nanoparticles. The results also showed that encapsulation efficiency of venom at different concentrations of 20, 40, 60, 500, and 1000 µg/mL were achieved for CS/TPP nanoparticles at different concentrations of 1.5, 2, and 3 mg/mL. The cytotoxicity of CS/TPP nanoparticles was evaluated by MTT (-3 (4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, a tetrazole) assay.

  6. Facile synthesis of cobalt-doped zinc oxide thin films for highly efficient visible light photocatalysts

    Altintas Yildirim, Ozlem; Arslan, Hanife; Sönmezoǧlu, Savaş


    Cobalt-doped zinc oxide (Co:ZnO) thin films with dopant contents ranging from 0 to 5 at.% were prepared using the sol-gel method, and their structural, morphological, optical, and photocatalytic properties were characterized. The effect of the dopant content on the photocatalytic properties of the films was investigated by examining the degradation behavior of methylene blue (MB) under visible light irradiation, and a detailed investigation of their photocatalytic activities was performed by determining the apparent quantum yields (AQYs). Co2+ ions were observed to be substitutionally incorporated into Zn2+ sites in the ZnO crystal, leading to lattice parameter constriction and band gap narrowing due to the photoinduced carriers produced under the visible light irradiation. Thus, the light absorption range of the Co:ZnO films was improved compared with that of the undoped ZnO film, and the Co:ZnO films exhibited highly efficient photocatalytic activity (∼92% decomposition of MB after 60-min visible light irradiation for the 3 at.% Co:ZnO film). The AQYs of the Co:ZnO films were greatly enhanced under visible light irradiation compared with that of the undoped ZnO thin film, demonstrating the effect of the Co doping level on the photocatalytic activity of the films.

  7. Rapid and Efficient Synthesis of Silver Nanofluid Using Electrical Discharge Machining

    Kuo-Hsiung Tseng


    Full Text Available The electrical discharge machining (EDM system has been proven feasible as a rapid and efficient method for silver nanofluid preparation. This study prepared the silver nano-fluid via EDM and investigated the relationship between its process parameters and product characteristics. The prior study had found that the silver nano-fluid prepared by EDM contained both silver nanoparticles and silver ions. Silver ions had revealed the cause of the high suspension of the silver nanoparticles. To examine the relationship between the stability of silver nanofluid and the process parameters, this study quantified the relationship of process parameters to the material removal rate (MRR of silver electrode and silver ion output rate (IOR in the fluid, in order to achieve the most effective process parameter condition. Furthermore, the stability of silver nano-fluid was analyzed by various devices, including UV-Vis spectroscopy, size-distribution, and Zeta-potential analyzer. The effects of MRR, IOR, particle size, Zeta-potential, and optical properties of silver nanofluid under different process parameters are also discussed.

  8. Efficient One-Pot Synthesis of 5-Chloromethylfurfural (CMF from Carbohydrates in Mild Biphasic Systems

    Dimitris S. Argyropoulos


    Full Text Available 5-Halomethylfurfurals can be considered as platform chemicals of high reactivity making them useful for the preparation of a variety of important compounds. In this study, a one-pot route for the conversion of carbohydrates into 5-chloromethylfurfural (CMF in a simple and efficient (HCl-H3PO4/CHCl3 biphasic system has been investigated. Monosaccharides such as D-fructose, D-glucose and sorbose, disaccharides such as sucrose and cellobiose and polysaccharides such as cellulose were successfully converted into CMF in satisfactory yields under mild conditions. Our data shows that when using D-fructose the optimum yield of CMF was about 47%. This understanding allowed us to extent our work to biomaterials, such as wood powder and wood pulps with yields of CMF obtained being comparable to those seen with some of the enumerated mono and disaccharides. Overall, the proposed (HCl-H3PO4/CHCl3 optimized biphasic system provides a simple, mild, and cost-effective means to prepare CMF from renewable resources.

  9. Design synthesis and optimization of permanent magnet synchronous machines based on computationally-efficient finite element analysis

    Sizov, Gennadi Y.

    In this dissertation, a model-based multi-objective optimal design of permanent magnet ac machines, supplied by sine-wave current regulated drives, is developed and implemented. The design procedure uses an efficient electromagnetic finite element-based solver to accurately model nonlinear material properties and complex geometric shapes associated with magnetic circuit design. Application of an electromagnetic finite element-based solver allows for accurate computation of intricate performance parameters and characteristics. The first contribution of this dissertation is the development of a rapid computational method that allows accurate and efficient exploration of large multi-dimensional design spaces in search of optimum design(s). The computationally efficient finite element-based approach developed in this work provides a framework of tools that allow rapid analysis of synchronous electric machines operating under steady-state conditions. In the developed modeling approach, major steady-state performance parameters such as, winding flux linkages and voltages, average, cogging and ripple torques, stator core flux densities, core losses, efficiencies and saturated machine winding inductances, are calculated with minimum computational effort. In addition, the method includes means for rapid estimation of distributed stator forces and three-dimensional effects of stator and/or rotor skew on the performance of the machine. The second contribution of this dissertation is the development of the design synthesis and optimization method based on a differential evolution algorithm. The approach relies on the developed finite element-based modeling method for electromagnetic analysis and is able to tackle large-scale multi-objective design problems using modest computational resources. Overall, computational time savings of up to two orders of magnitude are achievable, when compared to current and prevalent state-of-the-art methods. These computational savings allow

  10. Olive Recombinant Hydroperoxide Lyase, an Efficient Biocatalyst for Synthesis of Green Leaf Volatiles.

    Jacopini, Sabrina; Mariani, Magali; de Caraffa, Virginie Brunini-Bronzini; Gambotti, Claude; Vincenti, Sophie; Desjobert, Jean-Marie; Muselli, Alain; Costa, Jean; Berti, Liliane; Maury, Jacques


    Volatile C6-aldehydes are the main contributors to the characteristic odor of plants known as "green note" and are widely used by the flavor industry. Biotechnological processes were developed to fulfill the high demand in C6-aldehydes in natural flavorants and odorants. Recombinant hydroperoxide lyases (HPLs) constitute an interesting alternative to overcome drawbacks arising from the use of HPL from plant extracts. Thus, olive recombinant 13-HPL was assayed as biocatalysts to produce C6-aldehydes. Firstly, a cDNA encoding for olive HPL of Leccino variety was isolated and cloned in pQE-30 expression vector. In order to improve the enzyme solubility, its chloroplast transit peptide was deleted. Both enzymes (HPL wild type and HPL deleted) were expressed into Escherichia coli strain M15, purified, characterized, and then used for bioconversion of 13-hydroperoxides of linoleic and linolenic acids. Aldehydes produced were extracted, then identified and quantified using gas chromatography and mass spectrometry. Recombinant HPL wild type (HPLwt) allowed producing 5.61 mM of hexanal and 4.39 mM of 3Z-hexenal, corresponding to high conversion yields of 93.5 and 73 %, respectively. Using HPL deleted (HPLdel) instead of HPLwt failed to obtain greater quantities of hexanal or 3Z-hexenal. No undesirable products were formed, and no isomerization of 3Z-hexenal in 2E-hexenal occurred. The olive recombinant HPLwt appears to be a promising efficient biocatalyst for the production of C6-aldehydes.

  11. Amine-Free Synthesis of Cesium Lead Halide Perovskite Quantum Dots for Efficient Light-Emitting Diodes

    Yassitepe, Emre


    Cesium lead halide perovskite quantum dots (PQDs) have attracted significant interest for optoelectronic applications in view of their high brightness and narrow emission linewidth at visible wavelengths. A remaining challenge is the degradation of PQDs during purification from the synthesis solution. This is attributed to proton transfer between oleic acid and oleylamine surface capping agents that leads to facile ligand loss. Here, a new synthetic method is reported that enhances the colloidal stability of PQDs by capping them solely using oleic acid (OA). Quaternary alkylammonium halides are used as precursors, eliminating the need for oleylamine. This strategy enhances the colloidal stability of OA capped PQDs during purification, allowing us to remove excess organic content in thin films. Inverted red, green, and blue PQD light-emitting diodes (LED) are fabricated for the first time with solution-processed polymer-based hole transport layers due to higher robustness of OA capped PQDs to solution processing. The blue and green LEDs exhibit threefold and tenfold improved external quantum efficiency (EQE), respectively, compared to prior related reports for amine/ammonium capped cross-linked PQDs. The brightest blue LED based on all inorganic CsPb(Br1- xClx)3 PQDs is also reported. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Efficient formation of luminescent lanthanide(III) complexes by solid-phase synthesis and on-resin screening.

    Nakamura, Tatsuya; Mizukami, Shin; Tanaka, Miho; Kikuchi, Kazuya


    Time-resolved luminescence measurements of luminescent lanthanide complexes have advantages in biological assays and high-throughput screening, owing to their high sensitivity. In spite of the recent advances in their energy-transfer mechanism and molecular-orbital-based computational molecular design, it is still difficult to estimate the quantum yields of new luminescent lanthanide complexes. Herein, solid-phase libraries of luminescent lanthanide complexes were prepared through amide-condensation and Pd-catalyzed coupling reactions and their luminescent properties were screened with a microplate reader. Good correlation was observed between the time-resolved luminescence intensities of the solid-phase libraries and those of the corresponding complexes that were synthesized by using liquid-phase chemistry. This method enabled the rapid and efficient development of new sensitizers for Sm(III), Eu(III), and Tb(III) luminescence. Thus, solid-phase combinatorial synthesis combined with on-resin screening led to the discovery of a wide variety of luminescent sensitizers.

  13. Sodium alginate: An efficient biopolymeric catalyst for green synthesis of 2-amino-4H-pyran derivatives.

    Dekamin, Mohammad G; Peyman, S Zahra; Karimi, Zahra; Javanshir, Shahrzad; Naimi-Jamal, M Reza; Barikani, Mehdi


    Sodium alginate, a naturally occurring macromolecule, in its granular form and without any post-modification was found to be an efficient and recoverable bifunctional heterogeneous organocatalyst for the domino synthesis of various 2-amino-3-cyano-4H-pyran annulated derivatives through three-component condensation of different aldehydes, malononitrile and diverse 1,3-dicarbonyl compounds under mild conditions. Corresponding 4H-pyran derivatives were obtained in high to excellent yields after 25-150min stirring in 2mL EtOH under reflux conditions in the presence of 10mol% of sodium alginate, equimolar amounts of aldehydes, malononitrile and 1,3-dicarbonyl compounds. The catalyst was easily separated from the reaction mixture to obtain desired products in excellent purity as shown by FTIR and (1)H NMR spectroscopic methods. Avoiding the use of any transition metal, one-pot and multi-component procedure catalyzed by a renewable biopolymer, the reusability of the catalyst, broad substrate scope and operational simplicity are important features of this methodology for preparation of medicinally important compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Hydrothermal synthesis of rutile–anatase TiO{sub 2} nanobranched arrays for efficient dye-sensitized solar cells

    Kwon, Soon Jin; Im, Hyo Been [Graduate School of Energy Science and Technology, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Nam, Jung Eun; Kang, Jin Kyu [Advanced Convergence Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 50-1, Sang-ri, Hyeonpung-myeon, Dalseong-gun, Daegu 711-873 (Korea, Republic of); Hwang, Taek Sung [Department of Chemical Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Yi, Kwang Bok, E-mail: [Department of Chemical Engineering Education, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of)


    Highlights: • The unique rutile–anatase TiO{sub 2} nanobranched arrays have been synthesized for DSSC application. • TiO{sub 2} nano-structure consists of anatase nanobranches covering of rutile nanorod surfaces. • The successful attachment of anatase TiO{sub 2} nanobranches to the nanorods is achieved by TiCl{sub 4} treatment. - Abstract: Rutile–anatase TiO{sub 2} nanobranched arrays were prepared in two sequential hydrothermal-synthesis steps. The morphologies and crystalline nanostructures of the samples were investigated by controlling growth time and the concentration of the titanium precursor. All samples were characterized by field-emission scanning electron microscopy and X-ray diffraction analysis. It was found that treating the surfaces of rutile TiO{sub 2} nanorods with aqueous TiCl{sub 4} solutions allows the anatase TiO{sub 2} nanobranches to grow perpendicular to the main rutile TiO{sub 2} nanorods attached to the FTO glass. Irregularly shaped, dense TiO{sub 2} structures formed in the absence of TiCl{sub 4} treatment. A light-to-electricity conversion efficiency of 3.45% was achieved using 2.3 μm tall TiO{sub 2} nanobranched arrays in a dye-sensitized solar cell. This value is significantly higher than that observed for pure rutile TiO{sub 2} nanorods.

  15. Self-templated synthesis of TiO2 hierarchical structure photocatalyst with high efficiency and good sedimentation property

    Wang, Xiaoning; Sang, Yuanhua; Yu, Xin; Liu, Baishan; Liu, Hong


    The balance between highly efficient photocatalysis and a good emulsion/water extraction property is crucial for the practical application of TiO2 photocatalysts. The TiO2 hierarchical structure was synthesized via a hydrothermal treatment of H2Ti3O7 nanobelts with TiF4. The hydrolysis of TiF4 supplies the TiO2 nucleus, and HF, which is derived from the hydrolysis process, acts as a corrosive to etch the H2Ti3O7 nanobelt, resulting in a dynamic dissolution and precipitation process. The etching process resulted in self-generated TiF4 and initiated hydrolysis to generate new TiO2 primary particles. Induced by F etching process, Ti3+ defects were formed in the hierarchical structures, which was beneficial to the photocatalytic property. This hydrolysis-etching-hydrolysis process allows for template dissolution and self-assembly of anatase TiO2 nanobelts to form the TiO2 hierarchical structures. This process balances the nanominiaturization and sedimentation property requirements by the photocatalytic and emulsion/water extraction properties. This simple hydrolysis-etching-hydrolysis process can be applied to the synthesis of many other hierarchical structures.

  16. Polyoxometalate-mediated one-pot synthesis of Pd nanocrystals with controlled morphologies for efficient chemical and electrochemical catalysis.

    Kim, Dongheun; Seog, Ji Hyun; Kim, Minjune; Yang, MinHo; Gillette, Eleanor; Lee, Sang Bok; Han, Sang Woo


    Polyoxometalates (POMs), as inorganic ligands, can endow metal nanocrystals (NCs) with unique reactivities on account of their characteristic redox properties. In the present work, we present a facile POM-mediated one-pot aqueous synthesis method for the production of single-crystalline Pd NCs with controlled shapes and sizes. The POMs could function as both reducing and stabilizing agents in the formation of NCs, and thus gave a fine control over the nucleation and growth kinetics of NCs. The prepared POM-stabilized Pd NCs exhibited excellent catalytic activity and stability for electrocatalytic (formic acid oxidation) and catalytic (Suzuki coupling) reactions compared to Pd NCs prepared without the POMs. This shows that the POMs play a pivotal role in determining the catalytic performance, as well as the growth, of NCs. We envision that the present approach can offer a convenient way to develop efficient NC-based catalyst systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Controllable Electrochemical Synthesis of Reduced Graphene Oxide Thin-Film Constructed as Efficient Photoanode in Dye-Sensitized Solar Cells

    Soon Weng Chong


    Full Text Available A controllable electrochemical synthesis to convert reduced graphene oxide (rGO from graphite flakes was introduced and investigated in detail. Electrochemical reduction was used to prepare rGO because of its cost effectiveness, environmental friendliness, and ability to produce rGO thin films in industrial scale. This study aimed to determine the optimum applied potential for the electrochemical reduction. An applied voltage of 15 V successfully formed a uniformly coated rGO thin film, which significantly promoted effective electron transfer within dye-sensitized solar cells (DSSCs. Thus, DSSC performance improved. However, rGO thin films formed in voltages below or exceeding 15 V resulted in poor DSSC performance. This behavior was due to poor electron transfer within the rGO thin films caused by poor uniformity. These results revealed that DSSC constructed using 15 V rGO thin film exhibited high efficiency (η = 1.5211% attributed to its higher surface uniformity than other samples. The addition of natural lemon juice (pH ~ 2.3 to the electrolyte accelerated the deposition and strengthened the adhesion of rGO thin film onto fluorine-doped tin oxide (FTO glasses.

  18. Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions.

    Nad, Shreya; Gu, Yajun; Asmussen, Jes


    The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100-260 Torr pressure range and 1.5-2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficiencies (η(coup)) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance.

  19. Emulsion Synthesis of Size-Tunable CH3NH3PbBr3 Quantum Dots: An Alternative Route toward Efficient Light-Emitting Diodes.

    Huang, Hailong; Zhao, Fangchao; Liu, Lige; Zhang, Feng; Wu, Xian-gang; Shi, Lijie; Zou, Bingsuo; Pei, Qibing; Zhong, Haizheng


    We report a facile nonaqueous emulsion synthesis of colloidal halide perovskite quantum dots by controlled addition of a demulsifier into an emulsion of precursors. The size of resulting CH3NH3PbBr3 quantum dots can be tuned from 2 to 8 nm by varying the amount of demulsifier. Moreover, this emulsion synthesis also allows the purification of these quantum dots by precipitation from the colloidal solution and obtains solid-state powder which can be redissolved for thin film coating and device fabrication. The photoluminescence quantum yields of the quantum dots is generally in the range of 80-92%, and can be well-preserved after purification (∼80%). Green light-emitting diodes fabricated comprising a spin-cast layer of the colloidal CH3NH3PbBr3 quantum dots exhibited maximum current efficiency of 4.5 cd/A, power efficiency of 3.5 lm/W, and external quantum efficiency of 1.1%. This provides an alternative route toward high efficient solution-processed perovskite-based light-emitting diodes. In addition, the emulsion synthesis is versatile and can be extended for the fabrication of inorganic halide perovskite colloidal CsPbBr3 nanocrystals.

  20. Human Stn1 protects telomere integrity by promoting efficient lagging-strand synthesis at telomeres and mediating C-strand fill-in

    Chenhui Huang; Xueyu Dai; Weihang Chai


    Telomere maintenance is critical for genome stability.The newly-identified Ctc1/Stn1/Ten1 complex is important for telomere maintenance,though its precise role is unclear.We report here that depletion of hStn1 induces catastrophic telomere shortening,DNA damage response,and early senescence in human somatic cells.These phenotypes are likely due to the essential role of hStn1 in promoting efficient replication of lagging-strand telomeric DNA.Downregulation of hStn1 accumulates single-stranded G-rich DNA specifically at lagging-strand telomeres,increases telomere fragility,hinders telomere DNA synthesis,as well as delays and compromises telomeric C-strand synthesis.We further show that hStn1 deficiency leads to persistent and elevated association of DNA polymerase α(polα)to telomeres,suggesting that hStn1 may modulate the DNA synthesis activity of polα rather than controlling the loading of polα to telomeres.Additionally,our data suggest that hStn1 is unlikely to be part of the telomere capping complex.We propose that the hStn1 assists DNA polymerases to efficiently duplicate lagging-strand telomeres in order to achieve complete synthesis of telomeric DNA,therefore preventing rapid telomere loss.

  1. An efficient and convenient synthesis of N-substituted amides under heterogeneous condition using Al(HSO4)3 via Ritter reaction

    Elnaz Karimian; Batool Akhlaghinia; Sara S E Ghodsinia


    An efficient and inexpensive synthesis of N-substituted amides from the reaction of aliphatic and aromatic nitriles with various benzylic alcohols (secondary and tertiary) and tert-butyl alcohol by refluxing nitromethane via the Ritter reaction catalyzed by aluminum hydrogen sulfate [Al(HSO4)3] is described. Thecatalyst which is an air-stable, cost-effective solid acid could be readily recycled by filtration and reused four times without any significant loss of its activity.

  2. An efficient Biginelli one-pot synthesis of new benzoxazole-substituted dihydropyrimidinones and thiones catalysed by trifluoro acetic acid under solvent-free conditions

    D.Shobha; M.Adharvana Chari; K.H.Ahn


    An efficient synthesis of benzoxazole-substituted 3,4-dihydropyrimidinones(DHPMs)using trifluoro acetic acid as the catalyst for the first time from an aldehyde,β-keto ester and benzoxazole-substituted urea/thiourea under solvent-free conditions is described.Compared to the classical Biginelli reaction conditions,this new method consistently has the advantage of excellent yields(80-91%)and short reaction time(40-130 min)at reflux temperature.

  3. In vitro slow-release urea contained in rice straw-based diets to increase efficiency of rumen microbial protein synthesis

    Dede Kardaya; K. G. Wiryawan; A. Parakkasi; H.M Winugroho


    Effect of slow-release urea on efficiency of rumen microbial protein synthesis (EMPS) was examined using an in vitro technique. The objective of this experiment was to reveal the in vitro slow-release urea characteristics of zinc-urea, zeolites-urea, and zeolites-zinc-urea in relation to EMPS observed in different incubation time. The experimental design employed was randomized block design with 4 x 3 factorial plus a control treatment, and conducted in two replications. Factors were various ...

  4. A novel and an efficient catalyst for one-pot synthesis of 2,4,5-trisubstituted imidazoles by using microwave irradiation under solvent-free conditions

    Javad Safari; Shiva Dehghan Khalili; Sayed Hossein Banitaba


    (NH4)6Mo7O24.4H2O has been used as an efficient catalyst for an improved and rapid synthesis of 2,4,5-trisubstituted imidazoles by a three-component, one-pot condensation of benzil, aryl aldehydes and ammonium acetate in good yields under solvent-free conditions using microwave irradiation. The reactions in conventional heating conditions were compared with the microwave-assisted reactions.

  5. Efficient solvent-free synthesis of pyridopyrazine and quinoxaline derivatives using copper-DiAmSar complex anchored on SBA-15 as a reusable catalyst

    Marzieh Mohammadi; Ghasem Rezanejade Bardajee; Nader Noroozi Pesyan


    A catalytic system comprising mesoporous silica functionalized with Cu(II)-DiAmSar was synthe-sized. This was demonstrated as an efficient heterogeneous catalyst for the synthesis of biologically useful pyridopyrazine and quinoxaline heterocycles under solvent-free conditions. X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, Fourtier transformation infrared spectroscopy, and thermogravimetric analysis were used to characterize the catalyst and investi-gate the texture of SBA-15 during the grafting process.

  6. Zirconium Oxide Nanoparticles as an Efficient Catalyst for Three-Component Synthesis of Pyrazolo[1,2-A][1,2,4]Triazole-1,3-Diones Derivatives

    Hossein Anaraki-Ardakani


    Full Text Available An efficient and green protocol for the synthesis of pyrazolo[1,2-a][1,2,4]triazole-1,3-diones derivatives by one pot, three component coupling reaction of aromatic aldehyde, malononitrile, and 4-phenylurazole has been developed using ZrO2 nanoparticles (NPs as the catalyst. The procedure is formed in high yields, short reaction time and an environmentally friendly specificity

  7. Cellulose-Sulfuric Acid as an Efficient Biosupported Catalyst in One-Pot Synthesis of Novel Heteroaryl Substituted 1,4-Dihydropyridines

    Manouchehr Mamaghani


    Full Text Available An efficient method for the synthesis of new heteroaryl substituted dihydropyridine derivatives via a one-pot four-component coupling reaction of heteroaldehyde, 1,3-diketone, ethylacetoacetate, and amonium acetate in the presence of cellulose-sulfuric acid as a biosupported solid acid catalyst was developed. The reaction gave the new derivatives of fused 1,4-dihydropyridines in lower reaction times and excellent yields (85–95%.

  8. Efficient synthesis of 1-azadienes derived from alpha-aminoesters. Regioselective preparation of alpha-dehydroamino acids, vinylglycines, and alpha-amino acids.

    Palacios, Francisco; Vicario, Javier; Aparicio, Domitila


    An efficient synthesis of 1-azadienes derived from alpha-aminoesters is achieved through an aza-Wittig reaction of phosphazenes with beta,gamma-unsaturated alpha-ketoesters. Regioselective 1,2-reduction of these functionalized 1-azadienes affords vinylglycine derivatives, while conjugative 1,4-reduction gives alpha-dehydroamino acid compounds. Reduction of both the carbon-carbon and the imine-carbon-nitrogen double bonds leads to the formation of alpha-amino acid derivatives.

  9. Nanocrystalline MgAl2O4 as an efficient catalyst for one-pot synthesis of multisubstituted imidazoles under solvent-free conditions

    Javad Safari


    Full Text Available An efficient and eco-friendly procedure has been developed using nanocrystalline MgAl2O4 with specific surface area as catalyst for rapid and an improved synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted imidazoles under solvent-free conditions in excellent yields. The method has several benefits, such as shorter reaction time, recyclable catalyst and excellent yields.

  10. An Efficient Synthesis of de novo Imidates via Aza-Claisen Rearrangements of N-Allyl Ynamides.

    Dekorver, Kyle A; North, Troy D; Hsung, Richard P


    A novel thermal 3-aza-Claisen rearrangement of N-allyl ynamides for the synthesis of α-allyl imidates is described. Also, a sequential aza-Claisen, Pd-catalyzed Overman rearrangement is described for the synthesis of azapine-2-ones.

  11. Witting Reaction Using a Stabilized Phosphorus Ylid: An Efficient and Stereoselective Synthesis of Ethyl Trans-Cinnamate

    Speed, Traci J.; Mclntyre, Jean P.; Thamattoor, Dasan M.


    An instructive experiment for the synthesis of ethyl trans-cinnamate, a pleasant smelling ester used in perfumery and flavoring by the reaction of benzaldehyde with the stable ylid triphenylphosphorane is described. The synthesis, workup and characterization of trans-cinnamate may be accomplished in a single laboratory session with commonly…

  12. Efficient, green and solvent-free synthesis of tetrasubstituted imidazoles using SbCl3/SiO2 as heterogeneous catalyst

    Javad Safari; Soheila Gandomi-Ravandi; Simin Naseh


    Antimony trichloride absorbed on silica gel (SbCl3/SiO2) efficiently catalyses the four-component cyclocondensation of 1,2-diketone, aldehyde, ammonium acetate, and primary amine under solvent-free conditions to afford the corresponding tetrasubstituted imidazoles in high yields. The main merit of this study is introducing a novel catalyst to successful synthesis of a wide range of 1,2,4,5-tetrasubstituted imidazoles for the first time. The proposed method involves features such as simplicity, generality, fairly good efficiency, and reusability of the catalyst.

  13. Potassium phthalimide as efficient basic organocatalyst for the synthesis of 3,4-disubstituted isoxazol-5(4H-ones in aqueous medium

    Hamzeh Kiyani


    Full Text Available Potassium phthalimide (PPI is employed as an efficient and effective basic organocatalyst for the one-pot three-component reaction of β-oxoesters with hydroxylamine hydrochloride and various aromatic aldehydes. This cyclocondensation reaction was performed in water as an environmentally benign solvent at room temperature giving 3,4-disubstituted isoxazol-5(4H-ones in good to excellent yields. PPI was found to be an effective organocatalyst for the synthesis of isoxazol-5(4H-one system. The advantages of this method are efficiency, clean, easy work-up, high yields, shorter reaction times, inexpensive, and readily available catalyst.

  14. Synthesis of Sr2Si5N8:Ce3+ phosphors for white LEDs via an efficient chemical deposition

    Yang, Che-Yuan; Som, Sudipta; Das, Subrata; Lu, Chung-Hsin


    Novel chemical vapor deposition (CVD) process was successfully developed for the growth of Sr2Si5N8:Ce3+ phosphors with elevated luminescent properties. Metallic strontium was used as a vapor source for producing Sr3N2 vapor to react with Si3N4 powder via a homogeneous gas-solid reaction. The phosphors prepared via the CVD process showed high crystallinity, homogeneous particle size ranging from 8 to 10 μm, and high luminescence properties. In contrast, the phosphors prepared via the conventional solid-state reaction process exhibited relative low crystallinity, non-uniform particle size in the range of 0.5–5 μm and relatively lower luminescent properties than the phosphors synthesized via the CVD process. Upon the blue light excitation, Sr2−xCexSi5N8 phosphors exhibited a broad yellow band. A red shift of the emission band from 535 to 556 nm was observed with the increment in the doping amount of Ce3+ ions from x = 0.02 to x = 0.10. The maximum emission was observed at x = 0.06, and the external and internal quantum efficiencies were calculated to be 51% and 71%, respectively. Furthermore, the CVD derived optimum Sr1.94Ce0.06Si5N8 phosphor exhibited sufficient thermal stability for blue-LEDs and the activation energy was calculated to be 0.33 eV. The results demonstrate a potential synthesis process for nitride phosphors suitable for light emitting diodes. PMID:28361999

  15. Synthesis of highly phosphonic acid functionalized benzene-bridged periodic mesoporous organosilicas for use as efficient dye adsorbents

    Deka, Juti Rani; Liu, Chia-Ling; Wang, Tzu-Hua; Chang, Wei-Chieh; Kao, Hsien-Ming, E-mail:


    Highlights: • Synthesis of highly phosphonic acid functionalized benzene-bridged PMOs. • Phosphonic acid loaded PMOs as adsorbent for cationic and anionic dyes. • Due to electrostatic interaction the adsorbent has high dye adsorption capacity. • π–π stacking interaction between benzene and dye enhances adsorption capacity. • Intraparticle diffusion played a dominant role in the adsorption process. - Abstract: Periodic mesoporous organosilicas (PMOs) with benzene bridging groups in the silica wall were functionalized with a tunable content of phosphonic acid groups. These bifunctional materials were synthesized by co-condensation of two different organosilane precursors, that is, 1,4-bis(triethoxysilyl)benzene (BTEB) and sodium 3-(trihydroxysilyl)propyl methyl phosphate (SPMP), under acidic conditions using nonionic surfactant Brij-S10 as template. The materials exhibited well-ordered mesostructures and were characterized by X-ray diffraction, nitrogen sorption, TEM, TGA, FTIR, and solid-state NMR measurements. The materials thus obtained were employed as adsorbents to remove different types of dyes, for example, cationic dyes methylene blue and phenosafranine, anionic orange II, and amphoteric rhodamine B, from aqueous solutions. The materials exhibited a remarkably high adsorption capacity than activated carbon due to their ordered mesostructures, a large number of phosphonic acid groups, and high surface areas. The adsorption was mainly governed by electrostatic interaction, but also involved π–π stacking interaction as well as hydrogen bonding. The adsorption kinetics can be better fitted by the pseudo-second order model. The adsorption process was controlled by the mechanisms of external mass transfer and intraparticle diffusion. The materials retained more than 97% dye removal efficiency after use for five consecutive cycles.

  16. Template-Engaged Solid-State Synthesis of Barium Magnesium Silicate Yolk@Shell Particles and Their High Photoluminescence Efficiency.

    Chen, Xuncai; Kim, Woo-Sik


    This study presents a new synthetic method for fabricating yolk@shell-structured barium magnesium silicate (BMS) particles through a template-engaged solid-state reaction. First, as the core template, (BaMg)CO3 spherical particles were prepared based on the coprecipitation of Ba(2+) and Mg(2+) . These core particles were then uniformly shelled with silica (SiO2 ) by using CTAB as the structure-directing template to form (BaMg)CO3 @SiO2 particles with a core@shell structure. The (BaMg)CO3 @SiO2 particles were then converted to yolk@shell barium magnesium silicate (BMS) particles by an interfacial solid-state reaction between the (BaMg)CO3 (core) and the SiO2 (shell) at 750 °C. During this interfacial solid-state reaction, Kirkendall diffusion contributed to the formation of yolk@shell BMS particles. Thus, the synthetic temperature for the (BaMg)SiO4 :Eu(3+) phosphor is significantly reduced from 1200 °C with the conventional method to 750 °C with the proposed method. In addition, the photoluminescence intensity of the yolk@shell (BaMg)SiO4 :Eu(3+) phosphor was found to be 9.8 times higher than that of the conventional (BaMg)SiO4 :Eu(3+) phosphor. The higher absorption of excitation light by the structure of the yolk@shell phosphor is induced by multiple light-reflection and -scattering events in the interstitial void between the yolk and the shell. When preparing the yolk@shell (BaMg)SiO4 :Eu(3+) phosphor, a hydrogen environment for the solid-state reaction results in higher photoluminescence efficiency than nitrogen and air environments. The proposed synthetic method can be easily extended to the synthesis of other yolk@shell multicomponent metal silicates.

  17. Surface modified magnetic nanoparticles as efficient and green sorbents: Synthesis, characterization, and application for the removal of anionic dye

    Rajabi, Hamid Reza, E-mail:; Arjmand, Hooman; Hoseini, S. Jafar; Nasrabadi, Hasan


    The object of this study was to evaluate the removal efficiency of sunset yellow (SY) anionic dye from aqueous solutions by using new surface modified iron oxide magnetic nanoparticles (MNPs). Pure Fe{sub 3}O{sub 4} MNPs were synthesized and then functionalized by aminopropyltriethoxysilane (APTES), through a chemical precipitation method. Characterization of the prepared MNP adsorbents was performed by furrier transform infrared (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and transmission electron microscopy (TEM). According to XRD and TEM results, average size of the magnetic Fe{sub 3}O{sub 4}/APTES NPs was estimated to be around 12 nm. The prepared magnetic adsorbent can be well dispersed in the water and easily separated magnetically from the medium after loaded with adsorbate. In the adsorption process, the effect of main experimental parameters such as pH of dye solution, initial concentration of SY dye, reaction time, and amount of MNP adsorbent on the removal of SY were studied and optimized. The small amount of this adsorbent (10 mg) is applicable for the removal of high concentrations of SY dye in reasonable time (17 min), at pH 3.1. Additionally, the adsorption studies show that the Langmuir model is a suitable model to explain the experimental data with high correlation coefficient. - Highlights: • Synthesis of nano-sized modified iron oxide magnetic particles. • Characterization of the modified MNPs by XRD, TEM, VSM, FT-IR techniques. • Design of experiments for removal of SY dye using MNPs. • Adsorption isotherm and kinetic investigation of the reaction.

  18. Supplementation strategies to improve efficiency of rumen microbial protein synthesis on cattles fed with tropical grass hay

    Marthen L Mulik


    Full Text Available This experiment aimed at increasing rumen microbial protein supply into intestine through ration manipulation. Four Santa Gertrudis steers with a mean liveweight (W of 218 (±5.6 kg were used in a latin square design (4 x 4 to observe the effect of four diets on the efficiency of rumen microbial protein synthesis (EMPS. The steers were given pangola grass hay (8.5% protein as the basal diet. The treatments were 1 pangola grass hay alone (KON, 2 pangola grass hay + 19 g urea/kg dry matter (DM hay (URE, 3 as for treatment URE + a supplement mix at 0.5% W (SUP, and 4 as for treatment SUP + salt at 0.15% W (SUG. Urea was added into the hay to support a theoretical EMPS of 160 g MCP/kg digestible organic matter (DOM whereas supplement mix contains fast, medium, and slow rumen fermentable energy and protein to synchronise energy and protein release in the rumen. Salt was added to alter passage rate of digesta. Addition of urea alone or with supplement mix increased EMPS significantly compared to KON (77 g MCP/kg DOM but no difference between URE (119 g MCP/kg DOM and SUP (110 g MCP/kg DOM. Addition of salt into supplement mix increased EMPS by 84% (140 g MCP/kg DOM. It might be concluded that rumen degradable protein (RDP was deficient in steers fed low quality grass hay hence urea supplementation significantly increased EMPS to a similar extent as that of the supplement mix formulated to have a synchrony in protein and energy release. Increasing fluid dilution rate, by adding salt, also had a dramatic affect on EMPS as observed in treatment SUG. It increased up to the level suggested in the International feeding standards.

  19. B(C6F5)3 catalyzed one-pot three-component Biginelli reaction: An efficient and environmentally benign protocol for the synthesis of 3,4-dihydropyrimidin-2(1)-ones/thiones

    Santosh Kumar Prajapti; Keshav Kumar Gupta; Bathini Nagendra Babu


    Tris(pentafluorophenyl)borane catalyzed, one-pot, simple, efficient and environmentally benign protocol for the synthesis of dihydropyrimidinones/thiones via Biginelli reaction has been described. The main highlights of the present protocol is low catalyst loading, low toxicity, compatibility with acid-labile-protecting groups, short reaction time, consistently excellent yields and simple reaction/workup procedure. Moreover, the applicability of the present methodology for large-scale synthesis of monastrol highlights its potential for bulk synthesis.

  20. Trypsin-catalyzed multicomponent reaction: A novel and efficient one-pot synthesis of thiazole-2-imine derivatives.

    Zhou, Junbin; Huang, Xingtian; Zhang, Zhuan; Song, Ping; Li, Yiqun


    The first Trypsin from porcine pancreas catalyzed a novel one-pot three-component reaction of α-bromoketone, primary alkylamines, and phenylisothiocyanate for the synthesis of thiazole-imine derivatives with high yields (up to 98%) in a short time under mild conditions. The results revealed that Trypsin exhibited excellent catalytic activity and great tolerance for broad substrates. This Trypsin-catalyzed three component convergent method provides a novel strategy for the synthesis of thiazole-2-imine derivatives and expands the promiscuous functions of enzymes in organic synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Synthesis of modified proanthocyanidins: easy and general introduction of a hydroxy group at C-6 of catechin; efficient synthesis of elephantorrhizol.

    Boyer, François-Didier; Es-Safi, Nour-Eddine; Beauhaire, Josiane; Guernevé, Christine Le; Ducrot, Paul-Henri


    A general procedure for the oxidation of catechin derivatives is described, leading to the introduction of a new hydroxy group at C-6. This procedure has been applied for the synthesis of elephantorrhizol, a natural flavan-3-ol exhibiting a fully substituted cycle A.

  2. A Novel and Efficient Five-Component Synthesis of Pyrazole Based Pyrido[2,3-d]pyrimidine-diones in Water: A Triply Green Synthesis

    Majid M. Heravi


    Full Text Available A novel one pot synthesis of pyrazolo[4′,3′:5,6]pyrido[2,3-d]pyrimidine-diones, via a five-component reaction, involving, hydrazine hydrate, ethyl acetoacetate, and 1,3-dimethyl barbituric acid, an appropriate aryl aldehydes and ammonium acetate catalyzed via both of heterogeneous and homogeneous catalysis in water, is reported.

  3. An efficient method for the synthesis of dialkyl chlorophosphates from trialkyl phosphites using bis(trichloromethyl) carbonate

    Bo Wang; Chuan Ming Yu; Zhi Wei Chen; Wei Ke Su


    A mild and simple method for the synthesis of dialkyl clalorophosphates is described, bis(trichloromethyl) carbonate (BTC) is used as the effective reagent for the conversion of dialkyl phosphites to their corresponding dialkyl chlorophosphates under mild conditions.

  4. Ba/ZrO₂ nanoparticles as efficient heterogeneous base catalyst for the synthesis of β-nitro alcohols and 2-amino 2-chromenes



    Zirconia nanoparticles were synthesized by precipitation, urea hydrolysis, amorphous citrate and combustion synthesis methods. The zirconia surface was subsequently modified by grafting Ba²⁺ species. The Ba²⁺ modified zirconia (Ba/ZrO₂) materials were characterized using XRD, Fourier analysis, UV-vis-DRS, FESEM and HRTEM techniques. XRD study indicated selective stabilization of the tetragonal phase of zirconia in the presence of Ba²⁺ species. Fourier line profile analysis of the XRD peaks revealed that the average crystallite size of the zirconia nanoparticles is in the range of 5-15 nm. The surface area, basicity and barium content of the material depend strongly on the method of synthesis. The Ba/ZrO₂ catalyst prepared by urea hydrolysis method exhibited higher surface area and barium content compared to other samples. The catalytic activity of the Ba/ZrO₂ catalyst was evaluated for synthesis of β-nitro alcohols and 2-amino 2-chromenes. The β-nitro alcohols were synthesized by condensation of aryl aldehydes and nitromethane. Similarly, the 2-amino 2-chromenes were synthesized by condensation of arylaldehydes, α-naphthol and malononitrile. The Ba/ZrO₂ catalyst was found to be highly efficient for synthesis of both classes of compounds providing excellent yield and purity of the products.

  5. Water as a green solvent for efficient synthesis of isocoumarins through microwave-accelerated and Rh/Cu-catalyzed C-H/O-H bond functionalization

    Li, Qiu; Yan, Yunnan; Wang, Xiaowei; Gong, Binwei; Tang, Xiaobo; Shi, JingJing; Xu, H. Eric; Yi, Wei [Shenyang; (Gannan); (Van Andel); (UST - China); (Chinese Aca. Sci.)


    Green chemistry that uses water as a solvent has recently received great attention in organic synthesis. Here we report an efficient synthesis of biologically important isocoumarins through direct cleavage of C–H/O–H bonds by microwave-accelerated and Rh/Cu-catalyzed oxidative annulation of various substituted benzoic acids, where water is used as the only solvent in the reactions. The remarkable features of this “green” methodology include high product yields, wide tolerance of various functional groups as substrates, and excellent region-/site-specificities, thus rendering this methodology a highly versatile and eco-friendly alternative to the existing methods for synthesizing isocoumarins and other biologically important derivatives such as isoquinolones.

  6. An Efficient One-pot Synthesis of β-Amino/β-Acetamido Car-bonyl Compounds via ZrCl4-catalyzed Mannich-type Reaction



    Zirconium(IV) chloride catalyzed efficient one-pot synthesis of β-amino/β-acetamido carbonyl compounds at room temperature is described. In the presence of ZrCl4, the three-component Mannich-type reaction via a variety of in situ generated aldimines, with various ketones, aromatic aldehydes and aromatic amines in ethanol, led to the formation of β-amino carbonyl compounds and the four-component Mannich-type reaction of aromatic aldehydes with various ketones, acetonitrile and acetyl chloride resulted in the corresponding β-acetamido carbonyl com-pounds in high to excellent yields. This methodology has also been applied towards the synthesis of dimeric β-amino/β-acetamido carbonyl compounds.

  7. Rational design and synthesis of efficient Carbon and/or Silica functional nanomaterials for electrocatalysis and nanomedicine

    Da Silva, Rafael

    In nanomaterials there is a strong correlation between structure and properties. Thus, the design and synthesis of nanomaterials with well-defined structures and morphology is essential in order to produce materials with not only unique but also tailorable properties. The unique properties of nanomaterials in turn can be taken advantage of to create materials and nanoscale devices that can help address important societal issues, such as meeting renewable energy sources and efficient therapeutic and diagnostic methods to cure a range of diseases. In this thesis, the different synthetic approaches I have developed to produce functional nanomaterials composed of earth-abundant elements (mainly carbon and silica) at low cost in a very sustainable manner are discussed. In Chapter 1, the fundamental properties of nanomaterials and their properties and potential applications in many areas are introduced. In chapter 2, a novel synthetic method that allows polymerization of polyaniline (PANI), a conducting polymer, inside cylindrical channel pores of nanoporous silica (SBA-15) is discussed. In addition, the properties of the III resulting conducting polymer in the confined nanochannel spaces of SBA-15, and more importantly, experimental demonstration of the use of the resulting hybrid material (PANI/SBA-15 material) as electocatalyst for electrooxidation reactions with good overpotential, close to zero, are detailed. In chapter 3, the synthetic approach discussed in Chapter 2 is further extended to afford nitrogen- and oxygen-doped mesoporous carbons. This is possible by pyrolysis of the PANI/SBA-15 composite materials under inert atmosphere, followed by etching away their silica framework. The high catalytic activity of resulting carbon-based materials towards oxygen reduction reaction despite they do not possess any metal dopants is also included. The potential uses of nanomaterials in areas such as nanomedicine need deep understanding of the biocompatibility/ toxicity of

  8. Schwertmannite Synthesis through Ferrous Ion Chemical Oxidation under Different H2O2 Supply Rates and Its Removal Efficiency for Arsenic from Contaminated Groundwater.

    Liu, Fenwu; Zhou, Jun; Zhang, Shasha; Liu, Lanlan; Zhou, Lixiang; Fan, Wenhua


    Schwertmannite-mediated removal of arsenic from contaminated water has attracted increasing attention. However, schwertmannite chemical synthesis behavior under different H2O2 supply rates for ferrous ions oxidation is unclear. This study investigated pH, ferrous ions oxidation efficiency, and total iron precipitation efficiency during schwertmannite synthesis by adding H2O2 into FeSO4 · 7H2O solution at different supply rates. Specific surface area and arsenic (III) removal capacity of schwertmannite have also been studied. Results showed that pH decreased from ~3.48 to ~1.96, ~2.06, ~2.12, ~2.14, or ~2.17 after 60 h reaction when the ferrous ions solution received the following corresponding amounts of H2O2: 1.80 mL at 2 h (treatment 1); 0.90 mL at 2 h and 14 h (treatment 2); 0.60 mL at 2, 14, and 26 h (treatment 3); 0.45 mL at 2, 14, 26, and 38 h (treatment 4), or 0.36 mL at 2, 14, 26, 38, and 50 h (treatment 5). Slow H2O2 supply significantly inhibited the total iron precipitation efficiency but improved the specific surface area or arsenic (III) removal capacity of schwertmannite. For the initial 50.0 μg/L arsenic (III)-contaminated water under pH ~7.0 and using 0.25 g/L schwertmannite as an adsorbent, the total iron precipitation efficiency, specific surface area of the harvested schwertmannite, and schwertmannite arsenic(III) removal efficiency were 29.3%, 2.06 m2/g, and 81.1%, respectively, in treatment 1. However, the above parameters correspondingly changed to 17.3%, 16.30 m2/g, and 96.5%, respectively, in treatment 5.

  9. An Efficient, Simple and Green Zn(Phen2Cl2 Complex Catalyzed Synthesis of 4-H-Benzo[b]pyrans in Water at Ambient Temperature

    E. Mosaddegh


    Full Text Available An efficient method for the synthesis of 4-H-benzo[b]pyrans has been developed by the use of Zn(Phen2Cl2(2 mol% as an ecofriendly catalyst. The mixture of an appropriate aldehyde, malononitrile and dimedone in the presence of the Zn(Phen2Cl2 as an inorganic catalyst in water at room temperature resulted excellent yields of the corresponding products in 5 min. Very short experimental time of the reaction, excellent yields, use of water as a green solvent, simple work-up and uses no extra catalyst and purification are the advantages of this method.

  10. Rapid, efficient and eco-friendly procedure for the synthesis of quinoxalines under solvent-free conditions using sulfated polyborate as a recyclable catalyst



    An efficient and inexpensive sulfated polyborate catalyst was applied for the rapid synthesis of quinoxaline derivatives from various substituted o-phenylenediamines and 1,2-diketones/α-hydroxy ketones using sulfated polyborate is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and recyclability without significant loss in catalytic activity. The key advantages of the present method are high yields, short reaction times, solvent-free condition, easy workup, and ability to tolerate a variety of functional groups, which give economical as well as ecological rewards.

  11. Green and efficient synthesis of aryl/alkylbis(indolyl)methanes using Expanded Perlite-PPA as a heterogeneous solid acid catalyst in aqueous media



    Expanded Perlite-Polyphosphoric acid (EP-PPA) as a novel, efficient, recyclable and eco-benign heterogeneous catalyst has been applied for the green and rapid synthesis of aryl/alkylbis(indolyl)methanes, in water, in good to excellent yields. The catalyst was characterized by XRF, FT-IR, TGA/DTG, ICP-OES, SEMEDX and pH analysis. Importantly, the newly synthesized heterogeneous solid acid catalyst can be recovered and reused six times without any significant loss in its catalytic potential. The remarkable features of thepresent methodology are high conversions, shorter reaction times, cleaner reaction profiles and simple work-up procedures.

  12. Highly efficient solvent-free synthesis of pyranopyrazoles by a Brønsted-acidic ionic liquid as a green and reusable catalyst

    Javad Ebrahimi; Ali Mohammadi; Vahid Pakjoo; Esan Bahramzade; Amir Habibi


    A simple, green and efficient protocol for synthesis of dihydropyrano[2,3-c]pyrazole derivatives is developed by a four component reaction of various benzaldehydes, ethyl acetoacetate, hydrazine hydrate and malononitrile in the presence of 3-methyl-1-(4-sulphonic acid)butylimidazolium hydrogen sulphate [(CH2)4SO3HMIM][HSO4], an acidic ionic liquid and as a catalyst, under solvent-free conditions. The key advantages of this process are high yields, shorter reaction times, easy work-up, purification of products by non-chromatographic method and the reusability of the catalyst.

  13. Microwave-assisted efficient synthesis of 2-arylbenzo[b]furans and 2-ferrocenylbenzo[b]furans from readily prepared propargylic alcohols and -iodophenols

    Liansheng Wu; Xiaokang Shi; Xiaoyun Xu; Fen Liang; Guosheng Huang


    A simple, efficient and expeditious method for synthesis of 2-arylbenzo[b]furans and 2-ferrocenylbenzo[b]furans from readily prepared propargylic alcohols, -iodophenols and silica gel with the catalyst of PdCl2(PPh3)2 (2 mol%)/CuI (2mol%) and microwave-promoted Sonogashira coupling/cyclization reaction is developed. The methodology can produce good to excellent yields. In addition, this method can also be completed in one-pot with iodobenzene, 2-methyl-3-butyn-2-ol and 2-iodo-4-methylphenol as reactants.

  14. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    Chinnusamy, Tamilselvi R.


    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Nanocrystalline magnesium oxide: an efficient promoter and heterogeneous nano catalyst for the one-pot synthesis of pyrazolotriazoles in green medium

    Naeimi, Hossein; Rashid, Zahra; Zarnani, Amir-Hassan; Ghahremanzadeh, Ramin


    A simple, efficient, and relatively clean method for the synthesis of pyrazolo[1,2- a][1,2,4]triazole derivatives via a one-pot three-component reaction of aromatic aldehydes, 4-phenyl-1,2,4-triazolidine-3,5-dione, and malononitrile or alkyl cyanoacetates in the presence of a catalytic amount of nanocrystalline (NC) magnesium oxide has been developed. This method has several advantages such as, high to excellent product yields, reusability of catalyst, and simple work-up procedure in the nontoxic medium.

  16. Titanocene(III)-catalyzed 6-exo versus 7-endo cyclizations of epoxypolyprenes: efficient control and synthesis of versatile terpenic building blocks.

    Justicia, José; Jiménez, Tania; Miguel, Delia; Contreras-Montoya, Rafael; Chahboun, Rachid; Alvarez-Manzaneda, Enrique; Collado-Sanz, Daniel; Cárdenas, Diego J; Cuerva, Juan M


    In this article, a complete study on the selectivity of titanocene(III) cyclization of epoxypolyprenes is presented. The requirements for the formation of six- or seven-membered rings during these cyclizations are determined, taking into account the different substitution pattern in the epoxypolyprene precursor. Thus, a complete selectivity to 6-exo or 7-endo cyclization process has been achieved, yielding mono-, bi-, and even tricyclic compounds, constituting a new and efficient access to this type of derivative. Additionally, this procedure opens the possibility to prepare excellent building blocks for the synthesis of polycyclic compounds with a trisubstituted oxygenated function, which is present in several natural terpenes.

  17. New Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H-ones Catalyzed by Benzotriazolium-Based Ionic Liquids under Solvent-Free Conditions

    Zhiqing Liu


    Full Text Available An efficient synthesis of novel 3,4-dihydropyrimidin-2(1H-ones (DHPMs and their derivatives, using Brønsted acidic ionic liquid [C2O2BBTA][TFA] as a catalyst, from the condensation of aryl aldehyde, β-ketoester and urea was described. Reactions proceeded smoothly for 40 min under solvent-free conditions and gave the desirable products with good to excellent yields (up to 99%. The catalyst could be easily recycled and reused with similar efficacies for at least six cycles.

  18. Efficient Magnesium Bromide-Catalyzed One-pot Synthesis of Substituted 1,2,3,4-Tetrahydropyrimidin-2-ones Under Solvent-free Conditions

    沙里海·H; 郭庆祥


    An efficient and environmentally friendly procedure for the one-pot synthesis of tetrahydropyrimidinones from aldehydes, β-diketones and urea/thiourea by using magnesium bromide as an inexpensive and easily available catalyst under solvent-free conditions was described. Compared with the classical Biginelli reaction conditions, this new method has the advantage of good to excellent yields (74%-94%) and short reaction time (45-90 min). The structure of the Biginelli reaction product from β-diketone, salicylaldehyde and urea has been proposed to possess an oxygen-bridge by cyclization (intramolecular Michael-addition).

  19. An efficient and more sustainable one-step continuous-flow multicomponent synthesis approach to chromene derivatives

    A simple and rapid one-step continuous-flow synthesis route has been developed for the preparation of chromene derivatives from the reaction of aromatic aldehydes, α-cyanomethylene compounds and naphthols. In this contribution, a one-step continuous-flow protocol in a continuous ...

  20. N-Methylpyridinium tosylate catalyzed green and efficient synthesis of some novel 2,4-disubstituted thiazoles and 4-thiazolidinones

    Deepika Gautam; Poonam Gautam; R.P.Chaudhary


    A convenient solvent less cyclocondensation from thiosemicarbazone of benzofuranone and chloroacetic acid using an ionic liquid,N-methylpyridinium tosylate for obtaining novel 4-thiazolidinones in excellent yields is reported.Also,the green expedient synthesis of new 2,4-disubstituted thiazoles under grinding condition from phenacyl bromides and thiosemicarbazide derivatives in quantitative yields is reported.

  1. Amine-borane assisted synthesis of wavy palladium nanorods on graphene as efficient catalysts for formic acid oxidation.

    Du, Cheng; Liao, Yuxiang; Hua, Xing; Luo, Wei; Chen, Shengli; Cheng, Gongzhen


    Wavy palladium (Pd) nanorods were obtained by controlled synthesis by using amine-boranes as the reducing agents. Thanks to the unique structure and strong interaction with graphene, the as-synthesized Pd nanorods supported on graphene exhibit much enhanced electrocatalytic activity towards formic acid oxidation as compared with Pd nanoparticles.

  2. An efficient and mild protocol for the synthesis of unsymmetrical ureas in the absence of catalyst and additives

    Rahman Hosseinzadeh; Yaghoub Sarrafi; Nora Aghili


    A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in refluxing dioxane and does not require any catalyst or additives.

  3. A Highly Efficient and Environmentally Friendly CMC-Supported Lanthanide Catalyst for One-pot Synthesis of Substituted Imidazoles

    WANG Limin; YAO Yinfang; WANG Yonghong; ZOU Gang


    A CMC-supported lanthanide catalyst was prepared from CMC and isopropoxy lanthanide. This solid Lewis acid catalyst was used in synthesis of substituted imidazoles under mild conditions, showing catalytic activity com-parable to the expensive lanthanide Lewis acid Ln(Otf)3. Furthermore, the catalyst could be readily recycled and reused for five times without any appreciable loss in catalytic activity.

  4. Eco-friendly and Efficient Synthesis of 2,3-Dihydroquinazolin-4(1 H)-ones%Eco-friendly and Efficient Synthesis of 2,3-Dihydroquinazolin-4(1 H)-ones

    Majid, Ghashang; Kobra, Azizi; Hamed, Moulavi-Pordanjani; Hamid Reza, Shaterian


    A simple and facile method for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones through the direct cyclocon- densation of one-pot three-component cyclocondensation of isatoic anhydride, ammonium acetate (or primary amines) and aldehydes; and anthranilamide and aldehydes using silica supported ferric chloride (SiO2-FeCl3) as catalyst under solvent-free conditions is described.

  5. Synthesis of Won-WX2 (n=2.7, 2.9; X=S, Se) Heterostructures for Highly Efficient Green Quantum Dot Light-Emitting Diodes

    Han, Shikui


    Preparation of two-dimensional (2D) heterostructures is important not only fundamentally, but also technologically for applications in electronics and optoelectronics. Herein, we report a facile colloidal method for the synthesis of WOn -WX2 (n=2.7, 2.9; X=S, Se) heterostructures by sulfurization or selenization of WOn nanomaterials. The WOn -WX2 heterostructures are composed of WO2.9 nanoparticles (NPs) or WO2.7 nanowires (NWs) grown together with single- or few-layer WX2 nanosheets (NSs). As a proof-of-concept application, the WOn -WX2 heterostructures are used as the anode interfacial buffer layer for green quantum dot light-emitting diodes (QLEDs). The QLED prepared with WO2.9 NP-WSe2 NS heterostructures achieves external quantum efficiency (EQE) of 8.53 %. To our knowledge, this is the highest efficiency in the reported green QLEDs using inorganic materials as the hole injection layer.

  6. Synthesis of LiFePO4@carbon nanotube core-shell nanowires with a high-energy efficient method for superior lithium ion battery cathodes

    Wang, Guiling; Ma, Zhipeng; Shao, Guangjie; Kong, Lingxue; Gao, Weimin


    A high-energy efficient method is developed for the synthesis of LiFePO4@CNT core-shell nanowire structures. The method consists of two steps: liquid deposition approach to prepare FePO4@CNT core-shell nanowires and solvothermal lithiation to obtain the LiFePO4@CNT core-shell nanowires at a low temperature. The solution phase method can be easily scaled up for commercial application. The performance of the materials produced by this method is evaluated in Li ion batteries. The one-dimensional LiFePO4@CNT nanowires offer a stable and efficient backbone for electron transport. The LiFePO4@CNT core-shell nanowires exhibit a high capacity of 132.8 mAh g-1 at a rate of 0.2C, as well as high rate capability (64.4 mAh g-1 at 20C) for Li ion storage.

  7. Efficient enantioselective synthesis of (R)-[3,5-bis(trifluoromethyl)phenyl] ethanol by Leifsonia xyli CCTCC M 2010241 using isopropanol as co-substrate.

    Ouyang, Qi; Wang, Pu; Huang, Jin; Cai, Jinbo; He, Junyao


    (R)-[3,5-Bis(trifluoromethyl)phenyl] ethanol is a key chiral intermediate for the synthesis of aprepitant. In this paper, an efficient synthetic process for (R)-[3,5- bis(trifluoromethyl)phenyl] ethanol was developed via the asymmetric reduction of 3,5-bis(trifluoromethyl) acetophenone, catalyzed by Leifsonia xyli CCTCC M 2010241 cells using isopropanol as the co-substrate for cofactor recycling. Firstly, the substrate and product solubility and cell membrane permeability of biocatalysts were evaluated with different co-substrate additions into the reaction system, in which isopropanol manifested as the best hydrogen donor of coupled NADH regeneration during the bioreduction of 3,5-bis(trifluoromethyl) acetophenone. Subsequently, the optimization of parameters for the bioreduction were undertaken to improve the effectiveness of the process. The determined efficient reaction system contained 200 mM of 3,5-bis(trifluoromethyl) acetophenone, 20% (v/v) of isopropanol, and 300 g/l of wet cells. The bioreduction was executed at 30°C and 200 rpm for 30 h, and 91.8% of product yield with 99.9% of enantiometric excess (e.e.) was obtained. The established bioreduction reaction system could tolerate higher substrate concentrations of 3,5- bis(trifluoromethyl) acetophenone, and afforded a satisfactory yield and excellent product e.e. for the desired (R)-chiral alcohol, thus providing an alternative to the chemical synthesis of (R)-[3,5-bis(trifluoromethyl)phenyl] ethanol.

  8. Rumen microbial protein synthesis and nitrogen efficiency as affected by tanniferous and non-tanniferous forage legumes incubated individually or together in Rumen Simulation Technique.

    Brinkhaus, Anja Grosse; Bee, Giuseppe; Schwarm, Angela; Kreuzer, Michael; Dohme-Meier, Frigga; Zeitz, Johanna O


    A limited availability of microbial protein can impair productivity in ruminants. Ruminal nitrogen efficiency might be optimised by combining high-quality forage legumes such as red clover (RC), which have unfavourable great ruminal protein degradability, with tanniferous legumes like sainfoin (SF) and birdsfoot trefoil (BT). Silages from SF and from BT cultivars [Bull (BB) and Polom (BP)] were incubated singly or in combination with RC using the rumen simulation technique (n=6). The tanniferous legumes, when compared to RC, changed the total short-chain fatty acid profile by increasing propionate proportions at the expense of butyrate. Silage from SF contained the most condensed tannins (CTs) (136 g CT kg(-1) dry matter) and clearly differed in various traits from the BT and RC silages. The apparent nutrient degradability (small with SF), microbial protein synthesis, and calculated content of potentially utilizable crude protein (large with SF) indicated that SF had the greatest efficiency in ruminal protein synthesis. The effects of combining SF with RC were mostly linear. The potential of sainfoin to improve protein supply, demonstrated either individually or in combination with a high-performance forage legume, indicates its potential usefulness in complementing protein-deficient ruminant diets and high-quality forages rich in rumen-degradable protein. This article is protected by copyright. All rights reserved.

  9. Efficient solar-driven synthesis, carbon capture, and desalinization, STEP: solar thermal electrochemical production of fuels, metals, bleach.

    Licht, S


    STEP (solar thermal electrochemical production) theory is derived and experimentally verified for the electrosynthesis of energetic molecules at solar energy efficiency greater than any photovoltaic conversion efficiency. In STEP the efficient formation of metals, fuels, chlorine, and carbon capture is driven by solar thermal heated endothermic electrolyses of concentrated reactants occuring at a voltage below that of the room temperature energy stored in the products. One example is CO(2) , which is reduced to either fuels or storable carbon at a solar efficiency of over 50% due to a synergy of efficient solar thermal absorption and electrochemical conversion at high temperature and reactant concentration. CO(2) -free production of iron by STEP, from iron ore, occurs via Fe(III) in molten carbonate. Water is efficiently split to hydrogen by molten hydroxide electrolysis, and chlorine, sodium, and magnesium from molten chlorides. A pathway is provided for the STEP decrease of atmospheric carbon dioxide levels to pre-industial age levels in 10 years.

  10. Highly efficient synthetic method onpyroacm resin using the boc SPPS protocol for C-terminal cysteine peptide synthesis

    Juvekar, Vinayak; Kim, Kang Tae; Gong, Young Dae [Innovative Drug Library Research Center, Dept. of Chemistry, College of Science, Dongguk University, Seoul (Korea, Republic of)


    A very effective process on Pyroacm resin was developed for solid-phase peptide synthesis (SPPS) of C-terminal cysteine and cysteine ester peptides. The process uses cysteine side chain anchoring to the Pyroacm resin and the Boc protocol for SPPS. The Pyroacm resin showed remarkable stability under standard trifluoromethanesulfonic acid (TFMSA) cleavage condition. TFMSA cleavage of protecting groups generates a peptide-linked resin, which can be subjected to peptide modification reactions. Finally, the peptide can be cleaved from the resin using methoxycarbonylsulfenyl chloride. The utility of this protocol was demonstrated by its applications to the synthesis of model peptides, key intermediates in the preparation of natural products riparin 1.2 and a-factor.

  11. Efficient Synthesis of Bi-butenolides Derivatives through Oxidative Dimeric Cyclizing-Coupling Reaction of 2,3-Allenoic Acids

    MA Sheng-Ming; YU Zhan-Qian


    @@ Allenes are three carbon functional groups possessing two perpendicular π-orbitals. Their unique reaction be havior is spread over three carbon atoms, which shows great potential in organic synthesis in terms of chirality transfer and diversity, as a result of the axial chirality as well as the substituent-loading capability. Recently, we devoted ourselves to establish a new area of oxidative cyclization-dimerization reactions between two functionalized allenes to give interesting bicyclic compounds in a single step. The formidable challenges are to match the reactivities of two allenes, and regenerate the catalyst, which would be reduced after reductive-elimination. In this paper we wish to disclose our recent studies on the synthesis of bi-butenolides from oxidative cyclization self-coupling reaction of 2,3 allenoic acids, in which a new system (PdCl2/RI/air) for regeneration of the palladium(Ⅱ) species was observed.

  12. Efficient Synthesis of 2-Ethyl-A-ring Analogues of 19-Nor-1α,25-dihydroxy Vitamin D3


    The novel 19-nor-lα,25-dihydroxy vitamin D3 analogues possessing an ethyl at the 2-position(4 and 5), were synthesized by coupling 25-hydroxy Windaus-Grundmann ketone derivative 20 with A-ring synthons(15 and 19) respectively. The enantioselective synthesis of substituted bicyclic[3,1,0] hexanes structure A-ring synthons, started from all-cis-3,5-dihydroxy-4-ethyl-1-(methoxycarbonyl)cyclohexane via lipase-catalyzd asymmetrization, was demonstrated.

  13. BF3.SiO2: an efficient catalyst for the synthesis of azo dyes at room temperature

    Bi Bi Fatemeh Mirjalili


    Full Text Available A rapid one-pot method has been developed for the synthesis of azo dyes via ‎sequential diazotization–diazo coupling of aromatic amines with coupling agents at room ‎temperature in the presence of BF3.SiO2 as acidic catalyst. The obtained aryl diazonium salts bearing silica supported boron tri-flouride counter ion‎ was sufficiently stable to be kept at room ‎temperature in the dry state.‎

  14. Reduced Species(HSO-2,SO·-2)Promoted One-Pot Efficient Synthesis of Phenyl Alkyl Selenides

    TANG,Ri-Yuan; ZHONG,Ping; LIN,Qiu-Lian


    Reduced species(HSO-2,SO·-2)promoted one-pot synthesis of phenyl alkyl selenides has been developed.This synthetic method was achieved by reactions of diphenyl diselenide with alkyl halides at room temperature.It is noteworthy that the reactions were operated under mild reaction conditions,required short time,and got good resuits.A single electron transfer reaction mechanism was proposed for the reaction.

  15. Cerium(Ⅳ) ammonium nitrate catalysed facile and efficient synthesis of polyhydroquinoline derivatives through Hantzsch multicomponent condensation

    Cherkupally Sanjeeva Reddy; Mekala Raghu


    A general and convenient practical approach for the synthesis of polyhydroquinoline derivatives has been achieved via one-pot four-component Hantzsch condensation of aromatic aldehydes,dimedone,ethyl acetoacetate and ammonium acetate in the presence of a catalytic amount of cerium(Ⅳ) ammonium nitrate (CAN),in ethanol solvent at ambient temperature.Simple work-up,mild reaction conditions,inexpensive and non-toxic catalyst,and excellent product yields are the advantageous features of this method.

  16. ZnO nanoparticle as catalyst for efficient green one-pot synthesis of coumarins through Knoevenagel condensation

    B Vinay Kumar; Halehatty S Bhojya Naik; D Girija; B Vijaya Kumar


    Green chemistry protocols with the reusability of the nano particle as catalyst in the synthesis of coumarins is described. The zinc oxide (ZnO) nanoparticles functions as highly effective catalyst for the reactions of various -hydroxy benzaldehydes with 1,3-dicarbonyl compounds under microwave and thermal conditions to afford the corresponding coumarins in moderate to good yields. The catalyst is inexpensive, stable, can be easily recycled and reused for several cycles with consistent activity.

  17. Green Chemistry Approach for Efficient Synthesis of Schiff Bases of Isatin Derivatives and Evaluation of Their Antibacterial Activities

    Jnyanaranjan Panda


    Full Text Available Microwave-assisted organic synthesis, a green chemistry approach, is nowadays widely used in the drug synthesis. Microwave-assisted synthesis improves both throughput and turnaround time for medicinal chemists by offering the benefits of drastically reduced reaction times, increased yields, and pure products. Schiff bases are the important class of organic compounds due to their flexibility, and structural diversities due to the presence of azomethine group which is helpful for elucidating the mechanism of transformation and rasemination reaction in biological system. This novel compound could also act as valuable ligands for the development of new chemical entities. In the present work, some Schiff bases of Isatin derivatives was synthesized using microwave heating method. Schiff base of Isatin were synthesized by condensation of the keto group of Isatin with different aromatic primary amines. They were characterized by means of spectral data and subsequently subjected to the in vitro antibacterial activities against gram positive and gram negative strains of microbes. It was observed that the compound with electron withdrawing substituents exhibited good antibacterial activities against almost all the micro organisms.

  18. Arx: a toolset for the efficient simulation and direct synthesis of high-performance signal processing algorithms

    Hofstra, K.L.; Gerez, S.H.


    This paper addresses the efficient implementation of highperformance signal-processing algorithms. In early stages of such designs many computation-intensive simulations may be necessary. This calls for hardware description formalisms targeted for efficient simulation (such as the programming langua

  19. Efficient Catalyst One-Pot Synthesis of 7-(Aryl-10,10-dimethyl-10,11-dihydrochromeno[4,3-b]chromene-6,8(7H,9H-dione Derivatives Complemented by Antibacterial Activity

    Yasameen K. Al-Majedy


    Full Text Available The problem of bacteria resistance to many known agents has inspired scientists and researchers to discover novel efficient antibacterial drugs. Three rapid, clean, and highly efficient methods were developed for one-pot synthesis of 7-(aryl-10,10-dimethyl-10,11-dihydrochromeno[4,3-b]chromene-6,8(7H,9H-dione derivatives. Three components are condensed in the synthesis, 4-hydroxycoumarin, 5,5-dimethyl-1,3-cyclohexanedione, and aromatic aldehydes, using tetrabutylammonium bromide (TBAB, diammonium hydrogen phosphate (DAHP, or ferric chloride (FeCl3, respectively. Each method has different reaction mechanisms according to the catalyst. The present methods have advantages, including one-pot synthesis, excellent yields, short reaction times, and easy isolation of product. All catalysts utilized in our study could be reused several times without losing their catalytic efficiency. All synthesized compounds were fully characterized and evaluated for their antibacterial activity.

  20. An Efficient Protocol for the Synthesis of Quinoxaline Derivatives at Room Temperature Using Recyclable Alumina-Supported Heteropolyoxometalates

    Diego M. Ruiz


    Full Text Available We report a suitable quinoxaline synthesis using molybdophosphovanadates supported on commercial alumina cylinders as catalysts. These catalysts were prepared by incipient wetness impregnation. The catalytic test was performed under different reaction conditions in order to know the performance of the synthesized catalysts. The method shows high yields of quinoxaline derivatives under heterogeneous conditions. Quinoxaline formation was obtained using benzyl, o-phenylenediamine, and toluene as reaction solvent at room temperature. The CuH2PMo11VO40 supported on alumina showed higher activity in the tested reaction. Finally, various quinoxalines were prepared under mild conditions and with excellent yields.

  1. Investigation of efficient synthesis of 1, 8-dioxo-octahydroxanthene derivatives under solvent-free grinding method

    R. Borah


    Full Text Available In these studies, we had observed polyaniline (PANI supported p-toluene sulfonic acid (TsOH and FeCl3 (PANI- TsOH, PANI-FeCl3 as excellent reusable solid acid catalysts for the synthesis of 1, 8-dioxo-octahydroxanthene derivatives 4(a-g under solvent-free grinding method at mild conditions. Additionally, in the same optimized condition ferric nitrate nonahydrate also acted as (non-reusable very reactive inexpensive Lewis acid catalyst. The ferric nitrate nonahydrate lost its activity in the form of Clayfen (Clay-supported ferric nitrate catalyst.

  2. Zinc oxide nanoparticle promoted highly efficient one pot three-component synthesis of 2,3-disubstituted benzofurans

    Javad Safaei-Ghomi


    Full Text Available A convenient one-pot synthesis of 2,3-disubstituted benzo[b]furan derivatives has been developed using zinc oxide nanoparticles. The present approach provides a novel, effective and improved procedure for the three-component coupling of aldehydes, secondary amines and alkyne with several advantages such as short reaction times, high yields and little catalyst loading. ZnO nanoparticles are cheap, stable and can be easily recovered for several circles with consistent activity. Characterization and structural elucidation of the products have been done on the basis of chemical, analytical and spectral analyses.

  3. PCl5 as a mild and efficient catalyst for the synthesis of bis(indolylmethanes and di-bis(indolylmethanes

    Alireza Hasaninejad


    Full Text Available Phosphorus pentachloride (PCl5 can efficiently catalyze the condensation of indoles with aldehydes as well as ketones at room temperature to afford bis(indolylmethanes and di-bis(indolylmethanes in high yields and short reaction times.

  4. Efficient and Scalable Synthesis of 4-Carboxy-Pennsylvania Green Methyl Ester: A Hydrophobic Building Block for Fluorescent Molecular Probes.

    Woydziak, Zachary R; Fu, Liqiang; Peterson, Blake R


    Fluorinated fluorophores are valuable tools for studies of biological systems. However, amine-reactive single-isomer derivatives of these compounds are often very expensive. To provide an inexpensive alternative, we report a practical synthesis of 4-carboxy-Pennsylvania Green methyl ester. Derivatives of this hydrophobic fluorinated fluorophore, a hybrid of the dyes Oregon Green and Tokyo Green, are often cell permeable, enabling labeling of intracellular targets and components. Moreover, the low pKa of Pennsylvania Green (4.8) confers bright fluorescence in acidic cellular compartments such as endosomes, enhancing its utility for chemical biology investigations. To improve access to the key intermediate 2,7-difluoro-3,6-dihydroxyxanthen-9-one, we subjected bis-(2,4,5-trifluorophenyl)methanone to iterative nucleophilic aromatic substitution by hydroxide on scales of > 40 g. This intermediate was used to prepare over 15 grams of pure 4-carboxy-Pennsylvania Green methyl ester in 28% overall yield without requiring chromatography. This compound can be converted into the amine reactive N-hydroxysuccinimidyl ester in essentially quantitative yield for the synthesis of a wide variety of fluorescent molecular probes.

  5. Efficient synthesis of diverse heterobifunctionalized clickable oligo(ethylene glycol) linkers: potential applications in bioconjugation and targeted drug delivery.

    Goswami, Lalit N; Houston, Zachary H; Sarma, Saurav J; Jalisatgi, Satish S; Hawthorne, M Frederick


    Herein we describe the sequential synthesis of a variety of azide-alkyne click chemistry-compatible heterobifunctional oligo(ethylene glycol) (OEG) linkers for bioconjugation chemistry applications. Synthesis of these bioorthogonal linkers was accomplished through desymmetrization of OEGs by conversion of one of the hydroxyl groups to either an alkyne or azido functionality. The remaining distal hydroxyl group on the OEGs was activated by either a 4-nitrophenyl carbonate or a mesylate (-OMs) group. The -OMs functional group served as a useful precursor to form a variety of heterobifunctionalized OEG linkers containing different highly reactive end groups, e.g., iodo, -NH(2), -SH and maleimido, that were orthogonal to the alkyne or azido functional group. Also, the alkyne- and azide-terminated OEGs are useful for generating larger discrete poly(ethylene glycol) (PEG) linkers (e.g., PEG(16) and PEG(24)) by employing a Cu(I)-catalyzed 1,3-dipolar cycloaddition click reaction. The utility of these clickable heterobifunctional OEGs in bioconjugation chemistry was demonstrated by attachment of the integrin (α(v)β(3)) receptor targeting peptide, cyclo-(Arg-Gly-Asp-D-Phe-Lys) (cRGfKD) and to the fluorescent probe sulfo-rhodamine B. The synthetic methodology presented herein is suitable for the large scale production of several novel heterobifunctionalized OEGs from readily available and inexpensive starting materials.

  6. Methanobactin-Mediated Synthesis of Gold Nanoparticles Supported over Al2O3 toward an Efficient Catalyst for Glucose Oxidation

    Jia-Ying Xin


    Full Text Available Methanobactin (Mb is a copper-binding peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and reduce Au(III to Au(0. In this paper, Au/Al2O3 catalysts prepared by a novel incipient wetness-Mb-mediated bioreduction method were used for glucose oxidation. The catalysts were characterized, and the analysis revealed that very small gold nanoparticles with a particle size <4 nm were prepared by the incipient wetness-Mb-mediated bioreduction method, even at 1.0% Au loading (w/w. The influence of Au loading, calcination temperature and calcination time on the specific activity of Au/Al2O3 catalysts was systematically investigated. Experimental results showed that decomposing the Mb molecules properly by calcinations can enhance the specific activity of Au/Al2O3 catalysts, though they acted as reductant and protective agents during the catalyst preparation. Au/Al2O3 catalysts synthesized by the method exhibited optimum specific activity under operational synthesis conditions of Au loading of 1.0 wt % and calcined at 450 °C for 2 h. The catalysts were reused eight times, without a significant decrease in specific activity. To our knowledge, this is the first attempt at the preparation of Au/Al2O3 catalysts by Mb-mediated in situ synthesis of gold nanoparticles.

  7. In vitro slow-release urea contained in rice straw-based diets to increase efficiency of rumen microbial protein synthesis

    Dede Kardaya


    Full Text Available Effect of slow-release urea on efficiency of rumen microbial protein synthesis (EMPS was examined using an in vitro technique. The objective of this experiment was to reveal the in vitro slow-release urea characteristics of zinc-urea, zeolites-urea, and zeolites-zinc-urea in relation to EMPS observed in different incubation time. The experimental design employed was randomized block design with 4 x 3 factorial plus a control treatment, and conducted in two replications. Factors were various urea sources (urea, zinc-urea, zeolites-urea, and zeolites-zinc-urea and molasses concentrations (0%, 6%, and 12% in rice straw-based diets. The control treatment was the rice straw-based diets containing neither urea nor molasses. Diets consisting of 45% rice straw and 55% concentrates (DM basis were formulated to have similar N and TDN levels. Responses of parameters measured were subjected to MANOVA using the GLM procedure of SPSS 16.00 and differences among mean values, if applicable, were examined using HSD-test. Orthogonal comparisons were used to determine the effects of the control treatment vs. various urea sources. Results indicated that treatment of UZ combined with 6% of molasses showed the highest microbial biomass production (2.71 mg/l at 24 hours fermentation period with its peak production estimation (3.2 mg/l reached at 33.5 hours of fermentation period. Moreover, UZ treatment resulted in the highest microbial protein synthesis (1,381.45 ± 77.1 mg/l at 24 hours fermentation period with its peak microbial protein synthesis estimation (1,756.04 mg/l reached at 33.7 hours of fermentation period. The highest EMPS (25.98 ± 1.21 mg/100 mg OMD was achieved when ration contained 6% of molasses.

  8. Synthesis of core-shell heterostructured Cu/Cu2O nanowires monitored by in situ XRD as efficient visible-light photocatalysts

    Chen, Wei


    Core-shell heterostructured Cu/Cu2O nanowires with a high aspect ratio were synthesized from Cu foam using a novel oxidation/reduction process. In situ XRD was used as an efficient tool to acquire phase transformation details during the temperature-programmed oxidation of Cu foam and the subsequent reduction process. Based on knowledge of the crucial phase transformation, optimal synthesis conditions for producing high-quality CuO and core-shell Cu/Cu2O nanowires were determined. In favor of efficient charge separation induced by the special core-shell heterostructure and the advanced three-dimensional spatial configuration, Cu/Cu2O nanowires exhibited superior visible-light activity in the degradation of methylene blue. The present study illustrates a novel strategy for fabricating efficiently core-shell heterostructured nanowires and provides the potential for developing their applications in electronic devices, for environmental remediation and in solar energy utilization fields. This journal is © The Royal Society of Chemistry.

  9. Ultrasonic-assisted sol-gel synthesis of samarium, cerium co-doped TiO2 nanoparticles with enhanced sonocatalytic efficiency.

    Eskandarloo, Hamed; Badiei, Alireza; Behnajady, Mohammad A; Ziarani, Ghodsi Mohammadi


    In this work, pure TiO2 and samarium, cerium mono-doped and co-doped TiO2 catalysts were synthesized by an ultrasonic-assisted sol-gel method and their sonocatalytic efficiency studied toward removal of Methyl Orange as a model organic pollutant from the textile industry. The relationship of structure and sonocatalytic performance of catalysts was established by using various techniques, such as XRD, TEM, SEM, EDX, DRS, and PL. A comparison on the removal efficiency of sonolysis alone and sonocatalytic processes was performed. The results showed that the samarium, cerium co-doped TiO2 catalyst with narrower band gap energy and smaller particle size leads to a rapid removal of pollutant. It was believed that Sm(3+) and Ce(4+) ions can serve as superficial trapping for electrons at conduction band of TiO2 and prolonged the lifetime of electron-hole pairs. Finally, the effect of synthesis and operational variables on the sonocatalytic activity of co-doped TiO2 catalyst was studied and optimized using response surface methodology as a statistical technique. The results showed that the maximum removal efficiency (96.33%) was achieved at the optimum conditions: samarium content of 0.6 wt%, cerium content of 0.82 wt%, initial pollutant concentration of 4.31 mg L(-1), catalyst dosage of 0.84 mg L(-1), ultrasonic irradiation power of 700 W, and irradiation time of 50 min.

  10. Facile and efficient one-pot solvothermal and microwave-assisted synthesis of stable colloidal solutions of MFe{sub 2}O{sub 4} spinel magnetic nanoparticles

    Solano, Eduardo; Perez-Mirabet, Leonardo [Universitat Autonoma de Barcelona, Departament de Quimica (Spain); Martinez-Julian, Fernando; Guzman, Roger; Arbiol, Jordi; Puig, Teresa; Obradors, Xavier [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC (Spain); Yanez, Ramon [Universitat Autonoma de Barcelona, Departament de Quimica (Spain); Pomar, Alberto; Ricart, Susagna, E-mail: [Institut de Ciencia de Materials de Barcelona, ICMAB-CSIC (Spain); Ros, Josep [Universitat Autonoma de Barcelona, Departament de Quimica (Spain)


    Well-defined synthesis conditions of high quality MFe{sub 2}O{sub 4} (M = Mn, Fe, Co, Ni, Zn, and Cu) spinel ferrite magnetic nanoparticles, with diameters below 10 nm, have been described based on facile and efficient one-pot solvothermal or microwave-assisted heating procedures. Both methods are reproducible and scalable and allow forming concentrated stable colloidal solutions in polar solvents, but microwave-assisted heating allows reducing 15 times the required annealing time and leads to an enhanced monodispersity of the nanoparticles. Non-agglomerated nanoparticles dispersions have been achieved using a simple one-pot approach where a single compound, triethyleneglycol, behaves at the same time as solvent and capping ligand. A narrow nanoparticle size distribution and high quality crystallinity have been achieved through selected nucleation and growth conditions. High resolution transmission electron microscopy images and electron energy loss spectroscopy analysis confirm the expected structure and composition and show that similar crystal faceting has been formed in both synthetic approaches. The spinel nanoparticles behave as ferrimagnets with a high saturation magnetization and are superparamagnetic at room temperature. The influence of synthesis route on phase purity and unconventional magnetic properties is discussed in some particular cases such as CuFe{sub 2}O{sub 4}, CoFe{sub 2}O{sub 4}, and ZnFe{sub 2}O{sub 4}.

  11. Eco-Efficient Synthesis of Highly Porous CoCO3 Anodes from Supercritical CO2 for Li(+) and Na(+) Storage.

    Li, Hui-Ying; Tseng, Chuan-Ming; Yang, Cheng-Hsien; Lee, Tai-Chou; Su, Ching-Yuan; Hsieh, Chien-Te; Chang, Jeng-Kuei


    An eco-efficient synthetic route for the preparation of high-performance carbonate anodes for Li(+) and Na(+) batteries is developed. With supercritical CO2 (scCO2 ) as the precursor, which has gas-like diffusivity, extremely low viscosity, and near-zero surface tension, CoCO3 particles are uniformly formed and tightly connected on graphene nanosheets (GNSs). This synthesis can be conducted at 50 °C, which is considerably lower than the temperature required for conventional preparation methods, minimizing energy consumption. The obtained CoCO3 particles (ca. 20 nm in diameter), which have a unique interpenetrating porous structure, can increase the number of electroactive sites, promote electrolyte accessibility, shorten ion diffusion length, and readily accommodate the strain generated upon charging/discharging. With a reversible capacity of 1105 mAh g(-1) , the proposed CoCO3 /GNS anode shows an excellent rate capability, as it can deliver 745 mAh g(-1) in 7.5 min. More than 98 % of the initial capacity is retained after 200 cycles. These properties are clearly superior to those of previously reported CoCO3 -based electrodes for Li(+) storage, indicating the merit of our scCO2 -based synthesis, which is facile, green, and can be easily scaled up for mass production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Efficient synthesis of highly fluorescent nitrogen-doped carbon dots for cell imaging using unripe fruit extract of Prunus mume

    Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of); Sethuraman, Mathur Gopalakrishnan, E-mail: [Department of Chemistry, Gandhigram Rural Institute-Deemed University, Gandhigram 624 302, Tamilnadu (India); Lee, Yong Rok, E-mail: [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of)


    Graphical abstract: The green synthesis of highly fluorescent N-CDs was achieved using the extract of unripe P. mume fruit as a carbon precursor by a one-pot simple hydrothermal-carbonization method. The resulting N-CDs were used as a staining agent for the fluorescence imaging of MDA-MB-231 cells. Display Omitted - Highlights: • The green synthesis of highly fluorescent N-CDs using the extract of unripe P. mume. • The N-CDs were synthesized by one-pot hydrothermal-carbonization method. • This method of synthesis is a simple, cost effective and eco-friendly route. • N-CDs will be a good alternative for fluorescent dyes and SQDs for bio-applications. - Abstract: Highly fluorescent nitrogen-doped carbon dots (N-CDs) were synthesized using the extract of unripe Prunus mume (P. mume) fruit by a simple one step hydrothermal-carbonization method. The N-CDs were synthesized at different pH ranges, 2.3, 5, 7, and 9. The pH of the P. mume extract was adjusted using an aqueous ammonia solution (25%). The optical properties of N-CDs were examined by UV–vis and fluorescence spectroscopy. The N-CDs synthesized at pH 9 emitted high fluorescence intensity compared to other obtained N-CDs. The N-CDs synthesized at pH 9 was further characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform-infra red (FT-IR) spectroscopy. HR-TEM showed that the average size of the synthesized N-CDs was approximately 9 nm and the interlayer distance was 0.21 nm, which was validated by XRD. The graphitic nature of the synthesized N-CDs were confirmed by Raman spectroscopy. XPS and FT-IR spectroscopy confirmed the doping of the nitrogen moiety over the synthesized CDs. The synthesized nitrogen doped CDs (N-CDs) were low toxicity and were used as a staining probe for fluorescence cell imaging.

  13. OSU-6: A Highly Efficient, Metal-Free, Heterogeneous Catalyst for the Click Synthesis of 5-Benzyl and 5-Aryl-1H-tetrazoles.

    Nammalwar, Baskar; Muddala, Nagendra Prasad; Pitchimani, Rajasekar; Bunce, Richard A


    OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.

  14. [11C]PR04.MZ, a promising DAT ligand for low concentration imaging: synthesis, efficient 11C-0-methylation and initial small animal PET studies

    Riss, P.J.; Hooker, J.; Alexoff, D.; Kim, Sung-Won; Fowler, J.S.; Roesch, F.


    PR04.MZ was designed as a highly selective dopamine transporter inhibitor, derived from natural cocaine. Its binding profile indicates that [{sup 11}C]PR04.MZ may be suited as a PET radioligand for the non-invasive exploration of striatal and extrastriatal DAT populations. As a key feature, its structural design facilitates both, labelling with fluorine-18 at its terminally fluorinated butynyl moiety and carbon-11 at its methyl ester function. The present report concerns the efficient [{sup 11}C]MeI mediated synthesis of [{sup 11}C]PR04.MZ from an O-desmethyl precursor trifluoroacetic acid salt with Rb{sub 2}CO{sub 3} in DMF in up to 95 {+-} 5% labelling yield. A preliminary {mu}PET-experiment demonstrates the reversible, highly specific binding of [{sup 11}C]PR04.MZ in the brain of a male Sprague-Dawley rat.

  15. An Efficient Strategy for the Synthesis of 1-(Trifluoromethylsulfonamido)propan-2-yl Esters and the Evaluation of Their Cytotoxic Activity.

    Gómez-García, Omar; Gómez, Elizabeth; Monzón-González, César; Ramírez-Apan, Teresa; Álvarez-Toledano, Cecilio


    An efficient method for the synthesis of 1-(trifluoromethylsulfonamido)propan-2-yl benzoates is described, the products of the reaction were characterized by heteronuclear single quantum coherence spectroscopy (HSQC), heteronuclear multiple bond correlation (HMBC) and NMR experiments. The overall process began with the activation of the oxazoline ring by triflic anhydride, followed by the opening of the five-membered ring in the 5-methyl-2-phenyl-4,5-dihydrooxazole system. The cytotoxic activity of the new trifluoromethyl sulfonamides was evaluated with six cancer cell lines and human gingival fibroblasts, posteriorly analyzing the influence on cytotoxicity exerted by the withdrawing and donor substituents at the para-position of the phenyl ring. Compounds 3b-e showed cytotoxic activity, with IC50 values ranging from 17-17.44 µM for the cell lines tested, finding the highest effect for compound 3e.

  16. An adapted route to efficient synthesis of 1,8-dioxooctahydro-xanthene derivatives using InCl3 and (HPO3n as recyclable catalysts

    Bahador Karami


    Full Text Available Indium (III chloride (InCl3 and metaphosphoric acid ((HPO3n were found to be efficient and recyclable catalysts for the synthesis of 1,8-dioxooctahydroxanthene derivatives as biologically important molecules in high turnover numbers and rates. Several substituted xanthenes can be prepared in high yield and purity by direct reaction of cyclic β-diketones and aldehyde derivatives in the presence of a catalytic amount of InCl3 and (HPO3n as Lewis acids and at ambient temperature under solvent-free conditions. This newly reported procedure profit some advantages such as short reaction times, high yields of products, cheap, easy to use, facile practical conditions, and wholesome with green chemistry without using harmful solvents.

  17. Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications.

    Tao, Hua Bing; Yang, Hong Bin; Chen, Jiazang; Miao, Jianwei; Liu, Bin


    A biomolecule-assisted pyrolysis method has been developed to synthesize sulfur-doped graphitic carbon nitride (CNS) nanosheets. During the synthesis, sulfur could be introduced as a dopant into the lattice of carbon nitride (CN). Sulfur doping changed the texture as well as relative band positions of CN. By growing CN on preformed sulfur-doped CN nanosheets, composite CN/CNS heterojunction nanosheets were constructed, which significantly enhanced the photoelectrochemical performance as compared with various control counterparts including CN, CNS and physically mixed CN and CNS (CN+CNS). The enhanced photoelectrochemical performance of CN/CNS heterojunction nanosheets could be ascribed to the efficient separation of photoexcited charge carriers across the heterojunction interface. The strategy of designing and preparing CN/CNS heterojunction photocatalysts in this work can open up new directions for the construction of all CN-based heterojunction photocatalysts.

  18. Synthesis and spectroscopic studies of 4-Formyl-4'-N,N-dimethylamino-1,1'-biphenyl: The unusual red edge effect and efficient laser generation.

    Chou, P T; Chang, C P; Clements, J H; Meng-Shin, K


    The synthesis and photophysics of 4-formyl-4'-N,N-dimethylamino-1,1'-biphenyl are reported. The emission spectrum in various solvent polarities demonstrates solvatochromism, indicating that the fluorescence originates from an electronically excited species with a strong charge transfer character. The change in Δ[Formula: see text] [[Formula: see text] max(absorption) -[Formula: see text] max(emission)] varies from ∼1500 cm(-1) inn-heptane to as much as ∼7500 cm(-1) in acetonitrile. In protic solvents, the unusual excitation energy-dependent steady-state emission (red edge effect), resulting from solvent dielectric relaxation, was observed in media with a low viscosity. The large Stokes-shifted and high-yield fluorescence led to the observation of the efficient lasing action. The frequency tunability of the laser output is strongly solvent dependent, generating a new charge transfer laser dye in the blue-green region.

  19. Sulfamic acid as energy efficient catalyst for synthesis of flurophores, 1--spiro [isoindoline-1,2′-quinazoline]-3,4′(3′)-diones

    Mansing M Mane; Dattaprasad M Pore


    An energy efficient synthesis of 1--spiro[isoindoline-1,2′-quinazoline]-3,4′(3′)-diones has been expediently accomplished by a reaction of isatin(s) / cyclic ketone and anthranilamide in ethanol at ambient temprature. Excellent yields of the products in short time duration, operational simplicity, and simple work-up procedure are the attractive features of the present protocol. Synthesized 1--spiro[isoindoline-1,2′-quinazoline]-3,4′(3′)-diones were found to be fluorescent with absorption in UV region (302, 362 nm) and emission in visible region (413-436 nm) with Stokes shift of 44-72 nm.

  20. Microwave assisted synthesis of a noble metal-graphene hybrid photocatalyst for high efficient decomposition of organic dyes under visible light

    Ullah, Kefayat; Ye, Shu; Zhu, Lei; Meng, Ze-Da; Sarkar, Sourav; Oh, Won-Chun, E-mail:


    Highlights: • Pt/graphene nanocomposites were synthesized via facile, fast, and scalable microwave irradiation method. • MB and Rh.B were used as sample dye solutions. • The Pt/graphene nanocomposites displayed distinctly enhanced photocatalytic activities. • UV–vis spectroscopic analysis was carried out to measure decomposition effect. -- Abstract: We report fast and facile synthesis of Pt/graphene nanocomposite via microwave assisted techniques. The “as-prepared” composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with an energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), UV–vis absorbance spectra analysis, diffuse reflectance spectra (DRS) analysis and Raman spectroscopic analysis. The visible light photo catalytic activities of Pt/graphene nanocomposite were tested by rhodamine B (Rh.B) and methylene blue (MB) as a standard model dyes. These analysis provide a promising development toward graphene based high efficient photocatalyst under visible light as an energy source.

  1. Efficient Synthesis of 3-Phenylnaphtho[2,3-b]furan-4,9-diones in Water and Their Fluorimetric Study in Solutions

    张仁尊; 徐东成; 谢建武


    A simple and efficient protocol has been developed for the synthesis of 3-phenylnaphtho[2,3-b]furan-4,9-diones by domino reaction of a-bromonitroalkenes to 2-hydroxynaphthalene-1,4-dione. With the optimal reaction condi- tions [NaOAc (120 mol%), water, 70 ~C, 7 h], the scope of the domino reaction was explored and the green ap- proach provided the desired products in moderate to good yields at elevated temperature under aqueous-mediated conditions. A mechanistic rationalization for this reaction is also provided. The absorption characteristics of the compounds were examined by UV-Vis spectra and fluorescence spectroscopy. All compounds were fluorescent in solution emitting at blue light (432--433 nm), green light (512--536 nm), or yellow light (591 nm).

  2. Simple and Efficient One-Pot Synthesis, Spectroscopic Characterization and Crystal Structure of Methyl 5-(4-Chlorobenzoyloxy-1-phenyl-1H-pyrazole-3-carboxylate

    Imtiaz Khan


    Full Text Available A facile one-pot synthesis of methyl 5-(4-chlorobenzoyloxy-1-phenyl-1H-pyrazole-3-carboxylate (4 is described. The title compound was efficiently synthesized by the reaction of phenyl hydrazine, dimethyl acetylenedicarboxylate and 4-chlorobenzoyl chloride in dichloromethane under reflux in good yield. The structure of the target compound was deduced by modern spectroscopic and analytical techniques and unequivocally confirmed by a single crystal X-ray diffraction analysis. The crystal of the title compound belongs to orthorhombic system, space group P 21 21 21 with cell parameters a = 6.6491(3 Å, b = 7.9627(6 Å, c = 30.621(5 Å, α = β = γ = 90° and Z = 4. The crystal packing of the compound (4 is stabilized by an offset π-stacking between the planar benzoyl-substituted diazole moieties.

  3. OSU-6: A Highly Efficient, Metal-Free, Heterogeneous Catalyst for the Click Synthesis of 5-Benzyl and 5-Aryl-1H-tetrazoles

    Baskar Nammalwar


    Full Text Available OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.

  4. Efficient continuous-flow synthesis of novel 1,2,3-triazole-substituted β-aminocyclohexanecarboxylic acid derivatives with gram-scale production

    Sándor B. Ötvös


    Full Text Available The preparation of novel multi-substituted 1,2,3-triazole-modified β-aminocyclohexanecarboxylic acid derivatives in a simple and efficient continuous-flow procedure is reported. The 1,3-dipolar cycloaddition reactions were performed with copper powder as a readily accessible Cu(I source. Initially, high reaction rates were achieved under high-pressure/high-temperature conditions. Subsequently, the reaction temperature was lowered to room temperature by the joint use of both basic and acidic additives to improve the safety of the synthesis, as azides were to be handled as unstable reactants. Scale-up experiments were also performed, which led to the achievement of gram-scale production in a safe and straightforward way. The obtained 1,2,3-triazole-substituted β-aminocyclohexanecarboxylates can be regarded as interesting precursors for drugs with possible biological effects.

  5. 40% Efficiency enhancement in solar cells using ZnO nanorods as shell prepared via novel hydrothermal synthesis

    Ebadi, Mohammad; Zarghami, Zabihullah; Motevalli, Kourosh


    Herein, rod-like ZnO nanostructures were synthesized via a novel hydrothermal route using Zn(OAc)2, ethylenediamine and hydrazine as a new set of starting reagents. The as-synthesized products were characterized by techniques including XRD, EDS, SEM, XPS, Pl and FTIR. The prepared ZnO nanostructures were utilized as shell on TiO2 film in DSSCs. Effect of precursor type, morphology and thickness of ZnO shell (number of electrophoresis cycle) on solar cells efficiency were well studied. Our results showed that ethylenediamine has crucial effect on morphology of synthesized ZnO nanostructures and using ZnO nanostructures leads to an increase in DSSCs efficiency compared to bare TiO2 from 4.66 to 7.13% ( 40% improvement). Moreover, highest amount of solar cell efficiency (7.13%) was obtained by using ZnO nanorods with two cycle of electrophoresis for deposition.

  6. An efficient synthesis of pyrazolo[1,5-a]pyrimidines and evaluation of their antimicrobial activity



    A series of new pyrazolo[1,5-a]pyrimidine derivatives has been synthesized by using 7-hydrazinyl- 5-methylpyrazolo[1,5-a]pyrimidine-3-carbonitrile 1 and 7-amino-5-methylpyrazolo[1,5-a]pyrimidine-3-carbonitrile 2 as precursors. The pyrazolo[3,4-d] pyrimidines 3a–b have been synthesized by a three-step reactionstarting with 1. Compound 1 was utilized for the synthesis of dioxopyrrolidindolinylamio-pyrazolo-pyrimidines 4a–b, and dioxoisoindolin-pyrazolo-pyrimidines 4c–d. Also, compounds 4a-d were synthesized using deepeutectic solvents (DES). This method using DES provides several advantages such as benign environment, high yield, scalable and simple work-up procedure. Similarly, the cyclocondensation of 2 with α-acetyl- γ -butyrolactone afforded pyrazolo-pyrido-pyrimidine 5 and dihydrofuro-pyrido-pyrazolo-pyrimidine 6. All synthesized compounds were screened for antimicrobial activity.

  7. N,N-Diisopropyl-N-phosphonyl Imines Lead to Efficient Asymmetric Synthesis of Aziridine-2-Carboxylic Esters

    Kattamuri, Padmanabha V.; Xiong, Yiwen; Pan, Yi; Li, Guigen


    Highly diastereoselective asymmetric synthesis of chiral aziridine-2-carboxylic esters is reported for 20 examples with good yields (51–87%) and excellent diastereoselectivities (>99:1 dr for most cases). The modified N-phosphonyl imines are proven to be superior to previous imine auxiliaries for the aza Darzens reaction by using secondary isopropyl to replace primary benzyl group for N,N-diamino protection. In the meanwhile, a special operation by slowly adding the pre-cooled imine solution at −78 °C into the preformed β-bromo lithium enolate mixture at this temperature in the presence of 4 Å molecular sieves was found to be crucial in terms of yields and diastereoselectivity. The present method can provide an easy and general access to β-hydroxy α-amino acids and other important amino building blocks. PMID:23563304

  8. Gold Nanoparticles Supported on a Layered Double Hydroxide as Efficient Catalysts for the One-Pot Synthesis of Flavones.

    Yatabe, Takafumi; Jin, Xiongjie; Yamaguchi, Kazuya; Mizuno, Noritaka


    Flavones are a class of natural products with diverse biological activities and have frequently been synthesized by step-by-step procedures using stoichiometric amounts of reagents. Herein, a catalytic one-pot procedure for the synthesis of flavone and its derivatives is developed. In the presence of gold nanoparticles supported on a Mg-Al layered double hydroxide (Au/LDH), various kinds of flavones can be synthesized starting from 2'-hydroxyacetophenones and benzaldehydes (or benzyl alcohols). The present one-pot procedure consists of a sequence of several reactions, and Au/LDH can catalyze all these different types of reactions. The catalysis is shown to be truly heterogeneous, and Au/LDH can be readily recovered and reused.

  9. Synthesis and characterization of ion beam assisted silver nanosystems in silicon based materials for enhanced photocurrent collection efficiency

    Dhoubhadel, Mangal S.

    In recent years a great deal of interest has been focused on the synthesis of transitional metal (e.g. Ag, Cu, Fe, Au) nanosystems at the surface to sub-surface regions of Si and SiO2 matrices for fundamental understanding of their structures as well as for development of technological applications with enhanced electronic and optical properties. The applications of the metal nanoparticle or nanocluster (NC) systems range from plasmonics, photovoltaic devices, medical, and biosensors. In all of these applications; the size, shape and distribution of the metallic NCs in the silicon matrix play a key role. Low energy ion implantation followed by thermal annealing (in vacuum or gas environment) is one of the most suitable methods for synthesis of NCs at near surfaces to buried layers below the surfaces of the substrates. This technique can provide control over depth and concentration of the implanted ions in the host matrix. The implanted low energy metal ions initially amorphizes the Si substrates while being distributed at a shallow depth near the substrate surface. When subject to thermal annealing, the implanted ions agglomerate to form clusters of different sizes at different depths depending upon the fluence. However, for the heavier ions implanted with high fluences (˜1x10 16 - 1x1017 atoms/cm2), there lies challenges for accurately predicting the distribution of the implanted ions due to sputtering of the surface as well as redistribution of the implants within the host matrix. In this dissertation, we report the investigation of the saturation of the concentration of the implanted ion species in the depth profiles with low energies (ProQuest.).

  10. Design, synthesis, and evaluation of carnosine derivatives as selective and efficient sequestering agents of cytotoxic reactive carbonyl species.

    Vistoli, Giulio; Orioli, Marica; Pedretti, Alessandro; Regazzoni, Luca; Canevotti, Renato; Negrisoli, Gianpaolo; Carini, Marina; Aldini, Giancarlo


    Carnosine aryl derivatives as sequestering agents of RCS: Reactive carbonyl species (RCS) are cytotoxic mediators representing a novel drug target, as they are presumed to play a pathogenic role in several diseases. Carnosine is a selective RCS-sequestering agent, but is rapidly hydrolyzed by serum carnosinase. Herein we describe the in silico design, synthesis, and evaluation of a set of carnosine aryl derivatives.Reactive carbonyl species (RCS) are important cytotoxic mediators generated by lipid oxidation of polyunsaturated fatty acids (PUFAs) and represent a novel drug target, as they are presumed to play a pathogenic role in several diseases. L-Carnosine (L-CAR, beta-alanyl-L-histidine) is a specific detoxifying agent of RCS, but is rapidly hydrolyzed in human serum by carnosinase, a specific dipeptidase. Herein we describe the in silico design, synthesis, and biological evaluation of carnosine derivatives that are resistant to carnosinase and that have increased quenching efficacy. Stability against carnosinase-mediated turnover was achieved by isomerization of the histidine residue, leading to D-carnosine (D-CAR, beta-alanyl-D-histidine), which maintains the same quenching activity of L-carnosine. A molecular modeling approach was then used to design derivatives characterized by an increased quenching efficacy. The most promising candidates were synthesized, and their stability and quenching activity were evaluated. This study describes a set of aryl derivatives that are characterized by high stability in human plasma and a quenching activity toward 4-hydroxy-trans-2-nonenal (HNE), chosen as a model of RCS, up to threefold greater than D-carnosine.

  11. Modeling, synthesis and study of highly efficient solar cells based on III-nitride nanowire arrays grown on Si substrates

    Mozharov, A. M.; Bolshakov, A. D.; Kudryashov, D. A.; Kryzhanovskaya, N. V.; Cirlin, G. E.; Mukhin, I. S.; Harmand, J. C.; Tchernysheva, M.


    In this letter we investigate photovoltaic properties of GaN nanowires (NWs) - Si substrate heterostructure obtained by molecular beam epitaxy (MBE). Antireflection properties of the NW array were studied theoretically and experimentally to show an order of magnitude enhancement in antireflection comparing to the pure Si surface (2.5% vs. 33.8%). In order to determine optimal morphology and doping levels of the structure with maximum possible efficiency we simulated it's properties using a finite difference method. The carried out simulation showed that a maximum efficiency should be 20%.

  12. Uniformity's influence of silica xerogel on synthesis efficiency of SiC nanorods by carbothermal reduction

    Huynh Thi Ha; Nguyen Thi Thu Ha; Phan Viet Phong; Dao Tran Cao; Le Quang Huy; Nguyen The Quynh [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay Distr., Hanoi (Viet Nam); Cao Tuan Anh [Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan Street, Badinh Distr., Hanoi (Viet Nam)], E-mail:


    Silica xerogels containing nanocarbon were milled for several hours before the carbothermal reduction processing. The formation of SiC nanorods was investigated at different annealing temperatures. It is shown that the formation temperature of SiC nanorods can be decreased if the powder size of milled silica xerogels is lower than 100 nm. The morphology, structure and production efficiency of synthesized SiC were determined by scanning electron microscopy SEM, X-ray diffraction XRD and thermo-gravimetric analysis TGA measurements. It is evident that production efficiency of synthesized SiC nanorods clearly depends on uniformity of precursor materials.

  13. Efficient lipase-catalyzed Knoevenagel condensation: utilization of biocatalytic promiscuity for synthesis of benzylidene-indolin-2-ones.

    Ding, Yan; Xiang, Xinran; Gu, Mengjie; Xu, Haoran; Huang, He; Hu, Yi


    Based on the screening of biocatalysts and reaction conditions including solvent, water content, temperature, enzyme loading, and reaction time, lipase from porcine pancreas (PPL) showed the prominent promiscuity for the Knoevenagel condensation between 1,3-dihydroindol-2-one heterocycle and aromatic aldehydes. Under the optimized procedure, both electron-withdrawing and electron-donating substituent of aldehydes substrates could react efficiently, and benzylidene-indolin-2-ones were obtained in excellent yields (75.0-96.6%). Benzylidene-indolin-2-ones derivatives were efficiently synthesized by the Knoevenagel condensation between various aromatic aldehydes and 1,3-dihydroindol-2-one catalyzed by lipase from porcine pancreas with excellent yields obtained.

  14. Efficient Synthesis of β-Acetamido Ketones and Esters Using Aluminum Chloride as an Inexpensive and Green Catalyst%Efficient Synthesis of β-Acetamido Ketones and Esters Using Aluminum Chloride as an Inexpensive and Green Catalyst

    Mohammad Ali, Zolfigol; Ardeshir, Khazaei; Mohammad, Mokhlesi; Abdolkarim, Zare; Maliheh, Safaiee; Fatemeh, Derakhshan-Panah; Hassan, Keypour; Ahmad, Ali Dehghani-Firouzabadi; Maria, Merajoddin


    Aluminum chloride (AlCl3) efficiently catalyzes one-pot multicomponent condensation of enolizable ketones or alkyl acetoacetates with aldehydes, acetonitrile and acetyl chloride to afford β-acetamido ketone or ester derivatives in high to excellent yields and in relatively short reaction times. Moreover, by this synthetic method, some novel β-acetamido ketones and esters (i.e. one complex structure) are prepared.

  15. Silica Supported Methanesulfonic Acid as an Efficient and Reusable Heterogeneous Catalyst for the Synthesis of Amidoalkyl Naphthols%Silica Supported Methanesulfonic Acid as an Efficient and Reusable Heterogeneous Catalyst for the Synthesis of Amidoalkyl Naphthols

    王敏; 梁艳; 张婷婷; 高晶晶


    A green protocol for the preparation of amidoalkyl naphthols from three-component one-pot condensation of 2-naphthol, aldehydes, amides or urea in the presence of silica supported methanesulfonic acid under thermal sol- vent-free conditions has been described. The catalyst is stable, efficient, easily prepared, and reusable. The remarkable features of this methodology are short reaction time, excellent yields, simple experimental and work-up procedures.

  16. Efficient synthesis of glycosylated phenazine natural products and analogs with DISAL (methyl 3,5-dinitrosalicylate) glycosyl donors

    Laursen, Jane B.; Petersen, Lars; Jensen, K.J.


    Inspired by the occurrence and function of phenazines in natural products, new glycosylated analogs were designed and synthesized. DISAL (methyl 3,5-dinitrosalicylate) glycosyl donors were used in an efficient and easily-handled glycosylation protocol compatible with combinatorial chemistry...

  17. Efficient Synthesis of the Functionalized Spiro[indoline-3,4'-pyridine] via Four-component Reaction

    孙晶; 吴群; 张藜娟; 颜朝国


    An efficient synthetic procedure for the functionalized spiro[indoline-3,4'-pyridine] was developed via the four-component reactions of arylamines, acetylenedicarboxylates, isatins and malononitrile with triethylamine as the base catalyst. The advantages of this reaction are using common starting material, mild reaction conditions, broad scope of reactants and operational simplicity.

  18. An Efficient and Facile Procedure for Synthesis of Acetates from Alcohols Catalyzed by Poly(4-vinylpyridinium tribromide)



    Poly(4-vinylpyridinium tribromide) is an efficient catalyst for the conversion of various alcohols to their corresponding acetate derivatives with acetic anhydride.This method has some advantages such as mild reaction conditions,good to excellent yields,and ease of work-up.

  19. An efficient solvent-free synthesis of imidazolines and benzimidazoles using K 4[Fe(CN 6] catalysis

    Kabeer A. Shaikh


    Full Text Available Imidazolines and Benzimidazoles have been efficiently synthesized in high yields by treatment of 1,2-diamine with aldehydes using the metal co-ordinate complex K 4[Fe(CN 6] as a catalysis. The method was carried out under solvent free condition via oxidation of carbon-nitrogen bond. The process is green, mild and inexpensive.

  20. Zirconyl Chloride Promoted Highly Efficient Domino Synthesis of New 1, 2, 3, 4-Tetrahydroquinoline Derivatives in Water

    Rahul R. NAGAWADE; Devanand B. SHINDE


    The tetrahydroquinoline moiety is a structural feature of many natural products. By using a domino reaction of aromatic amines and cyclic enol ethers catalyzed by zirconyl chloride in water, various tetrahydroquinoline derivatives were synthesized efficiently. Most cyclized products showed cis selectivity. The cis selectivity was tentatively rationalized due to chelation control in water.

  1. A Rapid and Efficient Sonogashira Protocol and Improved Synthesis of Free Fatty Acid 1 (FFA1) Receptor Agonists

    Christiansen, Elisabeth; Due-Hansen, Maria E; Ulven, Trond


    A protocol for rapid and efficient Pd/Cu-catalyzed coupling of aryl bromides and iodides to terminal alkynes has been developed with use of 2-(di-tert-butylphosphino)-N-phenylindole (cataCXium PIntB) as ligand in TMEDA and water. The new protocol successfully couples substrates which failed with ...

  2. Hydrothermal synthesis of a crystalline rutile TiO2 nanorod based network for efficient dye-sensitized solar cells.

    Yu, Hua; Pan, Jian; Bai, Yang; Zong, Xu; Li, Xinyong; Wang, Lianzhou


    One-dimensional (1D) TiO2 nanostructures are desirable as photoanodes in dye-sensitized solar cells (DSSCs) due to their superior electron-transport capability. However, making use of the DSSC performance of 1D rutile TiO2 photoanodes remains challenging, mainly due to the small surface area and consequently low dye loading. Herein, a new type of photoanode with a three-dimensional (3D) rutile-nanorod-based network structure directly grown on fluorine-doped tin oxide (FTO) substrates was developed by using a facile two-step hydrothermal process. The resultant photoanode possesses oriented rutile nanorod arrays for fast electron transport as the bottom layer and radially packed rutile head-caps with an improved large surface area for efficient dye adsorption. The diffuse reflectance spectra showed that with the radially packed top layer, the light-harvesting efficiency was increased due to an enhanced light-scattering effect. A combination of electrochemical impedance spectroscopy (EIS), dark current, and open-circuit voltage decay (OCVD) analyses confirmed that the electron-recombiantion rate was reduced on formation of the nanorod-based 3D network for fast electron transport. As a resut, a light-to-electricity conversion efficiency of 6.31% was achieved with this photoanode in DSSCs, which is comparable to the best DSSC efficiencies that have been reported to date for 1D rutile TiO2 .


    N-aryl azacycloalkanes, an important class of building blocks in natural product and pharmaceuticals, are synthesized via an efficient and simple eco-friendly protocol that involves double N-alkylation of aniline derivatives. The reaction is accelerated by exposure to microwaves ...

  4. One-Pot Large-Scale Synthesis of Carbon Quantum Dots: Efficient Cathode Interlayers for Polymer Solar Cells.

    Yang, Yuzhao; Lin, Xiaofeng; Li, Wenlang; Ou, Jiemei; Yuan, Zhongke; Xie, Fangyan; Hong, Wei; Yu, Dingshan; Ma, Yuguang; Chi, Zhenguo; Chen, Xudong


    Cathode interlayers (CILs) with low-cost, low-toxicity, and excellent cathode modification ability are necessary for the large-scale industrialization of polymer solar cells (PSCs). In this contribution, we demonstrated one-pot synthesized carbon quantum dots (C-dots) with high production to serve as efficient CIL for inverted PSCs. The C-dots were synthesized by a facile, economical microwave pyrolysis in a household microwave oven within 7 min. Ultraviolet photoelectron spectroscopy (UPS) studies showed that the C-dots possessed the ability to form a dipole at the interface, resulting in the decrease of the work function (WF) of cathode. External quantum efficiency (EQE) measurements and 2D excitation-emission topographical maps revealed that the C-dots down-shifted the high energy near-ultraviolet light to low energy visible light to generate more photocurrent. Remarkably improvement of power conversion efficiency (PCE) was attained by incorporation of C-dots as CIL. The PCE was boosted up from 4.14% to 8.13% with C-dots as CIL, which is one of the best efficiency for i-PSCs used carbon based materials as interlayers. These results demonstrated that C-dots can be a potential candidate for future low cost and large area PSCs producing.

  5. One pot synthesis of multi-functional tin oxide nanostructures for high efficiency dye-sensitized solar cells

    Wali, Qamar; Fakharuddin, Azhar; Yasin, Amina; Ab Rahim, Mohd Hasbi; Ismail, Jamil; Jose, Rajan, E-mail:


    Photoanode plays a key role in dye sensitized solar cells (DSSCs) as a scaffold for dye molecules, transport medium for photogenerated electrons, and scatters light for improved absorption. Herein, tin oxide nanostructures unifying the above three characteristics were optimized by a hydrothermal process and used as photoanode in DSSCs. The optimized morphology is a combination of hollow porous nanoparticles of size ∼50 nm and micron sized spheres with BET surface area (up to 29 m{sup 2}/g) to allow large dye-loading and light scattering as well as high crystallinity to support efficient charge transport. The optimized morphology gave the highest photovoltaic conversion efficiency (∼7.5%), so far achieved in DSSCs with high open circuit voltage (∼700 mV) and short circuit current density (∼21 mA/cm{sup 2}) employing conventional N3 dye and iodide/triiodide electrolyte. The best performing device achieved an incident photon to current conversion efficiency of ∼90%. The performance of the optimized tin oxide nanostructures was comparable to that of conventional titanium based DSSCs fabricated at similar conditions. - Graphical abstract: Tin oxide hollow nanostructure simultaneously supporting improved light scattering, dye-loading, and charge transport yielded high photovoltaic conversion efficiency in dye-sensitized solar cells. - Highlights: • Uniformly and bimodelly distributed tin oxide hollow nanospheres (HNS) are synthesized. • Uniform HNS are of size ∼10 nm; bimodel HNS has additional size up to ∼800 nm. • They are evaluated as photoelectrodes in dye-sensitized solar cells (DSSCs). • The uniform HNS increase dye-loading and the larger increase light scattering in DSSCs. • Photo conversion efficiency ∼7.5% is achieved using bimodel HNS.

  6. Fully automated synthesis of (phosphopeptide arrays in microtiter plate wells provides efficient access to protein tyrosine kinase characterization

    Goldstein David J


    Full Text Available Abstract Background Synthetic peptides have played a useful role in studies of protein kinase substrates and interaction domains. Synthetic peptide arrays and libraries, in particular, have accelerated the process. Several factors have hindered or limited the applicability of various techniques, such as the need for deconvolution of combinatorial libraries, the inability or impracticality of achieving full automation using two-dimensional or pin solid phases, the lack of convenient interfacing with standard analytical platforms, or the difficulty of compartmentalization of a planar surface when contact between assay components needs to be avoided. This paper describes a process for synthesis of peptides and phosphopeptides on microtiter plate wells that overcomes previous limitations and demonstrates utility in determination of the epitope of an autophosphorylation site phospho-motif antibody and utility in substrate utilization assays of the protein tyrosine kinase, p60c-src. Results The overall reproducibility of phospho-peptide synthesis and multiplexed EGF receptor (EGFR autophosphorylation site (pY1173 antibody ELISA (9H2 was within 5.5 to 8.0%. Mass spectrometric analyses of the released (phosphopeptides showed homogeneous peaks of the expected molecular weights. An overlapping peptide array of the complete EGFR cytoplasmic sequence revealed a high redundancy of 9H2 reactive sites. The eight reactive phospopeptides were structurally related and interestingly, the most conserved antibody reactive peptide motif coincided with a subset of other known EGFR autophosphorylation and SH2 binding motifs and an EGFR optimal substrate motif. Finally, peptides based on known substrate specificities of c-src and related enzymes were synthesized in microtiter plate array format and were phosphorylated by c-Src with the predicted specificities. The level of phosphorylation was proportional to c-Src concentration with sensitivities below 0.1 Units of

  7. An efficient synthesis of 2,2-bis(1H-indol-3-yl)-2H-acenaphthen-1-one catalyzed by recyclable solid superacid SO42-/TiO2under grinding condition

    Guo Liang Feng


    An efficient synthesis of symmetrical 2,2-bis(1H-indol-3-yl)-2H-acenaphthen-1-one is achieved via a reaction of acenaphthe-nequinone and indoles catalyzed by solid superacid SO42-/TiO2 under solvent-free conditions at room temperature by grinding,which provides an efficient route to the synthesis of symmetrical 2,2-bis(1H-indol-3-yl)-2H-acenaphthen-1-one.This procedure offers several advantages including solvent-free conditions,excellent yields of products,simple work-up as well as reuse of catalysts which makes it a useful and attractive protocol for the synthesis of these compounds.

  8. Nickel-Catalyzed Oxidative C-H/N-H Isocyanide Insertion: An Efficient Synthesis of Iminoisoindolinone Derivatives.

    Hao, Wenyan; Tian, Jun; Li, Wu; Shi, Renyi; Huang, Zhiliang; Lei, Aiwen


    Transition metal-catalyzed isocyanide insertion has served as a fundamental and important chemical transformation. Classical isocyanide insertion usually occurs between organohalides and nucleophiles, which normally involves tedious and non-atom-economical prefunctionalization processes. However, oxidative C-H/N-H isocyanide insertion offers an efficient and green alternative. Herein, a nickel-catayzed oxidative C-H/N-H isocyanide insertion of aminoquinoline benzamides has been developed. Different kinds of iminoisoindolinone derivatives could be synthesized in good yields by utilizing Ni(acac)2 as the catalyst. In this transformation, isocyanide serves as an efficient C1 connector, which further inserted into two simple nucleophiles (C-H/N-H), representing an effective way to construct heterocycles.

  9. Synthesis and characterization of a porous and hydrophobic cellulose-based composite for efficient and fast oil-water separation.

    Wang, Xiangyun; Xu, Shimei; Tan, Yun; Du, Juan; Wang, Jide


    Oily wastewater is generated in diverse industrial processes, and its treatment has become crucial due to increasing environmental concerns. Herein, silanized cellulose was prepared by sol-gel reaction between microcrystalline cellulose (MCC) and hexadecyltrimethoxysilane (HDTMS) using for oil-water separation. The silanized cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). A higher mass ratio of HDTMS to MCC made silanized cellulose become looser, and showed lower water absorbency. The silanized cellulose exhibited specific separation performance towards vegetable oil-water mixture (not for mineral oil-water mixture) with separation efficiency of 99.93%. Moreover, the separation was fast with a water flux of 4628.5Lm(-2)h(-1). The separation efficiency still remained at 99.77% even after recycling for 10 times.

  10. Continuous Flow Polymer Synthesis toward Reproducible Large-Scale Production for Efficient Bulk Heterojunction Organic Solar Cells.

    Pirotte, Geert; Kesters, Jurgen; Verstappen, Pieter; Govaerts, Sanne; Manca, Jean; Lutsen, Laurence; Vanderzande, Dirk; Maes, Wouter


    Organic photovoltaics (OPV) have attracted great interest as a solar cell technology with appealing mechanical, aesthetical, and economies-of-scale features. To drive OPV toward economic viability, low-cost, large-scale module production has to be realized in combination with increased top-quality material availability and minimal batch-to-batch variation. To this extent, continuous flow chemistry can serve as a powerful tool. In this contribution, a flow protocol is optimized for the high performance benzodithiophene-thienopyrroledione copolymer PBDTTPD and the material quality is probed through systematic solar-cell evaluation. A stepwise approach is adopted to turn the batch process into a reproducible and scalable continuous flow procedure. Solar cell devices fabricated using the obtained polymer batches deliver an average power conversion efficiency of 7.2 %. Upon incorporation of an ionic polythiophene-based cathodic interlayer, the photovoltaic performance could be enhanced to a maximum efficiency of 9.1 %.

  11. Polyvinylpolypyrrolidone-Supported Boron Trifluoride; Highly Efficient Catalyst for the Synthesis of N-tert-Butyl Amides

    Masoud Mokhtary


    Full Text Available Highly efficient method for the preparation of N-tert-butyl amides by reaction of nitriles with tert-butyl acetate is described using polyvinylpolypyrrolidone-supported boron trifluoride (PVPP-BF3 at 70°C in good to excellent yields. Selective amidation of benzonitrile in the presence of acetonitrile was also achieved. polyvinylpolypyrrolidone-boron trifluoride complex shows non-corrosive and stable solid catalyst elevated Lewis acid property.

  12. PPA-SiO2 catalyzed efficient synthesis of polyhydroquinoline derivatives through Hantzsch multicomponent condensation under solvent-free conditions

    Amir Khojastehnezhad; Farid Moeinpour; Abolghasem Davoodnia


    Silica gel-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the one-pot four-component Hantzsch condensation reaction of aryl aldehydes, dimedone, ethyl acetoacetate and ammonium acetate to afford the corresponding polyhydroquinoline derivatives in high yields. The main advantages of the present approach are short reaction times, clean reaction profiles, simple experimental and workup procedures.

  13. Highly efficient synthesis of quinoxaline derivatives from 1,2-benzenediamine and α-aminoxylated 1,3-dicarbonyl compounds.

    Yan, Jianwei; Xu, Yanhong; Zhuang, Fangfang; Tian, Jie; Zhang, Guisheng


    Simple and efficient synthetic procedures for the preparation of quinoxaline, pyrazine, pyridopyrazine, and benzoxazin-2-one derivatives were developed. The one-pot cascade process involves the acidic elimination of α-aminoxylated dicarbonyl compounds to generate 1,2,3-tricarbonyl compounds and subsequent condensation with 1,4-N,N or -N,O dinucleophiles to afford quinoxaline, pyrazine, pyridopyrazine, and benzoxazin-2-one scaffolds. All the proposed processes do not need extra catalysts, dry solvents, or harsh reaction conditions.

  14. Design and efficient synthesis of novel haptens and complete antigens for the AOZ, a toxic metabolite of furazolidone


    A good strategy was brought forward for designing efficient haptens and complete antigens for 3-amino-2-oxazolidinone (AOZ).Haptens designed newly were achieved facilely in good yield by using LiCl-N(Et)3 as new catalysis system, the structure of which was elucidated by spectroscopy analysis, such as NMR and MS. Novel antigens for AOZ were prepared successfully by convenient indicated that the haptens with a short unsaturated side chain can evoke specific immune response effectively.

  15. CES as an Efficient Natural Catalyst for Synthesis of Schiff Bases under Solvent-Free Conditions: An Innovative Green Approach

    Suresh Patil


    Full Text Available A mild and efficient method has been reported for the preparation of Schiff base ligands through the condensation reaction of various aromatic aldehydes with substituted aromatic amines in the presence of CES (calcined eggshell as a heterogeneous catalyst under solvent-free conditions. The advantages of this ecofriendly, economic method are simplicity of the reaction procedure, moderate to good product yields, and very short reaction times.

  16. Solvothermal synthesis of InP quantum dots and their enhanced luminescent efficiency by post-synthetic treatments.

    Byun, Ho-June; Lee, Ju Chul; Yang, Heesun


    InP quantum dots (QDs) were solvothermally synthesized by using a greener phosphorus source of P(N(CH(3))(2))(3) instead of highly toxic P(TMS)(3) widely used, and subsequently subjected to a size-sorting processing. While as-grown QDs showed an undetectably low emission intensity, post-synthetic treatments such as photo-etching, photo-radiation, and photo-assisted ZnS shell coating gave rise to a substantial increase in emission efficiency due to the effective removal and passivation of surface states. The emission efficiency of the photo-etched QDs was further enhanced by a consecutive UV photo-radiation, attributable to the photo-oxidation at QD surface. Furthermore, a relatively thick ZnS shell on the surface of InP QDs that were surface-modified with hydrophilic ligands beforehand was photochemically generated in an aqueous solution at room temperature. The resulting InP/ZnS core/shell QDs, emitting from blue to red wavelengths, were more efficient than the above photo-treated InP QDs, and their luminescent properties (emission bandwidth and quantum yield) were comparable to those of InP QDs synthesized with P(TMS)(3). Structural, size, and compositional analyses on InP/ZnS QDs were also conducted to elucidate their core/shell structure.

  17. Synthesis of Zwitterionic Polymer Particles via Combined Distillation Precipitation Polymerization and Click Chemistry for Highly Efficient Enrichment of Glycopeptide.

    Liu, Jianxi; Yang, Kaiguang; Shao, Wenya; Li, Senwu; Wu, Qi; Zhang, Shen; Qu, Yanyan; Zhang, Lihua; Zhang, Yukui


    Because of the low abundance of glycopeptide in natural biological samples, methods for efficient and selective enrichment of glycopeptides play a significant role in mass spectrometry (MS)-based glycoproteomics. In this study, a novel kind of zwitterionic hydrophilic interaction chromatography polymer particles, namely, poly(N,N-methylenebisacrylamide-co-methacrylic acid)@l-Cys (poly(MBAAm-co-MAA)@l-Cys), for the enrichment of glycopeptides was synthesized by a facile and efficient approach that combined distillation precipitation polymerization (DPP) and "thiol-ene" click reaction. In the DPP approach, residual vinyl groups explored outside the core with high density, then the functional ligand cysteine was immobilized onto the surface of core particles by highly efficient thiol-ene click reaction. Taking advantage of the unique structure of poly(MBAAm-co-MAA)@l-Cys, the resulting particles possess remarkable enrichment selectivity for glycopeptides from the tryptic digested human immunoglobulin G. The polymer particles were successfully employed for the analysis of human plasma, and 208 unique glycopeptides corresponding to 121 glycoproteins were reliably identified in triple independent nano-LC-MS/MS runs. The selectivity toward glycopeptides of these particles poly(MBAAm-co-MAA)@l-Cys is ∼2 times than that of the commercial beads. These results demonstrated that these particles had great potential for large-scale glycoproteomics research. Moreover, the strategy with the combination of DPP and thiol-ene click chemistry might be a facile method to produce functional polymer particles for bioenrichment application.

  18. Highly efficient, quick and green synthesis of biarlys with chitosan supported catalyst using microwave irradiation in the absence of solvent.

    Baran, Talat; Açıksöz, Eda; Menteş, Ayfer


    The aim of this study was to develop a quick reaction that had high activity with a small amount of catalyst, which could be an eco-friendly alternative technique for the synthesis of biarlys in Suzuki coupling reactions. First, a novel chitosan Schiff base supported Pd(II) catalyst was synthesized, and its structure was illuminated with FTIR, (1)H NMR, (13)C NMR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV-vis, magnetic moment, and molar conductivity techniques. Subsequently, the catalytic activity of the catalyst was tested in Suzuki C-C reactions under microwave irradiation using a solvent-free reaction condition. The catalytic tests showed an excellent activity with a small load of the catalyst (0.02 mol%) in 4 min. The catalyst showed seven runs without loss of activity, and high values of turnover numbers (TON) and turnover frequency (TOF) were obtained. The novel biopolymer supported Pd(II) catalyst provided much faster reaction times, higher yields, and reusability under microwave heating compared to classic heating methods.

  19. Simple efficient synthesis of strongly luminescent polypyrene with intrinsic conductivity and high carbon yield by chemical oxidative polymerization of pyrene.

    Li, Xin-Gui; Liu, You-Wei; Huang, Mei-Rong; Peng, Sai; Gong, Ling-Zhi; Moloney, Mark G


    A wholly aromatic polypyrene was synthesized by direct chemical oxidative polymerization of pyrene with ferric chloride as oxidant in hexane/nitromethane. Successful synthesis of polypyrene was thoroughly confirmed by IR, UV/Vis, 1D (1)H NMR, 2D (1)H-(1)H COSY, 2D (1)H-(13)C HSQC, MALDI-TOF MS, elemental analysis, and X-ray diffraction methods. The results indicated that the polypyrene was formed mainly through dehydro coupling between 2- or 1- and 2'- or 1'-positions on pyrene rings having a degree of polymerization of around 24. The polypyrene was purified and then separated into THF-soluble (ca. 10 %) and THF-insoluble (ca. 90 %) fractions. Compared with insulating pyrene monomer, the polypyrene is a controllably conducting polymer that has low conductivity of 3.4x10(-8) S cm(-1) in its virgin state, moderate conductivity of 2.28x10(-4) S cm(-1) upon iodine doping, but much higher conductivity of up to 81.2 S cm(-1) after the insoluble polypyrene was heated up to 1300 degrees C in nitrogen with a high char yield of 70.6 %. In particular, the soluble polypyrene demonstrates much stronger visible color fluorescence and much lower toxicity than pyrene. The soluble polypyrene would be advantageous for detecting Fe(3+) with almost no interference of other metal ions. The soluble and insoluble polypyrene fractions have potential applications as intrinsically luminescent and highly conducting carbon materials, respectively.

  20. Template synthesis of Ag/AgCl microrods and their efficient visible light-driven photocatalytic performance

    Chen, Hua; Xiao, Liang; Huang, Jianhua, E-mail:


    Highlights: • Preparation ofAg/AgCl microrods by reaction of Ag{sub 2}WO{sub 4} microrods with NaCl solution. • Generation of metallic Ag is induced by the ambient light in the synthesis process. • Ag/AgCl shows excellent visible light-driven photodegradation of organic dyes. - Abstract: Ag/AgCl microrods, aggregated by nanoparticles with a diameter ranging from 100 nm to 2 μm, were prepared by an ion-exchange reaction at 80 °C between Ag{sub 2}WO{sub 4} template and NaCl solution. The existence of metallic Ag species was confirmed by XRD, DRS and XPS measurements. Ag/AgCl microrods showed excellent photocatalytic activity for the degradation of rhodamine B and methylene blue under visible light irradiation. The degradation rate constants of rhodamine B and methylene blue are 0.176 and 0.114 min{sup −1}, respectively. The cycling photodegradation experiments suggest that Ag/AgCl microds could be employed as stable plasmonic photocatalysts for the degradation of organic dyes under visible light irradiation.

  1. Synthesis of highly efficient antibacterial agent Ag doped ZnO nanorods: Structural, Raman and optical properties

    Jan, Tariq; Iqbal, Javed, E-mail: [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Ismail, Muhammad [Institute of Biomedical and Genetic Engineering (IBGE), Islamabad (Pakistan); Mahmood, Arshad [Nano Devices Labs, National Institute of Lasers and Optronics, Islamabad (Pakistan)


    Here, synthesis, structural, morphological, Raman, optical properties and antibacterial activity of undoped and Ag doped ZnO nanorods by chemical co-precipitation technique have been reported. Structural analysis has revealed that Ag doping cannot deteriorate the structure of ZnO and wurtzite phase is maintained. Lattice constants are found to be decreased with the Ag doping. Fourier transform infrared and Raman spectroscopy also confirm the X-ray diffraction results. Scanning electron microscopy results have demonstrated the formation of ZnO nanorods with average diameter and length of 96 nm and 700 nm, respectively. Raman spectroscopy results suggest that the Ag doping enhances the number of defects in ZnO crystal. It has been found from optical study that Ag doping results in positional shift of band edge absorption peak. This is attributed to the successful incorporation of Ag dopant into ZnO host matrix. The antibacterial activity of prepared nanorods has been determined by two different methods and compared to that of undoped ZnO nanorods. Ag doped ZnO nanorods exhibit excellent antibacterial activity as compared to that of undoped ZnO nanorods. This excellent antibacterial activity may be attributed to the presence of oxygen vacancies and Zn{sup 2+} interstitial defects. Our preliminary findings suggest that Ag doped ZnO nanorods can be used externally to control the spreading of infections related with tested bacterial strains.

  2. New, efficient synthesis of oseltamivir phosphate (Tamiflu) via enzymatic desymmetrization of a meso-1,3-cyclohexanedicarboxylic acid diester.

    Zutter, Ulrich; Iding, Hans; Spurr, Paul; Wirz, Beat


    A new, enantioselective synthesis of the influenza neuraminidase inhibitor prodrug oseltamivir phosphate 1 (Tamiflu) and its enantiomer ent-1 starting from cheap, commercially available 2,6-dimethoxyphenol 10 is described. The main features of this approach comprise the cis-hydrogenation of 5-(1-ethyl-propoxy)-4,6-dimethoxy-isophthalic acid diethyl ester (6a) and the desymmetrization of the resultant all-cis meso-diesters 7a and 7b, respectively. Enzymatic hydrolysis of the meso-diester 7b with pig liver esterase afforded the (S)-monoacid 8b, which was converted into cyclohexenol 17 via a Curtius degradation and a base-catalyzed decarboxylative elimination of the Boc-protected oxazolidinone 14. Introduction of the second amino function via S(N)2 substitution of the corresponding triflate 18 with NaN3 followed by azide reduction, N-acetylation, and Boc-deprotection gave oseltamivir phosphate 1 in a total of 10 steps and an overall yield of approximately 30%. The enantiomer ent-1 was similarly obtained via an enzymatic desymmetrization of meso-diester 7a with Aspergillus oryzae lipase, providing the (R)-monoacid ent-8a.

  3. An efficient rhythmic component expression and weighting synthesis strategy for classifying motor imagery EEG in a brain computer interface

    Wang, Tao; He, Bin


    The recognition of mental states during motor imagery tasks is crucial for EEG-based brain computer interface research. We have developed a new algorithm by means of frequency decomposition and weighting synthesis strategy for recognizing imagined right- and left-hand movements. A frequency range from 5 to 25 Hz was divided into 20 band bins for each trial, and the corresponding envelopes of filtered EEG signals for each trial were extracted as a measure of instantaneous power at each frequency band. The dimensionality of the feature space was reduced from 200 (corresponding to 2 s) to 3 by down-sampling of envelopes of the feature signals, and subsequently applying principal component analysis. The linear discriminate analysis algorithm was then used to classify the features, due to its generalization capability. Each frequency band bin was weighted by a function determined according to the classification accuracy during the training process. The present classification algorithm was applied to a dataset of nine human subjects, and achieved a success rate of classification of 90% in training and 77% in testing. The present promising results suggest that the present classification algorithm can be used in initiating a general-purpose mental state recognition based on motor imagery tasks.

  4. Efficient synthesis of hydroxystyrenes via biocatalytic decarboxylation/deacetylation of substituted cinnamic acids by newly isolated Pantoea agglomerans strains.

    Sharma, Upendra K; Sharma, Nandini; Salwan, Richa; Kumar, Rakesh; Kasana, Ramesh C; Sinha, Arun K


    Decarboxylation of substituted cinnamic acids is a predominantly followed pathway for obtaining hydroxystyrenes-one of the most extensively explored bioactive compounds in the food and flavor industry (e.g. FEMA GRAS approved 4-vinylguaiacol). For this, mild and green strategies providing good yields with high product selectivity are needed. Two newly isolated bacterial strains, i.e. Pantoea agglomerans KJLPB4 and P. agglomerans KJPB2, are reported for mild and effective decarboxylation of substituted cinnamic acids into corresponding hydroxystyrenes. Key operational parameters for the process, such as incubation temperature, incubation time, substrate concentration and effect of co-solvent, were optimized using ferulic acid as a model substrate. With strain KJLPB4, 1.51 g L⁻¹ 4-vinyl guaiacol (98% yield) was selectively obtained from 2 g L⁻¹ ferulic acid at 28 °C after 48 h incubation. However, KJPB2 provided vanillic acid in 85% yield after 72 h following the oxidative decarboxylation pathway. In addition, KJLPB4 was effectively exploited for the deacetylation of acetylated α-phenylcinnamic acids, providing corresponding compounds in 65-95% yields. Two newly isolated microbial strains are reported for the mild and selective decarboxylation of substituted cinnamic acids into hydroxystyrenes. Preparative-scale synthesis of vinyl guaiacol and utilization of renewable feedstock (ferulic acid extracted from maize bran) have been demonstrated to enhance the practical utility of the process. Copyright © 2011 Society of Chemical Industry.

  5. Metal-organic gel templated synthesis of magnetic porous carbon for highly efficient removal of organic dyes.

    Wang, Luhuan; Ke, Fei; Zhu, Junfa


    Magnetic porous carbon composites are promising materials in various applications, such as adsorbents, supercapacitors and catalyst supports, due to their high surface area, thermal and chemical stability, and easy separation. However, despite the increasing number of reports of magnetic porous carbon composites, the preparation of these materials with environmentally friendly procedures still remains a great challenge. Herein, we report a facile method to prepare a magnetic porous carbon composite with high surface area from a Fe-based metal-organic gel (MOG) template, an extended structure of a metal-organic framework (MOF). The obtained magnetic porous carbon composite was applied to remove organic dyes from an aqueous solution by selecting methyl orange (MO) as a model molecule. It exhibits excellent adsorption capacity (182.82 mg g(-1)), fast adsorption kinetics (8.13 × 10(-3) g mg(-1) min(-1)), and a perfect magnetic separation performance for the MO removal. This study demonstrates a new way to achieve clean synthesis of magnetic porous carbon materials, and opens a new door for the application of MOGs in organic dye removal.

  6. Facile synthesis of flower-like platinum nanostructures as an efficient electrocatalyst for methanol electro-oxidation.

    Zhang, Jie; Chen, Jinwei; Jiang, Yiwu; Zhou, Feilong; Zhong, Jing; Wang, Gang; Kiani, Maryam; Wang, Ruilin


    This paper presents a facile approach for the synthesis of a novel Pt/graphene-nickel foam (Pt/GNF) electrode composed of flower-like Pt nanoparticles (NPs) and 3D graphene. The fabrication process involved the chemical vapor deposition of graphene onto Ni foam as a substrate and the subsequent growth of Pt NPs via a galvanic replacement reaction without using any seed and organic solvent. The surface morphology and composition of the prepared materials were characterized. Meanwhile, cyclic voltammetry and electrochemical impedance spectroscopy were employed to confirm their typical electrochemical characteristics. The as-prepared nanocomposites displayed enhanced catalytic activity and kinetics toward methanol electro-oxidation. Such an excellent performance can be ascribed to the high dispersion of flower-like Pt NPs and to the exposure of more sites provided by the flower-like structure. The improved stability, decreased charge transfer resistance, and enhanced reaction rate of the nanocomposites promise new opportunities for the development of direct methanol fuel cells.

  7. Designed copper-amine complex as an efficient template for one-pot synthesis of Cu-SSZ-13 zeolite with excellent activity for selective catalytic reduction of NOx by NH3.

    Ren, Limin; Zhu, Longfeng; Yang, Chengguang; Chen, Yanmei; Sun, Qi; Zhang, Haiyan; Li, Caijin; Nawaz, Faisal; Meng, Xiangju; Xiao, Feng-Shou


    Low-cost copper-amine complex was rationally designed to be a novel template for one-pot synthesis of Cu-SSZ-13 zeolites. Proper confirmation and appropriate size make this complex fit well with CHA cages as an efficient template. The products exhibit superior catalytic performance on NH(3)-SCR reaction.

  8. Melamine trisulfonic acid: A new, efficient and recyclable catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones in the absence of solvent

    Farhad Shirini; Mohammad Ali Zolfigol; Jalal Albadi


    Melamine trisulfonic acid (MTSA) can be used as an efficient and recyclable catalyst for the promotion of the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones (DHPMs) in the absence of solvent. All reactions were performed at 80 ℃ in good to high yields.

  9. Regioselective ring opening of epoxides using NH4SCN/silica sulfuric acid: An efficient approach for the synthesis of β-hydroxy thiocyanate under solvent-free conditions

    Ali R. Kiasat; Maryam Zayadi; Mehdi Fallah Mehrjardi


    Silica sulfuric acid was developed as a stable and efficient heterogeneous catalyst in organic synthesis. This solid acid catalyzed the regioselective ring opening of epoxides by thiocyanate anion to give thiocyanohydrins as key intermediates in agricultural and pharmaceutical chemistry in high yields under solvent-free conditions.

  10. PEG-400 as an efficient reaction medium for the synthesis of 2,4,5-triaryl-1H-imidazoles and 1,2,4,5-tetraaryl-1H-imidazoles

    Xi Cun Wang; Hai Peng Gong; Zheng Jun Quan; Lei Li; He Lin Ye


    An efficient protocol for the one-pot multicomponent synthesis of various 2,4,5-triaryl- IH-imidazoles and 1,2,4,5-tetraaryl-1H-imidazoles using PEG-400 as reaction medium is described. This method has the advantages of good yields, less pollution and simple reaction conditions.

  11. Facile synthesis and characterization of Ti(1-x)CuxO2 nanoparticles for high efficiency dye sensitized solar cell applications

    Manju, J.; Jawhar, S. Joseph


    In this study, we demonstrate the facile synthesis of Ti(1-x)CuxO2 (x = 0.0, 0.03, 0.06 and 0.09) nanoparticles through solvothermal microwave irradiation (SMI) technique and explored their photocatalytic applications. A combined analysis of XRD, FESEM and TEM studies indicate that doping of Cu2+ in TiO2 lattice do not affect the microstructure of the particles. The UV-Vis. absorption study indicates that the introduction of Cu element lead to decrease in optical bandgap of TiO2 from 3.450 eV to 3.155 eV (for x = 0.0 to 0.09). By using Ti(1-x)CuxO2 nanoparticles photoanodes were prepared on transparent conductive fluorine doped tin oxide substrates by doctor-blade technique. The dye-sensitized solar cells (DSSCs) were assembled and an analysis was made to evaluate the variations in open-circuit voltage depending on the concentration of Cu in Ti(1-x)CuxO2. The optimum efficiency of 6.51% was found at Ti0.94Cu0.06O2 based DSSCs, which gives an efficiency improved by 4% compared with that of the cells based on pure TiO2 (6.26%). This work demonstrates that Ti(1-x)CuxO2 is a most fascinating material and has great potential for application in photoenergy conversion devices.

  12. Polycationic diblock and random polyethylene glycol- or tris(hydroxymethyl)methyl-grafted (co)telomers for gene transfer: synthesis and evaluation of their in vitro transfection efficiency.

    Le Bon, Bertrand; Van Craynest, Nathalie; Boussif, Otmane; Vierling, Pierre


    We report on the synthesis of a series of polycationic telomers, polycationic diblock and random polyethylene glycol (PEG)-grafted (co)telomers, and polycationic random tris(hydroxymethyl)methyl (THM) cotelomers, and on their in vitro gene transfer capability. These compounds were obtained by a telomerization process of various amino-, tetraethylene glycol-, or THM-acrylamide taxogens with thiols which might derive from PEG2000. For N/P ratios [N is the number of (co)telomer amine equivalents; P is the number of DNA phosphate equivalents] from 0.8 to 10, these (co)telomers condensed DNA, forming (co)teloplexes with mean sizes in the 85-330 nm range, even for an N/P ratio of 0.8 or 1.25. Some structure-transfection efficiency relationships were established. Among the new polycationic derivatives that were synthesized and investigated for their transfection efficiency, the (i)Bu-[NH](75) telomers and the diblock polyethylene glycol-conjugated PEG2000-[NH](n) telomers are very promising candidates for gene transfer purposes.

  13. Ultra rapid direct heating synthesis of ZnO nanorods with improved light trapping from stacked photoanodes for high efficiency photocatalytic water splitting

    Cheat Lee, Wei; Fang, Yuanxing; Commandeur, Daniel; Qian, Rong; Al-Abdullah, Zainab T. Y.; Chen, Qiao


    An ultra rapid growth method for vertically aligned ZnO nanorod (NR) thin films on metal meshes was developed using a direct heating synthesis technique. A typical NR growth rate of 10 μm h-1 was achieved. The effects of the applied heating power and growth duration on the morphologies of ZnO nanostructures were examined. High density surface defects were formed on the ZnO NRs, which is responsible for slow charge recombination and high efficiency in the photoelectrochemical (PEC) water splitting process. The light absorption for a photoanode was significantly improved by light trapping using a 3D stacked metal mesh photoanode structure. With the internal reflection between the stacked photoanodes, the final light leakage is minimised. The light absorption in the stacked photoanode is improved without restricting the charge transportation. In comparison with a single mesh photoanode and a chemical bath deposition grown flat photoanode, the PEC water splitting efficiency from the stacked photoanode was increased by a factor of 2.6 and 6.1 respectively.

  14. One-Pot Synthesis of Mesoporous TiO₂ Micropheres and Its Application for High-Efficiency Dye-Sensitized Solar Cells.

    Li, Zhao-Qian; Que, Ya-Ping; Mo, Li-E; Chen, Wang-Chao; Ding, Yong; Ma, Yan-Mei; Jiang, Ling; Hu, Lin-Hua; Dai, Song-Yuan


    TiO2 microspheres are of great interest for a great deal of applications, especially in the solar cell field. Because of their unique microstructure and light-scattering effect, TiO2 microsphere-based solar cells often exhibit superior photovoltaic performance. Hence, exploring new suitable TiO2 microspheres for high-efficiency solar cells is essential. In this work, we demonstrate a facile one-pot solvothermal approach for synthesis of TiO2 microspheres using acetone as solvent. The as-prepared TiO2 microspheres are composed of densely interconnected nanocrystals and possess a high specific surface area up to 138.47 m(2) g(-1). As the photoanode, the TiO2 microsphere-based DSSC gives higher dye loading and light adsorption ability as well as longer electron lifetime, resulting in higher short-circuit current value and superior power conversion efficiency (PCE) compared with Dyesol 18 nm TiO2 nanoparticle paste. Finally, the TiO2 microsphere-based DSSC were optimized by adding a TiO2 nanocrystal underlayer and TiCl4 post-treatment, giving a high PCE of 10.32%.

  15. Microwave Mediated Organic Reaction: A Convenient Approach for Rapid and Efficient Synthesis of Biologically Active Substituted 1,3-Dihydro-2H-indol-2-one Derivatives

    Jnyanaranjan Panda


    Full Text Available A simple and efficient method has been developed for the synthesis of 1,3-dihydro-2H-indol-2-one derivatives using microwave irradiation technique. By taking advantage of the efficient source of energy of microwave, compound libraries for lead generation and optimization can be assembled in a fraction of time. In the present work, first the Schiff’s bases are synthesized by reaction of isatin with substituted anilines in the presence of acetic acid under microwave heating. Then the condensation of Schiff bases with different secondary amines in the presence of formaldehyde produces Mannich bases. The newly synthesized Mannich bases were characterized by means of spectral data and then evaluated for anthelmintic activity against Pheretima posthuma (Indian earthworm and compared with standard albendazole. The compounds were evaluated at the concentrations of 10, 20, and 50 mg/mL. The effect of the standard drug albendazole at 10 mg/mL was also evaluated. The results of the present study indicate that some of the test compounds significantly demonstrated paralysis and also caused death of worms in a dose-dependent manner.

  16. Synthesis of butterfly-like ZnO nanostructures and study of their self-reducing ability toward Au(3+) ions for enhanced photocatalytic efficiency.

    Song, Xueling; Liu, Yumeng; Zheng, Yan; Ding, Kun; Nie, Shijie; Yang, Ping


    Zinc oxide (ZnO) nanostructures with diverse morphologies were successfully fabricated via a simple one-step hydrothermal synthesis and subsequent calcination. The formation of butterfly-like ZnO was mainly ascribed to a typical nucleation-growth-assembly process as a result of electrostatic interactions between the nanoparticles and the reconstructed sheets. Au nanoparticles (NPs) created from Au(3+) ions were deposited on the butterfly-like ZnO without the use of any reducing agents by simply stirring the solution at room temperature. Tartaric acid was present in the ZnO calcined at a low temperature (300 °C), which resulted in the self-reducing ability of ZnO toward the Au(3+) ions. The Au NPs were closely connected with the ZnO matrix. This close connection resulted in hierarchical ZnO-Au composites with efficient photocatalytic activity for use in environmental remediation. Compared with the pure ZnO sample calcined at 300 °C, the hierarchical ZnO-Au composites showed an enhanced photocatalytic performance toward rhodamine B. The results of photodegradation indicated that the incorporation of the Au NPs drastically increased the photocatalytic efficiency by promoting the separation of the electron-hole pairs created by the absorption of photons.

  17. Synthesis and characterization of cesium molybdo vanado phosphate immobilized on platelet SBA-15: An efficient inorganic composite ion-exchanger for gadolinium ion sorption

    Aghayan, H., E-mail: [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Tehran (Iran, Islamic Republic of); Khanchi, A.R., E-mail: [Nuclear Science and Technology Institute, P.O. Box. 11365-8486, Tehran (Iran, Islamic Republic of); Mahjoub, A.R. [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Tehran (Iran, Islamic Republic of)


    A series of cesium molybdo vanado phosphate (CsMVP) supported on platelet SBA-15 (SBA-15–%xCsMVP, x = 20, 30, 40 and 50 wt.%) was synthesized to develop an efficient inorganic composite ion-exchanger for gadolinium ion removal from aqueous solution. The preparation has been carried out using two-step aqueous impregnation methods. The obtained products were characterized by inductively coupled plasma (ICP), XRD, N{sub 2} adsorption–desorption isotherms, scanning electron microscopy (SEM) and FT-IR. In order to examine adsorption behavior of this compound on gadolinium removal, the effect of heteropoly metalate loading, pH, contact time, concentration of metal ion and temperature were investigated under batch system conditions. The SBA-15–30%CsMVP showed maximum adsorption capacity toward gadolinium removal. The results suggested that this methodology provides the general synthesis of supported heteropolymetalate with large surface areas, and ordered nano porous structures that can be used as inorganic composite ion-exchanger for efficient removal of gadolinium ions from aqueous solution.

  18. Facile synthesis of yeast cross-linked Fe3O4 nanoadsorbents for efficient removal of aquatic environment contaminated with As(V).

    Rajesh Kumar, S; Jayavignesh, V; Selvakumar, R; Swaminathan, K; Ponpandian, N


    A facile solvothermal method was adopted to prepare monodispersed surface functionalized Fe3O4 nanoparticles via self assembly process. The pure yeast, diethylamine functionalized Fe3O4 nanoparticles (DMNPs) and yeast cross-linked Fe3O4 nanoparticles (YcMNPs) were used for the efficient removal of arsenate from aqueous solution. The crystal structure, morphology and magnetic properties of these nanoparticles were characterized by using X-ray diffraction, field emission scanning electron microscopy and vibrating sample magnetometer. The observed physico-chemical properties confirms the metal binding nature of prepared samples. The adsorption of As(V) on the functionalized magnetite nanoparticles was tested under different operating conditions like contact time, adsorbate dosage, adsorbate concentration and pH. The faster removal of As(V) was obtained using YcMNPs (99%) than DMNPs and pure yeast. The adsorption equilibrium data obeys Langmuir isotherm than Freundlich model and the kinetics data well depicts the pseudo-second-order model. The batch column experiment confirms the adequate desorption as well as reusability without significant loss of efficiency. The results reveal the technical feasibility of the prepared nanoparticles for their easy synthesis, recovery, cost effective, eco-friendly and a promising advanced adsorbent for environmental pollution. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Eco-friendly and Efficient Synthesis, Characterisation and Antibacterial Studies of Unsymmetrical Bidentate Schiff Bases and their Zn(II Complexes

    K. P.Srivastava


    Full Text Available A rapid, efficient, clean and environmentally benign exclusive synthesis of Schiff bases as new ligands and their complexes with Zn(II have been developed using condensation of pyridoxalwith amoxicillin (L1, cephalexin (L2, sulphamethoxazole (L3 and trimethoprim (L4 efficiently in analcoholic suspension medium using alkali catalyst with excellent yields under microwaves irradiation. This method provides several advantages such as environmental friendliness, simple work-up procedure, short reaction times, non-hazardous and excellent yield of products.The results are compared with conventional methods for their yield and reaction time. The Schiff base ligands and the complexes were characterized by micro-analytical, thermo-gravimetric, magnetic and spectroscopic studies.All the Schiff bases were bidentate (NO donor ligands. All complexes were found to be six co-ordinate dihydrates and ML2[1:2 (metal: ligand ratio] type. The complexes are coloured and stable in air. All the complexes under investigation possess antibacterial activity. The antibacterial activity showed the following trend:

  20. Facile and selective synthesis of oligothiophene-based sensitizer isomers: an approach toward efficient dye-sensitized solar cells.

    Feng, Quanyou; Zhang, Qian; Lu, Xuefeng; Wang, Hong; Zhou, Gang; Wang, Zhong-Sheng


    Two sets of isomeric organic dyes with n-hexyl (DH and AH) or 2-ethylhexyl (DEH and AEH) groups substituted at the spacer part have been designed and straightforwardly synthesized via a facile and selective synthetic route. The structure difference between the isomers stands at the position of the incorporated alkyl chains which are introduced into the terthiophene spacer close to the donor (D) or anchor (A) side. The relationship between the isomeric structures and the optoelectronic properties are systematically investigated. It is found that, in the D series dyes, the alkyl group is much closer to the aromatic donor moiety, which brings about strong steric hindrance and therefore causes a remarkable twist in the molecular skeleton. In contrast, a more planar chemical structure and more effective π-conjugation are realized in the A series dye isomers. Consequently, the A series isomeric dyes demonstrate bathochromically shifted absorption bands, resulting in the improved light-harvesting capability and enhanced photo-generated current. However, the D series isomeric dyes with more twisted molecular skeleton have suppressed the intermolecular interactions and retarded the charge recombination more efficiently, which induces higher open-circuit photovoltage. Combining the two effects on the performance of the fabricated dye-sensitized solar cells (DSSC), the influence from the short-circuit photocurrent plays a more significant role on the power conversion efficiency (η). As a result, isomer AEH-based DSSC with quasi-solid-state electrolyte displays the highest η of 7.10% which remained at 98% of the initial value after continuous light soaking for 1000 h. Promisingly, a η of 8.66% has been achieved for AEH-based DSSC with liquid electrolyte containing Co(II)/(III) redox couple. This work presents the crucial issue of molecular engineering and paves a way to design organic sensitizers for highly efficient and stable DSSCs.

  1. A novel method of synthesis of small band gap SnS nanorods and its efficient photocatalytic dye degradation.

    Das, Dipika; Dutta, Raj Kumar


    A facile one pot method has been developed for synthesis of stable (ξ=-37.5 mV), orthorhombic structured SnS nanorods capped with mercaptoacetic acid by precipitation method. The SnS nanorods were measured to be about 45 nm long with a diameter of 20 nm, as studied by transmission electron microscopy (TEM). The band gap of the MAA capped SnS nanorods was 1.81 eV, measured by diffused reflectance spectroscopy and was larger than the bulk SnS. The relative positions of highest valence band and lowest conduction band were determined from theoretical band structure calculation as 1.58 eV and -0.23 eV, respectively. The UV-Visible-NIR fluorescence emission spectrum of the SnS nanorods revealed intense emission peak at 1000 nm (1.239 eV) and weaker peaks at 935 nm, 1080 nm, 1160 nm which is likely to be due to Sn(2+) vacancies. The as-synthesized SnS nanorods exhibited more than 95% sunlight induced photocatalytic degradation of trypan blue in 4 h, following first order kinetics with high rate of degradation (k) (0.0124 min(-1)). The observed dye degradation is attributable to generation of reactive oxygen species (ROS), confirmed from terephthalic acid assay. The ROS generation has been explained on the basis of interaction between photoexcited electrons from conduction band with molecular oxygen adhered to the surface of nanorods owing to favourable redox potentials of O2/O2(-) (-0.20 eV) in normal hydrogen electrode (NHE) scale.

  2. Synthesis, growth and optical properties of an efficient nonlinear optical single crystal: L-alanine DL-malic acid

    Kirubagaran, R.; Madhavan, J.


    Single crystals of L-alanine DL-malic acid (LADLMA) have been grown from aqueous solution by slow-cooling technique. Powder X-ray diffraction studies reveal the structure of the crystal to be orthorhombic. The nonlinear optical conversion efficiency test was carried out for the grown crystals using the Kurtz powder technique. The third order nonlinear refractive index and the nonlinear absorption coefficient where evaluated by Z-scan measurements. As the material have a negative refractive index it could be used in the protection of optical sensors such as night vision devices.

  3. One-step synthesis of xanthones catalyzed by a highly efficient copper-based magnetically recoverable nanocatalyst.

    Menéndez, Cintia A; Nador, Fabiana; Radivoy, Gabriel; Gerbino, Darío C


    A versatile and highly efficient strategy to construct a xanthone skeleton via a ligand-free intermolecular catalytic coupling of 2-substituted benzaldehydes and a wide range of phenols has been developed. For this purpose, a novel and magnetically recoverable catalyst consisting of copper nanoparticles on nanosized silica coated maghemite is presented. The reaction proceeds smoothly with easy recovery and reuse of the catalyst. The methodology is compatible with various functional groups and provides an attractive protocol for the generation of a small library of xanthones in very good yield.

  4. Design and Synthesis of TiO2 Hollow Spheres with Spatially Separated Dual Cocatalysts for Efficient Photocatalytic Hydrogen Production

    Jiang, Qianqian; Li, Li; Bi, Jinhong; Liang, Shijing; Liu, Minghua


    TiO2 hollow spheres modified with spatially separated Ag species and RuO2 cocatalysts have been prepared via an alkoxide hydrolysis–precipitation method and a facile impregnation method. High-resolution transmission electron microscopy studies indicate that Ag species and RuO2 co-located on the inner and outer surface of TiO2 hollow spheres, respectively. The resultant catalysts show significantly enhanced activity in photocatalytic hydrogen production under simulated sunlight attributed to spatially separated Ag species and RuO2 cocatalysts on TiO2 hollow spheres, which results in the efficient separation and transportation of photogenerated charge carriers. PMID:28336859

  5. Facile synthesis of BiOF/Bi{sub 2}O{sub 3}/reduced graphene oxide photocatalyst with highly efficient and stable natural sunlight photocatalytic performance

    Hu, Limin; Dong, Shuying; Li, Qilu; Feng, Jinglan; Pi, Yunqing; Liu, Menglin [School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China); Sun, Jingyu, E-mail: [Center for Nanochemistry (CNC), College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Sun, Jianhui, E-mail: [School of Environment, Henan Normal University, Key Laboratory for Yellow River and Huai River Water Environmental and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, Xinxiang, Henan 453007 (China)


    Highlights: • A dual Bi-based ball-shaped material BiOF/Bi{sub 2}O{sub 3} were facilely synthesized. • The composition effect of BiOF/Bi{sub 2}O{sub 3}/RGO hybrid were probed for the first time. • The photocatalytic performances were evaluated upon natural sunlight irradiation. • The composites showed a twofold augmentation in the degradation efficiency. • The hybrid photocatalyst can be easily recycled for three times. - Abstract: A facile and efficient route for the controllable synthesis of BiOF/Bi{sub 2}O{sub 3} nanostructures by hydrolysis method was reported, where the as-prepared BiOF/Bi{sub 2}O{sub 3} was subsequently incorporated with reduced graphene oxide (RGO) sheets to form BiOF/Bi{sub 2}O{sub 3}/RGO composites. The obtained BiOF/Bi{sub 2}O{sub 3} and BiOF/Bi{sub 2}O{sub 3}/RGO composites were well characterized with the aid of various techniques to probe their crystallographic, morphological, chemical and optical properties. Photocatalytic capacities of the pure BiOF/Bi{sub 2}O{sub 3} and BiOF/Bi{sub 2}O{sub 3}/RGO composites have been investigated by the degradation of Rhodamine B (RhB)-contained wastewater under natural sunlight irradiation. A twofold augmentation of degradation efficiency was in turn observed for BiOF/Bi{sub 2}O{sub 3}/RGO composites compared with that of pure BiOF/Bi{sub 2}O{sub 3} under the natural sunlight irradiation. The optimum conditions, the effects of the active species and stabilities in photocatalytic performances of the BiOF/Bi{sub 2}O{sub 3}/RGO composites have also been probed.

  6. Synthesis of novel ZrO2&GO@TiO2 nanocomposite as an efficient photoanode in dye-sensitized solar cells

    Mohamed, Ibrahim M. A.; Dao, Van-Duong; Yasin, Ahmed S.; Yassin, Mohamed A.; Barakat, Nasser A. M.; Choi, Ho-Suk


    Due to the physicochemical and photo-electro properties, TiO2 nanostructures still being the outstanding photoanode materials in the dye-sensitized solar cells (DSCs). However, it is well known that a low dye-loading and charge recombination constrain the limitation of large-scale application. This work introduces the synthesis of ZrO2&GO@TiO2 nanofibers (NFs) by facile two steps using electrospinning and hydrothermal treatment. Furthermore, the developed materials are applied as an efficient photoanode of DSCs. The synthesized NFs are described in terms of morphology, crystallography and chemistry via FESEM, TEM, XRD, Raman spectra and EDX analysis. As the results, the Ti, Zr, O and C elements are uniformly distributed in the synthesized sample. The percentages of the atomic elements are 10.77, 57.69, 1.45 and 30.09 for C, O, Zr and Ti, respectively. The synthesized composite shows only anatase with crystal size of 25.86 nm and cell volume of 142.39 Å3. The developed material is employed as working electrode of DSCs. The J-V characteristic showed 5.09% efficiency for device using the synthesized material, which is higher than those of cells assembled with TiO2 NFs and ZrO2@TiO2 NFs photoanodes. The obtained result is explained by enhanced dye-loading (1.055 × 1017 molecule/cm2) and improved charge transfer resistance (Rct = 9.18 Ω) of the photoanode substrate. Hence, the presented nanocomposite can be an efficient photoanode towards technology of DSC.

  7. Efficient synthesis of D-branched-chain amino acids and their labeled compounds with stable isotopes using D-amino acid dehydrogenase.

    Akita, Hironaga; Suzuki, Hirokazu; Doi, Katsumi; Ohshima, Toshihisa


    D-Branched-chain amino acids (D-BCAAs) such as D-leucine, D-isoleucine, and D-valine are known to be peptide antibiotic intermediates and to exhibit a variety of bioactivities. Consequently, much effort is going into achieving simple stereospecific synthesis of D-BCAAs, especially analogs labeled with stable isotopes. Up to now, however, no effective method has been reported. Here, we report the establishment of an efficient system for enantioselective synthesis of D-BCAAs and production of D-BCAAs labeled with stable isotopes. This system is based on two thermostable enzymes: D-amino acid dehydrogenase, catalyzing NADPH-dependent enantioselective amination of 2-oxo acids to produce the corresponding D-amino acids, and glucose dehydrogenase, catalyzing NADPH regeneration from NADP(+) and D-glucose. After incubation with the enzymes for 2 h at 65°C and pH 10.5, 2-oxo-4-methylvaleric acid was converted to D-leucine with an excellent yield (>99 %) and optical purity (>99 %). Using this system, we produced five different D-BCAAs labeled with stable isotopes: D-[1-(13)C,(15)N]leucine, D-[1-(13)C]leucine, D-[(15)N]leucine, D-[(15)N]isoleucine, and D-[(15)N]valine. The structure of each labeled D-amino acid was confirmed using time-of-flight mass spectrometry and nuclear magnetic resonance analysis. These analyses confirmed that the developed system was highly useful for production of D-BCAAs labeled with stable isotopes, making this the first reported enzymatic production of D-BCAAs labeled with stable isotopes. Our findings facilitate tracer studies investigating D-BCAAs and their derivatives.

  8. Effect of post-synthesis acid activation of TiO2 nanofilms on the photocatalytic efficiency under visible light

    Stambolova, I.; Blaskov, V.; Shipochka, M.; Eliyas, A.; Vassilev, S.


    Nanosized TiO2 films were deposited by spray pyrolysis and thermally treated at 400oC. Then the films were dipped in 1M aqueous solution of HCl. The activated samples were divided into two parts - one part was dried (A) and another was annealed (AT) in air. The photocatalytic degradation of Reactive Black (RB5) textile dye under visible light was tested. The following instrumental methods: X-ray diffraction (XRD), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) were applied for the phase and surface characterization of obtained samples. According to Raman and XRD analyses all films are anatase. The XRD showed that activated films are better crystallized than non activated TiO2 film. The presence of chlorine at 200.3 eV was registered for acid activated samples by X-Ray photoelectron spectroscopy. The acidic activated films exhibited higher rate of dye photodegradation than that of the reference TiO2 sample. The photocatalytic efficiency decreases in the order A > AT> non activated TiO2 films. The degradation rate constant for acid activated films is two times higher than those of the reference film. The hydroxyl content in TiO2 acidic activated films is greater than that of the non- activated films, which results in significant increase in the photocatalytic activity. In addition, the presence of chlorine may also lead to enhancement in efficiency.

  9. Synthesis of pH-sensitive and recyclable magnetic nanoparticles for efficient separation of emulsified oil from aqueous environments

    Lü, Ting; Zhang, Shuang; Qi, Dongming; Zhang, Dong; Vance, George F.; Zhao, Hongting


    Emulsified oil wastewaters, arisen from oil industry and oil spill accidents, cause severe environmental and ecological problems. In this study, a series of pH-sensitive magnetic nanomaterials (MNPs) were synthesized and characterized for their evaluation in separation of emulsified oil from aqueous environments. A coprecipitation method was used to produce Fe3O4 magnetic nanoparticles that were coated in a 2-step process with first silica to form a surface for anchoring an (3-aminopropyl)triethoxysilane (APTES) molecular layer. Detailed studies were conducted on effects of MNPs dosage, APTES anchoring density (DA) and pH on oil-water separation performance of the synthetic MNPs. Results showed that, under both acidic and neutral conditions, MNPs with high DA exhibited enhanced oil-water separation performance, while under alkaline condition, the oil-water separation process was minimal. Alkaline conditions allowed the MNPs to be recycled up to 9 cycles without showing any significant decrease in oil-water separation efficiency. An examination of the oil-water separation mechanism found that electrostatic interaction and interfacial activity both played important roles in oil-water separation. In conclusion, pH-sensitive MNPs can be easily synthesized and recycled, providing a promising, cost-effective and environmentally-friendly process for the efficient treatment of emulsified oil wastewater.

  10. Pt-Sn/γ-Al2O3-catalyzed highly efficient direct synthesis of secondary and tertiary amines and imines.

    He, Wei; Wang, Liandi; Sun, Chenglin; Wu, Kaikai; He, Songbo; Chen, Jiping; Wu, Ping; Yu, Zhengkun


    Versatile syntheses of secondary and tertiary amines by highly efficient direct N-alkylation of primary and secondary amines with alcohols or by deaminative self-coupling of primary amines have been successfully realized by means of a heterogeneous bimetallic Pt-Sn/γ-Al(2)O(3) catalyst (0.5 wt % Pt, Pt/Sn molar ratio=1:3) through a borrowing-hydrogen strategy. In the presence of oxygen, imines were also efficiently prepared from the tandem reactions of amines with alcohols or between two primary amines. The proposed mechanism reveals that an alcohol or amine substrate is initially dehydrogenated to an aldehyde/ketone or NH-imine with concomitant formation of a [PtSn] hydride. Condensation of the aldehyde/ketone species or deamination of the NH-imine intermediate with another molecule of amine forms an N-substituted imine which is then reduced to a new amine product by the in-situ generated [PtSn] hydride under a nitrogen atmosphere or remains unchanged as the final product under an oxygen atmosphere. The Pt-Sn/γ-Al(2)O(3) catalyst can be easily recycled without Pt metal leaching and has exhibited very high catalytic activity toward a wide range of amine and alcohol substrates, which suggests potential for application in the direct production of secondary and tertiary amines and N-substituted imines. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Confined-space alloying of nanoparticles for the synthesis of efficient PtNi fuel-cell catalysts.

    Baldizzone, Claudio; Mezzavilla, Stefano; Carvalho, Hudson W P; Meier, Josef Christian; Schuppert, Anna K; Heggen, Marc; Galeano, Carolina; Grunwaldt, Jan-Dierk; Schüth, Ferdi; Mayrhofer, Karl J J


    The efficiency of polymer electrolyte membrane fuel cells is strongly depending on the electrocatalyst performance, that is, its activity and stability. We have designed a catalyst material that combines both, the high activity for the decisive cathodic oxygen reduction reaction associated with nanoscale Pt alloys, and the excellent durability of an advanced nanostructured support. Owing to the high specific activity and large active surface area, the catalyst shows extraordinary mass activity values of 1.0 A mgPt(-1). Moreover, the material retains its initial active surface area and intrinsic activity during an extended accelerated aging test within the typical operation range. This excellent performance is achieved by confined-space alloying of the nanoparticles in a controlled manner in the pores of the support.

  12. An efficient synthesis of 3'-indolyl substituted pyrido[1,2-]benzimidazoles as potential antimicrobial and antioxidant agents

    Harshad G Kathrotiya; Manish P Patel


    A new class of indole-based pyrido[1,2-]benzimidazole derivatives 4a-r have been synthesized by one-pot cyclocondensation reaction of 2-phenyl-1-indole-3-carboxaldehyde 1a-i, malononitrile 2 and 2-cyanomethylbenzimidazole 3a-b in the presence of catalytic amount of NaOH. In vitro antimicrobial activity of the synthesized compounds were investigated against a representative panel of pathogenic strains specifically three Gram-positive bacteria (Streptococcus pneumoniae, Clostridium tetani, Bacillus subtilis), three Gram-negative bacteria (Salmonella typhi, Vibrio cholerae, Escherichia coli) and two fungi (Aspergillus fumigatus, Candida albicans) using broth microdilution MIC (minimum inhibitory concentration) method. In vitro antioxidant activity was evaluated by ferric-reducing antioxidant power (FRAP) assay method. Compounds 4c, 4e, 4l and 4q have been found to be most efficient antimicrobial members while compounds 4h and 4p possess better ferric reducing antioxidant power.

  13. Synthesis and characterization of the hybrid Ni-TiO2/PANI for an efficient hydrogen photoproduction under visible light

    Mohamed Faouzi Nsib


    Full Text Available NixZn1-xO/Polyaniline hybrid photocatalysts are synthesized by the impregnation method at ambient temperature and used for hydrogen photoproduction experiments. XRD, UV-Vis DRS, SEM and TGA are used to characterize the prepared materials. It is shown that the Ni2+ amount doped into ZnO controls its morphology and enhances its photoactivity for H2 generation. Polyaniline (PANI is shown to sensitize ZnO and to extend its light absorption toward the visible region. The hybrid photocatalyst with 10 mol. % Ni2+ and 10 wt. % PANI shows the maximum photocatalytic H2 production for one hour of visible irradiation: ~ 558 μmole while only ~ 178 μmole in the presence of pure ZnO. It is also observed that the hydrogen photoproduction efficiency depends strongly on the nature of the sacrificial electron donor and increases in the order: thiosulfate >sulfide> propanol.

  14. Synthesis and Characterization of Phenothiazine-Based Platinum(II)-Acetylide Photosensitizers for Efficient Dye-Sensitized Solar Cells.

    Siu, Chi-Ho; Lee, Lawrence Tien Lin; Yiu, Sze-Chun; Ho, Po-Yu; Zhou, Panwang; Ho, Cheuk-Lam; Chen, Tao; Liu, Jianyong; Han, Keli; Wong, Wai-Yeung


    Three new unsymmetrical phenothiazine-based platinum(II) bis(acetylide) complexes PT1-PT3 with different electron-donating arylacetylide ligands were synthesized and characterized. Their photophysical, electrochemical, and photovoltaic properties have been fully investigated and the density functional theory (DFT) calculations have been carried out. Under AM 1.5 irradiation (100 mW cm(-2)), the PT1-based dye-sensitized solar cell (DSSC) device exhibited an attractive power conversion efficiency (η) up to 5.78 %, with a short-circuit photocurrent density (J(sc)) of 10.98 mA cm(-2), an open-circuit photovoltage (V(oc)) of 0.738 V, and a fill factor (ff) of 0.713. These findings provide strong evidence that platinum-acetylide complexes have great potential as promising photosensitizers in DSSC applications.

  15. Synthesis and in vitro transfection efficiency of spermine-based cationic lipids with different central core structures and lipophilic tails.

    Niyomtham, Nattisa; Apiratikul, Nuttapon; Suksen, Kanoknetr; Opanasopit, Praneet; Yingyongnarongkul, Boon-Ek


    Twelve spermine-based cationic lipids with four different central core structures (di(oxyethyl)amino, di(oxyethyl)amino carboxy, 3-amino-1,2-dioxypropyl and 2-amino-1,3-dioxypropyl) and three hydrophobic tails (lauric acid, myristic acid and palmitic acid) were synthesized. The liposomes containing lipids and DOPE showed moderate to good in vitro DNA delivery into HeLa cells. GFP expression experiments revealed that liposomes composed of lipids with 3-amino-1,2-dioxypropyl as a central core structure exhibited highest transfection efficiency under serum-free condition. Whereas, lipid with 2-amino-1,3-dioxypropyl core structure showed highest transfection under 10% serum condition. Moreover, the liposomes and lipoplexes composted of these cationic lipids exhibited low cytotoxicity.

  16. Synthesis of Hierarchical (BiO)2CO3 Nanosheets Microspheres toward Efficient Photocatalystic Reduction of CO2 into CO

    Yang, Huohai; Bai, Yang; Chen, Ting; Shi, Xian; Zhu, Yu-chuan


    In this paper, hierarchical (BiO)2CO3 nanosheets microspheres were synthesized with dry ice as carbon source, and characterized by X-ray diffraction (XRD) patterns, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM) and UV-vis diffuse reflectance spectra (DRS). The photocatalytic results showed that (BiO)2CO3 display much higher photocatalytic activity than BiOCl and TiO2 for photocatalystic reduction of CO2 under UV-visible light. The photocatalytic mechanism study revealled that (BiO)2CO3 display better separation efficiency of photoinduced charge carriers due to the large interlayer spacing (1.3675 nm).

  17. Efficient and Convenient Route for the Synthesis of Some New Antipyrinyl Monoazo Dyes: Application to Polyester Fibers and Biological Evaluation

    Ahmed A. Fadda


    Full Text Available Nine variously substituted azo dye derivatives 2–10 of antipyrine were prepared. The effects of the nature and orientation of the substituents on the color and dyeing properties of these dyes for polyester fibers were evaluated. The newly synthesized compounds were characterized on the basis of elemental analyses and spectral data. On the other hand, the investigated dyes were applied to polyester fabrics and showed good light, washing, heat, and acid perspiration fastness. The remarkable degree of brightness after washings is indicative of the good penetration and the excellent affinity of these dyes for the fabric. The results in general revealed the efficiency of the prepared compounds as new monoazo disperse dyes. The newly synthesized compounds were screened for their antioxidant and cytotoxic activity against Vitamin C and 5-fluorouracil, respectively. The data showed clearly that most of the compounds exhibited good antioxidant and cytotoxic activities.

  18. The efficient synthesis of a molybdenum carbide catalyst via H2-thermal treatment of a Mo(VI)-hexamethylenetetramine complex.

    Wang, Zhi-Qiang; Zhang, Zhong-Biao; Zhang, Ming-Hui


    An efficient method for preparation of Mo(2)C catalyst is described, where Mo(2)C is obtained by the heat treatment of a single solid precursor containing (NH(4))(6)Mo(7)O(24) and hexamethylenetetramine (HMT) at 923 K in H(2) flow without conventional prolonged carbonization. The catalysts are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), BET surface area measurement, and transmission electron microscopy (TEM). Furthermore, these catalysts are evaluated in the dibenzothiophene (DBT) hydrodesulfurization (HDS) reaction, and proved to be superior to those prepared by a temperature-programmed reduction (TPRe) method. The better catalytic performance is ascribed to higher dispersion of Mo(2)C on the support and a lower surface polymeric carbon content. This hydrogen thermal treatment (HTT) method provided a new strategy for the preparation of a highly active molybdenum carbide catalyst.

  19. Simple and efficient synthesis of 5'-aryl-5'-deoxyguanosine analogs by azide-alkyne click reaction and their antileishmanial activities.

    Daligaux, Pierre; Pomel, Sébastien; Leblanc, Karine; Loiseau, Philippe M; Cavé, Christian


    A series of non-hydrolysable 5'-aryl substituted GDP analogs has been synthesized by reacting 5'-azido-5'-deoxyguanosine with different aryl- and benzyloxy-alkynes. Cu(I) nanoparticles in water were found to be the most efficient catalyst, producing the desired 5'-arylguanosines with good yields. The synthesized compounds were screened for in vitro antileishmanial activity against Leishmania donovani axenic amastigotes and intramacrophage amastigotes stages. The 4-(3-nitrobenzyl)-1,2,3-triazole 5'-substituted guanosine analog was found to be the most active in the series with an IC50 of 8.6 μM on axenic amastigotes. Despite a rather low in vitro antileishmanial activity on the intramacrophage amastigotes, the absence of cytotoxicity on RAW 264.7 macrophages justifies further pharmacomodulations making this antileishmanial series promising.

  20. An efficient photochemical route to Pd nanoparticles; application to the one-step synthesis of Pd@polymer nanocomposite films

    Wolak, Séverine; Vidal, Loïc; Becht, Jean-Michel; Michelin, Laure; Balan, Lavinia


    We have developed a facile, efficient, low cost and ‘green’ photochemical approach to preparing surfactant-free Pd nanoparticles and Pd-immobilized@acrylate photo-polymer films at room temperature, under air and without any additional treatment. The reaction system only includes a photo-initiator used as a generator of free radicals and a Pd(II) salt. In ethanol solution, the photochemical reduction of Pd(II) to Pd(0) generates very small metal particles with a narrow size distribution (2-4 nm). Furthermore, we have shown that the formation of Pd nanoparticles from a Pd(II) salt can be reversible thus allowing easy handling and safe storage with the possibility of generating the nanoparticles just before use. In the presence of an acrylate bifunctional monomer, Pd@polymer film was obtained through a ‘one-pot, one-step’ process resulting from a simultaneous photo-reduction of Pd(II) and photo-polymerization of acrylate units. The simultaneous generation of a 3D polymer network and of metal particles leads to a homogeneous distribution of Pd nanoparticles in the photo-polymer matrix with an average diameter of approximately 3.7 ± 1.1 nm. Such as-prepared Pd@polymer films were found to efficiently catalyze the Mizoroki-Heck reaction in the presence of only 0.9 mequiv. of supported palladium. The major interest of this arrangement is its recoverability and reusability, which makes it very attractive both from a practical and economical viewpoint. Finally, it is worth noting that this innovation offers a great advantage over concurrent methods in that it is simply generated within minutes, it is highly stable, and there is sharp monodispersity in the size of the Pd nanoparticles that can be stored for months without alteration of their physico-chemical properties and catalytic activity.