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Sample records for stereocontrolled total synthesis

  1. Synthesis of (±)-amathaspiramide F and discovery of an unusual stereocontrolling element for the [2,3]-Stevens rearrangement.

    Science.gov (United States)

    Soheili, Arash; Tambar, Uttam K

    2013-10-04

    A formal total synthesis of (±)-amathaspiramide F through a tandem palladium-catalyzed allylic amination/[2,3]-Stevens rearrangement is reported. The unexpected diastereoselectivity of the [2,3]-Stevens rearrangement was controlled by the substitution patterns of an aromatic ring. This discovery represents a new stereocontrolling element for [2,3]-sigmatropic rearrangements in complex molecular settings.

  2. Concise Stereocontrolled Formal Synthesis of (±)-Quinine and Total Synthesis of (±)-7-Hydroxyquinine via Merged Morita-Baylis-Hillman-Tsuji-Trost Cyclization

    Science.gov (United States)

    Webber, Peter; Krische, Michael J.

    2010-01-01

    Concise stereoselective syntheses of (±)-quinine and (±)-7-hydroxyquinine are achieved using a catalytic enone cycloallylation that combines the nucleophilic features of the Morita-Baylis-Hillman reaction and the electrophilic features of the Tsuji-Trost reaction. Cyclization of enone-allyl carbonate 11 delivers the product of cycloallylation 13 in 68% yield. Diastereoselective conjugate reduction of the enone 13 (>20:1 dr) followed by exchange of N-protecting groups provides the saturated N-Boc-protected methyl ketone 19, which upon aldol dehydration provides quinoline containing enone 15, possessing all carbon atoms of quinine. Exposure of ketone 15 to L-selectride enables diastereoselective carbonyl reduction (>20:1 dr) to furnish the allylic alcohol 16. Stereoselective hydroxyl-directed epoxidation using an oxovanadium catalyst modified by N-hydroxy-N-Me-pivalamide delivers epoxide 17 (17:1 dr). Cyclization of the resulting amine-epoxide 17 provides (±)-7-hydroxyquinine in 13 steps and 11% overall yield from aminoacetaldehyde diethyl acetal. Notably, highly stereoselective formation of five contiguous stereocenters is achieved through a series of 1,2-asymmetric induction events. A formal synthesis of (±)-quinine is achieved upon deoxygenation of the N-Cbz-protected allylic acetate 22 to provide olefin 23, which previously has been converted to quinine. Thus, (±)-quinine is accessible in 16 steps and 4% overall yield from commercial aminoacetaldehyde diethyl acetal, making this route the most concise approach to quinine, to date. PMID:18989927

  3. A cross-metathesis approach to the stereocontrolled synthesis of the AB ring segment of ciguatoxin

    OpenAIRE

    Kadota, Isao; Abe, Takashi; Uni, Miyuki; Takamura, Hiroyoshi; Yamamoto, Yoshinori

    2008-01-01

    Synthesis of the AB ring segments of ciguatoxin is described. The present synthesis includes a Lewis acid mediated cyclization of allylstannane with aldehyde, cross-metathesis reaction introducing the side chain, and Grieco-Nishizawa dehydration on the A ring.

  4. Stereocontrolled Synthesis of the C(1)-C(11) Subunit of the Iejimalides

    DEFF Research Database (Denmark)

    Mendlik, Matthew T.; Cottard, Muriel; Rein, Tobias

    1997-01-01

    An enantioselective synthesis of the C(1)-C(11) subunit of the iejimalides has been accomplished through a combination of an asymmetric Homer-Wadsworth-Emmons condensation and a chiral pool approach. (C) 1997 Elsevier Science Ltd....

  5. Total synthesis of Ivorenolide A following a base-induced elimination protocol.

    Science.gov (United States)

    Mohapatra, Debendra K; Umamaheshwar, Gonela; Rao, R Nageshwar; Rao, T Srinivasa; R, Sudheer Kumar; Yadav, Jhillu S

    2015-02-20

    A concise and stereocontrolled first total synthesis of Ivorenolide A (1) is reported in 16 longest linear steps with a 13.4% overall yield starting from (+)-diethyl tartrate (DET). Key features are base-induced elimination protocol for the construction of chiral propargyl alcohols in both fragments, Pd-catalyzed cross-coupling of terminal acetylenes, and Shiina's 2-methyl-6-nitrobezoic anhydride (MNBA) mediated macrolactonization.

  6. An Ultimate Stereocontrol in Asymmetric Synthesis of Optically Pure Fully Aromatic Helicenes

    Czech Academy of Sciences Publication Activity Database

    Šámal, Michal; Chercheja, Serghei; Rybáček, Jiří; Vacek Chocholoušová, Jana; Vacek, Jaroslav; Bednárová, Lucie; Šaman, David; Stará, Irena G.; Starý, Ivo

    2015-01-01

    Roč. 137, č. 26 (2015), s. 8469-8474 ISSN 0002-7863 R&D Projects: GA ČR GA203/09/1766 Institutional support: RVO:61388963 Keywords : helicenes * asymmetric synthesis * cycloisomerization Subject RIV: CC - Organic Chemistry Impact factor: 13.038, year: 2015

  7. Total synthesis of ciguatoxin.

    Science.gov (United States)

    Hamajima, Akinari; Isobe, Minoru

    2009-01-01

    Something fishy: Ciguatoxin (see structure) is one of the principal toxins involved in ciguatera poisoning and the target of a total synthesis involving the coupling of three segments. The key transformations in this synthesis feature acetylene-dicobalthexacarbonyl complexation.

  8. Remote Stereoinductive Intramolecular Nitrile Oxide Cycloaddition: Asymmetric Total Synthesis and Structure Revision of (-)-11β-Hydroxycurvularin.

    Science.gov (United States)

    Choe, Hyeonjeong; Pham, Thuy Trang; Lee, Joo Yun; Latif, Muhammad; Park, Haeil; Kang, Young Kee; Lee, Jongkook

    2016-03-18

    The first total synthesis and structure revision of (-)-11β-hydroxycurvularin (1b), a macrolide possessing a β-hydroxyketone moiety, were accomplished. The β-hydroxyketone moiety in this natural product was introduced by cleavage of the N-O bond in an isoxazoline ring that was formed diastereoselectively in a 1,5-remote stereocontrolled fashion by employing intramolecular nitrile oxide cycloaddition.

  9. Total Synthesis of Hyperforin.

    Science.gov (United States)

    Ting, Chi P; Maimone, Thomas J

    2015-08-26

    A 10-step total synthesis of the polycyclic polyprenylated acylphloroglucinol (PPAP) natural product hyperforin from 2-methylcyclopent-2-en-1-one is reported. This route was enabled by a diketene annulation reaction and an oxidative ring expansion strategy designed to complement the presumed biosynthesis of this complex meroterpene. The described work enables the preparation of a highly substituted bicyclo[3.3.1]nonane-1,3,5-trione motif in only six steps and thus serves as a platform for the construction of easily synthesized, highly diverse PPAPs modifiable at every position.

  10. A stereo-controlled route to conjugated E-enediynes

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lei; JIANG Huanfeng

    2007-01-01

    3-Ene-1,5-diynes are important components of many enediyne antitumor agents and luminescent materials.A stereo-controlled approach to the synthesis of E-enediynes was developed,and it consists of the following two steps:(1)a mild and economical synthesis of dihalo vinyl derivatives via addition of CuBr2 to alkynes;(2) the Sonogashira coupling reaction of the dihalo vinyl derivatives with terminal alkynes to form conjugated enediynes.

  11. Application of cyclic phosphonamide reagents in the total synthesis of natural products and biologically active molecules

    Directory of Open Access Journals (Sweden)

    Thilo Focken

    2014-08-01

    Full Text Available A review of the synthesis of natural products and bioactive compounds adopting phosphonamide anion technology is presented highlighting the utility of phosphonamide reagents in stereocontrolled bond-forming reactions. Methodologies utilizing phosphonamide anions in asymmetric alkylations, Michael additions, olefinations, and cyclopropanations will be summarized, as well as an overview of the synthesis of the employed phosphonamide reagents.

  12. First total synthesis of Boehmenan

    Indian Academy of Sciences (India)

    The first total synthesis of dilignan Boehmenan has been achieved. A biomimetic oxidative coupling of the ferulic acid methyl ester in the presence of silver oxide is the crucial step in the synthesis sequence, generating the dihydrobenzofuran skeleton. Hydroxyl group was protected with DHP and reducted with LiAlH4 to ...

  13. Total synthesis of (-)- and (+)-tedanalactam

    Digital Repository Service at National Institute of Oceanography (India)

    Majik, M.S.; Parameswaran, P.S.; Tilve, S.G.

    : The Journal of Organic Chemistry, vol.74(16); 6378-6381 1 Total Synthesis of (-) and (+)-Tedanalactam Mahesh S. Majik, † Peruninakulath S. Parameswaran, ‡ and Santosh G. Tilve* ,† Department of Chemistry, Goa University, Taleigao Plateau, Goa 403..., displaying a wide range of biological activities. 1 Piperidones are key synthetic intermediates 2 for the synthesis of piperidine ring due to the presence of keto function which allows the introduction of other groups. Piperidones are also known...

  14. Total Synthesis of Adunctin B.

    Science.gov (United States)

    Dethe, Dattatraya H; Dherange, Balu D

    2018-03-16

    Total synthesis of (±)-adunctin B, a natural product isolated from Piper aduncum (Piperaceae), has been achieved using two different strategies, in seven and three steps. The efficient approach features highly atom economical and diastereoselective Friedel-Crafts acylation, alkylation reaction and palladium catalyzed Wacker type oxidative cyclization.

  15. Total synthesis of nepetoidin B

    Science.gov (United States)

    The total synthesis of nepetoidin B (the 2-(3,4-dihydroxyphenyl)ethenyl ester of 3-(3,4-dihydroxy¬phenyl)-2-propenoic acid) has been achieved in two steps from commercially available 1,5-bis(3,4-dimethoxyphenyl)-1,4-pentadien-3-one. Tetramethylated nepetoidin B was prepared directly by Baeyer-Villig...

  16. Total synthesis of mycalamide A.

    Science.gov (United States)

    Sohn, Jeong-Hun; Waizumi, Nobuaki; Zhong, H Marlon; Rawal, Viresh H

    2005-05-25

    This communication describes a concise and efficient total synthesis of mycalamide A by the convergent coupling of pederic acid unit with the mycalamine unit. The left-half, (+)-7-benzoylpederic acid, was synthesized from (2R,3R)-3-methylpent-4-en-2-ol in seven steps and 34.6% overall yield through a route that features a one-step Pd(II)-catalyzed tandem Wacker/Heck cyclization reaction to prepare the tetrahydropyran ring system. The right-half, the mycalamine unit, was synthesized in 21 steps and 10.5% overall yield from diethyl d-tartrate. Effective, stereoselective methods were developed for the assembly of the two parts to yield either mycalamide A or C(10)-epi-mycalamide A.

  17. Total synthesis of solanoeclepin A

    Science.gov (United States)

    Tanino, Keiji; Takahashi, Motomasa; Tomata, Yoshihide; Tokura, Hiroshi; Uehara, Taketo; Narabu, Takashi; Miyashita, Masaaki

    2011-06-01

    Cyst nematodes are troublesome parasites that live on, and destroy, a range of important host vegetable plants. Damage caused by the potato cyst nematode has now been reported in over 50 countries. One approach to eliminating the problem is to stimulate early hatching of the nematodes, but key hatching stimuli are not naturally available in sufficient quantities to do so. Here, we report the first chemical synthesis of solanoeclepin A, the key hatch-stimulating substance for potato cyst nematode. The crucial steps in our synthesis are an intramolecular cyclization reaction for construction of the highly strained tricyclo[5.2.1.01,6]decane skeleton (DEF ring system) and an intramolecular Diels-Alder reaction of a furan derivative for the synthesis of the ABC carbon framework. The present synthesis has the potential to contribute to addressing one of the critical food issues of the twenty-first century.

  18. Studies towards a total synthesis of tagetitoxin

    OpenAIRE

    Mahoney, Brian

    2017-01-01

    Tagetitoxin was first isolated over thirty five years ago and a total synthesis has not been achieved to date. A vast amount of research has been carried out on the biological activity of tagetitoxin with hundreds of literature reports. However, very few papers have been published regarding the synthesis and within this thesis we will explore a number of synthetic pathways some towards tagetitoxin. The first chapter reviews previous developments regarding the total synthesis of...

  19. Asymmetric total synthesis of cladosporin and isocladosporin.

    Science.gov (United States)

    Zheng, Huaiji; Zhao, Changgui; Fang, Bowen; Jing, Peng; Yang, Juan; Xie, Xingang; She, Xuegong

    2012-07-06

    The first asymmetric total syntheses of cladosporin and isocladosporin were accomplished in 8 steps with 8% overall yield and 10 steps with 26% overall yield, respectively. The relative configuration of isocladosporin was determined via this total synthesis.

  20. Stereo-controlled synthesis of polyheterocycles via the diene-transmissive hetero-Diels-Alder reaction of β,γ-unsaturated α-keto esters.

    Science.gov (United States)

    Otani, Takashi; Tamai, Yumiko; Seki, Kazunori; Kikuchi, Tomohiro; Miyazawa, Taiichiro; Saito, Takao

    2015-06-07

    We describe the stereoselective synthesis of polyring-fused heterocyclic compounds based on diene-transmissive hetero-Diels-Alder reactions utilizing β,γ-unsaturated α-keto esters. This protocol involves the initial endo- or exo-selective Diels-Alder (DA) reactions with electron-rich dienophiles, methylenation of the ester carbonyl groups with the Tebbe reagent, and a stereoselective second DA reaction with electron-deficient dienophiles. The use of enantioselective DA reactions in the initial reaction enables access to chiral polyring-fused heterocyclic compounds with multiple chiral centres.

  1. Novel stereocontrolled syntheses of tashiromine and epitashiromine

    Directory of Open Access Journals (Sweden)

    Loránd Kiss

    2015-04-01

    Full Text Available A novel stereocontrolled approach has been developed for the syntheses of tashiromine and epitashiromine alkaloids from cyclooctene β-amino acids. The synthetic concept is based on the azetidinone opening of a bicyclic β-lactam, followed by oxidative ring opening through ring C–C double bond and reductive ring-closure reactions of the cis- or trans-cyclooctene β-amino acids.

  2. The Total Synthesis of Cephalosporin C

    Indian Academy of Sciences (India)

    IAS Admin

    The Total Synthesis of Cephalosporin C. Edited by Setty Mallikarjuna Babu and Subramania Ranganathan. Keywords. Cephalosporin C. The Nobel Prize in Chemistry for 1965 has been awarded for contributions to the art of chemical synthesis. It gives me much pleasure to record here my gratification with the citation, ...

  3. The First Total Synthesis of Isoliquiritin

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A first total synthesis of isoliquiritin was accomplished starting from p-hydroxy- benzaldehyde and 2,4-dihydroxyacetylphenone. The key step is condensation reaction. In synthetic process need not protect the hydroxy group of reacting substance.

  4. Stereocontrolled Synthesis of Methyl Silanediol Peptide Mimics

    DEFF Research Database (Denmark)

    Nielsen, Lone; Lindsay, Karl; Faber, Jesper

    2007-01-01

     The treatment of chiral sulfinimines with (methyldiphenylsilyl)lithium gives R-(methyldiphenylsilyl)-sulfinamides with excellent diastereoselectivity, and in good yield. The presence of α-protons on the imines is also well tolerated. The sulfinamide auxiliary is easily removed via treatment with...... corresponding bis-TMS siloxane via protection with TMSCl, and converted back to the desired silanediol via hydrolysis with aqueous KOH. Efforts to apply this approach to biologically relevant silanediol peptide mimics, with a view to protease inhibition, are described....

  5. Total synthesis of (±)-antroquinonol d.

    Science.gov (United States)

    Sulake, Rohidas S; Jiang, Yan-Feng; Lin, Hsiao-Han; Chen, Chinpiao

    2014-11-21

    Total synthesis of (±)-antroquinonol D, which is isolated from very expensive and rarely found Antrodia camphorata and which has potential anticancer properties, was achieved from 4-methoxyphenol. In addition, a Michael addition to dimethoxy cyclohexadienones was studied. The main step involved chelation and substrate-controlled diastereoselective reduction of cyclohexenone and lactonization. Lactone synthesis facilitated the diastereoselective reduction of ketone, which help control the desired stereochemistry at the crucial stereogenic center in the natural product. Other key reactions in the synthesis involved a Michael addition of dimethyl malonate on cyclohexadienone, dihydroxylation, and Wittig olefination. A sesquiterpene side chain was synthesized through coupling with geranyl phenyl sulfide and Bouveault-Blanc reduction.

  6. Concise stereocontrolled formal synthesis of (+/-)-quinine and total synthesis of (+/-)-7- hydroxyquinine via merged Morita-Baylis-Hillman-Tsuji-Trost cyclization.

    Science.gov (United States)

    Webber, Peter; Krische, Michael J

    2008-12-05

    Concise stereoselective syntheses of (+/-)-quinine and (+/-)-7-hydroxyquinine are achieved using a catalytic enone cycloallylation that combines the nucleophilic features of the Morita-Baylis-Hillman reaction and the electrophilic features of the Tsuji-Trost reaction. Cyclization of enone-allyl carbonate 11 delivers the product of cycloallylation 13 in 68% yield. Diastereoselective conjugate reduction of the enone 13 (>20:1 dr) followed by exchange of the N-protecting group provides the saturated N-Boc-protected methyl ketone 19, which upon aldol dehydration provides quinoline containing enone 15, possessing all carbon atoms of quinine. Exposure of ketone 15 to L-selectride enables diastereoselective carbonyl reduction (>20:1 dr) to furnish the allylic alcohol 16. Stereoselective hydroxyl-directed epoxidation using an oxovanadium catalyst modified by N-hydroxy-N-Me-pivalamide delivers epoxide 17 (17:1 dr). Cyclization of the resulting amine-epoxide 17 provides (+/-)-7-hydroxyquinine in 13 steps and 11% overall yield from aminoacetaldehyde diethyl acetal. Notably, highly stereoselective formation of five contiguous stereocenters is achieved through a series of 1,2-asymmetric induction events. Deoxygenation of the N-Cbz-protected allylic acetate 22 provides olefin 23, which previously has been converted to quinine. Thus, (+/-)-quinine is accessible in 16 steps and 4% overall yield from commercial aminoacetaldehyde diethyl acetal.

  7. Total Synthesis of balanol, Part 2

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Kelly, Nicholas; Tedenborg, Lars

    1997-01-01

    A convergent enantioselective total synthesis of the natural product (-)-balanol (1) is described. In addition to benzophenone fragment 8, key intermediates are chiral bicyclic aziridine 3 and the corresponding epoxide 4, both of which undergo highly regio- and stereoselective nucleophilic ring...

  8. Total synthesis of insect antifeedant drimane sesquiterpenes

    NARCIS (Netherlands)

    Jansen, B.J.M.

    1993-01-01

    The investigations described in this thesis deal with the total synthesis of sesquiterpenes of the drimane family, named for their widespread occurrence in the stem bark of South American Drimys species. These compounds contain the bicyclofarnesol nucleus

  9. Efficient total synthesis of (S)-14-azacamptothecin.

    Science.gov (United States)

    Liu, Guan-Sai; Yao, Yuan-Shan; Xu, Peng; Wang, Shaozhong; Yao, Zhu-Jun

    2010-06-01

    An efficient total synthesis of (S)-14-azacamptothecin has been accomplished in 10 steps and 56% overall yield from 5H-pyrano[4,3-d]pyrimidine 8. A mild Hendrickson reagent-triggered intramolecular cascade cyclization, a highly enantioselective dihydroxylation, and an efficient palladium-catalyzed transformation of an O-allyl into N-allyl group are the key steps in the synthesis. This work provides a much higher overall yield than the previous achievement and shows sound flexibility for the further applications that will lead to new bioactive analogues.

  10. The First Total Synthesis of Dragmacidin D

    OpenAIRE

    Garg, Neil K.; Sarpong, Richmond; Stoltz, Brian M.

    2002-01-01

    The first total synthesis of the biologically significant bis-indole alkaloid dragmacidin D (5) has been achieved. Thermal and electronic modulation provides the key for a series of palladium-catalyzed Suzuki cross-coupling reactions that furnished the core structure of the complex guanidine- and aminoimidazole-containing dragmacidins. Following this crucial sequence, a succession of meticulously controlled final events was developed leading to the completion of the natural product.

  11. Total synthesis of (+)-antroquinonol and (+)-antroquinonol D.

    Science.gov (United States)

    Sulake, Rohidas S; Chen, Chinpiao

    2015-03-06

    The first total synthesis of (+)-antroquinonol and (+)-antroquinonol D, two structurally unique quinonols with a sesquiterpene side chain, is described. The route features an iridium-catalyzed olefin isomerization-Claisen rearrangement reaction (ICR), lactonization, and Grubbs olefin metathesis. The requisite α,β-unsaturation was achieved via the selenylation/oxidation protocol and elimination of β-methoxy group to provide two natural products from a common intermediate.

  12. Total synthesis and biological investigation of (-)-promysalin.

    Science.gov (United States)

    Steele, Andrew D; Knouse, Kyle W; Keohane, Colleen E; Wuest, William M

    2015-06-17

    Compounds that specifically target pathogenic bacteria are greatly needed, and identifying the method by which they act would provide new avenues of treatment. Herein we report the concise, high-yielding total synthesis (eight steps, 35% yield) of promysalin, a natural product that displays antivirulence phenotypes against pathogenic bacteria. Guided by bioinformatics, four diastereomers were synthesized, and the relative and absolute stereochemistries were confirmed by spectral and biological analysis. Finally, we show for the first time that promysalin displays two antivirulence phenotypes: the dispersion of mature biofilms and the inhibition of pyoverdine production, hinting at a unique pathogenic-specific mechanism of action.

  13. First total synthesis of (-)-AL-2.

    Science.gov (United States)

    Miyakoshi, Naoki; Mukai, Chisato

    2003-06-26

    Treatment of the 3,4-dioxygenated-9-hydroxy-1-nonyn-5-one derivative, derived from diethyl l-tartrate, with a palladium catalyst in methanol under a CO atmosphere effected an intramolecular acetalization and a stereoselective construction of the (E)-methoxycarbonylmethylidene functionality resulting in formation of the core framework of the diacetylenic spiroacetal enol ether natural products. Chemical transformations of the 1,6-dioxaspiro[4.5]decane derivative thus formed led to the first total synthesis of (-)-AL-2. [reaction: see text

  14. Total Synthesis of (-)-Salvinorin A.

    Science.gov (United States)

    Line, Nathan J; Burns, Aaron C; Butler, Sean C; Casbohm, Jerry; Forsyth, Craig J

    2016-12-12

    Salvinorin A (1) is natural hallucinogen that binds the human κ-opioid receptor. A total synthesis has been developed that parlays the stereochemistry of l-(+)-tartaric acid into that of (-)-1 via an unprecedented allylic dithiane intramolecular Diels-Alder reaction to obtain the trans-decalin scaffold. Tsuji allylation set the C9 quaternary center and a late-stage stereoselective chiral ligand-assisted addition of a 3-titanium furan upon a C12 aldehyde/C17 methyl ester established the furanyl lactone moiety. The tartrate diol was finally converted into the C1,C2 keto-acetate. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Collagen synthesis in CBA mouse heart after total thoracic irradiation

    International Nuclear Information System (INIS)

    Murray, J.C.; Parkins, C.S.; Institute of Cancer Research, Sutton

    1988-01-01

    CBA mice were irradiated to the whole thorax with single doses of 240 kVp X-rays in the dose range 8-16 Gy. Collagen and total protein synthesis rates in the heart were measured at 2-monthly intervals using a radio-isotope incorporation techniques. Doses of 10 Gy or greater caused a slight increase in collagen synthesis, followed by significantly reduced collagen synthesis by 16 weeks or longer after treatment. The depression in synthesis appeared correspondingly earlier with increasing dose. Total protein synthesis in heart followed similar patterns although changes were not statistically significant, indicating that the changes reflected alterations to collagen synthesis specifally, and not protein synthesis in geneal. Total hydroxyproline measurements showed no significant changes in heart collagen at any time as a result of X-irradiation. 18 refs.; 7 figs

  16. Total synthesis of sannanine and analogues thereof

    Indian Academy of Sciences (India)

    BADHER NAVEEN

    2018-03-02

    Mar 2, 2018 ... further characterized HRMS and IR spectral analysis. For all the newly synthesized by solid ..... Burst in a Model of Gouty Arthritis J. Nat. Prod. 70. 936. 3. ... Synthesis, Spectroscopic Characterisation, X-ray Struc- ture and DFT ...

  17. Total synthesis of (±)-divanillyltetrahydrofuran ferulate

    Indian Academy of Sciences (India)

    Administrator

    College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China ... Synthesis; sesquilignan; stobbe reaction; divanillyltetrahydrofuran ferulate. 1. .... 500 MHz) δ: 2⋅44−2⋅50 (m, 4H, 2 × ArCH2CH),.

  18. The total synthesis of calcium atorvastatin.

    Science.gov (United States)

    Dias, Luiz C; Vieira, Adriano S; Barreiro, Eliezer J

    2016-02-21

    A practical and convergent asymmetric route to calcium atorvastatin (1) is reported. The synthesis of calcium atorvastatin (1) was performed using the remote 1,5-anti asymmetric induction in the boron-mediated aldol reaction of β-alkoxy methylketone (4) with pyrrolic aldehyde (3) as a key step. Calcium atorvastatin was obtained from aldehyde (3) after 6 steps, with a 41% overall yield.

  19. The Catalytic Enantioselective Total Synthesis of (+)‐Liphagal

    DEFF Research Database (Denmark)

    Day, Joshua J.; McFadden, Ryan M.; Virgil, Scott C.

    2011-01-01

    Ring a ding: The first catalytic enantioselective total synthesis of the meroterpenoid natural product (+)-liphagal is disclosed. The approach showcases a variety of technology including enantioselective enolate alkylation, a photochemical alkyne-alkene [2+2] reaction, microwaveassisted metal...

  20. Asymmetric Total Synthesis of Ieodomycin B

    Directory of Open Access Journals (Sweden)

    Shuangjie Lin

    2017-01-01

    Full Text Available Ieodomycin B, which shows in vitro antimicrobial activity, was isolated from a marine Bacillus species. A novel asymmetric total synthetic approach to ieodomycin B using commercially available geraniol was achieved. The approach involves the generation of 1,3-trans-dihydroxyl at C-3 and C-5 positions via a Crimmins-modified Evans aldol reaction and a chelation-controlled Mukaiyama aldol reaction of a p-methoxybenzyl-protected aldehyde, as well as the generation of a lactone ring in a deprotection–lactonization one-pot reaction.

  1. Total Synthesis and Absolute Configuration of the Marine Norditerpenoid Xestenone

    Directory of Open Access Journals (Sweden)

    Hiroaki Miyaoka

    2009-11-01

    Full Text Available Xestenone is a marine norditerpenoid found in the northeastern Pacific sponge Xestospongia vanilla. The relative configuration of C-3 and C-7 in xestenone was determined by NOESY spectral analysis. However the relative configuration of C-12 and the absolute configuration of this compound were not determined. The authors have now achieved the total synthesis of xestenone using their developed one-pot synthesis of cyclopentane derivatives employing allyl phenyl sulfone and an epoxy iodide as a key step. The relative and absolute configurations of xestenone were thus successfully determined by this synthesis.

  2. Total synthesis of the proposed structure of trichodermatide A.

    Science.gov (United States)

    Myers, Eddie; Herrero-Gómez, Elena; Albrecht, Irina; Lachs, Jennifer; Mayer, Peter; Hanni, Matti; Ochsenfeld, Christian; Trauner, Dirk

    2014-10-17

    A short total synthesis of the published structure of racemic trichodermatide A is reported. Our synthesis involves a Knoevenagel condensation/Michael addition sequence, followed by the formation of tricyclic hexahydroxanthene-dione and a diastereoselective bis-hydroxylation. The final product, the structure of which was confirmed by X-ray crystallography, has NMR spectra that are very similar, but not identical, to those of the isolated natural product. Quantum chemically computed (13)C shifts agree well with the present NMR measurements.

  3. The First Total Synthesis of Triprenylquinone and Hydroquinones

    Institute of Scientific and Technical Information of China (English)

    Chun Hong LI; Xue Song CHEN; Guang Lian ZHOU; Zhi Xiang XIE; Ying LI

    2005-01-01

    First total synthesis of triprenylquinone and hydroquinones, three naturally occurring compound 1, 2 and (±) 3, have been achieved from readily available 2-bromo-5-methyl-1,4-dimethoxybenzene 4 and geranyl bromide. The triprenylquinone and hydroquinones precursor were readily prepared with use of a Julia reaction.

  4. The total synthesis of 3Beta-hydroxynagilactone F

    NARCIS (Netherlands)

    Reuvers, J.T.A.

    1985-01-01

    The investigations described in this thesis deal with the total synthesis of physiologically active nor- and bisnorditerpenoid dilactones (fig.1).

    The goal was to design a synthetic route for this class of natural products and

  5. Total synthesis of putative 11-epi-lyngbouilloside aglycon

    Directory of Open Access Journals (Sweden)

    Amandine Kolleth

    2016-08-01

    Full Text Available We report here the total synthesis of 11-epi-lyngbouilloside aglycon. Our strategy features a Boeckman-type esterification followed by a RCM to form the 14-membered ring macrolactone and a late-stage side chain introduction via a Wittig olefination. Overall, the final product was obtained in 20 steps and 2% overall yield starting from commercially available 3-methyl-but-3-enol. Most importantly, the strategy employed is versatile enough to eventually allow us to complete the synthesis of the natural product and irrevocably confirm its structure.

  6. Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A

    International Nuclear Information System (INIS)

    Mallinger, A.

    2008-11-01

    When vegetables like mushrooms are contaminated by radioactive caesium 137, this radioactive caesium is associated to norbadione A, a natural pigment present in two mushroom species and which can be used as a caesium decorporation agent or maybe as protection agent against ionizing radiations. Within this perspective, this research report describes the biosynthesis and the structure and properties of the norbadione A and of pulvinic acids (physicochemical properties, anti-oxidizing properties). Then, it presents the various tetronic acids (3-acyl-, 3-alkyl-, 3-alkoxy-, 3-aryl-tetronic acids and non 3-substituted tetronic acids), their synthesis path as they are described in the literature, and presents a new synthesis approach using a tandem reaction (with different esters or hydroxy esters) and the synthesis of tetronic acids. The author also proposes a new synthesis way for methyl pulvinates, and finally reports the work on the development of a total synthesis of the norbadione A

  7. Total Synthesis of Marine Cyclic Enol-Phosphotriester Salinipostin Compounds

    Science.gov (United States)

    Zhao, Mingliang; Wei, Xianfeng; Liu, Xuemeng; Dong, Xueyang; Yu, Rilei; Wan, Shengbiao; Jiang, Tao

    2018-06-01

    Due to their structural diversity and variety of biological activities, marine natural products have been the subject of extensive study. These compounds, especially phospholipid polycyclic aromatic hydrocarbons, have a wide range of pharmacological applications, including embedded DNA and central nervous system, anti-tumor, anti-virus, anti-parasite, anti-bacterial, and antithrombotic effects. Unfortunately, the insufficient drug sources have limited the development of these compounds. In this study, we isolated salinpostin compounds from a fermentation solution of marine-derived Salinospora sp., which has a common bicyclic enol-phosphotriester core framework, as well as potent and selective antimalarial activities against P. falciparum with EC50 = 50 nmol L-1. The chemical synthesis of these compounds in greater quantities is necessary for their use in bioactivity studies. Thus we explored a short route with high yields and mild reaction conditions, which can generate combinatorial libraries for drug discovery and lead optimization. We developed a new total synthesis method for six cyclic enol-phosphotriester salinipotin compounds and their diastereomers. For the total synthesis of cyclipostin P, we prepared cyclic enol-phosphotriester salinipostin compounds in 10 steps from a readily accessible starting material, 1,3-dihydroxyacetone, and obtained an overall yield of 1.29%. We fully characterized these compounds by proton nuclear magnetic resonance (1H-NMR), carbon-13 NMR (13C-NMR), and high-resolution mass spectrometry (HRMS) analyses, and found they coincide absolutely with the same compounds reported previously.

  8. First total synthesis of (-)-ichthyothereol and its acetate.

    Science.gov (United States)

    Mukai, C; Miyakoshi, N; Hanaoka, M

    2001-08-24

    The first and stereoselective total syntheses of (-)-ichthyothereol (1) and its acetate ((+)-2) were achieved by incorporation of the two chiral centers of diethyl L-tartrate. The starting diethyl L-tartrate was converted into trans-2-ethynyl-3-hydroxytetrahydropyran 14 in a stereoselective manner via the endo mode cyclization of the epoxy-alkyne derivative 12. The alcohol 12 was then transformed into (E)-iodoolefin derivative 15, which was exposed to a coupling reaction with 1-tributylstannyl-1,3,5-heptyne (19), derived from the corresponding 1-trimethylsilyl-1,3,5-heptyne (18), under Stille conditions to produce the all-carbon framework of the target natural products. Chemical modification of the coupled product 20 under conventional conditions completed the first total synthesis of (-)-ichthyothereol (1) and its acetate ((+)-2).

  9. Microwave-Assisted Synthesis of Phenylpropanoids and Coumarins: Total Synthesis of Osthol

    Czech Academy of Sciences Publication Activity Database

    Konrádová, Daniela; Kozubíková, H.; Doležal, Karel; Pospíšil, Jiří

    2017-01-01

    Roč. 2017, č. 35 (2017), s. 5204-5213 ISSN 1434-193X R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Cyclization * Microwave chemistry * Oxygen heterocycles * Synthetic methods * Total synthesis Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Organic chemistry Impact factor: 2.834, year: 2016

  10. Total Synthesis and Stereochemical Assignment of Nostosin B

    Directory of Open Access Journals (Sweden)

    Xiaoji Wang

    2017-02-01

    Full Text Available Nostosins A and B were isolated from a hydrophilic extract of Nostoc sp. strain from Iran, which exhibits excellent tryps inhibitory activity. Nostosin A was the most potent natural tripeptide aldehyde as trypsin inhibitor up to now. Both R‐ and S‐2‐hydroxy‐4‐(4‐hydroxy‐phenyl butanoic acid (Hhpba were prepared and incorporated into the total synthesis of nostosin B, respectively. Careful comparison of the NMR spectra and optical rotation data of synthetic nostosin B (1a and 1b with the natural product led to the unambiguous identification of the R‐configuration of the Hhpba fragment, which was further confirmed by co‐injection with the authentic sample on HPLC using both reversed phase column and the chiral AD‐RH column.

  11. Total synthesis of broussonetine F: the orthoamide Overman rearrangement of an allylic diol.

    Science.gov (United States)

    Hama, Naoto; Aoki, Toshihiro; Miwa, Shohei; Yamazaki, Miki; Sato, Takaaki; Chida, Noritaka

    2011-02-18

    A first total synthesis of broussonetine F from diethyl L-tartrate was achieved. The cornerstone of our synthesis was an orthoamide Overman rearrangement, which provided an allylic amino alcohol with complete diastereoselectivity.

  12. Total Synthesis of Natural Products Using Hypervalent Iodine Reagents

    Directory of Open Access Journals (Sweden)

    Gaetan eMaertens

    2015-01-01

    Full Text Available We present a review of natural product syntheses accomplished in our laboratory during the last five years. Each synthetic route features a phenol dearomatization promoted by an environmentally benign hypervalent iodine reagent. The dearomatizations demonstrate the aromatic ring umpolung concept, and involve stereoselective remodeling of the inert unsaturations of a phenol into a highly functionalized key intermediate that may contain a quaternary carbon center and a prochiral dienone system. Several new oxidative strategies were employed, including transpositions (1,3-alkyl shift and Prins-pinacol, a polycyclization, an ipso rearrangement, and direct nucleophilic additions at the phenol para position. Several alkaloids, heterocyclic compounds, and a polycyclic core have been achieved, including sceletenone (a serotonin reuptake inhibitor, acetylaspidoalbidine (an antitumor agent, fortucine (antiviral and antitumor, erysotramidine (curare-like effect, platensimycin (an antibiotic, and the main core of a kaurane diterpene (immunosuppressive agent and stimulator of apoptosis. These concise and in some cases enantioselective syntheses effectively demonstrate the importance of hypervalent iodine reagents in the total synthesis of bioactive natural products.

  13. Total Synthesis of Bryostatins. Development of Methodology for Atom-Economic and Stereoselective Synthesis of the C-ring Subunit

    Science.gov (United States)

    Trost, Barry M.; Frontier, Alison J.; Thiel, Oliver R.; Yang, Hanbiao; Dong, Guangbin

    2012-01-01

    Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for stereoselective assembly of the C-ring subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the C-ring subunit of bryostatins. PMID:21793057

  14. Biomimetically inspired asymmetric total synthesis of (+)-19-dehydroxyl arisandilactone A

    Science.gov (United States)

    Han, Yi-Xin; Jiang, Yan-Long; Li, Yong; Yu, Hai-Xin; Tong, Bing-Qi; Niu, Zhe; Zhou, Shi-Jie; Liu, Song; Lan, Yu; Chen, Jia-Hua; Yang, Zhen

    2017-01-01

    Complex natural products are a proven and rich source of disease-modulating drugs and of efficient tools for the study of chemical biology and drug discovery. The architectures of complex natural products are generally considered to represent significant barriers to efficient chemical synthesis. Here we describe a concise and efficient asymmetric synthesis of 19-dehydroxyl arisandilactone A--which belongs to a family of architecturally unique, highly oxygenated nortriterpenoids isolated from the medicinal plant Schisandra arisanensis. This synthesis takes place by means of a homo-Michael reaction, a tandem retro-Michael/Michael reaction, and Cu-catalysed intramolecular cyclopropanation as key steps. The proposed mechanisms for the homo-Michael and tandem retro-Michael/Michael reactions are supported by density functional theory (DFT) calculation. The developed chemistry may find application for the synthesis of its other family members of Schisandraceae nortriterpenoids.

  15. The CP molecule labyrinth: a paradigm of how endeavors in total synthesis lead to discoveries and inventions in organic synthesis.

    Science.gov (United States)

    Nicolaou, K C; Baran, Phil S

    2002-08-02

    Imagine an artist carving a sculpture from a marble slab and finding gold nuggets in the process. This thought is not a far-fetched description of the work of a synthetic chemist pursuing the total synthesis of a natural product. At the end of the day, he or she will be judged by the artistry of the final work and the weight of the gold discovered in the process. However, as colorful as this description of total synthesis may be, it does not entirely capture the essence of the endeavor, for there is much more to be told, especially with regard to the contrast of frustrating failures and exhilarating moments of discovery. To fully appreciate the often Herculean nature of the task and the rewards that accompany it, one must sense the details of the enterprise behind the scenes. A more vivid description of total synthesis as a struggle against a tough opponent is perhaps appropriate to dramatize these elements of the experience. In this article we describe one such endeavor of total synthesis which, in addition to reaching the target molecule, resulted in a wealth of new synthetic strategies and technologies for chemical synthesis. The total synthesis of the CP molecules is compared to Theseus' most celebrated athlos (Greek for exploit, accomplishment): the conquest of the dreaded Minotaur, which he accomplished through brilliance, skill, and bravery having traversed the famous labyrinth with the help of Ariadne. This story from Greek mythology comes alive in modern synthetic expeditions toward natural products as exemplified by the total synthesis of the CP molecules which serve as a paradigm for modern total synthesis endeavors, where the objectives are discovery and invention in the broader sense of organic synthesis.

  16. Total synthesis of (7- sup 14 C)-(+-)-colchicine

    Energy Technology Data Exchange (ETDEWEB)

    Pontikis, Renee; Nguyenhoang Nam; Hoellinger, Henri (Paris-5 Univ., 75 (France). Lab. de Chimie et Biochimie Pharmacologiques et Toxicologiques)

    1989-08-01

    The synthesis of ({plus minus})-colchicine labelled with carbon-14 at the 7-position of the B ring was achieved by a sixteen step sequence with an overall radiochemical yield of 2.5% from (Ba{sup 14}CO{sub 3}) (Specific activity: 55 mCi-mmol{sup -1}). (author).

  17. Total synthesis of [7-14C]-(+-)-colchicine

    International Nuclear Information System (INIS)

    Pontikis, Renee; Nguyenhoang Nam; Hoellinger, Henri

    1989-01-01

    The synthesis of (±)-colchicine labelled with carbon-14 at the 7-position of the B ring was achieved by a sixteen step sequence with an overall radiochemical yield of 2.5% from [Ba 14 CO 3 ] (Specific activity: 55 mCi-mmol -1 ). (author)

  18. A Concise Total Synthesis of S-(+)-Tylophorine

    Institute of Scientific and Technical Information of China (English)

    JIN,Zhong; WANG,Qing-Min; LI,Hao; LIU,Yu-Xiu; LI,Shi-Pu; HUANG,Run-Qiu

    2004-01-01

    @@ Phenanthroindolizidine alkaloids, which exhibit extensively biological properties, are widely present at various plants of the Asclepiadaceae family.[1] The significantly biological importance of these natural products has attracted considerable synthetic efforts.[2] We herein report an efficiently asyinmetric synthesis of S-(+)-tylophorine (1), as a typically representative alkaloids.

  19. Total synthesis and allelopathic activity of cytosporones A-C

    Energy Technology Data Exchange (ETDEWEB)

    Zamberlam, Charles E.M.; Meza, Alisson; Lima, Denis P. de; Beatriz, Adilson [Centro de Ciencias Exatas e Tecnologia, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil); Leite, Carla Braga; Marques, Maria Rita [Centro de Ciencias Biologicas e da Saude, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil)

    2012-07-01

    The search for efficient, environmentally friendly herbicides has been the focus of numerous studies on the organic synthesis of compounds isolated from natural sources. Cytosporones, which are phenolic lipids isolated from fungi, exhibit noteworthy biological properties. This paper reports the preparation of cytosporones A-C from the same starting material through a short synthetic route, with good yields. All compounds were tested for allelopathic activity on lettuce (Lactuca sativa L) seeds. Cytosporone A and its methylated precursor showed remarkable allelopathic activity, inhibiting seed germination and plantule growth. (author)

  20. Total synthesis and allelopathic activity of cytosporones A-C

    International Nuclear Information System (INIS)

    Zamberlam, Charles E.M.; Meza, Alisson; Lima, Denis P. de; Beatriz, Adilson; Leite, Carla Braga; Marques, Maria Rita

    2012-01-01

    The search for efficient, environmentally friendly herbicides has been the focus of numerous studies on the organic synthesis of compounds isolated from natural sources. Cytosporones, which are phenolic lipids isolated from fungi, exhibit noteworthy biological properties. This paper reports the preparation of cytosporones A-C from the same starting material through a short synthetic route, with good yields. All compounds were tested for allelopathic activity on lettuce (Lactuca sativa L) seeds. Cytosporone A and its methylated precursor showed remarkable allelopathic activity, inhibiting seed germination and plantule growth. (author)

  1. Total synthesis of (3S, 5R, 3'S, 5'R)-capsorubin

    International Nuclear Information System (INIS)

    Frederico, Daniel; Constantino, Mauricio G.; Donate, Paulo M.

    2009-01-01

    The total synthesis of enantiomerically enriched (3S, 5R, 3'S, 5'R)-capsorubin (1) by aldol condensation of (1R, 4S)-1-(4-hydroxy-1,2,2-trimethyl-cyclopentyl)ethanone (2a) and crocetindial (3) is described. An alternative, short eight-step synthesis of the optically active compound 2a (ee 89%) is also reported. (author)

  2. Total synthesis of 1-hydroxydehydroherbarin and ascomycones A, B, naphthoquinone antibiotics

    International Nuclear Information System (INIS)

    Dong, Wen-Kai; Huang, Xiong; Xu, Dong-Cheng; Li, Xin-Shengi; Xie, Jian-Wu

    2012-01-01

    The first total synthesis of 1-hydroxydehydroherbarin and ascomycones A and B is reported. The biologically interesting ascomycones A and B were obtained in 18% overall yield starting from 3-chloro-2,5-dimethoxybenzaldehyde as building block. (author)

  3. Convergent synthesis of the right-hand segment of ciguatoxin.

    Science.gov (United States)

    Hamajima, Akinari; Isobe, Minoru

    2006-03-16

    [reaction: see text] A convergent synthesis of the right-hand half of ciguatoxin (the HIJKLM ring system) has been achieved with complete stereocontrol in the introduction of the stereocenters on the eight-membered I ring. Key steps are Sonogashira coupling, dicobalt complexation, intramolecular conjugate addition, and hydrogenation of an endo-olefin to provide the 39-alpha-methyl group.

  4. The Total Synthesis Problem of linear multivariable control. II - Unity feedback and the design morphism

    Science.gov (United States)

    Sain, M. K.; Antsaklis, P. J.; Gejji, R. R.; Wyman, B. F.; Peczkowski, J. L.

    1981-01-01

    Zames (1981) has observed that there is, in general, no 'separation principle' to guarantee optimality of a division between control law design and filtering of plant uncertainty. Peczkowski and Sain (1978) have solved a model matching problem using transfer functions. Taking into consideration this investigation, Peczkowski et al. (1979) proposed the Total Synthesis Problem (TSP), wherein both the command/output-response and command/control-response are to be synthesized, subject to the plant constraint. The TSP concept can be subdivided into a Nominal Design Problem (NDP), which is not dependent upon specific controller structures, and a Feedback Synthesis Problem (FSP), which is. Gejji (1980) found that NDP was characterized in terms of the plant structural matrices and a single, 'good' transfer function matrix. Sain et al. (1981) have extended this NDP work. The present investigation is concerned with a study of FSP for the unity feedback case. NDP, together with feedback synthesis, is understood as a Total Synthesis Problem.

  5. Total synthesis of ciguatoxin CTX3C: a venture into the problems of ciguatera seafood poisoning.

    Science.gov (United States)

    Hirama, Masahiro

    2005-01-01

    After a twelve-year struggle, the total synthesis of ciguatoxin CTX3C has been achieved. Annually, more than 20,000 people worldwide suffer from ciguatera seafood poisoning. The extremely small amounts of the causative neurotoxin, ciguatoxin, in fish hampered the isolation, structural elucidation, detailed biological study, and preparation of anti-ciguatoxin antibodies for detecting these toxins. The large (3 nanometers long) and complicated molecular structure of ciguatoxins hindered chemists from completing a total synthesis. The chemical synthesis of CTX3C, determination of the absolute configuration, and synthesis-based preparation of the monoclonal antibodies as well as the effect of synthetic CTX3C on voltage-sensitive sodium channels are outlined. (c) 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

  6. Total Synthesis of Ionic Liquid Systems for Dissolution of Lunar Simulant

    Science.gov (United States)

    Sharpe, Robert J.; Karr, Laurel J.; Paley, Mark S.

    2010-01-01

    For purposes of Space Resource Utilization, work in the total synthesis of a new ionic liquid system for the extraction of oxygen and metals from lunar soil is studied and described. Reactions were carried out according to procedures found in the chemical literature, analyzed via Thin-Layer Chromatography and 1H Nuclear Magnetic Resonance Spectroscopy and purified via vacuum distillation and rotary evaporation. Upon final analysis via 1H NMR, it was found that while the intermediates of the synthesis had been achieved, unexpected side products were also present. The mechanisms and constraints of the synthesis are described as well as the final results of the project and recommendations for continued study

  7. Total synthesis and stereochemical assignment of the salicylate antitumor macrolide lobatamide C(1).

    Science.gov (United States)

    Shen, Ruichao; Lin, Cheng Ting; Porco, John A

    2002-05-22

    The total synthesis and stereochemical assignment of the potent antitumor macrolide lobatamide C is reported. The synthesis involves Cu(I)-mediated enamide formation and Na(2)CO(3)-mediated esterification of a beta-hydroxy acid and a salicylate cyanomethyl ester. Macrolactonization was accomplished using a Mitsunobu protocol. The stereochemical assignment of lobatamide C was achieved by Mosher ester analysis and comparison with prepared stereoisomers.

  8. Total synthesis, structure, and oral absorption of a thiazole cyclic peptide, sanguinamide A

    DEFF Research Database (Denmark)

    Nielsen, Daniel S; Hoang, Huy N; Lohman, Rink-Jan

    2012-01-01

    The first total synthesis and three-dimensional solution structure are reported for sanguinamide A, a thiazole-containing cyclic peptide from the sea slug H. sanguineus. Solution phase fragment synthesis, solid phase fragment assembly, and solution macrocyclization were combined to give (1) in 10......% yield. Spectral properties were identical for the natural product, requiring revision of its structure from (2) to (1). Intramolecular transannular hydrogen bonds help to bury polar atoms, which enables oral absorption from the gut....

  9. Stereoselective total synthesis of the potent anti-asthmatic compound CMI-977 (LDP-977)

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Luiz Carlos; Farina, Lui Strambi; Ferreira, Marco Antonio Barbosa, E-mail: ldias@iqm.unicamp.br [Universidade de Campinas (UNICAMP), SP (Brazil). Instituto de Quimica

    2013-02-15

    A short and efficient stereoselective total synthesis of CMI-977 (LDP-977), a potent and orally active anti-asthmatic compound, was developed. The key steps involve a highly diastereoselective Mukaiyama oxidative cyclization, which provides the trans-THF (tetrahydrofuran) unit and a Seyferth-Gilbert homologation to construct the triple bond in the target molecule. The synthesis of the key chiral building block was performed using Jacobsen hydrolytic kinetic resolution. (author)

  10. Development of the Vinylogous Pictet-Spengler Cyclization and Total Synthesis of (±)-Lundurine A.

    Science.gov (United States)

    Nash, Aaron; Qi, Xiangbing; Maity, Pradip; Owens, Kyle; Tambar, Uttam K

    2018-04-16

    A novel vinylogous Pictet-Spengler cyclization has been developed for the generation of indole-annulated medium-sized rings. The method enables the synthesis of tetrahydroazocinoindoles with a fully substituted carbon center, a prevalent structural motif in many biologically active alkaloids. The strategy has been applied to the total synthesis of (±)-lundurine A. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Stereoselective total synthesis of the potent anti-asthmatic compound CMI-977 (LDP-977)

    International Nuclear Information System (INIS)

    Dias, Luiz Carlos; Farina, Lui Strambi; Ferreira, Marco Antonio Barbosa

    2013-01-01

    A short and efficient stereoselective total synthesis of CMI-977 (LDP-977), a potent and orally active anti-asthmatic compound, was developed. The key steps involve a highly diastereoselective Mukaiyama oxidative cyclization, which provides the trans-THF (tetrahydrofuran) unit and a Seyferth-Gilbert homologation to construct the triple bond in the target molecule. The synthesis of the key chiral building block was performed using Jacobsen hydrolytic kinetic resolution. (author)

  12. Total Synthesis of (+)-Cytosporolide A via a Biomimetic Hetero-Diels-Alder Reaction.

    Science.gov (United States)

    Takao, Ken-Ichi; Noguchi, Shuji; Sakamoto, Shu; Kimura, Mizuki; Yoshida, Keisuke; Tadano, Kin-Ichi

    2015-12-23

    The first total synthesis of (+)-cytosporolide A was achieved by a biomimetic hetero-Diels-Alder reaction of (-)-fuscoatrol A with o-quinone methide generated from (+)-CJ-12,373. The dienophile, highly oxygenated caryophyllene sesquiterpenoid (-)-fuscoatrol A, was synthesized from the synthetic intermediate in our previous total synthesis of (+)-pestalotiopsin A. The o-quinone methide precursor, isochroman carboxylic acid (+)-CJ-12,373, was synthesized through a Kolbe-Schmitt reaction and an oxa-Pictet-Spengler reaction. The hetero-Diels-Alder reaction of these two compounds proceeded with complete chemo-, regio-, and stereoselectivity to produce the complicated pentacyclic ring system of the cytosporolide skeleton. This total synthesis unambiguously demonstrates that natural cytosporolide A has the structure previously suggested.

  13. Evolution of a practical total synthesis of ciguatoxin CTX3C.

    Science.gov (United States)

    Inoue, Masayuki; Hirama, Masahiro

    2004-12-01

    More than 20 000 people suffer annually from ciguatera seafood poisoning in subtropical and tropical regions. The extremely low content of the causative neurotoxins, designated as ciguatoxins, in fish has hampered their isolation, detailed biological study, and preparation of anti-ciguatoxin antibodies for detecting these toxins. Ciguatoxins consist of 12 trans-fused polycyclic ethers, ranging from six- to nine-membered, and include a spirally attached five-membered cyclic ether at one end. The large (3 nm in length) and complicated molecular structure of ciguatoxins has impeded chemists from completing their total synthesis. In 2001, we achieved the first total synthesis of ciguatoxin CTX3C by assembly of four structural fragments. Since then, protocols to combine the fragments have significantly improved in terms of overall stereoselectivity, efficiency, and practicality. In this Account, we describe recently evolved methodologies for the total synthesis of CTX3C.

  14. Chemistry of Renieramycins. Part 14: Total Synthesis of Renieramycin I and Practical Synthesis of Cribrostatin 4 (Renieramycin H

    Directory of Open Access Journals (Sweden)

    Masashi Yokoya

    2015-08-01

    Full Text Available The first total synthesis of (±-renieramycin I, which was isolated from the Indian bright blue sponge Haliclona cribricutis, is described. The key step is the selenium oxide oxidation of pentacyclic bis-p-quinone derivative (3 stereo- and regioselectively. We also report a large-scale synthesis of cribrostatin 4 (renieramycin H via the C3-C4 double bond formation in an early stage based on the Avendaño’s protocol, from readily available 1-acetyl-3-(3-methyl-2,4,5-trimethylphenylmethyl-piperazine-2,5-dione (8 in 18 steps (8.3% overall yield. The synthesis provides unambiguous evidence supporting the original structure of renieramycin I.

  15. Intestinal mucosa in diabetes: synthesis of total proteins and sucrase-isomaltase

    International Nuclear Information System (INIS)

    Olsen, W.A.; Perchellet, E.; Malinowski, R.L.

    1986-01-01

    The effects of insulin deficiency on nitrogen metabolism in muscle and liver have been extensively studied with recent in vivo demonstration of impaired protein synthesis in rats with streptozotocin-induced diabetes. Despite the significant contribution of small intestinal mucosa to overall protein metabolism, the effect of insulin deficiency on intestinal protein synthesis have not been completely defined. The authors studied the effects of streptozotocin-induced diabetes on total protein synthesis by small intestinal mucosa and on synthesis of a single enzyme protein of the enterocyte brush-border membrane sucrase-isomaltase. They used the flood-dose technique to minimize the difficulties of measuring specific radioactivity of precursor phenylalanine and determined incorporation into mucosal proteins and sucrase-isomaltase 20 min after injection of the labeled amino acid. Diabetes did not alter mucosal mass as determined by weight and content of protein and DNA during the 5 days after injection of streptozotocin. Increased rates of sucrase-isomaltase synthesis developed beginning on day 3, and those of total protein developed on day 5. Thus intestinal mucosal protein synthesis is not an insulin-sensitive process

  16. Total synthesis of 4-F3t-neuroprostane and its 4-epimer

    Czech Academy of Sciences Publication Activity Database

    Auvinet, A. L.; Eignerová, Barbara; Guy, A.; Kotora, Martin; Durand, T.

    2009-01-01

    Roč. 50, č. 13 (2009), s. 1498-1500 ISSN 0040-4039 R&D Projects: GA MŠk 1M0508 Institutional research plan: CEZ:AV0Z40550506 Keywords : DPA * oxidative stress * neuroprostane * total synthesis Subject RIV: CC - Organic Chemistry Impact factor: 2.660, year: 2009

  17. Stereoselective total synthesis of Oxylipin from open chain gluco-configured building block.

    Science.gov (United States)

    Borkar, Santosh Ramdas; Aidhen, Indrapal Singh

    2017-04-18

    Total synthesis of naturally occurring Oxylipin has been achieved from open chain gluco-configured building block which is readily assembled from inexpensive and commercially available D-(+)-gluconolactone. Grignard reaction and Wittig olefination reactions are key steps for the requisite CC bond formation. Copyright © 2017. Published by Elsevier Ltd.

  18. Cu-Mediated Stille Reactions of Sterically Congested Fragments: Towards the Total Synthesis of Zoanthamine

    DEFF Research Database (Denmark)

    Nielsen, Thomas E.; Le Quement, Sebastian; Juhl, Martin

    2005-01-01

    A study on the Stille reaction of alkenyl iodides and starmanes with structural resemblance to retrosynthetic fragments of a projected total synthesis of the marine alkaloid zoanthamine was carried out. A range of reaction conditions was examined, and a protocol developed by Corey utilizing excess...

  19. Total synthesis of the putative structure of the novel triquinane natural product isocapnellenone

    OpenAIRE

    Mehta, Goverdhan; Murthy, Sai Krishna A; Umarye, Jayant D

    2002-01-01

    A total synthesis of the ‘putative structure’ 7, attributed to the novel triquinane sesquiterpene isolated recently from two Buddelia species has been accomplished. The spectral data for 7 is a complete mismatch with those reported for the natural product and warrants a revision of the assigned structure.

  20. Nazarov cyclization initiated by peracid oxidation: the total synthesis of (+/-)-rocaglamide.

    Science.gov (United States)

    Malona, John A; Cariou, Kevin; Frontier, Alison J

    2009-06-10

    The total syntheses of aglafolin, rocagloic acid, and rocaglamide using Nazarov cyclization are described. Generation of the necessary oxyallyl cation intermediate was accomplished via peracid oxidation of an allenol ether to generate an unusual oxycarbenium ion species that undergoes cyclization. The synthesis is efficient, highly diastereoselective, and strategically distinct from previous syntheses of rocaglamide.

  1. Total chemical synthesis and X-ray structure of kaliotoxin by racemic protein crystallography.

    Science.gov (United States)

    Pentelute, Brad L; Mandal, Kalyaneswar; Gates, Zachary P; Sawaya, Michael R; Yeates, Todd O; Kent, Stephen B H

    2010-11-21

    Here we report the total synthesis of kaliotoxin by 'one pot' native chemical ligation of three synthetic peptides. A racemic mixture of D- and L-kaliotoxin synthetic protein molecules gave crystals in the centrosymmetric space group P1 that diffracted to atomic-resolution (0.95 Å), enabling the X-ray structure of kaliotoxin to be determined by direct methods.

  2. Total synthesis of all stereoisomers of eudesm-II-en-4-ol

    NARCIS (Netherlands)

    Kesselmans, R.P.W.

    1992-01-01

    In this thesis the total synthesis of all stereoisomers of eudesm-11-en-4-ol e.g. selin-11-en-4α-ol I , intermedeol II , neointermedeol III , paradisiol IV , amiteol

  3. Synthesis of total protein (TP) and myosin heavy chain (HC) isozymes in pressure overloaded rabbit hearts

    International Nuclear Information System (INIS)

    Nagai, R.; Martin, B.J.; Pritzl, N.; Zak, R.; Low, R.B.; Stirewalt, W.S.; Alpert, N.R.; Litten, R.Z.

    1986-01-01

    Pulmonary artery banding (PO) leads to a rapid increase in right ventricular (RV) weight as well as a shift toward β myosin isozyme. They determined: (1) the contributions of changes in the capacity (RNA content) and efficiency of total protein synthesis to the increase in RV weight; and (2) the relative contributions of translational and pretranslational mechanisms to the shift in myosin HC isotypes. The rates of synthesis in vivo of TP, α- and β-HC were measured by a constant infusion technique using 3 H-leucine. TP synthesis was 7 +/- 2(SD) mg/day in control (RV:367 +/- 70 mg) and was increased by 2.6 fold at day 2 and 2.9 fold at day 4 following PO (p < 0.01). RV RNA content was increased by 83% at day 2 and 103% at day 4 PO (p < 0.05). The efficiency of synthesis (rate/RNA) was also significantly higher at these time points (1.4- and 1.3-fold). β-HC synthesis was 0.6 +/- 0.2 mg/day in control and increased by 2.6 fold at day 2 and 3.5 fold at day 4 following PO. In contrast, the rate of synthesis of α-HC was unchanged. The relative rates of β-HC to total HC synthesis was correlated linearly with the relative levels of β-myosin mRNA as measured by S1 nuclease mapping. They conclude that increases in the proportion of β-HC myosin following PO is due to increases in the relative amount of β-myosin mRNA and therefore involves modulation of a pretranslational mechanism

  4. Asymmetric Total Synthesis of Four Stereoisomers of the Sex Pheromone of the Western Corn Rootworm

    Directory of Open Access Journals (Sweden)

    Zhi-Feng Sun

    2018-03-01

    Full Text Available A convergent synthesis of four stereoisomers of the sex pheromone of the western corn rootworm (8-methyldecan-2-yl propionate, 1 from commercially available chiral starting materials is reported. The key step was Julia–Kocienski olefination between chiral BT-sulfone and chiral aldehyde. This synthetic route provided the four stereoisomers of 1 in 24–29% total yield via a six-step sequence. The simple scale-up strategy provides a new way to achieve the asymmetric synthesis of the sex pheromone.

  5. First- and second-generation total synthesis of ciguatoxin CTX3C.

    Science.gov (United States)

    Inoue, Masayuki; Miyazaki, Keisuke; Uehara, Hisatoshi; Maruyama, Megumi; Hirama, Masahiro

    2004-08-17

    More than 20,000 people suffer annually from ciguatera seafood poisoning in subtropical and tropical regions. The extremely low content of the causative neurotoxins, designated as ciguatoxins, in fish has hampered isolation, detailed biological studies, and preparation of anti-ciguatoxin antibodies for detecting these toxins. Furthermore, the large (3 nm in length) and complex molecular structure of ciguatoxins has impeded chemists from completing their total synthesis. In this article, the full details of studies leading to the total synthesis of ciguatoxin CTX3C are provided. The key elements of the first-generation approach include O,O-acetal formation from the right and left wing fragments, conversion from O,O-acetal to O,S-acetal, a radical reaction to cyclize the G ring, a ring-closing metathesis reaction to close the F ring, and final removal of the 2-naphtylmethyl protective groups. Subsequent studies provided a second-generation total synthesis, which is more concise and results in a higher yield. Second-generation synthesis was accomplished by using a direct method of constructing the key intermediate O,S-acetal from alpha-chlorosulfide and a secondary alcohol. These syntheses ensure a practical supply of ciguatoxin for biological applications.

  6. Studies of a Diazo Cyclopropanation Strategy for the Total Synthesis of (-)-Lundurine A.

    Science.gov (United States)

    Huang, Hong-Xiu; Jin, Shuai-Jiang; Gong, Jin; Zhang, Dan; Song, Hao; Qin, Yong

    2015-09-14

    The bioactive Kopsia alkaloids lundurines A-D are the only natural products known to contain indolylcyclopropane. Achieving their syntheses can provide important insights into their biogenesis, as well as novel synthetic routes for complex natural products. Asymmetric total synthesis of (-)-lundurine A has previously been achieved through a Simmons-Smith cyclopropanation strategy. Here, the total synthesis of (-)-lundurine A was carried out using a metal-catalyzed diazo cyclopropanation strategy. In order to avoid a carbene CH insertion side reaction during cyclopropanation of α-diazo- carboxylates or cyanides, a one-pot, copper-catalyzed Bamford-Stevens diazotization/diazo decomposition/cyclopropanation cascade was developed, involving hydrazone. This approach simultaneously generates the C/D/E ring system and the two chiral quaternary centers at C2 and C7. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Quinones as dienophiles in the Diels-Alder reaction: history and applications in total synthesis.

    Science.gov (United States)

    Nawrat, Christopher C; Moody, Christopher J

    2014-02-17

    In the canon of reactions available to the organic chemist engaged in total synthesis, the Diels-Alder reaction is among the most powerful and well understood. Its ability to rapidly generate molecular complexity through the simultaneous formation of two carbon-carbon bonds is almost unrivalled, and this is reflected in the great number of reported applications of this reaction. Historically, the use of quinones as dienophiles is highly significant, being the very first example investigated by Diels and Alder. Herein, we review the application of the Diels-Alder reaction of quinones in the total synthesis of natural products. The highlighted examples span some 60 years from the landmark syntheses of morphine (1952) and reserpine (1956) by Gates and Woodward, respectively, through to the present day examples, such as the tetracyclines. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. First- and second-generation total synthesis of ciguatoxin CTX3C

    OpenAIRE

    Inoue, Masayuki; Miyazaki, Keisuke; Uehara, Hisatoshi; Maruyama, Megumi; Hirama, Masahiro

    2004-01-01

    More than 20,000 people suffer annually from ciguatera seafood poisoning in subtropical and tropical regions. The extremely low content of the causative neurotoxins, designated as ciguatoxins, in fish has hampered isolation, detailed biological studies, and preparation of anti-ciguatoxin antibodies for detecting these toxins. Furthermore, the large (3 nm in length) and complex molecular structure of ciguatoxins has impeded chemists from completing their total synthesis. In this article, the f...

  9. Total Synthesis of Ustiloxin D Utilizing an Ammonia-Ugi Reaction.

    Science.gov (United States)

    Brown, Aaron L; Churches, Quentin I; Hutton, Craig A

    2015-10-16

    Total synthesis of the highly functionalized cyclic peptide natural product, ustiloxin D, has been achieved in a convergent manner. Our strategy incorporates an asymmetric allylic alkylation to construct the tert-alkyl aryl ether linkage between the dopa and isoleucine residues. The elaborated β-hydroxydopa derivative is rapidly converted to a linear tripeptide through an ammonia-Ugi reaction. Subsequent cyclization and global deprotection affords ustiloxin D in six steps from a known β-hydroxydopa derivative.

  10. The asymmetric total synthesis of (+)- and (-)-trypargine via Noyori asymmetric transfer hydrogenation

    International Nuclear Information System (INIS)

    Pilli, Ronaldo A.; Rodrigues Junior, Manoel Trindade

    2009-01-01

    A concise and efficient total synthesis of (+)- and (-)-trypargine (6 steps and 38% overall yield), a 1-substituted β-carboline guanidine alkaloid isolated from the skin of the African frog K. senegalensis, was developed based on the construction of the b-carboline moiety via Bischler-Napieralski reaction and the enantioselective reduction of the dihydro-β-carboline intermediate via an asymmetric transfer hydrogenation reaction using Noyori's protocol. (author)

  11. Natural Product Total Synthesis in the Organic Laboratory: Total Synthesis of Caffeic Acid Phenethyl Ester (CAPE), a Potent 5-Lipoxygenase Inhibitor from Honeybee Hives

    Science.gov (United States)

    Touaibia, Mohamed; Guay, Michel

    2011-01-01

    Natural products play a critical role in modern organic synthesis and learning synthetic techniques is an important component of the organic laboratory experience. In addition to traditional one-step organic synthesis laboratories, a multistep natural product synthesis is an interesting experiment to challenge students. The proposed three-step…

  12. Total synthesis of cytochrome b562 by native chemical ligation using a removable auxiliary

    Science.gov (United States)

    Low, Donald W.; Hill, Michael G.; Carrasco, Michael R.; Kent, Stephen B. H.; Botti, Paolo

    2001-01-01

    We have completed the total chemical synthesis of cytochrome b562 and an axial ligand analogue, [SeMet7]cyt b562, by thioester-mediated chemical ligation of unprotected peptide segments. A novel auxiliary-mediated native chemical ligation that enables peptide ligation to be applied to protein sequences lacking cysteine was used. A cleavable thiol-containing auxiliary group, 1-phenyl-2-mercaptoethyl, was added to the α-amino group of one peptide segment to facilitate amide bond-forming ligation. The amine-linked 1-phenyl-2-mercaptoethyl auxiliary was stable to anhydrous hydrogen fluoride used to cleave and deprotect peptides after solid-phase peptide synthesis. Following native chemical ligation with a thioester-containing segment, the auxiliary group was cleanly removed from the newly formed amide bond by treatment with anhydrous hydrogen fluoride, yielding a full-length unmodified polypeptide product. The resulting polypeptide was reconstituted with heme and folded to form the functional protein molecule. Synthetic wild-type cyt b562 exhibited spectroscopic and electrochemical properties identical to the recombinant protein, whereas the engineered [SeMet7]cyt b562 analogue protein was spectroscopically and functionally distinct, with a reduction potential shifted by ≈45 mV. The use of the 1-phenyl-2-mercaptoethyl removable auxiliary reported here will greatly expand the applicability of total protein synthesis by native chemical ligation of unprotected peptide segments. PMID:11390992

  13. Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

    Directory of Open Access Journals (Sweden)

    Peter H. Seeberger

    2017-01-01

    Full Text Available The Gram-positive bacterium Streptococcus pneumoniae causes severe disease globally. Vaccines that prevent S. pneumoniae infections induce antibodies against epitopes within the bacterial capsular polysaccharide (CPS. A better immunological understanding of the epitopes that protect from bacterial infection requires defined oligosaccharides obtained by total synthesis. The key to the synthesis of the S. pneumoniae serotype 12F CPS hexasaccharide repeating unit that is not contained in currently used glycoconjugate vaccines is the assembly of the trisaccharide β-D-GalpNAc-(1→4-[α-D-Glcp-(1→3]-β-D-ManpNAcA, in which the branching points are equipped with orthogonal protecting groups. A linear approach relying on the sequential assembly of monosaccharide building blocks proved superior to a convergent [3 + 3] strategy that was not successful due to steric constraints. The synthetic hexasaccharide is the starting point for further immunological investigations.

  14. Lobatamide C: total synthesis, stereochemical assignment, preparation of simplified analogues, and V-ATPase inhibition studies.

    Science.gov (United States)

    Shen, Ruichao; Lin, Cheng Ting; Bowman, Emma Jean; Bowman, Barry J; Porco, John A

    2003-07-02

    The total synthesis and stereochemical assignment of the potent antitumor macrolide lobatamide C, as well as synthesis of simplified lobatamide analogues, is reported. Cu(I)-mediated enamide formation methodology has been developed to prepare the highly unsaturated enamide side chain of the natural product and analogues. A key fragment coupling employs base-mediated esterification of a beta-hydroxy acid and a salicylate cyanomethyl ester. Three additional stereoisomers of lobatamide C have been prepared using related synthetic routes. The stereochemistry at C8, C11, and C15 of lobatamide C was assigned by comparison of stereoisomers and X-ray analysis of a crystalline derivative. Synthetic lobatamide C, stereoisomers, and simplified analogues have been evaluated for inhibition of bovine chromaffin granule membrane V-ATPase. The salicylate phenol, enamide NH, and ortho-substitution of the salicylate ester have been shown to be important for V-ATPase inhibitory activity.

  15. Total synthesis of TMG-chitotriomycin based on an automated electrochemical assembly of a disaccharide building block.

    Science.gov (United States)

    Isoda, Yuta; Sasaki, Norihiko; Kitamura, Kei; Takahashi, Shuji; Manmode, Sujit; Takeda-Okuda, Naoko; Tamura, Jun-Ichi; Nokami, Toshiki; Itoh, Toshiyuki

    2017-01-01

    The total synthesis of TMG-chitotriomycin using an automated electrochemical synthesizer for the assembly of carbohydrate building blocks is demonstrated. We have successfully prepared a precursor of TMG-chitotriomycin, which is a structurally-pure tetrasaccharide with typical protecting groups, through the methodology of automated electrochemical solution-phase synthesis developed by us. The synthesis of structurally well-defined TMG-chitotriomycin has been accomplished in 10-steps from a disaccharide building block.

  16. Total synthesis of TMG-chitotriomycin based on an automated electrochemical assembly of a disaccharide building block

    Directory of Open Access Journals (Sweden)

    Yuta Isoda

    2017-05-01

    Full Text Available The total synthesis of TMG-chitotriomycin using an automated electrochemical synthesizer for the assembly of carbohydrate building blocks is demonstrated. We have successfully prepared a precursor of TMG-chitotriomycin, which is a structurally-pure tetrasaccharide with typical protecting groups, through the methodology of automated electrochemical solution-phase synthesis developed by us. The synthesis of structurally well-defined TMG-chitotriomycin has been accomplished in 10-steps from a disaccharide building block.

  17. A Highly Stereocontrolled, One-Pot Approach toward Pyrrolobenzoxazinones and Pyrroloquinazolinones through a Lewis Acid-Catalyzed [3 + 2]-Cycloannulation Process.

    Science.gov (United States)

    Boomhoff, Michael; Ukis, Rostyslav; Schneider, Christoph

    2015-08-21

    We report herein a stereocontrolled [3 + 2]-cycloheteroannulation of bis-silyl dienediolate 1 with 2-aminobenzoic acid- and 2-aminobenzamide-derived imines to furnish highly substituted pyrrolo[1,2-a]benzoxazinones 3 and pyrrolo[1,2-a]quinazolinones 4, respectively, in good overall yields. This one-pot process rapidly generates molecular complexity and comprises a Lewis acid-catalyzed, vinylogous Mannich reaction of 1 followed by an intramolecular N,O-acetal- and N,N-aminal formation, respectively, which proceeds with good to excellent stereocontrol.

  18. Influence of hydroxylamine conformation on stereocontrol in Pd-catalyzed isoxazolidine-forming reactions.

    Science.gov (United States)

    Lemen, Georgia S; Giampietro, Natalie C; Hay, Michael B; Wolfe, John P

    2009-03-20

    Palladium-catalyzed carboamination reactions between N-Boc-O-(but-3-enyl)hydroxylamine derivatives and aryl or alkenyl bromides afford cis-3,5- and trans-4,5-disubstituted isoxazolidines in good yield with up to >20:1 dr. The diastereoselectivity observed in the formation of cis-3,5-disubstituted isoxazolidines is superior to selectivities typically obtained in other transformations, such as 1,3-dipolar cycloaddition reactions, that provide these products. In addition, the stereocontrol in the C-N bond-forming Pd-catalyzed carboamination reactions of N-Boc-O-(but-3-enyl)hydroxylamines is significantly higher than that of related C-O bond-forming carboetherification reactions of N-benzyl-N-(but-3-enyl)hydroxylamine derivatives. This is likely due to a stereoelectronic preference for cyclization via transition states in which the Boc group is placed in a perpendicular orientation relative to the plane of the developing ring, which derives from the conformational equilibria of substituted hydroxylamines.

  19. Stereocontrolled reduction of alpha- and beta-keto esters with micro green algae, Chlorella strains.

    Science.gov (United States)

    Ishihara, K; Yamaguchi, H; Adachi, N; Hamada, H; Nakajima, N

    2000-10-01

    The stereocontrolled reduction of alpha- and beta-keto esters using micro green algae was accomplished by a combination of the cultivation method and the introduction of an additive. The reduction of ethyl pyruvate and ethyl benzoylformate by the photoautotrophically cultivated Chlorella sorokiniana gave the corresponding alcohol in high e.e. (>99% e.e. (S) and >99% e.e. (R), respectively). In the presence of glucose as an additive, the reduction of ethyl 3-methyl-2-oxobutanoate by the heterotrophically cultivated C. sorokiniana afforded the corresponding (R)-alcohol. On the other hand, the reduction in the presence of ethyl propionate gave the (S)-alcohol. Ethyl 2-methyl-3-oxobutanoate was reduced in the presence of glycerol by the photoautotrophically cultivated C. sorokiniana or the heterotrophically cultivated C. sorokiniana to the corresponding syn-(2R,3S)-hydroxy ester with high diastereo- and enantiomeric excess (e.e.). Some additives altered the stereochemical course in the reduction of alpha- and beta-keto esters.

  20. Mono- and dinuclear bioxazoline-palladium complexes for the stereocontrolled synthesis of CO/styrene polyketones.

    Science.gov (United States)

    Scarel, Alessandro; Durand, Jérôme; Franchi, Davide; Zangrando, Ennio; Mestroni, Giovanni; Carfagna, Carla; Mosca, Luca; Seraglia, Roberta; Consiglio, Giambattista; Milani, Barbara

    2005-10-07

    The coordination chemistry of the chiral bioxazoline ligand (4S,4'S)-2,2'-bis(4-isopropyl-4,5-dihydrooxazole) to Pd(II) provides evidence that the ligand bonding can occur either through chelation of one Pd(II) ion leading to a mononuclear species with the expected cis geometry, or by double bridging of two Pd(II) ions giving a dinuclear complex with trans geometry. The species in solution are identified by 1H NMR spectroscopy. Both the mononuclear and the dinuclear complexes promote the CO/styrene copolymerization, yielding the corresponding polyketone with a fully or a predominantly isotactic microstructure, depending on the reaction medium. The nature of the anion present in the palladium precatalysts affects the polyketone stereochemistry. MALDI-TOF analysis of the copolymers synthesized reveals the presence of p-hydroxyphenolic end-groups, thus confirming and explaining the role of 1,4-hydroquinone as a molecular weight regulator.

  1. Highly stereocontrolled synthesis of trans-enediynes via carbocupration of fluoroalkylated diynes

    Directory of Open Access Journals (Sweden)

    Tsutomu Konno

    2012-12-01

    Full Text Available Treatment of readily prepared (Z-6-benzyloxy-1,1,1,2-tetrafluoro-6-methyl-2-hepten-4-yne with 1.5 equiv of LHMDS in −78 °C for 1 h gave the corresponding trifluoromethylated diyne in an excellent yield. This diyne was found to be a good substrate for the carbocupration with various higher-ordered cyanocuprates to give the corresponding vinylcuprates in a highly regio- and stereoselective manner. The in situ generated vinylcuprates could react very smoothly with an excess amount of iodine, the vinyl iodides being obtained in high yields. Thus-obtained iodides underwent a very smooth Sonogashira cross-coupling reaction to afford various trans-enediynes in high yields.

  2. Stereocontrolled synthesis of polyhydroxylated bicyclic azetidines as a new class of iminosugars.

    Science.gov (United States)

    Malinowski, Maciej; Hensienne, Raphaël; Kern, Nicolas; Tardieu, Damien; Bodlenner, Anne; Hazelard, Damien; Compain, Philippe

    2018-06-12

    We report herein the development of a stereodivergent route towards polyhydroxylated bicyclic azetidine scaffolds, namely 6-azabicyclo[3.2.0]heptane derivatives. The strategy hinges on a common bicyclic β-lactam precursor, which is forged by way of a rare example of a cationic Dieckmann-type reaction, followed by IBX-mediated desaturation. Substrate-controlled diastereoselective oxidations then allow the divergent preparation of novel iminosugar mimics.

  3. Total Synthesis, Proof of Absolute Configuration, and Biosynthetic Origin of Stylopsal, the First Isolated Sex Pheromone of Strepsiptera

    Czech Academy of Sciences Publication Activity Database

    Lagoutte, Roman; Šebesta, Petr; Jiroš, Pavel; Kalinová, Blanka; Jirošová, Anna; Straka, J.; Černá, K.; Šobotník, Jan; Cvačka, Josef; Jahn, Ullrich

    2013-01-01

    Roč. 19, č. 26 (2013), s. 8515-8524 ISSN 0947-6539 R&D Projects: GA ČR GAP506/10/1466 Institutional support: RVO:61388963 Keywords : asymmetric synthesis * configuration determination * pheromones * total synthesis * Wittig reactions Subject RIV: CC - Organic Chemistry Impact factor: 5.696, year: 2013

  4. Catalytic Asymmetric Total Synthesis of (+)- and (-)-Paeoveitol via a Hetero-Diels-Alder Reaction.

    Science.gov (United States)

    Li, Tian-Ze; Geng, Chang-An; Yin, Xiu-Juan; Yang, Tong-Hua; Chen, Xing-Long; Huang, Xiao-Yan; Ma, Yun-Bao; Zhang, Xue-Mei; Chen, Ji-Jun

    2017-02-03

    The first catalytic asymmetric total synthesis of (+)- and (-)-paeoveitol has been accomplished in 42% overall yield via a biomimetic hetero-Diels-Alder reaction. The chiral phosphoric acid catalyzed hetero-Diels-Alder reaction showed excellent diastereo- and enantioselectivity (>99:1 dr and 90% ee); two rings and three stereocenters were constructed in a single step to produce (-)-paeoveitol on a scale of 452 mg. This strategy enabled us to selectively synthesize both paeoveitol enantiomers from the same substrates by simply changing the enantiomer of the catalyst.

  5. Unscheduled DNA synthesis in spleen cells of mice exposed to low doses of total body irradiation

    International Nuclear Information System (INIS)

    Tuschl, H.; Kovac, R.; Hruby, E.

    1983-07-01

    Unscheduled DNA synthesis was induced by UV irradiation of spleen cells obtained from C 57 Bl mice after repeated total body irradiation of 0.05 Gy 60 Co (0.00125 Gy/mice) and determined autoradiographically. An enhancement in the ability for repair of UV induced DNA lesions was observed in cells of gamma irradiated animals. While the amount of 3 H-thymidine incorporated per cell was increased, the percentage of labeled cells remained unchanged. The present results are compared with previous data on low dose radiation exposure in men. (Author) [de

  6. Biosynthesis and Total Synthesis of Pyrronazol B: a Secondary Metabolite from Nannocystis pusilla.

    Science.gov (United States)

    Witte, Swjatoslaw N R; Hug, Joachim J; Géraldy, Magalie N E; Müller, Rolf; Kalesse, Markus

    2017-11-13

    The first stereoselective total synthesis of the natural product pyrronazol B, which contains a chlorinated pyrrole-oxazole-pyrone framework, has been achieved. Genome sequencing of the myxobacterial producer strain Nannocystis pusilla Ari7 led to the identification of the putative biosynthetic gene cluster. The proposed biosynthetic pathway was supported by feeding experiments with stable isotopes of three biosynthetic building blocks, namely l-proline, l-serine, and l-methionine. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Total synthesis of leopolic acid A, a natural 2,3-pyrrolidinedione with antimicrobial activity

    Directory of Open Access Journals (Sweden)

    Atul A. Dhavan

    2016-07-01

    Full Text Available The first total synthesis of leopolic acid A, a fungal metabolite with a rare 2,3-pyrrolidinedione nucleus linked to an ureido dipeptide, was designed and carried out. Crucial steps for the strategy include a Dieckmann cyclization to obtain the 2,3-pyrrolidinedione ring and a Wittig olefination to install the polymethylene chain. An oxazolidinone-containing leopolic acid A analogue was also synthesized. The antibacterial activity showed by both compounds suggests that they could be considered as promising candidates for future developments.

  8. Total synthesis of crocacins A, C and D: new antibiotics isolated from Chondromyces crocatus and Chondromyces pediculatus

    International Nuclear Information System (INIS)

    Oliveira, Luciana G. de; Dias, Luiz C.; Rosso, Giovanni B.

    2008-01-01

    This review describes the endeavors that led to the total synthesis of a novel class of antibiotic compounds: the crocacins A-D. Other aspects such as isolation, structural elucidation as well as the biological activities are also presented. (author)

  9. Total synthesis of complestatin: development of a Pd(0)-mediated indole annulation for macrocyclization.

    Science.gov (United States)

    Shimamura, Hiroyuki; Breazzano, Steven P; Garfunkle, Joie; Kimball, F Scott; Trzupek, John D; Boger, Dale L

    2010-06-09

    Full details of the initial development and continued examination of a powerful intramolecular palladium(0)-mediated indole annulation for macrocyclization closure of the strained 16-membered biaryl ring system found in complestatin (1, chloropeptin II) and the definition of factors impacting its intrinsic atropodiastereoselectivity are described. Its examination and use in an alternative, second-generation total synthesis of complestatin are detailed in which the order of the macrocyclization reactions was reversed from our first-generation total synthesis. In this approach and with the ABCD biaryl ether ring system in place, the key Larock cyclization was conducted with substrate 36 (containing four phenols, five secondary amides, one carbamate, and four labile aryl chlorides) and provided the product 37 (56%) exclusively as a single atropisomer (>20:1, detection limits) possessing the natural (R)-configuration. In this instance, the complexity of the substrate and the reverse macrocyclization order did not diminish the atropodiastereoselectivity; rather, it provided an improvement over the 4:1 selectivity that was observed with the analogous substrate used to provide the isolated DEF ring system in our first-generation approach. Just as significant, the atroposelectivity represents a complete reversal of the diasteroselectivity observed with analogous macrocyclizations conducted using a Suzuki biaryl coupling.

  10. Total synthesis of bryostatins: the development of methodology for the atom-economic and stereoselective synthesis of the ring C subunit.

    Science.gov (United States)

    Trost, Barry M; Frontier, Alison J; Thiel, Oliver R; Yang, Hanbiao; Dong, Guangbin

    2011-08-22

    Bryostatins, a family of structurally complicated macrolides, exhibit an exceptional range of biological activities. The limited availability and structural complexity of these molecules makes development of an efficient total synthesis particularly important. This article describes our initial efforts towards the total synthesis of bryostatins, in which chemoselective and atom-economical methods for the stereoselective assembly of the ring C subunit were developed. A Pd-catalyzed tandem alkyne-alkyne coupling/6-endo-dig cyclization sequence was explored and successfully pursued in the synthesis of a dihydropyran ring system. Elaboration of this methodology ultimately led to a concise synthesis of the ring C subunit of bryostatins. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Total synthesis of five lipoteichoic acids of Clostridium difficile

    DEFF Research Database (Denmark)

    Hogendorf, Wouter Frederik Johan; Gisch, Nicolas; Schwudke, Dominik

    2014-01-01

    The emergence of hypervirulent resistant strains have made Clostridium difficile a notorious nosocomial pathogen and has resulted in a renewed interest in preventive strategies, such as vaccines based on (synthetic) cell wall antigens. Recently, the structure of the lipoteichoic acid (LTA......) of this species has been elucidated. Additionally, this LTA was found to induce the formation of protective antibodies against C. difficile in rabbits and mice. The LTA from C. difficile is isolated as a microheterogenous mixture, differing in size and composition, impeding any structure-activity relationship...... studies. To ensure reliable biological results, pure and well-defined synthetic samples are required. In this work the total synthesis of LTAs from C. difficile with defined chain length is described and the initial biological results are presented....

  12. Total synthesis of ciguatoxin and 51-hydroxyCTX3C.

    Science.gov (United States)

    Inoue, Masayuki; Miyazaki, Keisuke; Ishihara, Yuuki; Tatami, Atsushi; Ohnuma, Yuyu; Kawada, Yuuya; Komano, Kazuo; Yamashita, Shuji; Lee, Nayoung; Hirama, Masahiro

    2006-07-26

    Ciguatoxins, the principal causative toxins of ciguatera seafood poisoning, are large ladder-like polycyclic ethers with the 13 ether rings ranging from five- to nine-membered. In this paper, we describe the total synthesis of the two most toxic members of the ciguatoxin family, ciguatoxin 1 and 51-hydroxyCTX3C 2, based on a unified synthetic strategy. The key features in our syntheses were (i) direct construction of the O,S-acetal from the corresponding left and right wing fragments (3, 4, 14); (ii) stereo- and chemoselective radical reaction of the alpha-oxyradical with pentafluorophenyl acrylate to achieve cyclization of the seven-membered G-ring; (iii) ring-closing metathesis reaction to build the nine-membered F-ring; and (iv) an efficient protective group strategy using the oxidatively removable 2-naphthylmethyl groups.

  13. Total synthesis of fully tritiated Leu-enkephalin by enzymatic coupling

    Energy Technology Data Exchange (ETDEWEB)

    Hellio, F.; Lecocq, G.; Morgat, J.L.; Gueguen, P. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Service de Biochimie)

    1990-09-01

    This paper describes the total enzymatic synthesis of Leu-enkephalin (Tyr-Gly-Gly-Phe-Leu) in which all residues were labelled with tritium. Carboxypeptidase Y from Saccharomyces cerevisiae was the coupling enzyme. ({sup 3}H)-Tyr-NH{sub 2}, ({sup 3}H)-Gly-Oet, ({sup 3}H)-Phe-NH{sub 2} and ({sup 3}H)-Leu-NH{sub 2} were prepared with specific radioactivities ranging between 20 and 60 Ci/mmol (740 to 2220 GBq/mmol). Using a microscale procedure, we obtained a fully tritiated hormone having a specific radioactivity equal to 139 Ci/mmol (5143 GBq/mmol), in agreement with the summation of the specific radioactivities of constituting residue. The radioactive hormone had antigenic properties identical to those of native Leu-enkephalin. It also bound to rat brain opiate receptors like the parental hormone. (author).

  14. Divergent solid-phase synthesis of natural product-inspired bipartite cyclodepsipeptides : total synthesis of seragamide A

    NARCIS (Netherlands)

    Arndt, H.-D.; Rizzo, S.; Nöcker, Chr.; Wackchaure, V.N.; Milroy, L.G.; Bieker, V.; Calderon, A.; Tran, T.T.N.; Brand, S.; Dehmelt, L.; Waldmann, H.

    2015-01-01

    Macrocyclic natural products (NPs) and analogues thereof often show high affinity, selectivity, and metabolic stability, and methods for the synthesis of NP-like macrocycle collections are of major current interest. We report an efficient solid-phase/cyclorelease method for the synthesis of a

  15. Concise Total Synthesis of (-)-Affinisine Oxindole, (+)-Isoalstonisine, (+)-Alstofoline, (-)-Macrogentine, (+)-Na -Demethylalstonisine, (-)-Alstonoxine A, and (+)-Alstonisine.

    Science.gov (United States)

    Stephen, Michael Rajesh; Rahman, M Toufiqur; Tiruveedhula, V V N Phani Babu; Fonseca, German O; Deschamps, Jeffrey R; Cook, James M

    2017-11-07

    A highly enantio- and diastereoselective strategy to access any member of the sarpagine/macroline family of oxindole alkaloids via internal asymmetric induction was developed from readily available d-(+)-tryptophan. At the center of this approach was the diastereospecific generation of the spiro[pyrrolidine-3,3'-oxindole] moiety at an early stage via a tert-butyl hypochlorite-promoted oxidative rearrangement of a chiral tetrahydro-β-carboline derivative. This key branching point determined the spatial configuration at the C-7 spiro center to be entirely 7R or 7S. Other key stereospecific processes were the asymmetric Pictet-Spengler reaction and Dieckmann cyclization, which were scalable to the 600 and 150 gram levels, respectively. Execution of this approach resulted in first enantiospecific total synthesis of (+)-isoalstonisine and (-)-macrogentine from the chitosenine series (7R), as well as (+)-alstonisine, (+)-alstofoline, (-)-alstonoxine A and (+)-N a -demethylalstonisine from the alstonisine series (7S). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Synthesis of 28a-homoselenolupanes and 28a-homoselenolupane saponins

    Czech Academy of Sciences Publication Activity Database

    Sidoryk, K.; Rárová, L.; Oklešťková, Jana; Pakulski, Z.; Strnad, Miroslav; Cmoch, P.; Luboradzki, R.

    2016-01-01

    Roč. 14, č. 43 (2016), s. 10238-10248 ISSN 1477-0520 R&D Projects: GA MŠk(CZ) LO1204; GA ČR GA14-19590S Institutional support: RVO:61389030 Keywords : organoselenium compounds * everninomicin 13,384-1 * coupling-constants * stereocontrolled synthesis * glycosidase inhibitors * cytotoxic agents * in-vitro * selenium * derivatives * thioglycosides Subject RIV: CE - Biochemistry Impact factor: 3.564, year: 2016

  17. A Convergent Enantioselective Total Synthesis of (-)-Perhydrohistrionicotoxin with an Intramolecular Imino Ene-type Reaction as a Key Step

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Hagberg, Lars

    1998-01-01

    A convergent enantioselective total synthesis of the neurotoxic spirocyclic alkaloid (-)-perhydrohistrionicotoxin (2) is described. A Lewis acid-mediated intramolecular imine ene-type reaction was used for the key spirocyclisation step (14 to 3, with 3 being obtained as a single diastereoisomer...

  18. Total synthesis of (-)-basiliskamide A and NMR studies on the conversion of basiliskamide A to basiliskamide B

    International Nuclear Information System (INIS)

    Dias, Luiz C.; Goncalves, Caroline C.S.

    2010-01-01

    We describe herein our approach to the total synthesis of the antifungal polyketide (-)-basiliskamide A, as well as 1 H NMR studies on the migration of the cinnamoyl side chain of basiliskamide A to form basiliskamide B in CDCl 3 solution. (author)

  19. Streamlined Total Synthesis of Trioxacarcins and Its Application to the Design, Synthesis, and Biological Evaluation of Analogues Thereof. Discovery of Simpler Designed and Potent Trioxacarcin Analogues.

    Science.gov (United States)

    Nicolaou, K C; Chen, Pengxi; Zhu, Shugao; Cai, Quan; Erande, Rohan D; Li, Ruofan; Sun, Hongbao; Pulukuri, Kiran Kumar; Rigol, Stephan; Aujay, Monette; Sandoval, Joseph; Gavrilyuk, Julia

    2017-11-01

    A streamlined total synthesis of the naturally occurring antitumor agents trioxacarcins is described, along with its application to the construction of a series of designed analogues of these complex natural products. Biological evaluation of the synthesized compounds revealed a number of highly potent, and yet structurally simpler, compounds that are effective against certain cancer cell lines, including a drug-resistant line. A novel one-step synthesis of anthraquinones and chloro anthraquinones from simple ketone precursors and phenylselenyl chloride is also described. The reported work, featuring novel chemistry and cascade reactions, has potential applications in cancer therapy, including targeted approaches as in antibody-drug conjugates.

  20. Application of diazene-directed fragment assembly to the total synthesis and stereochemical assignment of (+)-desmethyl-meso-chimonanthine and related heterodimeric alkaloids

    OpenAIRE

    Lathrop, Stephen; Movassaghi, Mohammad

    2013-01-01

    We describe the first application of our methodology for heterodimerization via diazene fragmentation towards the total synthesis of (−)-calycanthidine, meso-chimonanthine, and (+)-desmethyl-meso-chimonanthine. Our syntheses of these alkaloids feature an improved route to C3a-aminocyclotryptamines, an enhanced method for sulfamide synthesis and oxidation, in addition to a late-stage diversification leading to the first enantioselective total synthesis of (+)-desmethyl-meso-chimonanthine and i...

  1. Immobilization methods for the rapid total chemical synthesis of proteins on microtiter plates.

    Science.gov (United States)

    Zitterbart, Robert; Krumrey, Michael; Seitz, Oliver

    2017-07-01

    The chemical synthesis of proteins typically involves the solid-phase peptide synthesis of unprotected peptide fragments that are stitched together in solution by native chemical ligation (NCL). The process is slow, and throughput is limited because of the need for repeated high performance liquid chromatography purification steps after both solid-phase peptide synthesis and NCL. With an aim to provide faster access to functional proteins and to accelerate the functional analysis of synthetic proteins by parallelization, we developed a method for the high performance liquid chromatography-free synthesis of proteins on the surface of microtiter plates. The method relies on solid-phase synthesis of unprotected peptide fragments, immobilization of the C-terminal fragment and on-surface NCL with an unprotected peptide thioester in crude form. Herein, we describe the development of a suitable immobilization chemistry. We compared (i) formation of nickel(II)-oligohistidine complexes, (ii) Cu-based [2 + 3] alkine-azide cycloaddition and (iii) hydrazone ligation. The comparative study identified the hydrazone ligation as most suitable. The sequence of immobilization via hydrazone ligation, on-surface NCL and radical desulfurization furnished the targeted SH3 domains in near quantitative yield. The synthetic proteins were functional as demonstrated by an on-surface fluorescence-based saturation binding analysis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  2. Studies on the Total Synthesis of Amphidinolide O (II): A Stereoselective Synthesis of C1-C11 Fragment

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Mi Yeon; Kim, Jong Woo; Lee, Duck Hyung [Sogang University, Seoul (Korea, Republic of)

    2005-10-15

    Two ketones and, the C1-C11 fragment of Amphidinolide O, were prepared stereoselectively via 14 and 16 step sequences in 8.7% and 2.0% overall yield, respectively. The amphidinolides were isolated from the marine dinoflagellate Amphidinium sp., which produces a host of secondary metabolites endowed with potent cytotoxicity against various cancer cell lines. Amphidinolide O displayed potent in vitro cytotoxicity against L1210 marine leukemia cells and human epidermoid carcinoma KB cells with 1.7 and 3.6 μg/mL of IC50s, respectively. In addition to our recent reports regarding to the synthesis of C12-C17 and C3-C11 fragments of amphidinolide O, we describe herein a new route to diastereoselective synthesis of C1-C11 fragment of. The retrosynthetic analysis of led to the C1-C11 fragment and C12-C17 fragment. The hemiketal was expected from acyclic precursor 4 which, in turn, would be derived by diastereoselective aldol reaction between ketone and aldehyde.

  3. A 11-Steps Total Synthesis of Magellanine through a Gold(I)-Catalyzed Dehydro Diels-Alder Reaction.

    Science.gov (United States)

    McGee, Philippe; Bétournay, Geneviève; Barabé, Francis; Barriault, Louis

    2017-05-22

    We have developed an innovative strategy for the formation of angular carbocycles via a gold(I)-catalyzed dehydro Diels-Alder reaction. This transformation provides rapid access to a variety of complex angular cores in excellent diastereoselectivities and high yields. The usefulness of this Au I -catalyzed cycloaddition was further demonstrated by accomplishing a 11-steps total synthesis of (±)-magellanine. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis

    Directory of Open Access Journals (Sweden)

    Zheng Yang

    2016-02-01

    Full Text Available Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3, were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473, one of important cancer drugs target.

  5. Total Synthesis of Natural Products of Microbial Origins(Recent Topics of the Agricultunal Biological Science in Tohoku University)

    OpenAIRE

    Hiromasa, KIYOTA; Shigefumi, KUWAHARA; Laboratory of Applied Bioorganic Chemistry, Division of Bioscience & Biotechnology for Future Bioindustries, Graduate School of Agricultural Science, Tohoku University; Laboratory of Applied Bioorganic Chemistry, Division of Bioscience & Biotechnology for Future Bioindustries, Graduate School of Agricultural Science, Tohoku University

    2008-01-01

    Microorganisms are an important rich source of secondary metabolites, which could be useful leads to valuable agrochemicals and/or medicinal drugs. This mini-review describes our recent achievements on the total synthesis of biologically active natural products of microbial origins: pteridic acids A and B (strong plant growth promoters), epoxyquinols A and B (anti-angiogenic compounds), communiols A-F, G, and H, and macrotetrolide α (antibiotics), pyricuol and tabtoxinine-β-lactam (phytotoxin...

  6. Highly Convergent Total Synthesis of (+)-Lithospermic Acid via a Late-Stage Intermolecular C–H Olefination

    Science.gov (United States)

    Wang, Dong-Hui; Yu, Jin-Quan

    2011-01-01

    The total synthesis of (+)-lithospermic acid is reported, which exploits two successive C–H activation reactions as the key steps. Rh-catalyzed carbene C–H insertion reaction using Davies’ catalyst built the dihydrobenzofuran core, and a late-stage intermolecular C–H olefination coupled the olefin unit with the dihydrobenzofuran core to construct the molecule in a highly convergent manner. PMID:21443224

  7. Total Synthesis of (-)-Doliculide, Structure-Activity Relationship Studies and Its Binding to F-Actin

    NARCIS (Netherlands)

    Matcha, Kiran; Madduri, Ashoka V. R.; Roy, Sayantani; Ziegler, Slava; Waldmann, Herbert; Hirsch, Anna K. H.; Minnaard, Adriaan J.

    2012-01-01

    Actin, an abundant protein in most eukaryotic cells, is one of the targets in cancer research. Recently, a great deal of attention has been paid to the synthesis and function of actin-targeting compounds and their use as effective molecular probes in chemical biology. In this study, we have

  8. Asymmetric total synthesis of a putative sex pheromone component from the parasitoid wasp Trichogramma turkestanica

    NARCIS (Netherlands)

    Geerdink, Danny; Buter, Jeffrey; van Beek, Teris A.; Minnaard, Adriaan J.

    2014-01-01

    Virgin females of the parasitoid wasp Trichogramma turkestanica produce minute amounts of a sex pheromone, the identity of which has not been fully established. The enantioselective synthesis of a putative component of this pheromone, (6S,8S,10S)-4,6,8,10-tetramethyltrideca-2E,4E-dien-1-ol (2), is

  9. Total synthesis and structural validation of cyclodepsipeptides solonamide A and B

    DEFF Research Database (Denmark)

    Kitir, Betül; Baldry, Mara; Ingmer, Hanne

    2014-01-01

    , autoinducing peptide I (AIP-I). To enable more comprehensive studies, we embarked on the chemical synthesis of solonamides A and B. The key synthetic steps were formation of the (R)-β-hydroxy-fatty-acids by stereo-selective aldol reactions and a cyclative macrolactamization, which proceeded under highly dilute...

  10. Total Synthesis of Two 4, 5-Dioxo-seco-eudesmane Sesquiterpenes

    Institute of Scientific and Technical Information of China (English)

    Li Jing FANG; Chen Xi ZHANG; Jin Chun CHEN; Guo Jun ZHENG; Yu Lin LI

    2005-01-01

    A facile synthetic route to two seco-eudesmane, 4, 5-dioxo-10-epi-4, 5-seco-γeudesmane (1) and 4, 5-dioxo-10-epi-4, 5-seco-γ-eudesmol (2) from (+)-dihydrocarvone has been described. Avoiding expensive reagents, this highly economic method especially suits for the synthesis of 4, 5-seco-eudesman-type and ophianon-type sesquiterpenes with a double bond at position 11 and 12.

  11. Total chemical synthesis of histones and their analogs, assisted by native chemical ligation and palladium complexes.

    Science.gov (United States)

    Maity, Suman Kumar; Jbara, Muhammad; Mann, Guy; Kamnesky, Guy; Brik, Ashraf

    2017-11-01

    Chemical synthesis of histones allows precise control of the installation of post-translational modifications via the coupling of derivatized amino acids. Shortcomings of other approaches for obtaining modified histones for epigenetic studies include heterogeneity of the obtained product and difficulties in incorporating multiple modifications on the same histone. In this protocol, unprotected peptide fragments are prepared by Fmoc solid-phase synthesis and coupled in aqueous buffers via native chemical ligation (NCL; in NCL, a peptide bond is formed between a peptide with an N-terminal Cys and another peptide having a C-terminal thioester). This task is challenging, with obstacles relating to the preparation and ligation of hydrophobic peptides, as well as the requirement for multiple purification steps due to protecting-group manipulations during the polypeptide assembly process. To address this, our approach uses an easily removable solubilizing tag for the synthesis and ligation of hydrophobic peptides, as well as a more efficient and better-yielding method to remove Cys-protecting groups that uses palladium chemistry (specifically [Pd(allyl)Cl] 2 and PdCl 2 complexes). The utility of this approach is demonstrated in the syntheses of ubiquitinated H2B at Lys34, phosphorylated H2A at Tyr57 and unmodified H4. Each of these analogs can be prepared in milligram quantities within ∼20-30 d.

  12. Enantioselective Total Synthesis of Antibiotic CJ-16,264, Synthesis and Biological Evaluation of Designed Analogues, and Discovery of Highly Potent and Simpler Antibacterial Agents.

    Science.gov (United States)

    Nicolaou, K C; Pulukuri, Kiran Kumar; Rigol, Stephan; Buchman, Marek; Shah, Akshay A; Cen, Nicholas; McCurry, Megan D; Beabout, Kathryn; Shamoo, Yousif

    2017-11-08

    An improved and enantioselective total synthesis of antibiotic CJ-16,264 through a practical kinetic resolution and an iodolactonization reaction to form the iodo pyrrolizidinone fragment of the molecule is described. A series of racemic and enantiopure analogues of CJ-16,264 was designed and synthesized through the developed synthetic technologies and tested against drug-resistant bacterial strains. These studies led to interesting structure-activity relationships and the identification of a number of simpler, and yet equipotent, or even more potent, antibacterial agents than the natural product, thereby setting the foundation for further investigations in the quest for new anti-infective drugs.

  13. Synthetic Progress toward Azadirachtins. 1. Enantio- and Diastereoselective Synthesis of the Left-Wing Fragment of 11-epi-Azadirachtin I.

    Science.gov (United States)

    Shi, Hang; Tan, Ceheng; Zhang, Weibin; Zhang, Zichun; Long, Rong; Luo, Tuoping; Yang, Zhen

    2015-05-15

    A highly enantio- and diastereoselective synthesis of the left-wing fragment of 11-epi-azadirachtin I characterized with the pairwise use of palladium- and gold-catalyzed cascade reactions is presented. By enlisting a sequence of stereocontrolled transformations, our 21-step route established the stereocenters of the left-wing fragment from one chiral starting material, (-)-carvone, which would significantly facilitate the synthetic studies of the azadirachtin-type limonoids.

  14. Computer-guided total synthesis of natural products: Recent examples and future perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Della-Felice, Franco; Pilli, Ronaldo A. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Química; Sarotti, Ariel M., E-mail: pilli@iqm.unicamp.br, E-mail: sarotti@iquir-conicet.gov.ar [Instituto de Química, Universidad Nacional de Rosario-CONICET (Argentina)

    2018-05-01

    Quantum chemical calculations of nuclear magnetic resonance (NMR) shifts and coupling constants have been extensively employed in recent years mainly to facilitate structural elucidation of organic molecules. When the results of such calculations are used to determine the most likely structure of a natural product in advance, guiding the subsequent synthetic work, the term 'computer-guided synthesis' could be coined. This review article describes the most relevant examples from recent literature, highlighting the scope and limitations of this merged computational/experimental approach as well. (author)

  15. Computer-guided total synthesis of natural products: Recent examples and future perspectives

    International Nuclear Information System (INIS)

    Della-Felice, Franco; Pilli, Ronaldo A.

    2018-01-01

    Quantum chemical calculations of nuclear magnetic resonance (NMR) shifts and coupling constants have been extensively employed in recent years mainly to facilitate structural elucidation of organic molecules. When the results of such calculations are used to determine the most likely structure of a natural product in advance, guiding the subsequent synthetic work, the term 'computer-guided synthesis' could be coined. This review article describes the most relevant examples from recent literature, highlighting the scope and limitations of this merged computational/experimental approach as well. (author)

  16. Aligator: A computational tool for optimizing total chemical synthesis of large proteins.

    Science.gov (United States)

    Jacobsen, Michael T; Erickson, Patrick W; Kay, Michael S

    2017-09-15

    The scope of chemical protein synthesis (CPS) continues to expand, driven primarily by advances in chemical ligation tools (e.g., reversible solubilizing groups and novel ligation chemistries). However, the design of an optimal synthesis route can be an arduous and fickle task due to the large number of theoretically possible, and in many cases problematic, synthetic strategies. In this perspective, we highlight recent CPS tool advances and then introduce a new and easy-to-use program, Aligator (Automated Ligator), for analyzing and designing the most efficient strategies for constructing large targets using CPS. As a model set, we selected the E. coli ribosomal proteins and associated factors for computational analysis. Aligator systematically scores and ranks all feasible synthetic strategies for a particular CPS target. The Aligator script methodically evaluates potential peptide segments for a target using a scoring function that includes solubility, ligation site quality, segment lengths, and number of ligations to provide a ranked list of potential synthetic strategies. We demonstrate the utility of Aligator by analyzing three recent CPS projects from our lab: TNFα (157 aa), GroES (97 aa), and DapA (312 aa). As the limits of CPS are extended, we expect that computational tools will play an increasingly important role in the efficient execution of ambitious CPS projects such as production of a mirror-image ribosome. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Total synthesis and structural revision of TMG-chitotriomycin, a specific inhibitor of insect and fungal beta-N-acetylglucosaminidases.

    Science.gov (United States)

    Yang, You; Li, Yao; Yu, Biao

    2009-09-02

    TMG-chitotriomycin, a potent and selective inhibitor of the beta-N-acetylglucosaminidases that possesses an unique N,N,N-trimethyl-d-glucosamine (TMG) residue, is revised to be the TMG-beta-(1-->4)-chitotriose instead of the originally proposed alpha-anomer via its total synthesis, for which a highly convergent approach was developed in which the sterically demanding (1-->4)-glycosidic linkages are efficiently constructed by the Au(I)-catalyzed glycosylation protocol with glycosyl o-hexynylbenzoates as donors.

  18. A convergent approach to the total synthesis of telmisartan via a Suzuki cross-coupling reaction between two functionalized benzimidazoles.

    Science.gov (United States)

    Martin, Alex D; Siamaki, Ali R; Belecki, Katherine; Gupton, B Frank

    2015-02-06

    A direct and efficient total synthesis has been developed for telmisartan, a widely prescribed treatment for hypertension. This approach brings together two functionalized benzimidazoles using a high-yielding Suzuki reaction that can be catalyzed by either a homogeneous palladium source or graphene-supported palladium nanoparticles. The ability to perform the cross-coupling reaction was facilitated by the regio-controlled preparation of the 2-bromo-1-methylbenzimidazole precursor. This convergent approach provides telmisartan in an overall yield of 72% while circumventing many issues associated with previously reported processes.

  19. Heronapyrrole D: A case of co-inspiration of natural product biosynthesis, total synthesis and biodiscovery

    Directory of Open Access Journals (Sweden)

    Jens Schmidt

    2014-05-01

    Full Text Available The heronapyrroles A–C have first been isolated from a marine-derived Streptomyces sp. (CMB-0423 in 2010. Structurally, these natural products feature an unusual nitropyrrole system to which a partially oxidized farnesyl chain is attached. The varying degree of oxidation of the sesquiterpenyl subunit in heronapyrroles A–C provoked the hypothesis that there might exist other hitherto unidentified metabolites. On biosynthetic grounds a mono-tetrahydrofuran-diol named heronapyrrole D appeared a possible candidate. We here describe a short asymmetric synthesis of heronapyrrole D, its detection in cultivations of CMB-0423 and finally the evaluation of its antibacterial activity. We thus demonstrate that biosynthetic considerations and the joint effort of synthetic and natural product chemists can result in the identification of new members of a rare class of natural products.

  20. Recent approaches to the total synthesis of phytoprostanes, isoprostanes and neuroprostanes as important products of lipid oxidative stress and biomarkers of disease

    Czech Academy of Sciences Publication Activity Database

    Jahn, Emanuela; Durand, T.; Galano, J. M.; Jahn, Ullrich

    2014-01-01

    Roč. 108, č. 4 (2014), s. 301-319 ISSN 0009-2770 Institutional support: RVO:61388963 Keywords : lipids * oxidative stress * phytoprostanes * isoprostanes * neuroprostanes * total synthesis Subject RIV: CC - Organic Chemistry Impact factor: 0.272, year: 2014

  1. Total Synthesis of the Spirocyclic Oxindole Alkaloids Corynoxine, Corynoxine B, Corynoxeine, and Rhynchophylline

    NARCIS (Netherlands)

    Wanner, M.J.; Ingemann, S.; van Maarseveen, J.H.; Hiemstra, H.

    2013-01-01

    Racemic total syntheses of four spirocyclic oxindole alkaloids are reported. The general starting material was an N-2-butenylated 2-hydroxytryptamine, which underwent a base-mediated Mannich spirocyclisation with a functionalised aldehyde to generate the C-ring. The second key step was a

  2. Fluorine-Directed Glycosylation Enables the Stereocontrolled Synthesis of Selective SGLT2 Inhibitors for Type II Diabetes.

    Science.gov (United States)

    Sadurní, Anna; Kehr, Gerald; Ahlqvist, Marie; Wernevik, Johan; Sjögren, Helena Peilot; Kankkonen, Cecilia; Knerr, Laurent; Gilmour, Ryan

    2018-02-26

    Inhibition of the sodium-glucose co-transporters (SGLT1 and SGLT2) is a validated strategy to address the increasing prevalence of type II diabetes mellitus. However, achieving selective inhibition of human SGLT1 or SGLT2 remains challenging. Orally available small molecule drugs based on the d-glucose core of the natural product Gliflozin have proven to be clinically effective in this regard, effectively impeding glucose reabsorption. Herein, we disclose the influence of molecular editing with fluorine at the C2 position of the pyranose ring of Phlorizin analogues Remogliflozin Etabonate and Dapagliflozin (Farxiga ® ) to concurrently direct β-selective glycosylation, as is required for biological efficacy, and enhance aspects of the physicochemical profile. Given the abundance of glycosylated pharmaceuticals in diabetes therapy that contain a β-configured d-glucose nucleus, it is envisaged that this strategy may prove to be expansive. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Total asymmetric synthesis of the putative structure of the cytotoxic diterpenoid (-)-sclerophytin a and of the authentic natural sclerophytins A and B.

    Science.gov (United States)

    Bernardelli, P; Moradei, O M; Friedrich, D; Yang, J; Gallou, F; Dyck, B P; Doskotch, R W; Lange, T; Paquette, L A

    2001-09-19

    An enantioselective synthetic route to the thermodynamically most stable diastereomer of the structure assigned to sclerophytin A (5) has been realized. The required tricyclic ketone 33 was prepared by sequential Tebbe-Claisen rearrangement of lactones 29 and 30, which originated from the Diels-Alder cycloaddition of Danishefsky's diene to (5S)-5-(d-menthyloxy)-2(5H)-furanone (14). An allyl and a cyano group were introduced into the resulting adduct by means of stereocontrolled allylindation under aqueous Barbier-like conditions and by way of cyanotrimethylsilane, respectively. Following stereocontrolled nucleophilic addition of a methyl group to 33, ring A was elaborated by formation of the silyl enol ether, ytterbium triflate-catalyzed condensation with formaldehyde, O-silylation, and Cu(I)-promoted 1,4-addition of isopropylmagnesium chloride. The superfluous ketone carbonyl was subsequently removed and the second ether bridge introduced by means of oxymercuration chemistry. Only then was the exocyclic methylene group unmasked via elimination. An alternative approach to the alpha-carbinol diastereomer proceeds by initial alpha-oxygenation of 37 and ensuing 1,2-carbonyl transposition. Neither this series of steps nor the Wittig olefination to follow induced epimerization at C10. Through deployment of oxymercuration chemistry, it was again possible to elaborate the dual oxygen-bridge network of the target ring system. Oxidation of the organomercurial products with O(2) in the presence of sodium borohydride furnished 72, which was readily separated from its isomer 73 after oxidation to 61. Hydride attack on this ketone proceeded with high selectivity from the beta-direction to deliver (-)-60. Comparison of the high-field (1)H and (13)C NMR properties and polarity of synthetic 5 with natural material required that structural revision be made. Following a complete spectral reassessment of the structural assignments to many sclerophytin diterpenes, a general approach

  4. A Concise Total Synthesis of (R)-Fluoxetine, a Potent and Selective Serotonin Reuptake Inhibitor

    OpenAIRE

    de Fátima, Ângelo; Lapis, Alexandre Augusto M.; Pilli, Ronaldo A.

    2005-01-01

    (R)-Fluoxetine, potent and selective serotonin reuptake inhibitor, has been synthesized in six steps, 50% overall yield and 99% ee from benzaldehyde via catalytic asymmetric allylation with Maruoka's catalyst. (R)-Fluoxetina, um inibidor potente e seletivo da recaptação da serotonina, foi sintetizada em seis etapas, 50% de rendimento total e 99% de excesso enantiomérico a partir do benzaldeído via alilação catalítica assimétrica empregando-se o sistema catalítico desenvolvido por Maruoka e...

  5. Extending the Glucosyl Ceramide Cassette Approach: Application in the Total Synthesis of Ganglioside GalNAc-GM1b

    Directory of Open Access Journals (Sweden)

    Miku Konishi

    2013-12-01

    Full Text Available The development of a novel cyclic glucosyl ceramide cassette acceptor for efficient glycolipid syntheses was investigated. p-Methoxybenzyl (PMB groups were selected as protecting groups at C2 and C3 of the glucose residue with the aim of improving the functionality of the cassette acceptor. The choice of the PMB group resulted in a loss of β-selectivity, which was corrected by using an appropriate tether to control the spatial arrangement and the nitrile solvent effect. To investigate the effect of linker structure on the β-selectivity of intramolecular glycosylation, several linkers for tethering the glucose and ceramide moiety were designed and prepared, namely, succinyl, glutaryl, dimethylmalonyl, and phthaloyl esters. The succinyl ester linker was the best for accessing the cassette form. The newly designed glucosyl ceramide cassette acceptor was then applied in the total synthesis of ganglioside GalNAc-GM1b.

  6. A Mixed-Ligand Chiral Rhodium(II) Catalyst Enables the Enantioselective Total Synthesis of Piperarborenine B.

    Science.gov (United States)

    Panish, Robert A; Chintala, Srinivasa R; Fox, Joseph M

    2016-04-11

    A novel, mixed-ligand chiral rhodium(II) catalyst, Rh2(S-NTTL)3(dCPA), has enabled the first enantioselective total synthesis of the natural product piperarborenine B. A crystal structure of Rh2(S-NTTL)3(dCPA) reveals a "chiral crown" conformation with a bulky dicyclohexylphenyl acetate ligand and three N-naphthalimido groups oriented on the same face of the catalyst. The natural product was prepared on large scale using rhodium-catalyzed bicyclobutanation/ copper-catalyzed homoconjugate addition chemistry in the key step. The route proceeds in ten steps with an 8% overall yield and 92% ee. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. A strategy for complex dimer formation when biomimicry fails: total synthesis of ten coccinellid alkaloids.

    Science.gov (United States)

    Sherwood, Trevor C; Trotta, Adam H; Snyder, Scott A

    2014-07-09

    Although dimeric natural products can often be synthesized in the laboratory by directly merging advanced monomers, these approaches sometimes fail, leading instead to non-natural architectures via incorrect unions. Such a situation arose during our studies of the coccinellid alkaloids, when attempts to directly dimerize Nature's presumed monomeric precursors in a putative biomimetic sequence afforded only a non-natural analogue through improper regiocontrol. Herein, we outline a unique strategy for dimer formation that obviates these difficulties, one which rapidly constructs the coccinellid dimers psylloborine A and isopsylloborine A through a terminating sequence of two reaction cascades that generate five bonds, five rings, and four stereocenters. In addition, a common synthetic intermediate is identified which allows for the rapid, asymmetric formal or complete total syntheses of eight monomeric members of the class.

  8. Total observed organic carbon (TOOC in the atmosphere: a synthesis of North American observations

    Directory of Open Access Journals (Sweden)

    C. L. Heald

    2008-04-01

    Full Text Available Measurements of organic carbon compounds in both the gas and particle phases made upwind, over and downwind of North America are synthesized to examine the total observed organic carbon (TOOC in the atmosphere over this region. These include measurements made aboard the NOAA WP-3 and BAe-146 aircraft, the NOAA research vessel Ronald H. Brown, and at the Thompson Farm and Chebogue Point surface sites during the summer 2004 ICARTT campaign. Both winter and summer 2002 measurements during the Pittsburgh Air Quality Study are also included. Lastly, the spring 2002 observations at Trinidad Head, CA, surface measurements made in March 2006 in Mexico City and coincidentally aboard the C-130 aircraft during the MILAGRO campaign and later during the IMPEX campaign off the northwestern United States are incorporated. Concentrations of TOOC in these datasets span more than two orders of magnitude. The daytime mean TOOC ranges from 4.0 to 456 μgC m−3 from the cleanest site (Trinidad Head to the most polluted (Mexico City. Organic aerosol makes up 3–17% of this mean TOOC, with highest fractions reported over the northeastern United States, where organic aerosol can comprise up to 50% of TOOC. Carbon monoxide concentrations explain 46 to 86% of the variability in TOOC, with highest TOOC/CO slopes in regions with fresh anthropogenic influence, where we also expect the highest degree of mass closure for TOOC. Correlation with isoprene, formaldehyde, methyl vinyl ketone and methacrolein also indicates that biogenic activity contributes substantially to the variability of TOOC, yet these tracers of biogenic oxidation sources do not explain the variability in organic aerosol observed over North America. We highlight the critical need to develop measurement techniques to routinely detect total gas phase VOCs, and to deploy comprehensive suites of TOOC instruments in diverse environments to quantify the ambient evolution of organic carbon from source

  9. Crystal morphology modification by the addition of tailor-made stereocontrolled poly(N-isopropyl acrylamide).

    Science.gov (United States)

    Munk, Tommy; Baldursdottir, Stefania; Hietala, Sami; Rades, Thomas; Kapp, Sebastian; Nuopponen, Markus; Kalliomäki, Katriina; Tenhu, Heikki; Rantanen, Jukka

    2012-07-02

    The use of additives in crystallization of pharmaceuticals is known to influence the particulate properties critically affecting downstream processing and the final product performance. Desired functionality can be build into these materials, e.g. via optimized synthesis of a polymeric additive. One such additive is the thermosensitive polymer poly(N-isopropyl acrylamide) (PNIPAM). The use of PNIPAM as a crystallization additive provides a possibility to affect viscosity at separation temperatures and nucleation and growth rates at higher temperatures. In this study, novel PNIPAM derivatives consisting of both isotactic-rich and atactic blocks were used as additives in evaporative crystallization of a model compound, nitrofurantoin (NF). Special attention was paid to possible interactions between NF and PNIPAM and the aggregation state of PNIPAM as a function of temperature and solvent composition. Optical light microscopy and Raman and FTIR spectroscopy were used to investigate the structure of the NF crystals and possible interaction with PNIPAM. A drastic change in the growth mechanism of nitrofurantoin crystals as monohydrate form II (NFMH-II) was observed in the presence of PNIPAM; the morphology of crystals changed from needle to dendritic shape. Additionally, the amphiphilic nature of PNIPAM increased the solubility of nitrofurantoin in water. PNIPAMs with varying molecular weights and stereoregularities resulted in similar changes in the crystal habit of the drug regardless of whether the polymer was aggregated or not. However, with increased additive concentration slower nucleation and growth rates of the crystals were observed. Heating of the crystallization medium resulted in phase separation of the PNIPAM. The phase separation had an influence on the achieved crystal morphology resulting in fewer, visually larger and more irregular dendritic crystals. No proof of hydrogen bond formation between PNIPAM and NF was observed, and the suggested mechanism for

  10. Total Synthesis of Zoanthamine Alkaloids, Part 2. Construction of the C1-C5, C6-C10 and C11-C24 Fragments of Zoanthamine

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Tedenborg, Lars; Somfai, Peter

    1997-01-01

    This paper describes the construction of three key intermediates for a projected total synthesis of the marine alkaloid zoanthamine. These building blocks, corresponding to the C1-C5, C6-C10 and C11-C24 fragments of the target molecule, are synthesised efficiently form (R)-hydroxymethyl-butyrolac......This paper describes the construction of three key intermediates for a projected total synthesis of the marine alkaloid zoanthamine. These building blocks, corresponding to the C1-C5, C6-C10 and C11-C24 fragments of the target molecule, are synthesised efficiently form (R...

  11. Solid-Phase Synthesis for the Construction of Biologically Interesting Molecules and the Total Synthesis of Trioxacarcin DC-45-A2

    DEFF Research Database (Denmark)

    Mikkelsen, Remi Jacob Thomsen

    . Furthermore a route to another key building block was developed featuring a Stille cross-coupling.Synthesis of Poly-fused Heterocycles. In the search for new biologically active compounds a methodology for the synthesis of polyfused heterocycles was investigated. This led to the development and optimization...

  12. Truly Absorbed Microbial Protein Synthesis, Rumen Bypass Protein, Endogenous Protein, and Total Metabolizable Protein from Starchy and Protein-Rich Raw Materials

    NARCIS (Netherlands)

    Parand, Ehsan; Vakili, Alireza; Mesgaran, Mohsen Danesh; Duinkerken, Van Gert; Yu, Peiqiang

    2015-01-01

    This study was carried out to measure truly absorbed microbial protein synthesis, rumen bypass protein, and endogenous protein loss, as well as total metabolizable protein, from starchy and protein-rich raw feed materials with model comparisons. Predictions by the DVE2010 system as a more

  13. Toward the Elucidation of the Metabolism of 15-E2-Isoprostane: The Total Synthesis of the Methyl Ester of a Potential Central Metabolite

    Czech Academy of Sciences Publication Activity Database

    Jahn, Ullrich; Dinca, E.

    2010-01-01

    Roč. 75, č. 13 (2010), s. 4480-4491 ISSN 0022-3263 Grant - others:DFG(DE) Ja896/3-1 Institutional research plan: CEZ:AV0Z40550506 Keywords : isoprostane * total synthesis * radical anion cyclization Subject RIV: CC - Organic Chemistry Impact factor: 4.002, year: 2010

  14. Total Synthesis of Zoanthamine Alkaloids, Part 2. Construction of the C1-C5, C6-C10 and C11-C24 Fragments of Zoanthamine

    DEFF Research Database (Denmark)

    Tanner, David Ackland; Tedenborg, Lars; Somfai, Peter

    1997-01-01

    This paper describes the construction of three key intermediates for a projected total synthesis of the marine alkaloid zoanthamine. These building blocks, corresponding to the C1-C5, C6-C10 and C11-C24 fragments of the target molecule, are synthesised efficiently form (R...

  15. Combining cycloisomerization with trienamine catalysis: a regiochemically flexible enantio- and diastereoselective synthesis of hexahydroindoles.

    Science.gov (United States)

    Chintalapudi, V; Galvin, E A; Greenaway, R L; Anderson, E A

    2016-01-14

    The synthesis of polysubstituted hexahydroindoles through trienamine-organocatalyzed cycloadditions of pyrrolidinyl dienals, prepared by palladium-catalyzed cycloisomerization, is reported. The cycloadditions of this novel class of dienals proceed with excellent levels of enantio- and diastereoselectivity, with the regioselectivity of cycloaddition with respect to the tethering ring readily tuned through design of the cycloisomerization substrate. This work culminates in the first examples of double-stereodifferentiating trienamine catalysis, where catalyst stereocontrol dominates facial selectivity in the cycloaddition, affording azacyclic products that are specifically functionalized at every position.

  16. Total synthesis of (+/-)-taiwaniaquinol B via a domino intramolecular friedel-crafts acylation/carbonyl alpha-tert-alkylation reaction.

    Science.gov (United States)

    Fillion, Eric; Fishlock, Dan

    2005-09-28

    The first synthesis of taiwaniaquinol B, a 6-nor-5(6-->7)abeoabietane-type diterpenoid exhibiting the uncommon fused 6-5-6 tricyclic carbon skeleton, was accomplished in 15 steps. A Lewis acid-promoted tandem intramolecular Friedel-Crafts/carbonyl alpha-tert-alkylation reaction was exploited as the core strategy for the synthesis of the sterically congested 1-indanone-containing tricyclic structure. This multiple carbon-carbon bond forming reaction exploits the unique reactivity of Meldrum's acid. The facile precursor synthesis makes this a useful methodology for the expedient modification and assembly of sterically congested 1-indanone-containing ring systems.

  17. Total syntheses of hyperforin and papuaforins A-C, and formal synthesis of nemorosone through a gold(I)-catalyzed carbocyclization.

    Science.gov (United States)

    Bellavance, Gabriel; Barriault, Louis

    2014-06-23

    The remarkable biological activities of polyprenylated polycyclic acylphloroglucinols (PPAPs) combined with their highly decorated bicyclo[3.3.1]nonane-2,4,9-trione frameworks have inspired synthetic organic chemists over the last decade. The concise total syntheses of four natural products PPAPs; hyperforin and papuaforins A-C, and the formal synthesis of nemorosone are reported. Key to the realization of this strategy is the short and scalable synthesis of densely substituted PPAP scaffolds through a gold(I)-catalyzed 6-endo-dig carbocyclization of cyclic enol ethers for late-stage functionalization. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Total Synthesis and Antimicrobial Activity of (±-Laurelliptinhexadecan-1-one and (±-Laurelliptinoctadecan-1-one

    Directory of Open Access Journals (Sweden)

    Surachai Nimgirawath

    2008-11-01

    Full Text Available The structures previously assigned to (+-laurelliptinhexadecan-1-one (1a and (+-laurelliptinoctadecan-1-one (1b from Cocculus orbiculatus (L. DC. (Menispermaceae have been confirmed by total synthesis of the racemic alkaloids. The key step of the synthesis involved formation of ring C of the aporphines by a radical-intiated cyclisation. Both (±-laurelliptinhexadecan-1-one (1a and (±-laurelliptinoctadecan-1-one (1b were inactive against Staphylococcus aureus ATCC25932, Escherichia coli ATCC10536 and Candida albicans ATCC90028.

  19. Pharmacophore mapping in the laulimalide series: total synthesis of a vinylogue for a late-stage metathesis diversification strategy.

    Science.gov (United States)

    Wender, Paul A; Hilinski, Michael K; Skaanderup, Philip R; Soldermann, Nicolas G; Mooberry, Susan L

    2006-08-31

    An efficient synthesis of the macrocyclic core of laulimalide with a pendant vinyl group at C20 is described, allowing for late-stage introduction of various side chains through a selective and efficient cross metathesis diversification step. Representative analogues reported herein are the first to contain modifications to only the side chain dihydropyran of laulimalide and des-epoxy laulimalide. This step-economical strategy enables the rapid synthesis of new analogues using alkenes as an inexpensive, abundantly available diversification feedstock.

  20. Nicholas reactions in the construction of cyclohepta[de]naphthalenes and cyclohepta[de]naphthalenones. The total synthesis of microstegiol.

    Science.gov (United States)

    Taj, Rafiq A; Green, James R

    2010-12-03

    The application of the Nicholas reaction chemistry of 2,7-dioxygenated naphthalenes in the synthesis of cyclohepta[de]napthalenes and in the synthesis of (±)-microstegiol (1) is presented. The substitution profile of Nicholas monosubstitution (predominantly C-1) and disubstitution reactions (predominantly 1,6-) on 2,7-dioxygenated napthalenes is reported. Application of a 1,8-dicondensation product and selected C-1 monocondensation products to the construction of cyclohepta[de]naphthalenes by way of ring closing metathesis and intramolecular Friedel-Crafts reactions, respectively, is described. Deprotection of the C-7 oxygen function to the corresponding naphthol allows tautomerization to cyclohepta[de]naphthalene-1-ones upon seven-membered-ring closure in most cases, and replacement of the C-2 oxygen function in the naphthalene by a methyl group ultimately allows the synthesis of (±)-microstegiol.

  1. Synthesis of 1,3-diaminated stereotriads via rearrangement of 1,4-diazaspiro[2.2]pentanes.

    Science.gov (United States)

    Weatherly, Cale D; Rigoli, Jared W; Schomaker, Jennifer M

    2012-04-06

    The synthesis of 1,3-diaminated stereotriads via the bis-aziridination of allenes is reported. The reactive 1,4-diazaspiro[2.2]pentane intermediates undergo a mild Brønsted acid-promoted rearrangement to yield 1,3-diaminated ketones in good yields with excellent stereocontrol. Directed reduction of the ketone can be achieved to yield a C-N/C-O/C-N stereotriad in high dr. The ability to transfer the axial chirality of the substrates to the products allows for the facile preparation of enantioenriched stereotriads from allenes in two simple steps.

  2. Stimulation of glycogen synthesis in hepatocytes by added amino acids is related to the total intracellular content of amino acids

    NARCIS (Netherlands)

    Plomp, P. J.; Boon, L.; Caro, L. H.; van Woekom, G. M.; Meijer, A. J.

    1990-01-01

    Katz et al. [Katz, J., Golden, S. & Wals, P.A. (1976) Proc. Natl Acad. Sci. USA 73, 3433-3437] were the first to report that in hepatocytes isolated from fasted rats and incubated with either dihydroxyacetone, glucose or other sugars, glycogen synthesis was greatly accelerated by addition of amino

  3. Unified approach to catechin hetero-oligomers: first total synthesis of trimer EZ-EG-CA isolated from Ziziphus jujuba.

    Science.gov (United States)

    Yano, Takahisa; Ohmori, Ken; Takahashi, Haruko; Kusumi, Takenori; Suzuki, Keisuke

    2012-10-14

    A catechin hetero-trimer isolated from Ziziphus jujuba has been synthesized. Among three constituent monomers, (-)-epiafzelechin and (-)-epigallocatechin were prepared by de novo synthesis. Trimer formation relied on the unified approach to oligomers based on the bromo-capping and the orthogonal activation, reaching the reported structure of the natural product.

  4. Chemoenzymatic synthesis of statine side chain building blocks and application in the total synthesis of the cholesterol-lowering compound solistatin.

    Science.gov (United States)

    Rieder, Oliver; Wolberg, Michael; Foegen, Silke E; Müller, Michael

    2017-09-20

    The synthesis and enzymatic reduction of several 6-substituted dioxohexanoates are presented. Two-step syntheses of tert-butyl 6-bromo-3,5-dioxohexanoate and the corresponding 6-hydroxy compound have been achieved in 89% and 59% yield, respectively. Regio- and enantioselective reduction of these diketones and of the 6-chloro derivative with alcohol dehydrogenase from Lactobacillus brevis (LBADH) gave the (5S)-5-hydroxy-3-oxo products with enantiomeric excesses of 91%, 98.4%, and >99.5%, respectively. Chain elongation of the reduction products by one carbon via cyanide addition, and by more than one carbon by Julia-Kocienski olefination, gave access to well-established statine side-chain building blocks. Application in the synthesis of the cholesterol-lowering natural compound solistatin is given. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Bringing the science of proteins into the realm of organic chemistry: total chemical synthesis of SEP (synthetic erythropoiesis protein).

    Science.gov (United States)

    Kent, Stephen B H

    2013-11-11

    Erythropoietin, commonly known as EPO, is a glycoprotein hormone that stimulates the production of red blood cells. Recombinant EPO has been described as "arguably the most successful drug spawned by the revolution in recombinant DNA technology". Recently, the EPO glycoprotein molecule has re-emerged as a major target of synthetic organic chemistry. In this article I will give an account of an important body of earlier work on the chemical synthesis of a designed EPO analogue that had full biological activity and improved pharmacokinetic properties. The design and synthesis of this "synthetic erythropoiesis protein" was ahead of its time, but has gained new relevance in recent months. Here I will document the story of one of the major accomplishments of synthetic chemistry in a more complete way than is possible in the primary literature, and put the work in its contemporaneous context. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Solid-Phase Synthesis of Difficult Purine-Rich PNAs through Selective Hmb Incorporation: Application to the Total Synthesis of Cell Penetrating Peptide-PNAs

    Directory of Open Access Journals (Sweden)

    Julien Tailhades

    2017-10-01

    Full Text Available Antisense oligonucleotide (ASO-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino and Spinraza (2′-O-methoxyethyl-phosphorothioate in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here, we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl and Dmb (2,4-dimethoxybenzyl to ameliorate difficult couplings and reduce “on-resin” aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences.

  7. Solid-phase synthesis of difficult purine-rich PNAs through selective Hmb incorporation: Application to the total synthesis of cell penetrating peptide-PNAs

    Science.gov (United States)

    Tailhades, Julien; Takizawa, Hotake; Gait, Michael J.; Wellings, Don A.; Wade, John D.; Aoki, Yoshitsugu; Shabanpoor, Fazel

    2017-10-01

    Antisense oligonucleotide (ASO)-based drug development is gaining significant momentum following the recent FDA approval of Eteplirsen (an ASO based on phosphorodiamidate morpholino) and Spinraza (2’-O-methoxyethyl-phosphorothioate) in late 2016. Their attractiveness is mainly due to the backbone modifications which have improved the in vivo characteristics of oligonucleotide drugs. Another class of ASO, based on peptide nucleic acid (PNA) chemistry, is also gaining popularity as a platform for development of gene-specific therapy for various disorders. However, the chemical synthesis of long PNAs, which are more target-specific, remains an ongoing challenge. Most of the reported methodology for the solid-phase synthesis of PNA suffer from poor coupling efficiency which limits production to short PNA sequences of less than 15 residues. Here we have studied the effect of backbone modifications with Hmb (2-hydroxy-4-methoxybenzyl) and Dmb (2,4-dimethoxybenzyl) to ameliorate difficult couplings and reduce “on-resin” aggregation. We firstly synthesized a library of PNA dimers incorporating either Hmb or Dmb and identified that Hmb is superior to Dmb in terms of its ease of removal. Subsequently, we used Hmb backbone modification to synthesize a 22-mer purine-rich PNA, targeting dystrophin RNA splicing, which could not be synthesized by standard coupling methodology. Hmb backbone modification allowed this difficult PNA to be synthesized as well as to be continued to include a cell-penetrating peptide on the same solid support. This approach provides a novel and straightforward strategy for facile solid-phase synthesis of difficult purine-rich PNA sequences.

  8. Stereocontrol during the radical polymerization of methyl methacrylates with combined Lewis acids:Aluminium trichloride(AlCl3) and iron dichloride tetrahydrate

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The radical polymerization of methyl methacrylate(MMA) was carried out in the presence of combined Lewis acids of the AlCl3-FeCl2 system.Compared with the polymerization produced in the presence of single Lewis acids,AlCl3 or FeCl2,the MMA polymerization in the presence of AlCl3-FeCl2 composite in CHCl3 or 1-butanol produced a polymer with a higher isotacticity and in toluene produced a polymer with a much higher isotacticity(mm=50%) .The molecular weight and polydispersity of PMMA in the presence of Lewis acids were similar with those in the absence of Lewis acids,although Lewis acids decelerate the polymerization of MMA.The effects of the Lewis acids were greater in a solvent with a lower polarity.A possible stereocontrol mechanism of the polymerization was proposed.The Lewis acid composite of AlCl3-FeCl2 readily formed a complex with growing species.These complexes possessed apparent bulkiness that changes the direction of monomer addition to the growing radical center.

  9. Diverted Total Synthesis of Promysalin Analogs Demonstrates That an Iron-Binding Motif Is Responsible for Its Narrow-Spectrum Antibacterial Activity.

    Science.gov (United States)

    Steele, Andrew D; Keohane, Colleen E; Knouse, Kyle W; Rossiter, Sean E; Williams, Sierra J; Wuest, William M

    2016-05-11

    Promysalin is a species-specific Pseudomonad metabolite with unique bioactivity. To better understand the mode of action of this natural product, we synthesized 16 analogs utilizing diverted total synthesis (DTS). Our analog studies revealed that the bioactivity of promysalin is sensitive to changes within its hydrogen bond network whereby alteration has drastic biological consequences. The DTS library not only yielded three analogs that retained potency but also provided insights that resulted in the identification of a previously unknown ability of promysalin to bind iron. These findings coupled with previous observations hint at a complex multifaceted role of the natural product within the rhizosphere.

  10. Rhodium-Catalyzed Asymmetric N-H Functionalization of Quinazolinones with Allenes and Allylic Carbonates: The First Enantioselective Formal Total Synthesis of (-)-Chaetominine.

    Science.gov (United States)

    Zhou, Yirong; Breit, Bernhard

    2017-12-22

    An unprecedented asymmetric N-H functionalization of quinazolinones with allenes and allylic carbonates was successfully achieved by rhodium catalysis with the assistance of chiral bidentate diphosphine ligands. The high efficiency and practicality of this method was demonstrated by a low catalyst loading of 1 mol % as well as excellent chemo-, regio-, and enantioselectivities with broad functional group compatibility. Furthermore, this newly developed strategy was applied as key step in the first enantioselective formal total synthesis of (-)-chaetominine. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Total synthesis of crocacins A, C and D: new antibiotics isolated from Chondromyces crocatus and Chondromyces pediculatus; Sinteses totais das crocacinas A, C e D: novos antibioticos isolados de Chondromyces crocatus e Chondromyces pediculatus

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Luciana G. de; Dias, Luiz C.; Rosso, Giovanni B. [Universidade Estadual de Campinas (UNICAMP), Campinas, SP (Brazil). Inst. de Quimica]. E-mail: luciana@iqm.unicamp.br

    2008-07-01

    This review describes the endeavors that led to the total synthesis of a novel class of antibiotic compounds: the crocacins A-D. Other aspects such as isolation, structural elucidation as well as the biological activities are also presented. (author)

  12. Total synthesis of fluoxetine and duloxetine through an in situ imine formation/borylation/transimination and reduction approach.

    Science.gov (United States)

    Calow, Adam D J; Fernández, Elena; Whiting, Andrew

    2014-08-28

    We report efficient, catalytic, asymmetric total syntheses of both (R)-fluoxetine and (S)-duloxetine from α,β-unsaturated aldehydes conducting five sequential one-pot steps (imine formation/copper mediated β-borylation/transimination/reduction/oxidation) followed by the specific ether group formation which deliver the desired products (R)-fluoxetine in 45% yield (96% ee) and (S)-duloxetine in 47% yield (94% ee).

  13. An efficient, second-generation synthesis of the signature dioxabicyclo[3.2.1]octane core of (+)-sorangicin A and elaboration of the (Z,Z,E)-triene acid system.

    Science.gov (United States)

    Smith, Amos B; Dong, Shuzhi

    2009-03-05

    An efficient, second-generation synthesis of the signature dioxabicyclo[3.2.1]octane core of (+)-sorangicin A (1), in conjunction with an effective, stereocontrolled protocol to arrive at the requisite (Z,Z,E)-triene acid system has been developed. Highlights of the core construction entail a three-component union, a KHMDS-promoted epoxide ring formation-ring opening cascade, a Takai olefination, and a chemoselective Sharpless dihydroxylation. Assembly of the triene acid system was then achieved via Stille cross-coupling with the ethyl ester of (Z,Z)-5-tributylstannyl-2,4-pentadienoic acid, followed by mild hydrolysis preserving the triene configuration.

  14. Autonomous assembly of synthetic oligonucleotides built from an expanded DNA alphabet. Total synthesis of a gene encoding kanamycin resistance

    Directory of Open Access Journals (Sweden)

    Kristen K. Merritt

    2014-10-01

    Full Text Available Background: Many synthetic biologists seek to increase the degree of autonomy in the assembly of long DNA (L-DNA constructs from short synthetic DNA fragments, which are today quite inexpensive because of automated solid-phase synthesis. However, the low information density of DNA built from just four nucleotide “letters”, the presence of strong (G:C and weak (A:T nucleobase pairs, the non-canonical folded structures that compete with Watson–Crick pairing, and other features intrinsic to natural DNA, generally prevent the autonomous assembly of short single-stranded oligonucleotides greater than a dozen or so.Results: We describe a new strategy to autonomously assemble L-DNA constructs from fragments of synthetic single-stranded DNA. This strategy uses an artificially expanded genetic information system (AEGIS that adds nucleotides to the four (G, A, C, and T found in standard DNA by shuffling hydrogen-bonding units on the nucleobases, all while retaining the overall Watson–Crick base-pairing geometry. The added information density allows larger numbers of synthetic fragments to self-assemble without off-target hybridization, hairpin formation, and non-canonical folding interactions. The AEGIS pairs are then converted into standard pairs to produce a fully natural L-DNA product. Here, we report the autonomous assembly of a gene encoding kanamycin resistance using this strategy. Synthetic fragments were built from a six-letter alphabet having two AEGIS components, 5-methyl-2’-deoxyisocytidine and 2’-deoxyisoguanosine (respectively S and B, at their overlapping ends. Gaps in the overlapped assembly were then filled in using DNA polymerases, and the nicks were sealed by ligase. The S:B pairs in the ligated construct were then converted to T:A pairs during PCR amplification. When cloned into a plasmid, the product was shown to make Escherichia coli resistant to kanamycin. A parallel study that attempted to assemble similarly sized genes

  15. Synthesis, structure and total conductivity of A-site doped LaTiO3−δ perovskites

    International Nuclear Information System (INIS)

    Bradha, M.; Hussain, S.; Chakravarty, Sujay; Amarendra, G.; Ashok, Anuradha

    2015-01-01

    Highlights: • A-site divalent alkaline earth metal doped LaTiO 3−δ perovskites were synthesised by sol–gel method. • Structural studies revealed no change in crystal symmetry but change in cell dimensions after doping. • After doping divalent cations in A-site, an enhancement in total conductivity was observed in LaTiO 3−δ . • Temperature dependent electrical property was observed in all synthesised perovskites. - Abstract: Oxygen deficient perovskites LaTiO 3−δ and La 0.8 A 0.2 TiO 3−δ (A = Ba, Sr, Ca) were synthesized by sol–gel method. The effect of divalent dopants on microstructure is investigated in detail using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The oxidation states of La 3+ and Ti 3+ ions have been deduced using X-ray Photoelectron Spectroscopy (XPS). Impedance spectroscopy was used to analyze the total conductivity, an increase in conductivity was observed after doping in the A-site with divalent cations Ba, Ca and Sr. Among the investigated perovskites La 0.8 Ca 0.2 TiO 3−δ exhibited the maximum conductivity of 1.22 × 10 −2 S/cm in air atmosphere at 650 °C

  16. Synthesis, structure and total conductivity of A-site doped LaTiO{sub 3−δ} perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Bradha, M. [Nanotech Research Facility, PSG Institute of Advanced Studies, Coimbatore 641 004, TN (India); Hussain, S.; Chakravarty, Sujay [UGC-DAE CSR, Kalpakkam Node, Kokilamedu 603 104, TN (India); Amarendra, G. [UGC-DAE CSR, Kalpakkam Node, Kokilamedu 603 104, TN (India); Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, TN (India); Ashok, Anuradha, E-mail: anu.machina@gmail.com [Nanotech Research Facility, PSG Institute of Advanced Studies, Coimbatore 641 004, TN (India)

    2015-03-25

    Highlights: • A-site divalent alkaline earth metal doped LaTiO{sub 3−δ} perovskites were synthesised by sol–gel method. • Structural studies revealed no change in crystal symmetry but change in cell dimensions after doping. • After doping divalent cations in A-site, an enhancement in total conductivity was observed in LaTiO{sub 3−δ}. • Temperature dependent electrical property was observed in all synthesised perovskites. - Abstract: Oxygen deficient perovskites LaTiO{sub 3−δ} and La{sub 0.8}A{sub 0.2}TiO{sub 3−δ} (A = Ba, Sr, Ca) were synthesized by sol–gel method. The effect of divalent dopants on microstructure is investigated in detail using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The oxidation states of La{sup 3+} and Ti{sup 3+} ions have been deduced using X-ray Photoelectron Spectroscopy (XPS). Impedance spectroscopy was used to analyze the total conductivity, an increase in conductivity was observed after doping in the A-site with divalent cations Ba, Ca and Sr. Among the investigated perovskites La{sub 0.8}Ca{sub 0.2}TiO{sub 3−δ} exhibited the maximum conductivity of 1.22 × 10{sup −2} S/cm in air atmosphere at 650 °C.

  17. Determination of the X-ray structure of the snake venom protein omwaprin by total chemical synthesis and racemic protein crystallography.

    Science.gov (United States)

    Banigan, James R; Mandal, Kalyaneswar; Sawaya, Michael R; Thammavongsa, Vilasak; Hendrickx, Antoni P A; Schneewind, Olaf; Yeates, Todd O; Kent, Stephen B H

    2010-10-01

    The 50-residue snake venom protein L-omwaprin and its enantiomer D-omwaprin were prepared by total chemical synthesis. Radial diffusion assays were performed against Bacillus megaterium and Bacillus anthracis; both L- and D-omwaprin showed antibacterial activity against B. megaterium. The native protein enantiomer, made of L-amino acids, failed to crystallize readily. However, when a racemic mixture containing equal amounts of L- and D-omwaprin was used, diffraction quality crystals were obtained. The racemic protein sample crystallized in the centrosymmetric space group P2(1)/c and its structure was determined at atomic resolution (1.33 A) by a combination of Patterson and direct methods based on the strong scattering from the sulfur atoms in the eight cysteine residues per protein. Racemic crystallography once again proved to be a valuable method for obtaining crystals of recalcitrant proteins and for determining high-resolution X-ray structures by direct methods.

  18. Total replacement of corn by mesquite pod meal considering nutritional value, performance, feeding behavior, nitrogen balance, and microbial protein synthesis of Holstein-Zebu crossbred dairy steers.

    Science.gov (United States)

    de Oliveira Moraes, Gláucia Sabrine; de Souza, Evaristo Jorge Oliveira; Véras, Antonia Sherlânea Chaves; de Paula Almeida, Marina; da Cunha, Márcio Vieira; Torres, Thaysa Rodrigues; da Silva, Camila Sousa; Pereira, Gerfesson Felipe Cavalcanti

    2016-10-01

    The objective of the present study to assess the effects of mesquite pod addition replacing corn (0, 250, 500, 750, and 1000 g/kg in the dry matter basis) on nutrient intake, animal performance, feeding behavior, nutrient digestibility, nitrogen balance, and microbial protein synthesis. Twenty-five Holstein-Zebu crossbred dairy steers at 219 ± 22 kg initial body weight and 18 months of age were used. The experiment lasted 84 days, divided into three periods of 28 days. A completely randomized design was used, and data were submitted to analysis using PROC GLM for analysis of variance and PROC REG for regression analysis using the software Statistical Analysis Systems version 9.1. Experimental diets were composed of Tifton 85 hay, soybean meal, ground corn, mesquite pod meal, and mineral salt. Samples of food offered were collected during the last 3 days of each period, and the leftovers were collected daily, with samples bulked per week. At the end of each 28-day period, the remaining animals were weighed to determine total weight gain and average daily gain. The assessment of behavioral patterns was performed through instantaneous scans in 5-min intervals for three consecutive 12-h days. A single urine sample from each animal was collected on the last day of each collection period at about 4 h after the first feeding. The replacement of corn by mesquite pod meal did not significantly influence treatments regarding nutrients intake, animal performance, and feeding behavior. Retained and consumed nitrogen ratio did not statistically differ between replacement levels. Likewise, there were no statistical differences regarding microbial protein synthesis and efficiency between replacement levels. Mesquite pod meal can be used in Holstein-Zebu crossbred dairy steers' diet with total corn replacement.

  19. Asymmetric catalysis in organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, S.D.; Click, D.R.; Grumbine, S.K.; Scott, B.L.; Watkins, J.G.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of the project was to prepare new catalyst systems, which would perform chemical reactions in an enantioselective manner so as to produce only one of the possible optical isomers of the product molecule. The authors have investigated the use of lanthanide metals bearing both diolate and Schiff-base ligands as catalysts for the enantioselective reduction of prochiral ketones to secondary alcohols. The ligands were prepared from cheap, readily available starting materials, and their synthesis was performed in a ''modular'' manner such that tailoring of specific groups within the ligand could be carried out without repeating the entire synthetic procedure. In addition, they have developed a new ligand system for Group IV and lanthanide-based olefin polymerization catalysts. The ligand system is easily prepared from readily available starting materials and offers the opportunity to rapidly prepare a wide range of closely related ligands that differ only in their substitution patterns at an aromatic ring. When attached to a metal center, the ligand system has the potential to carry out polymerization reactions in a stereocontrolled manner.

  20. Stereocontrolled generation of nucleophilic (Z)- or (E)-α-fluoroalkenylchromium reagents via carbon-fluorine bond activation: highly stereoselective synthesis of (E)- or (Z)-β-fluoroallylic alcohols.

    Science.gov (United States)

    Nihei, Takashi; Yokotani, Saya; Ishihara, Takashi; Konno, Tsutomu

    2014-02-14

    Highly nucleophilic (Z)- or (E)-α-fluoroalkenylchromium species could be generated in a stereoselective manner via C-F bond activation of CBrF2-containing molecules, and they reacted smoothly with various aldehydes to give (E)- or (Z)-β-fluoroallylic alcohol derivatives in high yields, respectively.

  1. Utilization of acidic α-amino acids as acyl donors: an effective stereo-controllable synthesis of aryl-keto α-amino acids and their derivatives.

    Science.gov (United States)

    Wang, Lei; Murai, Yuta; Yoshida, Takuma; Okamoto, Masashi; Tachrim, Zetryana Puteri; Hashidoko, Yasuyuki; Hashimoto, Makoto

    2014-05-16

    Aryl-keto-containing α-amino acids are of great importance in organic chemistry and biochemistry. They are valuable intermediates for the construction of hydroxyl α-amino acids, nonproteinogenic α-amino acids, as well as other biofunctional components. Friedel-Crafts acylation is an effective method to prepare aryl-keto derivatives. In this review, we summarize the preparation of aryl-keto containing α-amino acids by Friedel-Crafts acylation using acidic α-amino acids as acyl-donors and Lewis acids or Brönsted acids as catalysts.

  2. Lipase-catalyzed asymmetric synthesis of naphtho[2,3-c]furan-1(3H)-one derivatives by a one-pot dynamic kinetic resolution/intramolecular Diels-Alder reaction: Total synthesis of (-)-himbacine.

    Science.gov (United States)

    Sugiyama, Koji; Kawanishi, Shinji; Oki, Yasuhiro; Kamiya, Marin; Hanada, Ryosuke; Egi, Masahiro; Akai, Shuji

    2018-04-01

    One-pot sequential reactions using the acyl moieties installed by enzymatic dynamic kinetic resolution of alcohols have been little investigated. In this work, the acryloyl moiety installed via the lipase/oxovanadium combo-catalyzed dynamic kinetic resolution of a racemic dienol [4-(cyclohex-1-en-1-yl)but-3-en-2-ol or 1-(cyclohex-1-en-1-yl)but-2-en-1-ol] with a (Z)-3-(phenylsulfonyl)acrylate underwent an intramolecular Diels-Alder reaction in a one-pot procedure to produce an optically active naphtho[2,3-c]furan-1(3H)-one derivative (98% ee). This method was successfully applied to the asymmetric total synthesis of (-)-himbacine. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Total protein synthesis in elderly people; a comparison of results with (/sup 15/N)glycine and (/sup 14/C)leucine

    Energy Technology Data Exchange (ETDEWEB)

    Golden, M H.N.; Waterlow, J C [London School of Hygiene and Tropical Medicine (UK)

    1977-09-01

    Total body protein turnover was studied in six elderly patients. During the study they were fed by continuous infusion of a liquid formula through a nasogastric tube. L-(1-/sup 14/C)leucine and (/sup 15/N)-glycine were infused at a constant rate for 30 h. The labelled glycine was infused into the intragastric line; the labelled leucine was given either by this route or intravenously. The specific radioactivity of free leucine in plasma and the rate of output of /sup 14/CO/sub 2/ in expired air both reached a plateau at 10 h, and remained constant until the end of the infusion at 30 h. The /sup 15/N abundance in urinary urea and total N was very similar. In neither was a plateau reached by 30 h but in four out of the six patients the abundance in urinary NH/sub 4//sup +/ had attained a plateau by the end of the infusion. Flux rates and rates of protein synthesis were calculated in four ways and a comparison of methods was used to examine the validity of the assumptions on which the different methods depended. The results suggest that the rate of protein turnover is reduced in the elderly, compared with younger subjects.

  4. [Ag67(SPhMe2)32(PPh3)8]3+: Synthesis, Total Structure, and Optical Properties of a Large Box-Shaped Silver Nanocluster

    KAUST Repository

    Alhilaly, Mohammad J.; Bootharaju, Megalamane Siddaramappa; Joshi, Chakra Prasad; Besong, Tabot M.D.; Emwas, Abdul-Hamid M.; Juarez-Mosqueda, Rosalba; Kaappa, Sami; Malola, Sami; Adil, Karim; Shkurenko, Aleksander; Hakkinen, Hannu; Eddaoudi, Mohamed; Bakr, Osman

    2016-01-01

    Engineering the surface ligands of metal nanoparticles is critical in designing unique arrangements of metal atoms. Here, we report the synthesis and total structure determination of a large box-shaped Ag-67 nanocluster (NC) protected by a mixed shell of thiolate (2,4-dimethylbenzenethiolate, SPhMe2) and phosphine (triphenylphosphine, PPh3) ligands. Single crystal X-ray diffraction (SCXRD) and electrospray ionization mass spectrometry (ESI-MS) revealed the cluster formula to be [Ag-67(SPhMe2)(32)(PPh3)(8)](3+). The crystal structure shows an Ag-23 metal core covered by a layer of Ag44S32P8 arranged in the shape of a box. The Ag-13, core was formed through an unprecedented centered cuboctahedron, i.e., Ag-13, unlike the common centered Ag-13 icosahedron geometry. Two types of ligand motifs, eight AgS3P and eight bridging thiols, were found to stabilize the whole cluster. The optical spectrum of this NC displayed highly structured multiple absorption peaks. The electronic structure and optical spectrum of Ag-67 were computed using time-dependent density functional theory (TDDFT) for both the full cluster [Ag-67(SPhMe2)(32)(PPh3)(8)](3+) and a reduced model [Ag-67(SH)(32)(PH3)(8)](3+). The lowest metal-to-metal transitions in the range 500-800 nm could be explained by considering the reduced model that shows almost identical electronic states to 32 free electrons in a jellium box. The successful synthesis of the large box-shaped Ag-67 NC facilitated by the combined use of phosphine and thiol paves the way for synthesizing other metal clusters with unprecedented shapes by judicious choice of thiols and phosphines.

  5. [Ag67(SPhMe2)32(PPh3)8]3+: Synthesis, Total Structure, and Optical Properties of a Large Box-Shaped Silver Nanocluster

    KAUST Repository

    Alhilaly, Mohammad J.

    2016-10-13

    Engineering the surface ligands of metal nanoparticles is critical in designing unique arrangements of metal atoms. Here, we report the synthesis and total structure determination of a large box-shaped Ag-67 nanocluster (NC) protected by a mixed shell of thiolate (2,4-dimethylbenzenethiolate, SPhMe2) and phosphine (triphenylphosphine, PPh3) ligands. Single crystal X-ray diffraction (SCXRD) and electrospray ionization mass spectrometry (ESI-MS) revealed the cluster formula to be [Ag-67(SPhMe2)(32)(PPh3)(8)](3+). The crystal structure shows an Ag-23 metal core covered by a layer of Ag44S32P8 arranged in the shape of a box. The Ag-13, core was formed through an unprecedented centered cuboctahedron, i.e., Ag-13, unlike the common centered Ag-13 icosahedron geometry. Two types of ligand motifs, eight AgS3P and eight bridging thiols, were found to stabilize the whole cluster. The optical spectrum of this NC displayed highly structured multiple absorption peaks. The electronic structure and optical spectrum of Ag-67 were computed using time-dependent density functional theory (TDDFT) for both the full cluster [Ag-67(SPhMe2)(32)(PPh3)(8)](3+) and a reduced model [Ag-67(SH)(32)(PH3)(8)](3+). The lowest metal-to-metal transitions in the range 500-800 nm could be explained by considering the reduced model that shows almost identical electronic states to 32 free electrons in a jellium box. The successful synthesis of the large box-shaped Ag-67 NC facilitated by the combined use of phosphine and thiol paves the way for synthesizing other metal clusters with unprecedented shapes by judicious choice of thiols and phosphines.

  6. Total Synthesis of Plukenetione A

    Science.gov (United States)

    Zhang, Qiang; Mitasev, Branko; Qi, Ji; Porco, John A.

    2010-01-01

    We describe an alkylative dearomatization/acid-mediated adamantane annulation sequence which allows facile access to type A polyprenylated acylphloroglucinol (PPAP) natural products including plukenetione A. Introduction of the 2-methyl-1-propenyl moiety was achieved via stereodivergent SN2 and SN1 cyclizations of allylic alcohol substrates. PMID:20843036

  7. The Total Synthesis of Chlorophyll

    Indian Academy of Sciences (India)

    IAS Admin

    led to the porphyrin14, which when held at 110oC in AcOH afforded the purpurine 15. This is the first example of porphyrin → purpurin change. Indeed Woodward anticipated this because such a change not only makes 7 and 8 tetrahedral, but also relieves the strain around the lower bridge! As the next step, the CH. 2. CH.

  8. The Total Synthesis of Strychnine

    Indian Academy of Sciences (India)

    IAS Admin

    Strychnine! No other molecule has captured the popular imagina- tion as strychnine, perhaps because thousands of writers of fiction have used it to dispatch the recipient and then several have made thrillers using ingenious deduction to catch the perpetrator! Known since the 16th century from the forests including the ...

  9. Total synthesis of amaminol A

    OpenAIRE

    Selkälä, Sami

    2003-01-01

    This thesis includes an extensive review of preparation of bicyclo[4.3.0]nonane derivatives. Bicyclo[4.3.0]nonanes can be prepared by several methods. The most important preparation method of bicyclo[4.3.0]nonanes is intramolecular Diels-Alder cycloaddition (IMDA). Several biologically active natural and unnatural compounds contain bicyclo[4.3.0]nonanes in their molecular framework. The synthetic efforts toward natural compounds such as pulo'upone, isopulo'upone, indanomycin, stawamycin, coch...

  10. Plant sterol ester diet supplementation increases serum plant sterols and markers of cholesterol synthesis, but has no effect on total cholesterol levels.

    Science.gov (United States)

    Weingärtner, Oliver; Bogeski, Ivan; Kummerow, Carsten; Schirmer, Stephan H; Husche, Constanze; Vanmierlo, Tim; Wagenpfeil, Gudrun; Hoth, Markus; Böhm, Michael; Lütjohann, Dieter; Laufs, Ulrich

    2017-05-01

    This double-blind, randomized, placebo-controlled, cross-over intervention-study was conducted in healthy volunteers to evaluate the effects of plant sterol ester supplemented margarine on cholesterol, non-cholesterol sterols and oxidative stress in serum and monocytes. Sixteen volunteers, average age 34 years, with no or mild hypercholesterolemia were subjected to a 4 week period of daily intake of 3g plant sterols per day supplied via a supplemented margarine on top of regular eating habits. After a wash-out period of one week, volunteers switched groups. Compared to placebo, a diet supplementation with plant sterols increased serum levels of plant sterols such as campesterol (+0.16±0.19mg/dL, p=0.005) and sitosterol (+0.27±0.18mg/dL, psynthesis such as desmosterol (+0.05±0.07mg/dL, p=0.006) as well as lathosterol (+0.11±0.16mg/dL, p=0.012). Cholesterol serum levels, however, were not changed significantly (+18.68±32.6mg/dL, p=0.052). These findings could not be verified in isolated circulating monocytes. Moreover, there was no effect on monocyte activation and no differences with regard to redox state after plant sterol supplemented diet. Therefore, in a population of healthy volunteers with no or mild hypercholesterolemia, consumption of plant sterol ester supplemented margarine results in increased concentrations of plant sterols and cholesterol synthesis markers without affecting total cholesterol in the serum, activation of circulating monocytes or redox state. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Total synthesis of a CD-ring: side-chain building block for preparing 17-epi-calcitriol derivatives from the Hajos-Parrish dione.

    Science.gov (United States)

    Michalak, Karol; Wicha, Jerzy

    2011-08-19

    An efficient synthesis of the key building block for 17-epi-calctriol from the Hajos-Parrish dione involving a sequence of diastereoselective transformation of the azulene core and the side-chain construction is presented.

  12. A stereoselective, catalytic strategy for the in-flow synthesis of advanced precursors of rasagiline and tamsulosin.

    Science.gov (United States)

    Brenna, Davide; Pirola, Margherita; Raimondi, Laura; Burke, Anthony J; Benaglia, Maurizio

    2017-12-01

    The diastereoselective, trichlorosilane-mediate reduction of imines, bearing different and removable chiral auxiliaries, in combination either with achiral bases or catalytic amounts of chiral Lewis bases, was investigated to afford immediate precursors of chiral APIs (Active Pharmaceutical Ingredients). The carbon-nitrogen double bond reduction was successfully performed in batch and in flow mode, in high yields and almost complete stereocontrol. By this metal-free approach, the formal synthesis of rasagiline and tamsulosin was successfully accomplished in micro(meso) flow reactors, under continuous flow conditions. The results of these explorative studies represent a new, important step towards the development of automated processes for the preparation of enantiopure biologically active compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Bicyclic Guanidine Catalyzed Asymmetric Tandem Isomerization Intramolecular-Diels-Alder Reaction: The First Catalytic Enantioselective Total Synthesis of (+)-alpha-Yohimbine.

    Science.gov (United States)

    Feng, Wei; Jiang, Danfeng; Kee, Choon-Wee; Liu, Hongjun; Tan, Choon-Hong

    2016-02-04

    Hydroisoquinoline derivatives were prepared in moderate to good enantioselectivities via a bicyclic guanidine-catalyzed tandem isomerization intramolecular-Diels-Alder (IMDA) reaction of alkynes. With this synthetic method, the first enantioselective synthesis of (+)-alpha-yohimbine was completed in 9 steps from the IMDA products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Total synthesis of [2-11C]thymidine from [11C]urea: A tracer of choice for measurement of cellular proliferation using PET

    International Nuclear Information System (INIS)

    Labar, D.; Vander Borght, T.

    1990-01-01

    In preliminary studies of cellular proliferation with [methyl- 11 C]thymidine, the labelled degradative products mask the progressive incorporation of the tracer into DNA. The authors have developed a procedure for the synthesis of [2- 11 C]thymidine to circumvent this difficulty, using a [ 11 C]urea precursor

  15. Peptide synthesis by enzymatic catalysis: new application to the total radiosynthesis of the tritiated leucine-enkephalin hormone, using Y carboxypeptidase

    International Nuclear Information System (INIS)

    Hellio, F.

    1986-01-01

    A new method of enzymatic labelling of peptide hormones is described. The enzyme used, a protease, Y carboxypeptidase is able, in some conditions, to catalyze the formation of peptide bounds. This property has been used for the synthesis of a pentapeptide, the tritiated leucine-enkephalin, with the incorporation of every radioactive amino acid. The specific radioactivity of the labelled molecule is 139 Ci/mmole and its biological properties (receptor binding and immunoreactivity) are identical with native leucine-enkephalin properties [fr

  16. Asymmetric synthesis of α-amino acids via homologation of Ni(II) complexes of glycine Schiff bases. Part 3: Michael addition reactions and miscellaneous transformations.

    Science.gov (United States)

    Aceña, José Luis; Sorochinsky, Alexander E; Soloshonok, Vadim

    2014-09-01

    The major goal of this review is a critical discussion of the literature data on asymmetric synthesis of α-amino acids via Michael addition reactions involving Ni(II)-complexes of amino acids. The material covered is divided into two conceptually different groups dealing with applications of: (a) Ni(II)-complexes of glycine as C-nucleophiles and (b) Ni(II)-complexes of dehydroalanine as Michael acceptors. The first group is significantly larger and consequently subdivided into four chapters based on the source of stereocontrolling element. Thus, a chiral auxiliary can be used as a part of nucleophilic glycine Ni(II) complex, Michael acceptor or both, leading to the conditions of matching vs. mismatching stereochemical preferences. The particular focus of the review is made on the practical aspects of the methodology under discussion and mechanistic considerations.

  17. First Total Synthesis of 4,5-Secoeudesmane-type and Iphionane-type Compounds- Synthesis of 4,5-Dioxo-seco-γ-eudesmol and 5β ,11-Dihydroxyiphionan-4-one

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@ 4, 5-Secoeudesmane-type and iphionane-type compounds are sesquiterpenes with new carbon skeletons found in natrual sources in recent years.1-6 The co-occurence of 4, 5-secoeudesmanes, iphionanes and eudesmanes as natrual products suggests that 4, 5-secoeudesmanes, iphionanes most likely are generated biogenetically from eudesmanes, and iphionanes are formed biogenetically by aldol reaction of 4, 5-dioxosecoeudesmanes1,4,6,7. The study on the synthesis of this two kind of new sesquiterpenes has not been reported in the literature.

  18. Total protein

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003483.htm Total protein To use the sharing features on this page, please enable JavaScript. The total protein test measures the total amount of two classes ...

  19. Imino Diels-Alder-Based Construction of a Piperidine A-Ring Unit for Total Synthesis of the Marine Hepatotoxin Cylindrospermopsin.

    Science.gov (United States)

    Heintzelman, Geoffrey R.; Weinreb, Steven M.; Parvez, Masood

    1996-07-12

    The synthesis of a piperidine A-ring precursor to the alkaloid cylindrospermopsin (1) is described. The initial approach to the A-ring precursor focused on the imino Diels-Alder reaction of diene 8 with ethyl (N-tosylimino)acetate (9) to form the cycloadduct 10 as a single stereoisomer. However, all attempts to convert ester 10 to a requisite diene such as 5 were unsuccessful. An alternative strategy involved the Diels-Alder cycloaddition of N-tosylimine 9 with oxygenated diene 19 under either thermal or Lewis acid-catalyzed conditions to produce a mixture of cis and trans enones 20 and 21. Although the undesired cis-enone 20 was the major product under all reaction conditions, it could be converted to the desired trans enone 21 by acid-catalyzed isomerization. Copper-mediated conjugate addition of vinylmagnesium bromide to cis-enone 20 followed by stereoselective ketone reduction with L-Selectride produced alcohol 23, whose structure was confirmed by X-ray crystallography. Similarly, trans-enone 21 was converted to alcohol 25 whose structure and stereochemistry were also established by X-ray analysis. Alcohol 25 was then protected as the silyl ether 26, which was hydroborated at the terminal olefin to produce primary alcohol ester 28having the stereochemistry and functionality needed for cylindrospermopsin.

  20. Synthesis of 2,6-trans- and 3,3,6-trisubstituted tetrahydropyran-4-ones from Maitland-Japp derived 2H-dihydropyran-4-ones: a total synthesis of diospongin B.

    Science.gov (United States)

    Clarke, Paul A; Nasir, Nadiah Mad; Sellars, Philip B; Peter, Alejandra M; Lawson, Connor A; Burroughs, James L

    2016-07-12

    6-Substituted-2H-dihydropyran-4-one products of the Maitland-Japp reaction have been converted into tetrahydropyrans containing uncommon substitution patterns. Treatment of 6-substituted-2H-dihydropyran-4-ones with carbon nucleophiles led to the formation of tetrahydropyran rings with the 2,6-trans-stereochemical arrangement. Reaction of the same 6-substituted-2H-dihydropyran-4-ones with l-Selectride led to the formation of 3,6-disubstituted tetrahydropyran rings, while trapping of the intermediate enolate with carbon electrophiles in turn led to the formation 3,3,6-trisubstituted tetrahydropyran rings. The relative stereochemical configuration of the new substituents was controlled by the stereoelectronic preference for pseudo-axial addition of the nucleophile and trapping of the enolate from the opposite face. Application of these methods led to a synthesis of the potent anti-osteoporotic diarylheptanoid natural product diospongin B.

  1. The truth about false unicorn (Chamaelirium luteum): total synthesis of 23R,24S-chiograsterol B defines the structure and stereochemistry of the major saponins from this medicinal herb.

    Science.gov (United States)

    Matovic, Nicholas J; Stuthe, Julia M U; Challinor, Victoria L; Bernhardt, Paul V; Lehmann, Reginald P; Kitching, William; De Voss, James J

    2011-06-27

    Chamaelirium luteum is used in traditional medicine systems and commercial botanical dietary supplements for the treatment of female reproductive health problems. Despite the wide use of this herb, only very limited phytochemical characterisation is available. Our investigation of C. luteum roots led to the isolation of two new steroidal saponins 1 and 2 that contain an unusual aglycone 3. The absolute configurations of these molecules were unable to be determined spectroscopically and thus the total synthesis of 3 was undertaken and achieved in 16 steps and 1.6 % overall yield from pregnenolone. The key step in the synthesis was the stereoselective installation of the side chain at C-17 and C-20, which employed anion-accelerated oxy-Cope methodology. The relative configuration of aglycone 3 was determined by X-ray crystallography of an advanced synthetic intermediate. The absolute configuration was based upon that of the pregnenolone-derived steroidal skeleton and determined to be 23R,24S. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Total Synthesis and Stereochemical Assignment of Delavatine A: Rh-Catalyzed Asymmetric Hydrogenation of Indene-Type Tetrasubstituted Olefins and Kinetic Resolution through Pd-Catalyzed Triflamide-Directed C-H Olefination.

    Science.gov (United States)

    Zhang, Zhongyin; Wang, Jinxin; Li, Jian; Yang, Fan; Liu, Guodu; Tang, Wenjun; He, Weiwei; Fu, Jian-Jun; Shen, Yun-Heng; Li, Ang; Zhang, Wei-Dong

    2017-04-19

    Delavatine A (1) is a structurally unusual isoquinoline alkaloid isolated from Incarvillea delavayi. The first and gram-scale total synthesis of 1 was accomplished in 13 steps (the longest linear sequence) from commercially available starting materials. We exploited an isoquinoline construction strategy and developed two reactions, namely Rh-catalyzed asymmetric hydrogenation of indene-type tetrasubstituted olefins and kinetic resolution of β-alkyl phenylethylamine derivatives through Pd-catalyzed triflamide-directed C-H olefination. The substrate scope of the first reaction covered unfunctionalized olefins and those containing polar functionalities such as sulfonamides. The kinetic resolution provided a collection of enantioenriched indane- and tetralin-based triflamides, including those bearing quaternary chiral centers. The selectivity factor (s) exceeded 100 for a number of substrates. These reactions enabled two different yet related approaches to a key intermediate 28 in excellent enantiopurity. In the synthesis, the triflamide served as not only an effective directing group for C-H bond activation but also a versatile functional group for further elaborations. The relative and absolute configurations of delavatine A were unambiguously assigned by the syntheses of the natural product and its three stereoisomers. Their cytotoxicity against a series of cancer cell lines was evaluated.

  3. Rapid formation of complexity in the total synthesis of natural products enabled by oxabicyclo[2.2.1]heptene building blocks.

    Science.gov (United States)

    Schindler, Corinna S; Carreira, Erick M

    2009-11-01

    This critical review showcases examples of rapid formation of complexity in total syntheses starting from 7-oxabicyclo[2.2.1]hept-5-ene derivatives. An overview of methods allowing synthetic access to these building blocks is provided and their application in recently developed synthetic transformations to structurally complex systems is illustrated. In addition, the facile access to a novel oxabicyclo[2.2.1]heptene derived building block is presented which significantly enlarges the possibilities of previously known chemical transformations and is highlighted in the enantioselective route to the core of the banyaside and suomilide natural products (107 references).

  4. Total algorithms

    NARCIS (Netherlands)

    Tel, G.

    We define the notion of total algorithms for networks of processes. A total algorithm enforces that a "decision" is taken by a subset of the processes, and that participation of all processes is required to reach this decision. Total algorithms are an important building block in the design of

  5. Effect of Different Light Intensities on Total Phenolics and Flavonoids Synthesis and Anti-oxidant Activities in Young Ginger Varieties (Zingiber officinale Roscoe)

    Science.gov (United States)

    Ghasemzadeh, Ali; Jaafar, Hawa Z. E.; Rahmat, Asmah; Wahab, Puteri Edaroyati Megat; Halim, Mohd Ridzwan Abd

    2010-01-01

    Nowadays, phytochemicals and antioxidants in plants are raising interest in consumers for their roles in the maintenance of human health. Phenolics and flavonoids are known for their health-promoting properties due to protective effects against cardiovascular disease, cancers and other disease. Ginger (Zingiber officinale) is one of the traditional folk medicinal plants and it is widely used in cooking in Malaysia. In this study, four levels of glasshouse light intensities (310, 460, 630 and 790 μmol m−2s−1) were used in order to consider the effect of light intensity on the production, accumulation and partitioning of total phenolics (TP), total flavonoids (TF) and antioxidant activities in two varieties of Malaysian young ginger (Zingiber officinale). TF biosynthesis was highest in the Halia Bara variety under 310 μmol m−2s−1 and TP was high in this variety under a light intensity of 790 μmol m−2s−1. The highest amount of these components accumulated in the leaves and after that in the rhizomes. Also, antioxidant activities determined by the 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) assay in both of varieties, increased significantly (p ≤ 0.01) with increasing TF concentration, and high antioxidant activity was observed in the leaves of Halia Bara grown under 310 μmol m−2s−1. The ferric reducing (FRAP) activity of the rhizomes was higher than that of the leaves in 310 μmol m−2s−1 of sun light. This study indicates the ability of different light intensities to enhance the medicinal components and antioxidant activities of the leaves and young rhizomes of Zingiber officinale varieties. Additionally, this study also validated their medicinal potential based on TF and TP contents. PMID:21152306

  6. Effect of Different Light Intensities on Total Phenolics and Flavonoids Synthesis and Anti-oxidant Activities in Young Ginger Varieties (Zingiber officinale Roscoe

    Directory of Open Access Journals (Sweden)

    Ali Ghasemzadeh

    2010-10-01

    Full Text Available Nowadays, phytochemicals and antioxidants in plants are raising interest in consumers for their roles in the maintenance of human health. Phenolics and flavonoids are known for their health-promoting properties due to protective effects against cardiovascular disease, cancers and other disease. Ginger (Zingiber officinale is one of the traditional folk medicinal plants and it is widely used in cooking in Malaysia. In this study, four levels of glasshouse light intensities (310, 460, 630 and 790 μmol m−2s−1 were used in order to consider the effect of light intensity on the production, accumulation and partitioning of total phenolics (TP, total flavonoids (TF and antioxidant activities in two varieties of Malaysian young ginger (Zingiber officinale. TF biosynthesis was highest in the Halia Bara variety under 310 μmol m−2s−1 and TP was high in this variety under a light intensity of 790 μmol m−2s−1. The highest amount of these components accumulated in the leaves and after that in the rhizomes. Also, antioxidant activities determined by the 1,1-Diphenyl-2-picryl-hydrazyl (DPPH assay in both of varieties, increased significantly (p ≤ 0.01 with increasing TF concentration, and high antioxidant activity was observed in the leaves of Halia Bara grown under 310 μmol m−2s−1. The ferric reducing (FRAP activity of the rhizomes was higher than that of the leaves in 310 μmol m−2s−1 of sun light. This study indicates the ability of different light intensities to enhance the medicinal components and antioxidant activities of the leaves and young rhizomes of Zingiber officinale varieties. Additionally, this study also validated their medicinal potential based on TF and TP contents.

  7. Totally James

    Science.gov (United States)

    Owens, Tom

    2006-01-01

    This article presents an interview with James Howe, author of "The Misfits" and "Totally Joe". In this interview, Howe discusses tolerance, diversity and the parallels between his own life and his literature. Howe's four books in addition to "The Misfits" and "Totally Joe" and his list of recommended books with lesbian, gay, bisexual, transgender,…

  8. Enantiopure N-Acyldihydropyridones as Synthetic Intermediates: Asymmetric Synthesis of (-)-Septicine and (-)-Tylophorine.

    Science.gov (United States)

    Comins, Daniel L.; Chen, Xinghai; Morgan, Lawrence A.

    1997-10-17

    A concise asymmetric synthesis of (-)-septicine (1) and (-)-tylophorine (2) was accomplished with a high degree of stereocontrol in eight and nine steps, respectively. Addition of 4-(1-butenyl)magnesium bromide to 1-acylpyridinium salt 3, prepared in situ from 4-methoxy-3-(triisopropylsilyl)pyridine and the chloroformate of (-)-trans-2-(alpha-cumyl)cyclohexanol, gave a 91% yield of diastereomerically pure dihydropyridone 7. Oxidative cleavage of 7 and subsequent reduction provided alcohol 6 in 81% yield. Conversion of 6 to the chloride followed by treatment with sodium methoxide gave indolizidinone 9 in high yield. Bromination and conjugate reduction of 9 with L-Selectride, and trapping the intermediate enolate with N-(5-chloro-2-pyridyl)triflimide, provided bromovinyl triflate 11. Palladium-catalyzed cross-coupling of excess (3,4-dimethoxyphenyl)zinc bromide and 11 gave (-)-septicine (1). On the basis of this synthesis, (-)-1 was assigned the Rconfiguration. Reaction of 1 with vanadium(V) trifluoride oxide in TFA/CH(2)Cl(2) effected oxidative coupling to give a 68% yield of (-)-tylophorine (2).

  9. Effects of Synchronization of Carbohydrate and Protein Supply in Total Mixed Ration with Korean Rice Wine Residue on Ruminal Fermentation, Nitrogen Metabolism and Microbial Protein Synthesis in Holstein Steers

    Directory of Open Access Journals (Sweden)

    Min Yu Piao

    2012-11-01

    Full Text Available Three Holstein steers in the growing phase, each with a ruminal cannula, were used to test the hypothesis that the synchronization of the hourly rate of carbohydrate and nitrogen (N released in the rumen would increase the amount of retained nitrogen for growth and thus improve the efficiency of microbial protein synthesis (EMPS. In Experiment 1, in situ degradability coefficients of carbohydrate and N in feeds including Korean rice wine residue (RWR were determined. In Experiment 2, three total mixed ration (TMR diets having different rates of carbohydrate and N release in the rumen were formulated using the in situ degradability of the feeds. All diets were made to contain similar contents of crude protein (CP and neutral detergent fiber (NDF but varied in their hourly pattern of nutrient release. The synchrony index of the three TMRs was 0.51 (LS, 0.77 (MS and 0.95 (HS, respectively. The diets were fed at a restricted level (2% of the animal’s body weight in a 3×3 Latin-square design. Synchronizing the hourly supply of energy and N in the rumen did not significantly alter the digestibility of dry matter, organic matter, crude protein, NDF or acid detergent fiber (ADF (p>0.05. The ruminal NH3-N content of the LS group at three hours after feeding was significantly higher (p0.05. In addition, the purine derivative (PD excretion in urine and microbial-N production (MN among the three groups were not significantly different (p>0.05. In conclusion, synchronizing dietary energy and N supply to the rumen did not have a major effect on nutrient digestion or microbial protein synthesis (MPS in Holstein steers.

  10. The Catalytic Enantioselective Total Synthesis of (+)-Liphagal

    KAUST Repository

    Day, Joshua J.

    2011-06-10

    Ring a ding: The meroterpenoid natural product (+)-liphagal has been synthesized enantioselectively in 19 steps from commercially available materials. The trans-homodecalin system was achieved by ring expansion followed by stereoselective hydrogenation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The enantioselective total synthesis of (+)-clusianone.

    Science.gov (United States)

    Horeischi, Fiene; Guttroff, Claudia; Plietker, Bernd

    2015-02-11

    (+)-Clusianone, an exo-type B PPAP with reported anti-HIV and chemoprotective activities, was synthesized in eleven steps with 97% ee starting from acetylacetone. An enantioselective decarboxylative Tsuji-Trost-allylation and a Ru-catalyzed ring-closing metathesis-decarboxylative allylation were used to control both diastereo- and enantioselectivity.

  12. The Catalytic Enantioselective Total Synthesis of (+)-Liphagal

    KAUST Repository

    Day, Joshua J.; McFadden, Ryan M.; Virgil, Scott C.; Kolding, Helene; Alleva, Jennifer L.; Stoltz, Brian M.

    2011-01-01

    Ring a ding: The meroterpenoid natural product (+)-liphagal has been synthesized enantioselectively in 19 steps from commercially available materials. The trans-homodecalin system was achieved by ring expansion followed by stereoselective hydrogenation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Total synthesis of lactarane and marasmane sesquiterpenes

    NARCIS (Netherlands)

    Bell, R.P.L.

    2000-01-01

    Lactarane and marasmane sesquiterpenes are mostly found in nature as metabolites from mushrooms of the genera Lactarius and Russula . Because a considerable number of these compounds possesses a variety of interesting biological activities, they are

  14. A Modular Approach to Aryl-C-ribonucleosides via the Allylic Substitution and Ring-Closing Metathesis Sequence. A Stereocontrolled Synthesis of All Four alpha-/beta- and D-/L-C-Nucleoside Stereoisomers

    Czech Academy of Sciences Publication Activity Database

    Štambaský, J.; Kapras, V.; Štefko, Martin; Kysilka, O.; Hocek, Michal; Malkov, A. V.; Kočovský, P.

    2011-01-01

    Roč. 76, č. 19 (2011), s. 7781-7803 ISSN 0022-3263 R&D Projects: GA MŠk LC512; GA AV ČR IAA400550902 Institutional research plan: CEZ:AV0Z40550506 Keywords : C-nucleosides * allylic substitution * metathesis * dihydroxylation Subject RIV: CC - Organic Chemistry Impact factor: 4.450, year: 2011

  15. Hamiltonian Algorithm Sound Synthesis

    OpenAIRE

    大矢, 健一

    2013-01-01

    Hamiltonian Algorithm (HA) is an algorithm for searching solutions is optimization problems. This paper introduces a sound synthesis technique using Hamiltonian Algorithm and shows a simple example. "Hamiltonian Algorithm Sound Synthesis" uses phase transition effect in HA. Because of this transition effect, totally new waveforms are produced.

  16. Analogues of amphibian alkaloids: total synthesis of (5R,8S,8aS-(--8-methyl-5-pentyloctahydroindolizine (8-epi-indolizidine 209B and [(1S,4R,9aS-(--4-pentyloctahydro-2H-quinolizin-1-yl]methanol

    Directory of Open Access Journals (Sweden)

    de Koning Charles B

    2008-01-01

    Full Text Available Abstract Background Prior work from these laboratories has centred on the development of enaminones as versatile intermediates for the synthesis of alkaloids and other nitrogen-containing heterocycles. In this paper we describe the enantioselective synthesis of indolizidine and quinolizidine analogues of bicyclic amphibian alkaloids via pyrrolidinylidene- and piperidinylidene-containing enaminones. Results Our previously reported synthesis of racemic 8-epi-indolizidine 209B has been extended to the laevorotatory enantiomer, (--9. Attempts to adapt the synthetic route in order to obtain quinolizidine analogues revealed that a key piperidinylidene-containing enaminone intermediate (+-28 was less tractable than its pyrrolidinylidene counterpart, thereby necessitating modifications that included timing changes and additional protection-deprotection steps. A successful synthesis of [(1S,4R,9aS-4-pentyloctahydro-2H-quinolizin-1-yl]methanol (--41 from the chiral amine tert-butyl (3R-3-{benzyl [(1R-1-phenylethyl]amino}octanoate (+-14 was achieved in 14 steps and an overall yield of 20.4%. Conclusion The methodology reported in this article was successfully applied to the enantioselective synthesis of the title compounds. It paves the way for the total synthesis of a range of cis-5,8-disubstituted indolizidines and cis-1,4-disubstituted quinolizidines, as well as the naturally occurring trans-disubstituted alkaloids.

  17. From synthesis to function via iterative assembly of N-methyliminodiacetic acid boronate building blocks.

    Science.gov (United States)

    Li, Junqi; Grillo, Anthony S; Burke, Martin D

    2015-08-18

    The study and optimization of small molecule function is often impeded by the time-intensive and specialist-dependent process that is typically used to make such compounds. In contrast, general and automated platforms have been developed for making peptides, oligonucleotides, and increasingly oligosaccharides, where synthesis is simplified to iterative applications of the same reactions. Inspired by the way natural products are biosynthesized via the iterative assembly of a defined set of building blocks, we developed a platform for small molecule synthesis involving the iterative coupling of haloboronic acids protected as the corresponding N-methyliminodiacetic acid (MIDA) boronates. Here we summarize our efforts thus far to develop this platform into a generalized and automated approach for small molecule synthesis. We and others have employed this approach to access many polyene-based compounds, including the polyene motifs found in >75% of all polyene natural products. This platform further allowed us to derivatize amphotericin B, the powerful and resistance-evasive but also highly toxic last line of defense in treating systemic fungal infections, and thereby understand its mechanism of action. This synthesis-enabled mechanistic understanding has led us to develop less toxic derivatives currently under evaluation as improved antifungal agents. To access more Csp(3)-containing small molecules, we gained a stereocontrolled entry into chiral, non-racemic α-boryl aldehydes through the discovery of a chiral derivative of MIDA. These α-boryl aldehydes are versatile intermediates for the synthesis of many Csp(3) boronate building blocks that are otherwise difficult to access. In addition, we demonstrated the utility of these types of building blocks in accessing pharmaceutically relevant targets via an iterative Csp(3) cross-coupling cycle. We have further expanded the scope of the platform to include stereochemically complex macrocyclic and polycyclic molecules

  18. Synthesis of Acetylhomoagmatine

    Directory of Open Access Journals (Sweden)

    Carmenza Duque

    2006-08-01

    Full Text Available Abstract: The first total synthesis of acetylhomoagmatine, a natural product isolated form the methanolic extracts from the sponge Cliona celata, is performed in four steps in a very high yield.

  19. Total Thyroidectomy

    Directory of Open Access Journals (Sweden)

    Lopez Moris E

    2016-06-01

    Full Text Available Total thyroidectomy is a surgery that removes all the thyroid tissue from the patient. The suspect of cancer in a thyroid nodule is the most frequent indication and it is presume when previous fine needle puncture is positive or a goiter has significant volume increase or symptomes. Less frequent indications are hyperthyroidism when it is refractory to treatment with Iodine 131 or it is contraindicated, and in cases of symptomatic thyroiditis. The thyroid gland has an important anatomic relation whith the inferior laryngeal nerve and the parathyroid glands, for this reason it is imperative to perform extremely meticulous dissection to recognize each one of these elements and ensure their preservation. It is also essential to maintain strict hemostasis, in order to avoid any postoperative bleeding that could lead to a suffocating neck hematoma, feared complication that represents a surgical emergency and endangers the patient’s life.It is essential to run a formal technique, without skipping steps, and maintain prudence and patience that should rule any surgical act.

  20. Aminodiols via stereocontrolled oxidation of methyleneaziridines.

    Science.gov (United States)

    Rigoli, Jared W; Guzei, Ilia A; Schomaker, Jennifer M

    2014-03-21

    A highly diastereoselective Ru-catalyzed oxidation/reduction sequence of bicyclic methyleneaziridines provides a facile route to complex 1-amino-2,3-diol motifs. The relative anti stereochemistry between the amine and the vicinal alcohol are proposed to result from 1,3-bischelation in the transition state by the C1 and C3 heteroatoms.

  1. A concise synthesis of the cortistatin core

    OpenAIRE

    Dai, Mingji; Danishefsky, Samuel J.

    2008-01-01

    We describe a concise and convergent route to the core matrix of the cortistatin steroidal alkaloids. The salient features of the synthesis are the Snieckus cascade methodology and the Masamune alkylative dearomatization. This chemistry lends itself to a total synthesis of the cortistatins and to the development of a SAR program based on diverted total synthesis.

  2. Níveis de proteína na dieta de bovinos Nelore de três condições sexuais: consumo, digestibilidades total e parcial, produção microbiana e parâmetros ruminais Increasing crude protein levels in diets of Nellore cattle: intake, ruminal and total tract digestibility, microbial protein synthesis, and ruminal metabolism

    Directory of Open Access Journals (Sweden)

    Robson Magno Liberal Véras

    2007-08-01

    .Twelve Nellore cattle fitted with ruminal and duodenal cannulas were used to investigate the effects of increasing dietary crude protein level (7, 10, 13, and 15% on intake, ruminal and total tract digestibility of nutrients, microbial protein synthesis, degradabilities of corn silage, corn starch, and cottonseed meal, and ruminal metabolism. Animals were blocked by sexual category (heifers, bulls and steers averaging 254.8, 285.1, and 265.6 kg of body weight, respectively and then assigned to one out of three Latin squares. Samples were incubated in the rumen of one animal of each sexual category to estimate ingredient degradability after determination of DM, CP and NDF in the incubation residues. Ruminal fluid was collected before and after-feeding to determine pH and concentration of ammonia while ruminal samples for bacterial isolation were taken 6 hours post-feeding. Blood (BUN and urine (UU were also collected for measurement of urea concentration. The degradation rates of DM and CP were both lower in corn silage than on corn starch and cottonseed meal. The interaction sexual condition x dietary crude protein level was not significant for nutrient intake. With the exception of EE and NFC, no other significant effect of dietary CP level was observed for daily intake of nutrients. Increasing dietary CP level affected total tract digestibilities of DM, OM, CP, NDF, and NFC and also resulted in higher concentrations of BUN and UU. A significant dietary crude protein level x collection time interaction was observed for ruminal NH3 but not for ruminal pH. It was concluded that increasing dietary CP levels affected intake and total tract digestibility of most nutrients.

  3. Asymmetric aminolytic kinetic resolution of racemic epoxides using recyclable chiral polymeric Co(III)-salen complexes: a protocol for total utilization of racemic epoxide in the synthesis of (R)-Naftopidil and (S)-Propranolol.

    Science.gov (United States)

    Kumar, Manish; Kureshy, Rukhsana I; Shah, Arpan K; Das, Anjan; Khan, Noor-ul H; Abdi, Sayed H R; Bajaj, Hari C

    2013-09-20

    Chiral polymeric Co(III) salen complexes with chiral ((R)/(S)-BINOL, diethyl tartrate) and achiral (piperazine and trigol) linkers with varying stereogenic centers were synthesized for the first time and used as catalysts for aminolytic kinetic resolution (AKR) of a variety of terminal epoxides and glycidyl ethers to get enantio-pure epoxides (ee, 99%) and N-protected β-amino alcohols (ee, 99%) with quantitative yield in 16 h at RT under optimized reaction conditions. This protocol was also used for the synthesis of two enantiomerically pure drug molecules (R)-Naftopidil (α1-blocker) and (S)-Propranolol (β-blocker) as a key step via AKR of single racemic naphthylglycidyl ether with Boc-protected isoproylamine with 100% epoxide utilization at 1 g level. The catalyst 1 was successfully recycled for a number of times.

  4. Protective effect of a non specific inflammation on bone marrow protein synthesis in irradiated mice

    International Nuclear Information System (INIS)

    Herodin, F.; Roques, P.; Court, L.

    1988-01-01

    Gamma radiations exert a decrease in mouse bone marrow total protein synthesis. A non-specific inflammatory process induced with polyacrylamide microbeads stimulates spleen and marrow protein synthesis and protects the medullar protein synthesis in irradiated mice [fr

  5. Organic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, S.E.

    1991-01-01

    This paper reports on reactions of organoboranes. Organoboron routes to unsaturated hydrocarbons. Boronic ester homologation. Properties of organosilicon compounds. Alkene synthesis (Peterson olefination). Allylsilanes and acylsilanes.

  6. On the effect of small radiation doses: Desoxyribonucleic acid (DNA) synthesis and DNA repair of thymus, spleen, and bone marrow cells in the rat after fractionated total body X-ray irradiation. Zur Wirkung kleiner Strahlendosen: Desoxyribonukleinsaeure-(DNA-)Synthese und DNA-Reparatur von Thymus-, Milz- und Knochenmarkszellen der Ratte nach fraktionierter Ganzkoerperroentgenbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Tempel, K.; Ehling, G. (Muenchen Univ. (Germany, F.R.). Inst. fuer Pharmakologie, Toxikologie und Pharmazie)

    1989-09-01

    After three to seven days following to fractionated total body X-ray irradiation (TBI) (four expositions with doses of 0.3 to 5.0 cGy per fraction at intervals of 24 hours), a maximum 50 percent stimulation of the semiconservative DNA synthesis (SDS) of spleen cells was measured in vitro. This was not dependent of the fact if an acute high-dose (400 and/or 800 cGy) unique irradiation was applied after the fractionated TBI at the moment of stimulation. A significant increase of {sup 3}H-thymidine incorporation into the DNA of bone marrow and thymus cells was only found when doses of 1.25 cGy per fraction had been used. After fractionated TBI with doses of {ge}5 cGy per fraction, an increase of DNA synthesis resistant to hydroxyurea ('unprogrammed' DNA synthesis, UDS) was demonstrated in spleen cells. The UV-simulated UDS decreased proportionately. The sedimentation of thymus, spleen, and bone marrow nucleoids in a neutral saccharose gradient gave no evidence of an increased DNA repair capacity after fractionated TBI. Whereas the SDS stimulation by fractionated TBI with small doses can be explained by a modified proliferation behavior of exposed cells, the UDS behavior of spleen cells after considerably higher radiation doses suggests regenerative processes correlated with an increased number of cells resistant to hydroxyurea and cells presenting an UV repair deficiency. These findings can be considered to be a further proof of the assumed immune-stimulating effect of small radiation doses. (orig.).

  7. Synthesis of sulfadiazine and silver sulfadiazine in semi-micro scale, as an experimental practice in drug synthesis

    International Nuclear Information System (INIS)

    Borges, Aurea Donizete Lanchote; Del Ponte, Gino; Federman Neto, Alberto; Carvalho, Ivone

    2005-01-01

    The total synthesis of sulfadiazine and silver sulfadiazine from readily available starting materials was adapted to semi-micro laboratory scale and is proposed as an experiment in drug synthesis for undergraduate courses. (author)

  8. Organic synthesis

    International Nuclear Information System (INIS)

    Lallemand, J.Y.; Fetizon, M.

    1988-01-01

    The 1988 progress report of the Organic Synthesis Chemistry laboratory (Polytechnic School, France), is presented. The laboratory activities are centered on the chemistry of natural products, which have a biological activity and on the development of new reactions, useful in the organic synthesis. The research works involve the following domains: the natural products chemistry which are applied in pharmacology, the plants and insects chemistry, the organic synthesis, the radical chemistry new reactions and the bio-organic physicochemistry. The published papers, the congress communications and the thesis are listed [fr

  9. Synthesis-on” and “synthesis-off” modes of carbon arc operation during synthesis of carbon nanotubes

    International Nuclear Information System (INIS)

    Yatom, Shurik; Selinsky, Rachel S.

    2017-01-01

    Arc discharge synthesis of single-walled carbon nanotubes (SWCNTs) remains largely uncontrollable, due to incomplete understanding of the synthetic process itself. Here, we show that synthesis of SWCNTs by a carbon arc may not constitute a single continuous process, but may instead consist of two distinct modes. One of these, a “synthesis-on” mode, produces the majority of the nanomaterials. During the synthesis-on mode, proportionally more carbon nanotubes are collected than in another mode, a “synthesis-off” mode. Both synthesis-on and synthesis-off modes for a typical arc configuration, employing a hollow anode filled with a mixture of powdered metal catalyst and graphite, were characterized by using in situ electrical, imaging, and spectroscopic diagnostics, along with ex situ imaging and spectroscopy. The synthesis-on mode duration is rare compared to the total arc run-time, helping to explain the poor selectivity found in the final collected products, a known inadequacy of arc synthesis. Finally, the rarity of the synthesis on mode occurence may be due to the synthesis off mode being more favorable energetically.

  10. Total parenteral nutrition - infants

    Science.gov (United States)

    ... medlineplus.gov/ency/article/007239.htm Total parenteral nutrition - infants To use the sharing features on this page, please enable JavaScript. Total parenteral nutrition (TPN) is a method of feeding that bypasses ...

  11. Total parenteral nutrition

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000177.htm Total parenteral nutrition To use the sharing features on this page, please enable JavaScript. Total parenteral nutrition (TPN) is a method of feeding that bypasses ...

  12. Technique of total thyroidectomy

    International Nuclear Information System (INIS)

    Rao, R.S.

    1999-01-01

    It is essential to define the various surgical procedures that are carried out for carcinoma of the thyroid gland. They are thyroid gland, subtotal lobectomy, total thyroidectomy and near total thyroidectomy

  13. Total iron binding capacity

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003489.htm Total iron binding capacity To use the sharing features on this page, please enable JavaScript. Total iron binding capacity (TIBC) is a blood test to ...

  14. Total well dominated trees

    DEFF Research Database (Denmark)

    Finbow, Arthur; Frendrup, Allan; Vestergaard, Preben D.

    cardinality then G is a total well dominated graph. In this paper we study composition and decomposition of total well dominated trees. By a reversible process we prove that any total well dominated tree can both be reduced to and constructed from a family of three small trees....

  15. Total Radiosynthesis: Thinking outside "the box".

    Science.gov (United States)

    Liang, Steven H; Vasdev, Neil

    2015-09-01

    The logic of total synthesis transformed a stagnant state of medicinal and synthetic organic chemistry when there was a paucity of methods and reagents to synthesize drug molecules and/or natural products. Molecular imaging by positron emission tomography (PET) is now experiencing a renaissance in the way radiopharmaceuticals for molecular imaging are synthesized, however, a paradigm shift is desperately needed in the discovery pipeline to accelerate in vivo imaging studies. A significant challenge in radiochemistry is the limited choice of labeled reagents (or building blocks) available for the synthesis of novel radiopharmaceuticals with the most commonly used short-lived radionuclides carbon-11 ( 11 C; half-life ~20 minutes) and fluorine-18 ( 18 F; half-life ~2 hours). In fact, most drugs cannot be labeled with 11 C or 18 F due to a lack of efficient and diverse radiosynthetic methods. In general, routine radiopharmaceutical production relies on the incorporation of the isotope at the last or penultimate step of synthesis, ideally within one half-life of the radionuclide, to maximize radiochemical yields and specific activities thereby reducing losses due to radioactive decay. Reliance on radiochemistry conducted within the constraints of an automated synthesis unit ("box") has stifled the exploration of multi-step reactions with short-lived radionuclides. Radiopharmaceutical synthesis can be transformed by considering logic of total synthesis to develop novel approaches for 11 C- and 18 F-radiolabeling complex molecules via retrosynthetic analysis and multi-step reactions. As a result of such exploration, new methods, reagents and radiopharmaceuticals for in vivo imaging studies are discovered. A new avenue to develop radiotracers that were previously unattainable due to the lack of efficient radiosynthetic methods is necessary to work towards our ultimate, albeit impossible goal - the concept we term total radiosynthesis - to radiolabel virtually any molecule

  16. First total synthesis and biological evaluation of halolitoralin A

    Directory of Open Access Journals (Sweden)

    RAJIV DAHIYA

    2007-02-01

    Full Text Available A new potent bioactive alanine-rich cyclic hexapeptide halolitoralin A(8, which was previously isolated from the marine sediment-derived bacterial strain Halobacillus litoralis YS3016, has been synthesized by the solution phase technique. All the coupling reactions were performed at room temperature utilizing dicyclohexylcarbodiimide (DCC as the coupling reagent and N-methylmorpholine (NMM as the base. The structure of the peptide was characterized by IR, 1H-NMR, 13C-NMR, FAB MS spectral data, as well as elemental analysis and DSC. The synthesized cyclopeptide was also screened for its antimicrobial and anthelmintic activities and found to exhibit potent antifungal activity against the pathogenic fungi Candida albicans and Trichophyton mentagrophytes along with potent antibacterial activity against the gram negative bacteria Pseudomonas aeruginosa and Escherichia coli. Gram negative bacteria were found to be more sensitive than gram positive bacteria towards the newly synthesized peptide. In addition, the peptide was also found to exhibit moderate anthelmintic activity against the earthworms Megascoplex konkanensis and Eudrilus sp.

  17. Strategy Toward the Total Synthesis of Epothilones A and B

    Science.gov (United States)

    1999-07-01

    would result in the formation of a secondary neopentyl center. Further evidence that the initial step in the annulation sequence is conjugate addition...0.37 mmol) was dissolved in anhydrous benzene (10 mL) and ethylene glycol (2.1 mL, 37 mmol) was added followed by p-toluenesulfonic acid (7 mg, 0.04

  18. Total Synthesis of Dolatrienoic Acid: A Subunit of Dolastatin 14.

    Science.gov (United States)

    Mouné, Sylvie; Niel, Gilles; Busquet, Magali; Eggleston, Ian; Jouin, Patrick

    1997-05-16

    The (7R,15R)- and (7S,15R)-diastereomers of dolatrienoic acid were synthesized using a convergent strategy. Fragment C5-C9 was obtained through enantiodifferentiation of racemic pentane-1,3,5-triol as the key step, fixing the chirality at C7 of fragments 4 and ent-4. The chirality at C15 of the fragment C10-C16 was introduced from L-glutamic acid. Coupling of these two fragments led to the aldehydes (7R,15R)- and (7S,15R)-2 which were homologated by Horner-Wadsworth-Emmons condensation to give (7R,15R)- and (7S,15R)-dolatrienoic acids.

  19. Total Quality Leadership

    Science.gov (United States)

    1991-01-01

    More than 750 NASA, government, contractor, and academic representatives attended the Seventh Annual NASA/Contractors Conference on Quality and Productivity. The panel presentations and Keynote speeches revolving around the theme of total quality leadership provided a solid base of understanding of the importance, benefits, and principles of total quality management (TQM). The presentations from the conference are summarized.

  20. Genoptraening efter total knaealloplastik

    DEFF Research Database (Denmark)

    Holm, Bente; Kehlet, Henrik

    2009-01-01

    The short- and long-term benefits of post-discharge physiotherapy regimens after total knee arthroplasty are debatable. A national survey including hospitals in Denmark that perform total knee arthroplasty showed a large variability in indication and regimen for post-knee arthroplasty...

  1. Laparoscopic total pancreatectomy

    Science.gov (United States)

    Wang, Xin; Li, Yongbin; Cai, Yunqiang; Liu, Xubao; Peng, Bing

    2017-01-01

    Abstract Rationale: Laparoscopic total pancreatectomy is a complicated surgical procedure and rarely been reported. This study was conducted to investigate the safety and feasibility of laparoscopic total pancreatectomy. Patients and Methods: Three patients underwent laparoscopic total pancreatectomy between May 2014 and August 2015. We reviewed their general demographic data, perioperative details, and short-term outcomes. General morbidity was assessed using Clavien–Dindo classification and delayed gastric emptying (DGE) was evaluated by International Study Group of Pancreatic Surgery (ISGPS) definition. Diagnosis and Outcomes: The indications for laparoscopic total pancreatectomy were intraductal papillary mucinous neoplasm (IPMN) (n = 2) and pancreatic neuroendocrine tumor (PNET) (n = 1). All patients underwent laparoscopic pylorus and spleen-preserving total pancreatectomy, the mean operative time was 490 minutes (range 450–540 minutes), the mean estimated blood loss was 266 mL (range 100–400 minutes); 2 patients suffered from postoperative complication. All the patients recovered uneventfully with conservative treatment and discharged with a mean hospital stay 18 days (range 8–24 days). The short-term (from 108 to 600 days) follow up demonstrated 3 patients had normal and consistent glycated hemoglobin (HbA1c) level with acceptable quality of life. Lessons: Laparoscopic total pancreatectomy is feasible and safe in selected patients and pylorus and spleen preserving technique should be considered. Further prospective randomized studies are needed to obtain a comprehensive understanding the role of laparoscopic technique in total pancreatectomy. PMID:28099344

  2. Estonian total ozone climatology

    Directory of Open Access Journals (Sweden)

    K. Eerme

    Full Text Available The climatological characteristics of total ozone over Estonia based on the Total Ozone Mapping Spectrometer (TOMS data are discussed. The mean annual cycle during 1979–2000 for the site at 58.3° N and 26.5° E is compiled. The available ground-level data interpolated before TOMS, have been used for trend detection. During the last two decades, the quasi-biennial oscillation (QBO corrected systematic decrease of total ozone from February–April was 3 ± 2.6% per decade. Before 1980, a spring decrease was not detectable. No decreasing trend was found in either the late autumn ozone minimum or in the summer total ozone. The QBO related signal in the spring total ozone has an amplitude of ± 20 DU and phase lag of 20 months. Between 1987–1992, the lagged covariance between the Singapore wind and the studied total ozone was weak. The spring (April–May and summer (June–August total ozone have the best correlation (coefficient 0.7 in the yearly cycle. The correlation between the May and August total ozone is higher than the one between the other summer months. Seasonal power spectra of the total ozone variance show preferred periods with an over 95% significance level. Since 1986, during the winter/spring, the contribution period of 32 days prevails instead of the earlier dominating 26 days. The spectral densities of the periods from 4 days to 2 weeks exhibit high interannual variability.

    Key words. Atmospheric composition and structure (middle atmosphere – composition and chemistry; volcanic effects – Meteorology and atmospheric dynamics (climatology

  3. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-06-01

    The present discussion is limited to a presentation of the most recent total photonuclear absorption experiments performed with real photons at intermediate energy, and more precisely in the region of nucleon resonances. The main sources of real photons are briefly reviewed and the experimental procedures used for total photonuclear absorption cross section measurements. The main results obtained below 140 MeV photon energy as well as above 2 GeV are recalled. The experimental study of total photonuclear absorption in the nuclear resonance region (140 MeV< E<2 GeV) is still at its beginning and some results are presented

  4. [Total artificial heart].

    Science.gov (United States)

    Antretter, H; Dumfarth, J; Höfer, D

    2015-09-01

    To date the CardioWest™ total artificial heart is the only clinically available implantable biventricular mechanical replacement for irreversible cardiac failure. This article presents the indications, contraindications, implantation procedere and postoperative treatment. In addition to a overview of the applications of the total artificial heart this article gives a brief presentation of the two patients treated in our department with the CardioWest™. The clinical course, postoperative rehabilitation, device-related complications and control mechanisms are presented. The total artificial heart is a reliable implant for treating critically ill patients with irreversible cardiogenic shock. A bridge to transplantation is feasible with excellent results.

  5. SYNTHESIS, HIRSHFELD SURFACE ANALYSES AND ...

    African Journals Online (AJOL)

    2016 Chemical Society of Ethiopia ... We report here the synthesis of a dinuclear Mn(II) complex with mixed co-ligands. The ... The total lattice energy is partitioned .... The χMT value for the complex 1 was 8.51 cm3 K mol−1 at 300 K, and this is ...

  6. Total 2004 results

    International Nuclear Information System (INIS)

    2005-02-01

    This document presents the 2004 results of Total Group: consolidated account, special items, number of shares, market environment, adjustment for amortization of Sanofi-Aventis merger-related intangibles, 4. quarter 2004 results (operating and net incomes, cash flow), upstream (results, production, reserves, recent highlights), downstream (results, refinery throughput, recent highlights), chemicals (results, recent highlights), Total's full year 2004 results (operating and net income, cash flow), 2005 sensitivities, Total SA parent company accounts and proposed dividend, adoption of IFRS accounting, summary and outlook, main operating information by segment for the 4. quarter and full year 2004: upstream (combined liquids and gas production by region, liquids production by region, gas production by region), downstream (refined product sales by region, chemicals), Total financial statements: consolidated statement of income, consolidated balance sheet (assets, liabilities and shareholder's equity), consolidated statements of cash flows, business segments information. (J.S.)

  7. Total 2004 results

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-02-01

    This document presents the 2004 results of Total Group: consolidated account, special items, number of shares, market environment, adjustment for amortization of Sanofi-Aventis merger-related intangibles, 4. quarter 2004 results (operating and net incomes, cash flow), upstream (results, production, reserves, recent highlights), downstream (results, refinery throughput, recent highlights), chemicals (results, recent highlights), Total's full year 2004 results (operating and net income, cash flow), 2005 sensitivities, Total SA parent company accounts and proposed dividend, adoption of IFRS accounting, summary and outlook, main operating information by segment for the 4. quarter and full year 2004: upstream (combined liquids and gas production by region, liquids production by region, gas production by region), downstream (refined product sales by region, chemicals), Total financial statements: consolidated statement of income, consolidated balance sheet (assets, liabilities and shareholder's equity), consolidated statements of cash flows, business segments information. (J.S.)

  8. Genoptraening efter total knaealloplastik

    DEFF Research Database (Denmark)

    Holm, Bente; Kehlet, Henrik

    2009-01-01

    The short- and long-term benefits of post-discharge physiotherapy regimens after total knee arthroplasty are debatable. A national survey including hospitals in Denmark that perform total knee arthroplasty showed a large variability in indication and regimen for post-knee arthroplasty rehabilitat......The short- and long-term benefits of post-discharge physiotherapy regimens after total knee arthroplasty are debatable. A national survey including hospitals in Denmark that perform total knee arthroplasty showed a large variability in indication and regimen for post-knee arthroplasty...... rehabilitation. Since hospital stay duration has decreased considerably, the need for post-discharge physiotherapy may also have changed. Thus, the indication for and types of rehabilitation programmes need to be studied within the context of fast-track knee arthroplasty....

  9. Genoptraening efter total knaealloplastik

    DEFF Research Database (Denmark)

    Holm, Bente; Kehlet, Henrik

    2009-01-01

    The short- and long-term benefits of post-discharge physiotherapy regimens after total knee arthroplasty are debatable. A national survey including hospitals in Denmark that perform total knee arthroplasty showed a large variability in indication and regimen for post-knee arthroplasty rehabilitat......The short- and long-term benefits of post-discharge physiotherapy regimens after total knee arthroplasty are debatable. A national survey including hospitals in Denmark that perform total knee arthroplasty showed a large variability in indication and regimen for post-knee arthroplasty...... rehabilitation. Since hospital stay duration has decreased considerably, the need for post-discharge physiotherapy may also have changed. Thus, the indication for and types of rehabilitation programmes need to be studied within the context of fast-track knee arthroplasty. Udgivelsesdato: 2009-Feb-23...

  10. Supravaginal eller total hysterektomi?

    DEFF Research Database (Denmark)

    Edvardsen, L; Madsen, E M

    1994-01-01

    There has been a decline in the rate of hysterectomies in Denmark in general over the last thirteen years, together with a rise in the number of supravaginal operations over the last two years. The literature concerning the relative merits of the supravaginal and the total abdominal operation is ...... indicate a reduced frequency of orgasm after the total hysterectomy compared with the supravaginal operation. When there are technical problems peroperatively with an increased urologic risk the supravaginal operation is recommended....

  11. Total lymphoid irradiation

    International Nuclear Information System (INIS)

    Sutherland, D.E.; Ferguson, R.M.; Simmons, R.L.; Kim, T.H.; Slavin, S.; Najarian, J.S.

    1983-01-01

    Total lymphoid irradiation by itself can produce sufficient immunosuppression to prolong the survival of a variety of organ allografts in experimental animals. The degree of prolongation is dose-dependent and is limited by the toxicity that occurs with higher doses. Total lymphoid irradiation is more effective before transplantation than after, but when used after transplantation can be combined with pharmacologic immunosuppression to achieve a positive effect. In some animal models, total lymphoid irradiation induces an environment in which fully allogeneic bone marrow will engraft and induce permanent chimerism in the recipients who are then tolerant to organ allografts from the donor strain. If total lymphoid irradiation is ever to have clinical applicability on a large scale, it would seem that it would have to be under circumstances in which tolerance can be induced. However, in some animal models graft-versus-host disease occurs following bone marrow transplantation, and methods to obviate its occurrence probably will be needed if this approach is to be applied clinically. In recent years, patient and graft survival rates in renal allograft recipients treated with conventional immunosuppression have improved considerably, and thus the impetus to utilize total lymphoid irradiation for its immunosuppressive effect alone is less compelling. The future of total lymphoid irradiation probably lies in devising protocols in which maintenance immunosuppression can be eliminated, or nearly eliminated, altogether. Such protocols are effective in rodents. Whether they can be applied to clinical transplantation remains to be seen

  12. Totally optimal decision rules

    KAUST Repository

    Amin, Talha

    2017-11-22

    Optimality of decision rules (patterns) can be measured in many ways. One of these is referred to as length. Length signifies the number of terms in a decision rule and is optimally minimized. Another, coverage represents the width of a rule’s applicability and generality. As such, it is desirable to maximize coverage. A totally optimal decision rule is a decision rule that has the minimum possible length and the maximum possible coverage. This paper presents a method for determining the presence of totally optimal decision rules for “complete” decision tables (representations of total functions in which different variables can have domains of differing values). Depending on the cardinalities of the domains, we can either guarantee for each tuple of values of the function that totally optimal rules exist for each row of the table (as in the case of total Boolean functions where the cardinalities are equal to 2) or, for each row, we can find a tuple of values of the function for which totally optimal rules do not exist for this row.

  13. Totally optimal decision rules

    KAUST Repository

    Amin, Talha M.; Moshkov, Mikhail

    2017-01-01

    Optimality of decision rules (patterns) can be measured in many ways. One of these is referred to as length. Length signifies the number of terms in a decision rule and is optimally minimized. Another, coverage represents the width of a rule’s applicability and generality. As such, it is desirable to maximize coverage. A totally optimal decision rule is a decision rule that has the minimum possible length and the maximum possible coverage. This paper presents a method for determining the presence of totally optimal decision rules for “complete” decision tables (representations of total functions in which different variables can have domains of differing values). Depending on the cardinalities of the domains, we can either guarantee for each tuple of values of the function that totally optimal rules exist for each row of the table (as in the case of total Boolean functions where the cardinalities are equal to 2) or, for each row, we can find a tuple of values of the function for which totally optimal rules do not exist for this row.

  14. Total volume versus bouts

    DEFF Research Database (Denmark)

    Chinapaw, Mai; Klakk, Heidi; Møller, Niels Christian

    2018-01-01

    BACKGROUND/OBJECTIVES: Examine the prospective relationship of total volume versus bouts of sedentary behaviour (SB) and moderate-to-vigorous physical activity (MVPA) with cardiometabolic risk in children. In addition, the moderating effects of weight status and MVPA were explored. SUBJECTS....../METHODS: Longitudinal study including 454 primary school children (mean age 10.3 years). Total volume and bouts (i.e. ≥10 min consecutive minutes) of MVPA and SB were assessed by accelerometry in Nov 2009/Jan 2010 (T1) and Aug/Oct 2010 (T2). Triglycerides, total cholesterol/HDL cholesterol ratio (TC:HDLC ratio......, with or without mutual adjustments between MVPA and SB. The moderating effects of weight status and MVPA (for SB only) were examined by adding interaction terms. RESULTS: Children engaged daily in about 60 min of total MVPA and 0-15 min/week in MVPA bouts. Mean total sedentary time was around 7 h/day with over 3...

  15. Total versus subtotal hysterectomy

    DEFF Research Database (Denmark)

    Gimbel, Helga; Zobbe, Vibeke; Andersen, Anna Birthe

    2005-01-01

    The aim of this study was to compare total and subtotal abdominal hysterectomy for benign indications, with regard to urinary incontinence, postoperative complications, quality of life (SF-36), constipation, prolapse, satisfaction with sexual life, and pelvic pain at 1-year postoperative. Eighty...... women chose total and 105 women chose subtotal abdominal hysterectomy. No significant differences were found between the 2 operation methods in any of the outcome measures at 12 months. Fourteen women (15%) from the subtotal abdominal hysterectomy group experienced vaginal bleeding and three women had...

  16. Qualità totale e mobilità totale Total Quality and Total Mobility

    Directory of Open Access Journals (Sweden)

    Giuseppe Trieste

    2010-05-01

    Full Text Available FIABA ONLUS (Italian Fund for Elimination of Architectural Barriers was founded in 2000 with the aim of promoting a culture of equal opportunities and, above all, it has as its main goal to involve public and private institutions to create a really accessible and usable environment for everyone. Total accessibility, Total usability and Total mobility are key indicators to define quality of life within cities. A supportive environment that is free of architectural, cultural and psychological barriers allows everyone to live with ease and universality. In fact, people who access to goods and services in the urban context can use to their advantage time and space, so they can do their activities and can maintain relationships that are deemed significant for their social life. The main aim of urban accessibility is to raise the comfort of space for citizens, eliminating all barriers that discriminate people, and prevent from an equality of opportunity. “FIABA FUND - City of ... for the removal of architectural barriers” is an idea of FIABA that has already affected many regions of Italy as Lazio, Lombardy, Campania, Abruzzi and Calabria. It is a National project which provides for opening a bank account in the cities of referring, in which for the first time, all together, individuals and private and public institutions can make a donation to fund initiatives for the removal of architectural barriers within its own territory for a real and effective total accessibility. Last February the fund was launched in Rome with the aim of achieving a Capital without barriers and a Town European model of accessibility and usability. Urban mobility is a prerequisite to access to goods and services, and to organize activities related to daily life. FIABA promotes the concept of sustainable mobility for all, supported by the European Commission’s White Paper. We need a cultural change in management and organization of public means, which might focus on

  17. CSF total protein

    Science.gov (United States)

    CSF total protein is a test to determine the amount of protein in your spinal fluid, also called cerebrospinal fluid (CSF). ... The normal protein range varies from lab to lab, but is typically about 15 to 60 milligrams per deciliter (mg/dL) ...

  18. Total body irradiation

    International Nuclear Information System (INIS)

    Novack, D.H.; Kiley, J.P.

    1987-01-01

    The multitude of papers and conferences in recent years on the use of very large megavoltage radiation fields indicates an increased interest in total body, hemibody, and total nodal radiotherapy for various clinical situations. These include high dose total body irradiation (TBI) to destroy the bone marrow and leukemic cells and provide immunosuppression prior to a bone marrow transplant, high dose total lymphoid irradiation (TLI) prior to bone marrow transplantation in severe aplastic anemia, low dose TBI in the treatment of lymphocytic leukemias or lymphomas, and hemibody irradiation (HBI) in the treatment of advanced multiple myeloma. Although accurate provision of a specific dose and the desired degree of dose homogeneity are two of the physicist's major considerations for all radiotherapy techniques, these tasks are even more demanding for large field radiotherapy. Because most large field radiotherapy is done at an extended distance for complex patient geometries, basic dosimetry data measured at the standard distance (isocenter) must be verified or supplemented. This paper discusses some of the special dosimetric problems of large field radiotherapy, with specific examples given of the dosimetry of the TBI program for bone marrow transplant at the authors' hospital

  19. Total design of participation

    DEFF Research Database (Denmark)

    Munch, Anders V.

    2016-01-01

    The idea of design as an art made not only for the people, but also by the people is an old dream going back at least to William Morris. It is, however, reappearing vigoriously in many kinds of design activism and grows out of the visions of a Total Design of society. The ideas of participation b...

  20. Total Quality Management Simplified.

    Science.gov (United States)

    Arias, Pam

    1995-01-01

    Maintains that Total Quality Management (TQM) is one method that helps to monitor and improve the quality of child care. Lists four steps for a child-care center to design and implement its own TQM program. Suggests that quality assurance in child-care settings is an ongoing process, and that TQM programs help in providing consistent, high-quality…

  1. Total Quality Management Seminar.

    Science.gov (United States)

    Massachusetts Career Development Inst., Springfield.

    This booklet is one of six texts from a workplace literacy curriculum designed to assist learners in facing the increased demands of the workplace. The booklet contains seven sections that cover the following topics: (1) meaning of total quality management (TQM); (2) the customer; (3) the organization's culture; (4) comparison of management…

  2. Total photon absorption

    International Nuclear Information System (INIS)

    Carlos, P.

    1985-01-01

    Experimental methods using real photon beams for measurements of total photonuclear absorption cross section σ(Tot : E/sub γ/) are recalled. Most recent σ(Tot : E/sub γ/)results for complex nuclei and in the nucleon resonance region are presented

  3. Total 2004 annual report

    International Nuclear Information System (INIS)

    2004-01-01

    This annual report of the Group Total brings information and economic data on the following topics, for the year 2004: the corporate governance, the corporate social responsibility, the shareholder notebook, the management report, the activities, the upstream (exploration and production) and downstream (refining and marketing) operating, chemicals and other matters. (A.L.B.)

  4. Total Water Management - Report

    Science.gov (United States)

    There is a growing need for urban water managers to take a more holistic view of their water resource systems as population growth, urbanization, and current operations put different stresses on the environment and urban infrastructure. Total Water Management (TWM) is an approac...

  5. Development of a new family of conformationally restricted peptides as potent nucleators of beta-turns. Design, synthesis, structure, and biological evaluation of a beta-lactam peptide analogue of melanostatin.

    Science.gov (United States)

    Palomo, Claudio; Aizpurua, Jesus M; Benito, Ana; Miranda, José Ignacio; Fratila, Raluca M; Matute, Carlos; Domercq, Maria; Gago, Federico; Martin-Santamaria, Sonsoles; Linden, Anthony

    2003-12-31

    Novel enantiopure (i)-(beta-lactam)-(Gly)-(i+3) peptide models, defined by the presence of a central alpha-alkyl-alpha-amino-beta-lactam ring placed as the (i+1) residue, have been synthesized in a totally stereocontrolled way by alpha-alkylation of suitable N-[bis(trimethylsilyl)methyl]-beta-lactams. The structural properties of these beta-lactam pseudopeptides have been studied by X-ray crystallography, Molecular Dynamics simulation, and NOESY-restrained NMR simulated annealing techniques, showing a strong tendency to form stable type II or type II' beta-turns either in the solid state or in highly coordinating DMSO solutions. Tetrapeptide models containing syn- or anti-alpha,beta-dialkyl-alpha-amino-beta-lactam rings have also been synthesized and their conformations analyzed, revealing that alpha-alkyl substitution is essential for beta-turn stabilization. A beta-lactam analogue of melanostatin (PLG amide) has also been prepared, characterized as a type-II beta-turn in DMSO-d6 solution, and tested by competitive binding assay as a dopaminergic D2 modulator in rat neuron cultured cells, displaying moderate agonist activity in the micromolar concentration range. On the basis of these results, a novel peptidomimetic design concept, based on the separation of constraint and recognition elements, is proposed.

  6. Stereocontrolled Introduction of the Quaternary Stereogenic Centre in Lyngbyatoxin A

    DEFF Research Database (Denmark)

    Tønder, Janne Ejrnæs; Tanner, David Ackland

    , a methodology developed by Jung et al(1). For model studies, the requisite vinyl epoxides were obtained by Sharpless asymmetric epoxidation of the corresponding allylic alcohols, followed by a TPAP oxidation and a Wittig reaction. It was observed that the choice of protective group on the indole nitrogen in had...

  7. Remote stereocontrol by sulfinyl groups: reduction of delta-ketosulfoxides.

    Science.gov (United States)

    García Ruano, José L; Fernández-Ibáñez, M Angeles; Maestro, M Carmen; Rodríguez-Fernández, M Mercedes

    2005-03-04

    The reduction of delta-ketosulfoxides constitutes the first evidence of the efficiency of the sulfinyl group to control the stereoselectivity of 1,5-asymmetric induction processes. The use of DIBAL/Yb(OTf)3 or L-Selectride as the reducing agents provides delta-hydroxysulfoxides with the opposite configuration at the hydroxylic carbon in a highly stereoselective way.

  8. Total 2003 Results

    International Nuclear Information System (INIS)

    2003-01-01

    This document presents the 2003 results of Total Group: consolidated account, special items, number of shares, market environment, 4. quarter 2003 results, full year 2003 results, upstream (key figures, proved reserves), downstream key figures, chemicals key figures, parent company accounts and proposed dividends, 2004 sensitivities, summary and outlook, operating information by segment for the 4. quarter and full year 2003: upstream (combined liquids and gas production by region, liquids production by region, gas production by region), downstream (refinery throughput by region, refined product sales by region, chemicals), impact of allocating contribution of Cepsa to net operating income by business segment: equity in income (loss) and affiliates and other items, Total financial statements: consolidated statement of income, consolidated balance sheet (assets, liabilities and shareholder's equity), consolidated statements of cash flows, business segments information. (J.S.)

  9. TOTAL PERFORMANCE SCORECARD

    Directory of Open Access Journals (Sweden)

    Anca ȘERBAN

    2013-06-01

    Full Text Available The purpose of this paper is to present the evolution of the Balanced Scorecard from a measurement instrument to a strategic performance management tool and to highlight the advantages of implementing the Total Performance Scorecard, especially for Human Resource Management. The study has been accomplished using the methodology of bibliographic study and various secondary sources. Implementing the classical Balanced Scorecard indicated over the years, repeatedly failure. It can be indicated that the crucial level is determined by the learning and growth perspective. It has been developed from a human perspective, which focused on staff satisfaction, innovation perspective with focus on future developments. Integrating the Total Performance Scorecard in an overall framework assures the company’s success, by keeping track of the individual goals, the company’s objectives and strategic directions. Like this, individual identity can be linked to corporate brand, individual aspirations to business goals and individual learning objectives to needed organizational capabilities.

  10. Totally parallel multilevel algorithms

    Science.gov (United States)

    Frederickson, Paul O.

    1988-01-01

    Four totally parallel algorithms for the solution of a sparse linear system have common characteristics which become quite apparent when they are implemented on a highly parallel hypercube such as the CM2. These four algorithms are Parallel Superconvergent Multigrid (PSMG) of Frederickson and McBryan, Robust Multigrid (RMG) of Hackbusch, the FFT based Spectral Algorithm, and Parallel Cyclic Reduction. In fact, all four can be formulated as particular cases of the same totally parallel multilevel algorithm, which are referred to as TPMA. In certain cases the spectral radius of TPMA is zero, and it is recognized to be a direct algorithm. In many other cases the spectral radius, although not zero, is small enough that a single iteration per timestep keeps the local error within the required tolerance.

  11. Total space in resolution

    Czech Academy of Sciences Publication Activity Database

    Bonacina, I.; Galesi, N.; Thapen, Neil

    2016-01-01

    Roč. 45, č. 5 (2016), s. 1894-1909 ISSN 0097-5397 R&D Projects: GA ČR GBP202/12/G061 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : total space * resolution random CNFs * proof complexity Subject RIV: BA - General Mathematics Impact factor: 1.433, year: 2016 http://epubs.siam.org/doi/10.1137/15M1023269

  12. MFTF TOTAL benchmark

    International Nuclear Information System (INIS)

    Choy, J.H.

    1979-06-01

    A benchmark of the TOTAL data base management system as applied to the Mirror Fusion Test Facility (MFTF) data base was implemented and run in February and March of 1979. The benchmark was run on an Interdata 8/32 and involved the following tasks: (1) data base design, (2) data base generation, (3) data base load, and (4) develop and implement programs to simulate MFTF usage of the data base

  13. Total - annual report 2005

    International Nuclear Information System (INIS)

    2006-01-01

    This annual report presents the activities and results of TOTAL S.A., french society on oil and gas. It deals with statistics, the managers, key information on financial data and risk factors, information on the Company, unresolved Staff Comments, employees, major Shareholders, consolidated statements, markets, security, financial risks, defaults dividend arrearages and delinquencies, controls and procedures, code of ethics and financial statements. (A.L.B.)

  14. Total Absorption Spectroscopy

    International Nuclear Information System (INIS)

    Rubio, B.; Gelletly, W.

    2007-01-01

    The problem of determining the distribution of beta decay strength (B(GT)) as a function of excitation energy in the daughter nucleus is discussed. Total Absorption Spectroscopy is shown to provide a way of determining the B(GT) precisely. A brief history of such measurements and a discussion of the advantages and disadvantages of this technique, is followed by examples of two recent studies using the technique. (authors)

  15. Sobredentadura total superior implantosoportada

    Directory of Open Access Journals (Sweden)

    Luis Orlando Rodríguez García

    2010-06-01

    Full Text Available Se presenta un caso de un paciente desdentado total superior, rehabilitado en la consulta de implantología de la Clínica "Pedro Ortiz" del municipio Habana del Este en Ciudad de La Habana, Cuba, en el año 2009, mediante prótesis sobre implantes osteointegrados, técnica que se ha incorporado a la práctica estomatológica en Cuba como alternativa al tratamiento convencional en los pacientes desdentados totales. Se siguió un protocolo que comprendió una fase quirúrgica, procedimiento con o sin realización de colgajo y carga precoz o inmediata. Se presenta un paciente masculino de 56 años de edad, que acudió a la consulta multidisciplinaria, preocupado, porque se le habían elaborado tres prótesis en los últimos dos años y ninguna reunía los requisitos de retención que él necesitaba para sentirse seguro y cómodo con las mismas. El resultado final fue la satisfacción total del paciente, con el mejoramiento de la calidad estética y funcional.

  16. Total quality is people

    International Nuclear Information System (INIS)

    Vogel, C.E.

    1991-01-01

    Confronted by changing market conditions and increased global competition, in 1983 the Commercial Nuclear Fuel Division (CNFD) of Westinghouse Electric embarked on an ambitious plan to make total quality the centerpiece of its long-term business strategy. Five years later, the division's efforts in making continuous quality improvement a way of life among its more than 2,000 employees gained national recognition when it was named a charter recipient of the Malcolm Baldridge National Quality Award. What CNFD achieved during the 1980s was a cultural transformation, characterized by an empowered work force committed to a common vision. The company's quality program development strategy is described

  17. Total quality accounting

    Directory of Open Access Journals (Sweden)

    Andrijašević Maja

    2008-01-01

    Full Text Available The focus of competitive "battle" shifted from the price towards non-price instruments, above all, towards quality that became the key variable for profitability increase and achievement of better comparative position of a company. Under such conditions, management of a company, which, according to the established and certified system of total quality, strives towards achieving of a better market position, faces the problem of quality cost measurement and determination. Management, above all, cost accounting can help in solving of this problem, but the question is how much of its potential is being used for that purpose.

  18. Total_Aktion

    DEFF Research Database (Denmark)

    Søndergaard, Morten

    2008-01-01

    digitale medier er registreringen og muligheden for at opbevare og håndtere digital data uden begrænsninger. Oplevelse, registrering og bevaring knyttes sammen i en ny museal virkelighed, hvor samlingens særlige dokumentariske karakter og fokus, som er unikt for Museet for Samtidskunst, er i centrum...... at mikse deres personlige drinks. TOTAL_AKTION viser Hørbar#3, som er en videreudvikling af den første version. METASYN af Carl Emil Carlsen: Metadata er centralt for Carl Emil Carlsens projekt, der betragter museets samling som et ”univers” af værker (analoge og digitale), beskrivelser og relationer. I...

  19. Total Logistic Plant Solutions

    Directory of Open Access Journals (Sweden)

    Dusan Dorcak

    2016-02-01

    Full Text Available The Total Logistics Plant Solutions, plant logistics system - TLPS, based on the philosophy of advanced control processes enables complex coordination of business processes and flows and the management and scheduling of production in the appropriate production plans and planning periods. Main attributes of TLPS is to create a comprehensive, multi-level, enterprise logistics information system, with a certain degree of intelligence, which accepts the latest science and research results in the field of production technology and logistics. Logistic model of company understands as a system of mutually transforming flows of materials, energy, information, finance, which is realized by chain activities and operations

  20. Total Factbook 2003

    International Nuclear Information System (INIS)

    2003-01-01

    This report presents the activities and results of the Group Total-Fina-Elf for the year 2003. It brings information and economic data on the following topics: the corporate and business; the upstream activities with the reserves, the costs, standardized measure and changes of discounted future net cash flow,oil and gas acreage, drilling, liquefied natural gas, pipelines; downstream activities with refining and marketing maps, refinery, petroleum products, sales, retail gasoline outlets; chemicals with sales and operating income by sector, major applications, base chemicals and polymers, intermediates and performance polymers. (A.L.B.)

  1. Total 2004 fact book

    International Nuclear Information System (INIS)

    2004-01-01

    This report presents the activities and results of the Group Total-Fina-Elf for the year 2004. It brings information and economic data on the following topics: the corporate and business; the upstream activities with the reserves, the costs, standardized measure and changes of discounted future net cash flow,oil and gas acreage, drilling, liquefied natural gas, pipelines; downstream activities with refining and marketing maps, refinery, petroleum products, sales, retail gasoline outlets; chemicals with sales and operating income by sector, major applications, base chemicals and polymers, intermediates and performance polymers. (A.L.B.)

  2. TOTAL annual report 2003

    International Nuclear Information System (INIS)

    2004-01-01

    This 2003 annual report of the Group Total provides economical results and information of the society on the following topics: keys data, the corporate governance (Directors charter, board of directors, audit committee, nomination and remuneration committee, internal control procedures, compensation of directors and executive officers), the corporate social responsibility (environmental stewardship, the future of energy management, the safety enhancement, the human resources, ethics and local development), the investor relations, the management report, the upstream exploration and production, the downstream refining, marketing, trading and shipping, the chemicals and financial and legal information. (A.L.B.)

  3. Total knee arthroplasty

    DEFF Research Database (Denmark)

    Schrøder, Henrik M.; Petersen, Michael M.

    2016-01-01

    Total knee arthroplasty (TKA) is a successful treatment of the osteoarthritic knee, which has increased dramatically over the last 30 years. The indication is a painful osteoarthritic knee with relevant radiographic findings and failure of conservative measures like painkillers and exercise...... surgeon seems to positively influence the rate of surgical complications and implant survival. The painful TKA knee should be thoroughly evaluated, but not revised except if a relevant indication can be established. The most frequent indications for revision are: aseptic loosening, instability, infection...

  4. Synthesis of allocolchicinoids: a 50 year journey

    International Nuclear Information System (INIS)

    Sitnikov, N S; Fedorov, A Yu

    2013-01-01

    Published data on the stereo- and enantioselective synthesis of allocolchicinoids, which are of interest as antitumour agents, are summarized. The stereochemistry of these compounds is described. Two key approaches to their preparation are considered, namely, the synthesis from natural colchicine and total synthesis from commercially available reagents. Various total syntheses of N-acetylcolchicinol are performed using biaryl oxidative and reductive coupling, cyclopropanation–ring expansion and Nicholas reaction. The synthetic routes to allocolchicine are based on Diels–Alder cycloaddition, combination of metathesis and Diels–Alder reaction and direct catalytic CH-arylation. Analogues of the colchicine site ligands incorporating heteroaromatic rings are briefly considered; their structural features and methods of synthesis are discussed. The bibliography includes 144 references.

  5. TOTAL user manual

    Science.gov (United States)

    Johnson, Sally C.; Boerschlein, David P.

    1994-01-01

    Semi-Markov models can be used to analyze the reliability of virtually any fault-tolerant system. However, the process of delineating all of the states and transitions in the model of a complex system can be devastatingly tedious and error-prone. Even with tools such as the Abstract Semi-Markov Specification Interface to the SURE Tool (ASSIST), the user must describe a system by specifying the rules governing the behavior of the system in order to generate the model. With the Table Oriented Translator to the ASSIST Language (TOTAL), the user can specify the components of a typical system and their attributes in the form of a table. The conditions that lead to system failure are also listed in a tabular form. The user can also abstractly specify dependencies with causes and effects. The level of information required is appropriate for system designers with little or no background in the details of reliability calculations. A menu-driven interface guides the user through the system description process, and the program updates the tables as new information is entered. The TOTAL program automatically generates an ASSIST input description to match the system description.

  6. Total process surveillance: (TOPS)

    International Nuclear Information System (INIS)

    Millar, J.H.P.

    1992-01-01

    A Total Process Surveillance system is under development which can provide, in real-time, additional process information from a limited number of raw measurement signals. This is achieved by using a robust model based observer to generate estimates of the process' internal states. The observer utilises the analytical reduncancy among a diverse range of transducers and can thus accommodate off-normal conditions which lead to transducer loss or damage. The modular hierarchical structure of the system enables the maximum amount of information to be assimilated from the available instrument signals no matter how diverse. This structure also constitutes a data reduction path thus reducing operator cognitive overload from a large number of varying, and possibly contradictory, raw plant signals. (orig.)

  7. Total and EDF invest

    International Nuclear Information System (INIS)

    Signoret, St.

    2008-01-01

    So as to prepare the future of their industrial sector,the Total company plans to invest (14 billion Euros in 2008) to increase its production capacities and strengthen in of other activities as the liquefied natural gas and the renewable energies; EDF plans to inject 35 billion Euros over three years to multiply the new projects of power plants (wind turbines, coal in Germany, gas in Great Britain and nuclear power in Flamanville). EDF wants to exploit its knowledge of leader to run more than ten E.P.R.(European pressurized water reactor) in the world before 2020, projects are in examination with China, Great Britain, South Africa and United States. (N.C.)

  8. Total quality at source

    International Nuclear Information System (INIS)

    Chiandone, A.C.

    1990-01-01

    The Total Quality at Source philosophy is based on optimizing the effectiveness of people in achieving ZERO-DEFECT results. In this paper a philosophy of what, I have come to perceive, it takes to get people to perform to the very best of their abilities and thereby achieve the best results they can, is presented. In the examples I shall describe I have played an instrumental role since it has become my belief that any job can always be done better provided that the people doing it can themselves become convinced that they can do better. Clearly there are many ideas on how to do this. The philosophy that I am presenting in this paper is based on my own experience, where I have both participated and observed it being applied; its effectiveness may be judged by the results. (author)

  9. Total ankle joint replacement.

    Science.gov (United States)

    2016-02-01

    Ankle arthritis results in a stiff and painful ankle and can be a major cause of disability. For people with end-stage ankle arthritis, arthrodesis (ankle fusion) is effective at reducing pain in the shorter term, but results in a fixed joint, and over time the loss of mobility places stress on other joints in the foot that may lead to arthritis, pain and dysfunction. Another option is to perform a total ankle joint replacement, with the aim of giving the patient a mobile and pain-free ankle. In this article we review the efficacy of this procedure, including how it compares to ankle arthrodesis, and consider the indications and complications. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  10. Synthesis of Polycyclic Natural Products

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tuan Hoang [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    With the continuous advancements in molecular biology and modern medicine, organic synthesis has become vital to the support and extension of those discoveries. The isolations of new natural products allow for the understanding of their biological activities and therapeutic value. Organic synthesis is employed to aid in the determination of the relationship between structure and function of these natural products. The development of synthetic methodologies in the course of total syntheses is imperative for the expansion of this highly interdisciplinary field of science. In addition to the practical applications of total syntheses, the structural complexity of natural products represents a worthwhile challenge in itself. The pursuit of concise and efficient syntheses of complex molecules is both gratifying and enjoyable.

  11. Towards the total synthesis of stawamycin. Synthesis of C11-C21 fragment.

    OpenAIRE

    Dias, LC; Jardim, LSA; Ferreira, AA; Soarez, HU

    2001-01-01

    The carbocyclic (C11-C21) fragment of Stawamycin has been prepared by a sequence involving 11 steps (10% overall yield) from methyl (R)-(-)-3-hydroxy-2-methylpropionate. Key steps are Pd-catalyzed Stille coupling reaction between a vinyl iodide and a vinylstannane followed by an intramolecular Diels-Alder cycloaddition reaction to afford the desired adduct as the major isomer together with three other possible adducts in 78% overall yield. A porção carbocíclica (C11-C21) da Estavamicina fo...

  12. Towards the total synthesis of Stawamycin. Synthesis of C11-C21 fragment

    Directory of Open Access Journals (Sweden)

    Dias Luiz C.

    2001-01-01

    Full Text Available The carbocyclic (C11-C21 fragment of Stawamycin has been prepared by a sequence involving 11 steps (10% overall yield from methyl (R-(--3-hydroxy-2-methylpropionate. Key steps are Pd-catalyzed Stille coupling reaction between a vinyl iodide and a vinylstannane followed by an intramolecular Diels-Alder cycloaddition reaction to afford the desired adduct as the major isomer together with three other possible adducts in 78% overall yield.

  13. Total lymphoid irradiation

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    An outline review notes recent work on total lymphoid irradiation (TLI) as a means of preparing patients for grafts and particularly for bone-marrow transplantation. T.L.I. has proved immunosuppressive in rats, mice, dogs, monkeys and baboons; when given before bone-marrow transplantation, engraftment took place without, or with delayed rejection or graft-versus-host disease. Work with mice has indicated that the thymus needs to be included within the irradiation field, since screening of the thymus reduced skin-graft survival from 50 to 18 days, though irradiation of the thymus alone has proved ineffective. A more lasting tolerance has been observed when T.L.I. is followed by an injection of donor bone marrow. 50% of mice treated in this way accepted allogenic skin grafts for more than 100 days, the animals proving to be stable chimeras with 50% of their peripheral blood lymphocytes being of donor origin. Experiments of a similar nature with dogs and baboons were not so successful. (U.K.)

  14. The total artificial heart.

    Science.gov (United States)

    Cook, Jason A; Shah, Keyur B; Quader, Mohammed A; Cooke, Richard H; Kasirajan, Vigneshwar; Rao, Kris K; Smallfield, Melissa C; Tchoukina, Inna; Tang, Daniel G

    2015-12-01

    The total artificial heart (TAH) is a form of mechanical circulatory support in which the patient's native ventricles and valves are explanted and replaced by a pneumatically powered artificial heart. Currently, the TAH is approved for use in end-stage biventricular heart failure as a bridge to heart transplantation. However, with an increasing global burden of cardiovascular disease and congestive heart failure, the number of patients with end-stage heart failure awaiting heart transplantation now far exceeds the number of available hearts. As a result, the use of mechanical circulatory support, including the TAH and left ventricular assist device (LVAD), is growing exponentially. The LVAD is already widely used as destination therapy, and destination therapy for the TAH is under investigation. While most patients requiring mechanical circulatory support are effectively treated with LVADs, there is a subset of patients with concurrent right ventricular failure or major structural barriers to LVAD placement in whom TAH may be more appropriate. The history, indications, surgical implantation, post device management, outcomes, complications, and future direction of the TAH are discussed in this review.

  15. Protein synthesis in the growing rat lung

    International Nuclear Information System (INIS)

    Kelley, J.; Chrin, L.

    1986-01-01

    Developmental control of protein synthesis in the postnatal growth of the lung has not been systematically studied. In male Fischer 344 rats, lung growth continues linearly as a function of body weight (from 75 to 450 g body weight). To study total protein synthesis in lungs of growing rats, we used the technique of constant intravenous infusion of tritiated leucine, an essential amino acid. Lungs of sacrificed animals were used to determine the leucine incorporation rate into newly synthesized protein. The specific radioactivity of the leucine associated with tRNA extracted from the same lungs served as an absolute index of the precursor leucine pool used for lung protein synthesis. On the basis of these measurements, we were able to calculate the fractional synthesis rate (the proportion of total protein destroyed and replaced each day) of pulmonary proteins for each rat. Under the conditions of isotope infusion, leucyl-tRNA very rapidly equilibrates with free leucine of the plasma and of the extracellular space of the lung. Infusions lasting 30 minutes or less yielded linear rates of protein synthesis without evidence of contamination of lung proteins by newly labeled intravascular albumin. The fractional synthesis rate is considerably higher in juvenile animals (55% per day) than in adult rats (20% per day). After approximately 12 weeks of age, the fractional synthesis rate remains extremely constant in spite of continued slow growth of the lung. It is apparent from these data that in both young and adult rats the bulk of total protein synthesis is devoted to rapidly turning over proteins and that less than 4 percent of newly made protein is committed to tissue growth

  16. Incapacidad laboral total

    Directory of Open Access Journals (Sweden)

    Orlando Díaz Tabares

    1997-04-01

    Full Text Available Se realizó un estudio longitudinal, descriptivo y retrospectivo con el objetivo de conocer el comportamiento de la incapacidad permanente para el trabajo en el municipio "San Cristóbal" durante el decenio 1982-1991, y se aplicó el método de encuesta por el que se recogieron datos que fueron extraídos del modelo oficial de peritaje médico laboral y de la entrevista con el peritado. Los resultados fueron plasmados en tablas de contingencias donde se relacionan las variables por cada año estudiado, y se aplicó la prueba estadística de chi cuadrado. El número de individuos dictaminados con incapacidad laboral total fue de 693; predominó en reportes el año 1988 con 114 casos y muy discretamente el sexo femenino sobre el masculino, el grupo etáreo de 45 a 54 años con 360 casos y la artrosis como entidad valorada por ortopedia, con análisis estadísticos significativos. No resultó estadísticamente significativo, el predominio de la hipertensión arterial sistémica entre las entidades valoradas por la especialidad de medicina interna como causas de incapacidad laboral. Fue muy significativa la variación del número de dictaminados por la comisión en cada uno de los años estudiados y que el porcentaje de ellos que se encontraban realizando trabajos que demandan esfuerzo físico de moderado a intenso al momento de aplicar la encuesta, ascendió al 64,9.A longitudinal, descriptive and retrospective study was conducted in order to know the behavior of permanent labor disability at the municipality of San Cristóbal during 1982-1991. A survey was done to collect data taken from the official model of medical inspections and from the interview with the disabled worker. The results were shown in contingency tables where the variables are related by every year studied. The chi square statistical test was applied. The number of individuals with labor disability was 693. As for reports, the year 1988 predominated with 114. There was a discreet

  17. A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.

    Science.gov (United States)

    Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L

    2015-04-01

    The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.

  18. Fungal Anticancer Metabolites: Synthesis Towards Drug Discovery.

    Science.gov (United States)

    Barbero, Margherita; Artuso, Emma; Prandi, Cristina

    2018-01-01

    Fungi are a well-known and valuable source of compounds of therapeutic relevance, in particular of novel anticancer compounds. Although seldom obtainable through isolation from the natural source, the total organic synthesis still remains one of the most efficient alternatives to resupply them. Furthermore, natural product total synthesis is a valuable tool not only for discovery of new complex biologically active compounds but also for the development of innovative methodologies in enantioselective organic synthesis. We undertook an in-depth literature searching by using chemical bibliographic databases (SciFinder, Reaxys) in order to have a comprehensive insight into the wide research field. The literature has been then screened, refining the obtained results by subject terms focused on both biological activity and innovative synthetic procedures. The literature on fungal metabolites has been recently reviewed and these publications have been used as a base from which we consider the synthetic feasibility of the most promising compounds, in terms of anticancer properties and drug development. In this paper, compounds are classified according to their chemical structure. This review summarizes the anticancer potential of fungal metabolites, highlighting the role of total synthesis outlining the feasibility of innovative synthetic procedures that facilitate the development of fungal metabolites into drugs that may become a real future perspective. To our knowledge, this review is the first effort to deal with the total synthesis of these active fungi metabolites and demonstrates that total chemical synthesis is a fruitful means of yielding fungal derivatives as aided by recent technological and innovative advancements. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. Total Radiosynthesis: Thinking outside “the box”

    OpenAIRE

    Liang, Steven H.; Vasdev, Neil

    2015-01-01

    The logic of total synthesis transformed a stagnant state of medicinal and synthetic organic chemistry when there was a paucity of methods and reagents to synthesize drug molecules and/or natural products. Molecular imaging by positron emission tomography (PET) is now experiencing a renaissance in the way radiopharmaceuticals for molecular imaging are synthesized, however, a paradigm shift is desperately needed in the discovery pipeline to accelerate in vivo imaging studies. A significant cha...

  20. Total syntheses of Prelactone V and Prelactone B.

    Science.gov (United States)

    Raghavendra, S; Tadiparthi, Krishnaji; Yadav, J S

    2017-04-10

    The total syntheses of natural products Prelactone-V and Prelactone-B have been accomplished by a novel Chiron approach starting from d-glucose. The synthesis involves isopropylidene acetal formation of d-glucose using Poly(4-vinylpyridine) supported iodine as a catalyst, Tebbe olefination, Grignard reaction, Wittig olefination, selective mono deprotection of acetal using PMA/SiO 2 , hydrogenation and anti-1,3-diol formation are as key steps. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. The Interpretation of Cholesterol Balance Derived Synthesis Data and Surrogate Noncholesterol Plasma Markers for Cholesterol Synthesis under Lipid Lowering Therapies

    Directory of Open Access Journals (Sweden)

    Frans Stellaard

    2017-01-01

    Full Text Available The cholesterol balance procedure allows the calculation of cholesterol synthesis based on the assumption that loss of endogenous cholesterol via fecal excretion and bile acid synthesis is compensated by de novo synthesis. Under ezetimibe therapy hepatic cholesterol is diminished which can be compensated by hepatic de novo synthesis and hepatic extraction of plasma cholesterol. The plasma lathosterol concentration corrected for total cholesterol concentration (R_Lath as a marker of de novo cholesterol synthesis is increased during ezetimibe treatment but unchanged under treatment with ezetimibe and simvastatin. Cholesterol balance derived synthesis data increase during both therapies. We hypothesize the following. (1 The cholesterol balance data must be applied to the hepatobiliary cholesterol pool. (2 The calculated cholesterol synthesis value is the sum of hepatic de novo synthesis and the net plasma—liver cholesterol exchange rate. (3 The reduced rate of biliary cholesterol absorption is the major trigger for the regulation of hepatic cholesterol metabolism under ezetimibe treatment. Supportive experimental and literature data are presented that describe changes of cholesterol fluxes under ezetimibe, statin, and combined treatments in omnivores and vegans, link plasma R_Lath to liver function, and define hepatic de novo synthesis as target for regulation of synthesis. An ezetimibe dependent direct hepatic drug effect cannot be excluded.

  2. Gene Synthesis with H G Khorana

    Indian Academy of Sciences (India)

    IAS Admin

    student with Robert Letsinger at Northwestern University and had written to Gobind about a ... range aim must be the development of methods for the total synthesis of ... There is a good deal of evidence now to suggest that in addition to a.

  3. Synthesis and Identification of Selected Impurities

    Energy Technology Data Exchange (ETDEWEB)

    Zhiqiang, Zhou [Department of Applied Chemistry, China Agricultural University, Beijing (China)

    2009-07-15

    Non-active substances undesired, but often unavoidable compounds accompanying target active ingredients in various pesticide formulations have been synthesized for supporting product registration and evaluation of the total toxicological and physicochemical properties of formulated products. The synthesis and structural characterization of various impurities of pesticide active ingredients are described and illustrated by IR, NMR, GC and GC/MS data. (author)

  4. Synthesis of (+)-Antroquinonol: An Antihyperglycemic Agent.

    Science.gov (United States)

    Sulake, Rohidas S; Lin, Hsiao-Han; Hsu, Chia-Yu; Weng, Ching-Feng; Chen, Chinpiao

    2015-06-19

    The total synthesis of antroquinonol has been accomplished through Suzuki-Miyaura cross-coupling and Barton-McCombie reaction, and the α,β-unsaturation was achieved through selenylation and oxidation protocols. In vitro and in vivo studies on the glucose-lowering properties of antroquinonol indicate that it is a potential antidiabetic agent.

  5. Total Site Heat Integration Considering Pressure Drops

    Directory of Open Access Journals (Sweden)

    Kew Hong Chew

    2015-02-01

    Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

  6. Fluorometric determination of free and total isocitrate in bovine milk

    DEFF Research Database (Denmark)

    Larsen, Torben

    2014-01-01

    Isocitrate is an intermediate metabolite in the citric acid cycle found both inside the mitochondria as well as outside in the cytosolic shunt. Oxidation of isocitrate is believed to deliver large fractions of energy [i.e., reducing equivalents (NADPH) in the bovine udder] used for fatty acid...... and cholesterol synthesis. This study describes a new analytical method for determination of free and total isocitrate in bovine milk where time-consuming pretreatment of the sample is not necessary. Methods for estimation of both total isocitrate and free isocitrate are described, the difference being...

  7. Total Radiosynthesis: Thinking outside “the box”

    Science.gov (United States)

    Liang, Steven H.; Vasdev, Neil

    2016-01-01

    The logic of total synthesis transformed a stagnant state of medicinal and synthetic organic chemistry when there was a paucity of methods and reagents to synthesize drug molecules and/or natural products. Molecular imaging by positron emission tomography (PET) is now experiencing a renaissance in the way radiopharmaceuticals for molecular imaging are synthesized, however, a paradigm shift is desperately needed in the discovery pipeline to accelerate in vivo imaging studies. A significant challenge in radiochemistry is the limited choice of labeled reagents (or building blocks) available for the synthesis of novel radiopharmaceuticals with the most commonly used short-lived radionuclides carbon-11 (11C; half-life ~20 minutes) and fluorine-18 (18F; half-life ~2 hours). In fact, most drugs cannot be labeled with 11C or 18F due to a lack of efficient and diverse radiosynthetic methods. In general, routine radiopharmaceutical production relies on the incorporation of the isotope at the last or penultimate step of synthesis, ideally within one half-life of the radionuclide, to maximize radiochemical yields and specific activities thereby reducing losses due to radioactive decay. Reliance on radiochemistry conducted within the constraints of an automated synthesis unit (“box”) has stifled the exploration of multi-step reactions with short-lived radionuclides. Radiopharmaceutical synthesis can be transformed by considering logic of total synthesis to develop novel approaches for 11C- and 18F-radiolabeling complex molecules via retrosynthetic analysis and multi-step reactions. As a result of such exploration, new methods, reagents and radiopharmaceuticals for in vivo imaging studies are discovered. A new avenue to develop radiotracers that were previously unattainable due to the lack of efficient radiosynthetic methods is necessary to work towards our ultimate, albeit impossible goal – the concept we term total radiosynthesis - to radiolabel virtually any molecule

  8. Comparison of Serum Concentrations of Total Cholesterol and Total ...

    African Journals Online (AJOL)

    Tuberculosis (TB) is one of the most dangerous tropical diseases that complicates HIV infection in Nigeria to date. Over two million Nigerians are known to be infected with TB and many more are at risk of the infection. Serum concentrations of total cholesterol and total lipid of 117 female TB patients attending chest clinic at ...

  9. Changes in total and differential white cell counts, total lymphocyte ...

    African Journals Online (AJOL)

    Background: Published reports on the possible changes in the various immune cell populations, especially the total lymphocyte and CD4 cell counts, during the menstrual cycle in Nigerian female subjects are relatively scarce. Aim: To determine possible changes in the total and differential white blood cell [WBC] counts, ...

  10. In vivo determination of arterial collagen synthesis in atherosclerotic rabbits

    International Nuclear Information System (INIS)

    Opsahl, W.P.; DeLuca, D.J.; Ehrhart, L.A.

    1986-01-01

    Collagen and non-collagen protein synthesis rates were determined in vivo in tissues from rabbits fed a control or atherogenic diet supplemented with 2% peanut oil and 0.25% cholesterol for 4 months. Rabbits received a bolus intravenous injection of L-[ 3 H]-proline (1.0 mCi/kg) and unlabeled L-proline (7 mmoles/kg) in 0.9% NaCl. Plasma proline specific activity decreased only 20% over 5 hr and was similar to the specific activity of free proline in tissues. Thoracic aortas from atherosclerotic rabbits exhibited raised plaques covering at least 75% of the surface. Thoracic intima plus a portion of the media (TIM) was separated from the remaining media plus adventitia (TMA). Dry delipidated weight, total collagen content, and collagen as a percent of dry weight were increased significantly in the TIM of atherosclerotic rabbits. Collagen synthesis rates and collagen synthesis as a percent of total protein synthesis were likewise increased both in the TIM and in the abdominal aortas. No differences from controls either in collagen content or collagen synthesis rates were observed in the TMA, lung or skin. These results demonstrate for the first time in vivo that formation of atherosclerotic plaques is associated with increased rates of collagen synthesis. Furthermore, as previously observed with incubations in vitro, collagen synthesis was elevated to a greater extent than noncollagen protein synthesis in atherosclerotic aortas from rabbits fed cholesterol plus peanut oil

  11. N-acetylcysteine stimulates protein synthesis in enterocytes independently of glutathione synthesis.

    Science.gov (United States)

    Yi, Dan; Hou, Yongqing; Wang, Lei; Long, Minhui; Hu, Shengdi; Mei, Huimin; Yan, Liqiong; Hu, Chien-An Andy; Wu, Guoyao

    2016-02-01

    Dietary supplementation with N-acetylcysteine (NAC) has been reported to improve intestinal health and treat gastrointestinal diseases. However, the underlying mechanisms are not fully understood. According to previous reports, NAC was thought to exert its effect through glutathione synthesis. This study tested the hypothesis that NAC enhances enterocyte growth and protein synthesis independently of cellular glutathione synthesis. Intestinal porcine epithelial cells were cultured for 3 days in Dulbecco's modified Eagle medium containing 0 or 100 μM NAC. To determine a possible role for GSH (the reduced form of glutathione) in mediating the effect of NAC on cell growth and protein synthesis, additional experiments were conducted using culture medium containing 100 μM GSH, 100 μM GSH ethyl ester (GSHee), diethylmaleate (a GSH-depletion agent; 10 μM), or a GSH-synthesis inhibitor (buthionine sulfoximine, BSO; 20 μM). NAC increased cell proliferation, GSH concentration, and protein synthesis, while inhibiting proteolysis. GSHee enhanced cell proliferation and GSH concentration without affecting protein synthesis but inhibited proteolysis. Conversely, BSO or diethylmaleate reduced cell proliferation and GSH concentration without affecting protein synthesis, while promoting protein degradation. At the signaling level, NAC augmented the protein abundance of total mTOR, phosphorylated mTOR, and phosphorylated 70S6 kinase as well as mRNA levels for mTOR and p70S6 kinase in IPEC-1 cells. Collectively, these results indicate that NAC upregulates expression of mTOR signaling proteins to stimulate protein synthesis in enterocytes independently of GSH generation. Our findings provide a hitherto unrecognized biochemical mechanism for beneficial effects of NAC in intestinal cells.

  12. Total hip arthroplasty in Denmark

    DEFF Research Database (Denmark)

    Pedersen, Alma Becic; Johnsen, Søren Paaske; Overgaard, Søren

    2005-01-01

    The annual number of total hip arthroplasties (THA) has increased in Denmark over the past 15 years. There is, however, limited detailed data available on the incidence of THAs.......The annual number of total hip arthroplasties (THA) has increased in Denmark over the past 15 years. There is, however, limited detailed data available on the incidence of THAs....

  13. Congruences of totally geodesic surfaces

    International Nuclear Information System (INIS)

    Plebanski, J.F.; Rozga, K.

    1989-01-01

    A general theory of congruences of totally geodesic surfaces is presented. In particular their classification, based on the properties of induced affine connections, is provided. In the four-dimensional case canonical forms of the metric tensor admitting congruences of two-dimensional totally geodesic surfaces of rank one are given. Finally, congruences of two-dimensional extremal surfaces are studied. (author)

  14. Accelerating spirocyclic polyketide synthesis using flow chemistry.

    Science.gov (United States)

    Newton, Sean; Carter, Catherine F; Pearson, Colin M; de C Alves, Leandro; Lange, Heiko; Thansandote, Praew; Ley, Steven V

    2014-05-05

    Over the past decade, the integration of synthetic chemistry with flow processing has resulted in a powerful platform for molecular assembly that is making an impact throughout the chemical community. Herein, we demonstrate the extension of these tools to encompass complex natural product synthesis. We have developed a number of novel flow-through processes for reactions commonly encountered in natural product synthesis programs to achieve the first total synthesis of spirodienal A and the preparation of spirangien A methyl ester. Highlights of the synthetic route include an iridium-catalyzed hydrogenation, iterative Roush crotylations, gold-catalyzed spiroketalization and a late-stage cis-selective reduction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Asymmetric synthesis II more methods and applications

    CERN Document Server

    Christmann, Mathias

    2012-01-01

    After the overwhelming success of 'Asymmetric Synthesis - The Essentials', narrating the colorful history of asymmetric synthesis, this is the second edition with latest subjects and authors. While the aim of the first edition was mainly to honor the achievements of the pioneers in asymmetric syntheses, the aim of this new edition was bringing the current developments, especially from younger colleagues, to the attention of students. The format of the book remained unchanged, i.e. short conceptual overviews by young leaders in their field including a short biography of the authors. The growing multidisciplinary research within chemistry is reflected in the selection of topics including metal catalysis, organocatalysis, physical organic chemistry, analytical chemistry, and its applications in total synthesis. The prospective reader of this book is a graduate or undergraduate student of advanced organic chemistry as well as the industrial chemist who wants to get a brief update on the current developments in th...

  16. Totality eclipses of the Sun

    CERN Document Server

    Littmann, Mark; Willcox, Ken

    2008-01-01

    A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. - ;A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. Totality: Eclipses of the Sun is the best guide and reference book on solar eclipses ever written. It explains: how to observe them; how to photograph and videotape them; why they occur; their history and mythology; and future eclipses - when and where to see them. Totality also tells the remarkable story of how eclipses shocked scientists, revealed the workings of the Sun, and made Einstein famous. And the book shares the experiences and advice of many veteran eclipse observers. Totality: Eclipses of the Sun is profusely ill...

  17. Synthesis of Mechanisms

    DEFF Research Database (Denmark)

    Hansen, John Michael

    1999-01-01

    These notes describe an automated procedure for analysis and synthesis of mechanisms. The analysis method is based on the body coordinate formulation, and the synthesis is based on applying optimization methods, used to minimize the difference between an actual and a desired behaviour...

  18. Synthesis of oligonucleotide phosphorodithioates

    DEFF Research Database (Denmark)

    Beaton, G.; Brill, W. K D; Grandas, A.

    1991-01-01

    The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described.......The synthesis of DNA containing sulfur at the two nonbonding internucleotide valencies is reported. Several different routes using either tervalent or pentavalent mononucleotide synthons are described....

  19. Synthesis of Isoiminosugars

    DEFF Research Database (Denmark)

    Hyldtoft, Lene; Godskesen, Michael Anders; Lundt, Inge

    1998-01-01

    A short synthesis of isoiminosugars have been developed. Bromolactones are diastereoselectively alkylated at C-2 followed by ring closure to the corresponding lactams. Reduction of these then gives isoiminosugars......A short synthesis of isoiminosugars have been developed. Bromolactones are diastereoselectively alkylated at C-2 followed by ring closure to the corresponding lactams. Reduction of these then gives isoiminosugars...

  20. Integrated biofuels process synthesis

    DEFF Research Database (Denmark)

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

    2017-01-01

    Second and third generation bioethanol and biodiesel are more environmentally friendly fuels than gasoline and petrodiesel, andmore sustainable than first generation biofuels. However, their production processes are more complex and more expensive. In this chapter, we describe a two-stage synthesis......% used for bioethanol process), and steam and electricity from combustion (54%used as electricity) in the bioethanol and biodiesel processes. In the second stage, we saved about 5% in equipment costs and 12% in utility costs for bioethanol separation. This dual synthesis methodology, consisting of a top......-level screening task followed by a down-level intensification task, proved to be an efficient methodology for integrated biofuel process synthesis. The case study illustrates and provides important insights into the optimal synthesis and intensification of biofuel production processes with the proposed synthesis...

  1. VHDL for logic synthesis

    CERN Document Server

    Rushton, Andrew

    2011-01-01

    Many engineers encountering VHDL (very high speed integrated circuits hardware description language) for the first time can feel overwhelmed by it. This book bridges the gap between the VHDL language and the hardware that results from logic synthesis with clear organisation, progressing from the basics of combinational logic, types, and operators; through special structures such as tristate buses, register banks and memories, to advanced themes such as developing your own packages, writing test benches and using the full range of synthesis types. This third edition has been substantially rewritten to include the new VHDL-2008 features that enable synthesis of fixed-point and floating-point hardware. Extensively updated throughout to reflect modern logic synthesis usage, it also contains a complete case study to demonstrate the updated features. Features to this edition include: * a common VHDL subset which will work across a range of different synthesis systems, targeting a very wide range of technologies...

  2. Total Product Life Cycle (TPLC)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Total Product Life Cycle (TPLC) database integrates premarket and postmarket data about medical devices. It includes information pulled from CDRH databases...

  3. Nutritional management after total laryngectomy

    African Journals Online (AJOL)

    28 September 2010 with a known diagnosis of cancer of the larynx. The patient, who underwent a total laryngectomy on 13 October, had a tracheostomy inserted .... status, leading to improved quality of life and better response to treatment.4.

  4. Catalytic asymmetric synthesis of enantiopure isoprenoid building blocks : application in the synthesis of apple leafminer pheromones

    NARCIS (Netherlands)

    Summeren, Ruben P. van; Reijmer, Sven J.W.; Minnaard, Adriaan J.; Feringa, Bernard

    2005-01-01

    The first catalytic asymmetric procedure capable of preparing all 4 diastereoisomers (ee > 99%, de > 98%) of a versatile saturated isoprenoid building block was developed and the value of this new method was demonstrated in its application to the concise total synthesis of two pheromones.

  5. Transmandibular approach to total maxillectomy

    OpenAIRE

    Tiwari, R. M.

    2001-01-01

    Total Maxillectomy through transfacial approach has been practiced in the treatment of Cancer for more than a decade. Its role in T3 - T4 tumors extending posteriorly through gthe bony wall is questionable, since an oncological radical procedure is often not possible. Recurrences in the infratemporal fossa are common. Despite the addition of radiotherapy five year survivals have not significantly improved. Transmandibular approach to Total Maxillectomy overcomes this shortcoming by including ...

  6. Leadership and Total Quality Management

    Science.gov (United States)

    1992-04-15

    leadership and management skills yields increased productivity. This paper will focus on the skills required of senior level leaders (leaders at the...publication until it has been cleared by the appropriate mii..-, service or government agency. Leadership and Total Quality Management An Individual Study...llty Codes fAvti1 and/or DltISpecial Abstract AUTHOR: Harry D. Gatanas, LTC, USA TITLE: Leadership and Total Quality Management FORMAT- Individual

  7. Total body water and total body potassium in anorexia nervosa

    Energy Technology Data Exchange (ETDEWEB)

    Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

    1984-08-01

    In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation.

  8. Total body water and total body potassium in anorexia nervosa

    International Nuclear Information System (INIS)

    Dempsey, D.T.; Crosby, L.O.; Lusk, E.; Oberlander, J.L.; Pertschuk, M.J.; Mullen, J.L.

    1984-01-01

    In the ill hospitalized patient with clinically relevant malnutrition, there is a measurable decrease in the ratio of the total body potassium to total body water (TBK/TBW) and a detectable increase in the ratio of total exchangeable sodium to total exchangeable potassium (Nae/Ke). To evaluate body composition analyses in anorexia nervosa patients with chronic uncomplicated semistarvation, TBK and TBW were measured by whole body K40 counting and deuterium oxide dilution in 10 females with stable anorexia nervosa and 10 age-matched female controls. The ratio of TBK/TBW was significantly (p less than 0.05) higher in anorexia nervosa patients than controls. The close inverse correlation found in published studies between TBK/TBW and Nae/Ke together with our results suggest that in anorexia nervosa, Nae/Ke may be low or normal. A decreased TBK/TBW is not a good indicator of malnutrition in the anorexia nervosa patient. The use of a decreased TBK/TBW ratio or an elevated Nae/Ke ratio as a definition of malnutrition may result in inappropriate nutritional management in the patient with severe nonstressed chronic semistarvation

  9. Total 2004 annual report; TOTAL 2004 rapport annuel

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This annual report of the Group Total brings information and economic data on the following topics, for the year 2004: the corporate governance, the corporate social responsibility, the shareholder notebook, the management report, the activities, the upstream (exploration and production) and downstream (refining and marketing) operating, chemicals and other matters. (A.L.B.)

  10. Oxidative allene amination for the synthesis of azetidin-3-ones.

    Science.gov (United States)

    Burke, Eileen G; Schomaker, Jennifer M

    2015-10-05

    Regioselectivity in the aziridination of silyl-substituted homoallenic sulfamates is readily diverted to the distal double bond of the allene to yield endocyclic bicyclic methyleneaziridines with excellent stereocontrol. Subsequent reaction with electrophilic oxygen sources initiates facile rearrangement to densely functionalized, fused azetidin-3-ones in excellent d.r., effectively transferring the axial chirality of the allene to central chirality in the products. The steric nature of the silyl group dictates which of the two rings of the fused azetidin-3-one will undergo further functionalization, providing an additional element of diversity for the preparation of enantioenriched azetidine scaffolds with potential biological activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Enantiospecific Synthesis of Trisubstituted Butyrolactone Natural Products and Their Analogs.

    Science.gov (United States)

    Sibi, Mukund P.; Lu, Jianliang; Talbacka, Chelsy L.

    1996-11-01

    A general methodology for the synthesis of highly substituted butyrolactones in enantiomerically pure form has been developed. The application of this process in a highly efficient synthesis of lactone natural products blastmycinone (1), NFX-2 (2), antimycinone (3), and NFX-4 (4) and two lipid metabolites (5, 6) are described. Additionally, the total synthesis of 5-epi-blastmycinone (22), 5-epi-NFX-2 (21b), 5-epi-NFX-4 (21c), and lipid metabolite analogs (19, 20) are also described. The overall yields for the target molecules are the highest reported so far in the literature.

  12. Calidad total en el ICESI

    OpenAIRE

    González Zamora, José Hipólito

    2010-01-01

    En primer lugar deseo dar la bienvenida esta reunión al ingeniero Francisco Gensini, director ejecutivo de INCOLDA, quien ha sido fuente constante de inspiración para el trabajo relacionado con Control Total de Calidad (C.T.C.) que se ha venido desarrollando en el ICESI. El ingeniero Gensini ha logrado aglutinar alrededor de INCOLDA al grupo de seis empresas de la región, líderes en el estudio y aplicación de los principios del Control Total de Calidad , es decir Rica Rondo S.A., Banco de Oc...

  13. Gas Phase Nanoparticle Synthesis

    Science.gov (United States)

    Granqvist, Claes; Kish, Laszlo; Marlow, William

    This book deals with gas-phase nanoparticle synthesis and is intended for researchers and research students in nanomaterials science and engineering, condensed matter physics and chemistry, and aerosol science. Gas-phase nanoparticle synthesis is instrumental to nanotechnology - a field in current focus that raises hopes for environmentally benign, resource-lean manufacturing. Nanoparticles can be produced by many physical, chemical, and even biological routes. Gas-phase synthesis is particularly interesting since one can achieve accurate manufacturing control and hence industrial viability.

  14. Radiation chemical synthesis

    International Nuclear Information System (INIS)

    Zagoretz, P.A.; Poluetkov, V.A.; Shostenko, A.G.

    1986-01-01

    The authors consider processes in radiation chemical synthesis which are being developed in various scientific-research organizations. The important advantages of radiation chlorination, viz. the lower temperature compared with the thermal method and the absence of dehydrochlorination products are discussed. The authors examine the liquid-phase chlorination of trifluorochloroethyltrichloromethyl ether to obtain the pentachloro-contining ether, trifluorodichloroethyltrichloromethyl ether. The authors discuss radiation synthesis processes that have be used formulated kinetic equations on which models have been based. It is concluded that the possibilities of preparative (micro- and low-tonnage) radiation synthesis are promising

  15. Sobredentadura total superior implantosoportada Superior total overdenture on implants

    Directory of Open Access Journals (Sweden)

    Luis Orlando Rodríguez García

    2010-06-01

    Full Text Available Se presenta un caso de un paciente desdentado total superior, rehabilitado en la consulta de implantología de la Clínica "Pedro Ortiz" del municipio Habana del Este en Ciudad de La Habana, Cuba, en el año 2009, mediante prótesis sobre implantes osteointegrados, técnica que se ha incorporado a la práctica estomatológica en Cuba como alternativa al tratamiento convencional en los pacientes desdentados totales. Se siguió un protocolo que comprendió una fase quirúrgica, procedimiento con o sin realización de colgajo y carga precoz o inmediata. Se presenta un paciente masculino de 56 años de edad, que acudió a la consulta multidisciplinaria, preocupado, porque se le habían elaborado tres prótesis en los últimos dos años y ninguna reunía los requisitos de retención que él necesitaba para sentirse seguro y cómodo con las mismas. El resultado final fue la satisfacción total del paciente, con el mejoramiento de la calidad estética y funcional.This is the case of a total maxilla edentulous patient seen in consultation of the "Pedro Ortíz" Clinic Implant of Habana del Este municipality in 2009 and con rehabilitation by prosthesis over osteointegration implants added to stomatology practice in Cuba as an alternative to conventional treatment in patients totally edentulous. We follow a protocol including a surgery or surgical phase, technique without or with flap creation and early or immediate load. This is a male patient aged 56 came to our multidisciplinary consultation worried because he had three prostheses in last two years and any fulfilled the requirements of retention to feel safe and comfortable with prostheses. The final result was the total satisfaction of rehabilitated patient improving its aesthetic and functional quality.

  16. Total phenolics and total flavonoids in selected Indian medicinal plants.

    Science.gov (United States)

    Sulaiman, C T; Balachandran, Indira

    2012-05-01

    Plant phenolics and flavonoids have a powerful biological activity, which outlines the necessity of their determination. The phenolics and flavonoids content of 20 medicinal plants were determined in the present investigation. The phenolic content was determined by using Folin-Ciocalteu assay. The total flavonoids were measured spectrophotometrically by using the aluminium chloride colorimetric assay. The results showed that the family Mimosaceae is the richest source of phenolics, (Acacia nilotica: 80.63 mg gallic acid equivalents, Acacia catechu 78.12 mg gallic acid equivalents, Albizia lebbeck 66.23 mg gallic acid equivalents). The highest total flavonoid content was revealed in Senna tora which belongs to the family Caesalpiniaceae. The present study also shows the ratio of flavonoids to the phenolics in each sample for their specificity.

  17. Protein chemical synthesis by α-ketoacid-hydroxylamine ligation.

    Science.gov (United States)

    Harmand, Thibault J; Murar, Claudia E; Bode, Jeffrey W

    2016-06-01

    Total chemical synthesis of proteins allows researchers to custom design proteins without the complex molecular biology that is required to insert non-natural amino acids or the biocontamination that arises from methods relying on overexpression in cells. We describe a detailed procedure for the chemical synthesis of proteins with the α-ketoacid-hydroxylamine (KAHA ligation), using (S)-5-oxaproline (Opr) as a key building block. This protocol comprises two main parts: (i) the synthesis of peptide fragments by standard fluorenylmethoxycarbonyl (Fmoc) chemistry and (ii) the KAHA ligation between fragments containing Opr and a C-terminal peptide α-ketoacid. This procedure provides an alternative to native chemical ligation (NCL) that could be valuable for the synthesis of proteins, particularly targets that do not contain cysteine residues. The ligation conditions-acidic DMSO/H2O or N-methyl-2-pyrrolidinone (NMP)/H2O-are ideally suited for solubilizing peptide segments, including many hydrophobic examples. The utility and efficiency of the protocol is demonstrated by the total chemical synthesis of the mature betatrophin (also called ANGPTL8), a 177-residue protein that contains no cysteine residues. With this protocol, the total synthesis of the betatrophin protein has been achieved in around 35 working days on a multimilligram scale.

  18. Edge colouring by total labellings

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Stiebitz, M.

    2010-01-01

    We introduce the concept of an edge-colouring total k-labelling. This is a labelling of the vertices and the edges of a graph G with labels 1, 2, ..., k such that the weights of the edges define a proper edge colouring of G. Here the weight of an edge is the sum of its label and the labels of its...

  19. What is Total Quality Management?

    Science.gov (United States)

    Bryan, William A.

    1996-01-01

    Provides a general overview of Total Quality Management (TQM) and explains why there is pressure for change in higher education institutions. Defines TQM and the various themes, tools, and beliefs that make it different from other management approaches. Presents 14 principles and how they might be applied to student affairs. (RJM)

  20. A totally diverting loop colostomy.

    Science.gov (United States)

    Merrett, N. D.; Gartell, P. C.

    1993-01-01

    A technique is described where the distal limb of a loop colostomy is tied with nylon or polydioxanone. This ensures total faecal diversion and dispenses with the supporting rod, enabling early application of stoma appliances. The technique does not interfere with the traditional transverse closure of a loop colostomy. PMID:8379632

  1. A generalization of total graphs

    Indian Academy of Sciences (India)

    M Afkhami

    2018-04-12

    Apr 12, 2018 ... product of any lower triangular matrix with the transpose of any element of U belongs to U. The ... total graph of R, which is denoted by T( (R)), is a simple graph with all elements of R as vertices, and ...... [9] Badawi A, On dot-product graph of a commutative ring, Communications in Algebra 43 (2015). 43–50.

  2. The "Total Immersion" Meeting Environment.

    Science.gov (United States)

    Finkel, Coleman

    1980-01-01

    The designing of intelligently planned meeting facilities can aid management communication and learning. The author examines the psychology of meeting attendance; architectural considerations (lighting, windows, color, etc.); design elements and learning modes (furniture, walls, audiovisuals, materials); and the idea of "total immersion meeting…

  3. Total syntheses of naturally occurring diacetylenic spiroacetal enol ethers.

    Science.gov (United States)

    Miyakoshi, Naoki; Aburano, Daisuke; Mukai, Chisato

    2005-07-22

    A highly stereoselective method for constructing a (2E)-methoxymethylidene-1,6-dioxaspiro[4.5]decane skeleton has been developed on the basis of the palladium(II)-catalyzed ring-closing reaction of the 3,4-dioxygenated-9-hydroxy-1-nonyn-5-one derivatives as a crucial step. The newly developed procedures could be successfully applied to the first total synthesis of five diacetylenic spiroacetal enol ether natural products starting from commercially available (R,R)- or (S,S)-diethyl tartrate.

  4. MODIFIED TECHNIQUE OF TOTAL LARYNGECTOMY

    Directory of Open Access Journals (Sweden)

    Predrag Spirić

    2010-12-01

    Full Text Available Surgical technique of total laryngectomy is well presented in many surgical textbooks. Essentially, it has remained the same since Gluck an Soerensen in 1922 described all its details. Generally, it stresses the U shape skin incision with releasing laryngeal structures and removing larynx from up to down. Further, pharyngeal reconstruction is performed with different kinds of sutures in two or more layers and is finished with skin suture and suction drainage. One of worst complications following this surgery is pharyngocutaneous fistula (PF. Modifications proposed in this this article suggests vertical skin incision with larynx removal from below upwards. In pharyngeal reconstruction we used the running locked suture in submucosal plan with „tobacco sac“ at the end on the tongue base instead of traditional T shaped suture. Suction drains were not used.The aim of study was to present the modified surgical technique of total laryingectomy and its impact on hospital stay duration and pharyngocutanous fistula formation. In this randomized study we analyzed 49 patients operated with modified surgical technique compared to 49 patient operated with traditional surgical technique of total laryngectomy. The modified technique of total laryngectomy was presented. Using modified technique we managed to decrease the PF percentage from previous 20,41% to acceptable 8,16% (p=0,0334. Also, the average hospital stay was shortened from 14,96 to 10,63 days (t =-2.9850; p=0.0358.The modified technique of total laryngectomy is safe, short and efficient surgical intervention which decreases the number of pharyngocutaneos fistulas and shortens the hospital stay.

  5. 2002 Annual report: synthesis

    International Nuclear Information System (INIS)

    2003-01-01

    This synthesis of the Annual Report 2002 presents information of the main activities on the scope of the radiation protection and nuclear safety of the Nuclear Regulatory Authority (ARN) of the Argentina during 2002

  6. Principles of asymmetric synthesis

    CERN Document Server

    Gawley, Robert E; Aube, Jeffrey

    2012-01-01

    The world is chiral. Most of the molecules in it are chiral, and asymmetric synthesis is an important means by which enantiopure chiral molecules may be obtained for study and sale. Using examples from the literature of asymmetric synthesis, this book presents a detailed analysis of the factors that govern stereoselectivity in organic reactions. After an explanation of the basic physical-organic principles governing stereoselective reactions, the authors provide a detailed, annotated glossary of stereochemical terms. A chapter on "Practical Aspects of Asymmetric Synthesis" provides a critical overview of the most common methods for the preparation of enantiomerically pure compounds, techniques for analysis of stereoisomers using chromatographic, spectroscopic, and chiroptical methods. The authors then present an overview of the most important methods in contemporary asymmetric synthesis organized by reaction type. Thus, there are four chapters on carbon-carbon bond forming reactions, one chapter on reductions...

  7. Synthesis of protargol

    International Nuclear Information System (INIS)

    Baratova, Z.R.; Sattarova, M.A.; Abdurakhmanov, A.Kh.; Solojenkin, P.M.

    1997-01-01

    This paper is devoted to synthesis of protargol containing 7,5-8,3% of silver. The flowsheet of obtaining of protargol was elaborated. The obtained protargol contains 7,5% of silver, insoluble in alcohol, ether and chloroform.

  8. Synthesis Polarimetry Calibration

    Science.gov (United States)

    Moellenbrock, George

    2017-10-01

    Synthesis instrumental polarization calibration fundamentals for both linear (ALMA) and circular (EVLA) feed bases are reviewed, with special attention to the calibration heuristics supported in CASA. Practical problems affecting modern instruments are also discussed.

  9. SYNTHESIS, CHARACTERIZATION AND PHOTOCATALYTIC ...

    African Journals Online (AJOL)

    ISSN 1011-3924. © 2018 Chemical Society of Ethiopia and The Authors. Printed in Ethiopia ... SYNTHESIS, CHARACTERIZATION AND PHOTOCATALYTIC ACTIVITY OF .... cm−1 to determine the surface functional groups. 10 mg of sample ...

  10. 2000 Annual report: synthesis

    International Nuclear Information System (INIS)

    2001-01-01

    This synthesis of the Annual Report 2000 present information of the main activities on the scope of the radiation protection and nuclear safety of the Nuclear Regulatory Authority (NRA) of the Argentina during 2000

  11. 2001 Annual report: synthesis

    International Nuclear Information System (INIS)

    2001-01-01

    This synthesis of the Annual Report 2001 presents information of the main activities on the scope of the radiation protection and nuclear safety of the Nuclear Regulatory Authority (ARN) of the Argentina during 2001

  12. Two-directional synthesis as a tool for diversity-oriented synthesis: Synthesis of alkaloid scaffolds

    Directory of Open Access Journals (Sweden)

    Kieron M. G. O’Connell

    2012-06-01

    Full Text Available Two-directional synthesis represents an ideal strategy for the rapid elaboration of simple starting materials and their subsequent transformation into complex molecular architectures. As such, it is becoming recognised as an enabling technology for diversity-oriented synthesis. Herein, we provide a thorough account of our work combining two-directional synthesis with diversity-oriented synthesis, with particular reference to the synthesis of polycyclic alkaloid scaffolds.

  13. Reduction Expansion Synthesis for Magnetic Alloy Powders

    Science.gov (United States)

    2015-12-01

    in Figure 1, the Army was able to address its need for printable plastic components, thus enabling a reduction in the total quantity of spare...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited REDUCTION EXPANSION SYNTHESIS FOR...Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202–4302, and to the Office of Management and Budget, Paperwork Reduction Project

  14. Instrument Modeling and Synthesis

    Science.gov (United States)

    Horner, Andrew B.; Beauchamp, James W.

    During the 1970s and 1980s, before synthesizers based on direct sampling of musical sounds became popular, replicating musical instruments using frequency modulation (FM) or wavetable synthesis was one of the “holy grails” of music synthesis. Synthesizers such as the Yamaha DX7 allowed users great flexibility in mixing and matching sounds, but were notoriously difficult to coerce into producing sounds like those of a given instrument. Instrument design wizards practiced the mysteries of FM instrument design.

  15. Nitrocyclopropanes: synthesis and properties

    Energy Technology Data Exchange (ETDEWEB)

    Averina, Elena B; Yashin, N V; Kuznetsova, Tamara S; Zefirov, Nikolai S [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2009-10-31

    State-of-the-art data on the methods of synthesis, properties and transformations of nitro- and- dinitrocyclopropanes of different structure is generalized and described systematically. The attention is focused on stereoselective cyclopropanation methods, new approaches to the synthesis of natural products and their synthetic analogues with diversified biological activities, in particular, of aminocyclopropane acids based on nitrocyclopropanes, and the formation of structures of energetic compounds.

  16. Build/Couple/Pair and Multifunctional Catalysis Strategies for the Synthesis of Heterocycles from Simple Starting Materials

    DEFF Research Database (Denmark)

    Ascic, Erhad

    . Multifunctional Catalysis: Synthesis of Heterocycles from Simple Starting Materials A multifunctional catalysis approach, involving a ruthenium-catalyzed tandem ringclosing metathesis/isomerization/N-acyliminium cyclization sequence, is described. Double bonds created during ring-closing metathesis isomerize......, a series of interesting indolizidinones are formed in good yields with excellent diastereoselectivities, including a formal total synthesis of the antiparasitic natural product harmicine and the first total synthesis of mescalotam. Furthermore, preliminary asymmetric variants of the tandem process have...

  17. Subtotal versus total abdominal hysterectomy

    DEFF Research Database (Denmark)

    Andersen, Lea Laird; Ottesen, Bent; Alling Møller, Lars Mikael

    2015-01-01

    OBJECTIVE: The objective of the study was to compare long-term results of subtotal vs total abdominal hysterectomy for benign uterine diseases 14 years after hysterectomy, with urinary incontinence as the primary outcome measure. STUDY DESIGN: This was a long-term follow-up of a multicenter......, randomized clinical trial without blinding. Eleven gynecological departments in Denmark contributed participants to the trial. Women referred for benign uterine diseases who did not have contraindications to subtotal abdominal hysterectomy were randomized to subtotal (n = 161) vs total (n = 158) abdominal...... from discharge summaries from all public hospitals in Denmark. The results were analyzed as intention to treat and per protocol. Possible bias caused by missing data was handled by multiple imputation. The primary outcome was urinary incontinence; the secondary outcomes were pelvic organ prolapse...

  18. Cytomatrix synthesis in MDCK epithelial cells

    International Nuclear Information System (INIS)

    Mitchell, J.J.; Low, R.B.; Woodcock-Mitchell, J.L.

    1990-01-01

    Detailed information regarding the synthesis rates of individual protein components is important in understanding the assembly and dynamics of the cytoskeletal matrix of eukaryotic cells. As an approach to this topic, the dual isotope technique of Clark and Zak, was employed to measure fractional synthesis rates (FSRs) in growing and quiescent cultures of MDCK epithelial cells. Cell protein was labeled to equilibrium with [14C]leucine over several days and then pulse-labeled for 4 hours with [3H]leucine. FSRs (as percent per hour) were calculated from the 3H/14C ratio of cell extracts or individual proteins separated by two-dimensional polyacrylamide gel electrophoresis and the 3H/14C ratio of free leucine in the medium. Synthesis of total cell protein rose from approximately 1.4%/hour in quiescent cells to 3.5%/hour in the growing cultures. The latter rate was sufficient to account for the rate of protein accumulation and a low level of turnover in the growing cultures. The FSR of the buffered-Triton soluble extract was higher and the cytoskeletal FSR significantly lower than that for total protein in quiescent monolayers. This difference, however, was not observed in growing cultures. A distinct pattern of differences was seen in the FSRs of individual cytoskeletal proteins in the quiescent cultures. Vimentin synthesis was significantly lower than that of the keratins and the keratin FSRs were not obviously matched in pairwise fashion. Unexpectedly, the FSRs of alpha- and beta-tubulin diverged in quiescent cells with alpha-tubulin turnover exceeding beta-tubulin. Likewise, components of the microfilament lattice showed unequal fractional synthesis rates, myosin and alpha-actinin being faster than actin. In addition, the FSR for globular actin exceeded that of the cytoskeletal associated form

  19. Institutional total energy case studies

    Energy Technology Data Exchange (ETDEWEB)

    Wulfinghoff, D.

    1979-07-01

    Profiles of three total energy systems in institutional settings are provided in this report. The plants are those of Franciscan Hospital, a 384-bed facility in Rock Island, Illinois; Franklin Foundation Hospital, a 100-bed hospital in Franklin, Louisiana; and the North American Air Defense Command Cheyenne Mountain Complex, a military installation near Colorado Springs, Colorado. The case studies include descriptions of plant components and configurations, operation and maintenance procedures, reliability, relationships to public utilities, staffing, economic efficiency, and factors contributing to success.

  20. Intrathoracic Hernia after Total Gastrectomy

    Directory of Open Access Journals (Sweden)

    Yoshihiko Tashiro

    2016-05-01

    Full Text Available Intrathoracic hernias after total gastrectomy are rare. We report the case of a 78-year-old man who underwent total gastrectomy with antecolic Roux-Y reconstruction for residual gastric cancer. He had alcoholic liver cirrhosis and received radical laparoscopic proximal gastrectomy for gastric cancer 3 years ago. Early gastric cancer in the remnant stomach was found by routine upper gastrointestinal endoscopy. We initially performed endoscopic submucosal dissection, but the vertical margin was positive in a pathological result. We performed total gastrectomy with antecolic Roux-Y reconstruction by laparotomy. For adhesion of the esophageal hiatus, the left chest was connected with the abdominal cavity. A pleural defect was not repaired. Two days after the operation, the patient was suspected of having intrathoracic hernia by chest X-rays. Computed tomography showed that the transverse colon and Roux limb were incarcerated in the left thoracic cavity. He was diagnosed with intrathoracic hernia, and emergency reduction and repair were performed. Operative findings showed that the Roux limb and transverse colon were incarcerated in the thoracic cavity. After reduction, the orifice of the hernia was closed by suturing the crus of the diaphragm with the ligament of the jejunum and omentum. After the second operation, he experienced anastomotic leakage and left pyothorax. Anastomotic leakage was improved with conservative therapy and he was discharged 76 days after the second operation.

  1. NIF total neutron yield diagnostic

    International Nuclear Information System (INIS)

    Cooper, Gary W.; Ruiz, Carlos L.

    2001-01-01

    We have designed a total neutron yield diagnostic for the National Ignition Facility (NIF) which is based on the activation of In and Cu samples. The particular approach that we have chosen is one in which we calibrate the entire counting system and which we call the ''F factor'' method. In this method, In and/or Cu samples are exposed to known sources of DD and DT neutrons. The activated samples are then counted with an appropriate system: a high purity Ge detector for In and a NaI coincidence system for Cu. We can then calculate a calibration factor, which relates measured activity to total neutron yield. The advantage of this approach is that specific knowledge of such quantities as cross sections and detector efficiencies is not needed. Unless the actual scattering environment of the NIF can be mocked up in the calibration experiment, the F factor will have to be modified using the results of a numerical simulation of the NIF scattering environment. In this article, the calibration factor methodology will be discussed and experimental results for the calibration factors will be presented. Total NIF neutron yields of 10 9 --10 19 can be measured with this method assuming a 50 cm stand-off distance can be employed for the lower yields

  2. Synthesis of the Sex Pheromone of the Tea Tussock Moth Based on a Resource Chemistry Strategy

    Directory of Open Access Journals (Sweden)

    Hong-Li Zhang

    2018-06-01

    Full Text Available Synthesis of the sex pheromone of the tea tussock moth in 33% overall yield over 10 steps was achieved. Moreover, the chiral pool concept was applied in the asymmetric synthesis. The synthesis used a chemical available on a large-scale from recycling of wastewater from the steroid industry. The carbon skeleton was constructed using the C4+C5+C8 strategy. Based on this strategy, the original chiral center was totally retained.

  3. An Approach to Interface Synthesis

    DEFF Research Database (Denmark)

    Madsen, Jan; Hald, Bjarne

    1995-01-01

    Presents a novel interface synthesis approach based on a one-sided interface description. Whereas most other approaches consider interface synthesis as optimizing a channel to existing client/server modules, we consider the interface synthesis as part of the client/server module synthesis (which...... may contain the re-use of existing modules). The interface synthesis approach describes the basic transformations needed to transform the server interface description into an interface description on the client side of the communication medium. The synthesis approach is illustrated through a point...

  4. Total eclipses of the sun

    CERN Document Server

    Zirker, Jack B

    2014-01-01

    Eclipses have captured attention and sparked curiosity about the cosmos since the first appearance of humankind. Having been blamed for everything from natural disasters to the fall of kings, they are now invaluable tools for understanding many celestial as well as terrestrial phenomena. This clear, easy-to-understand guide explains what causes total eclipses and how they can be used in experiments to examine everything from the dust between the planets to general relativity. A new chapter has been added on the eclipse of July 11, 1991 (the great Hawaiian eclipse). Originally published in 19

  5. Reverse hybrid total hip arthroplasty

    DEFF Research Database (Denmark)

    Wangen, Helge; Havelin, Leif I.; Fenstad, Anne M

    2017-01-01

    Background and purpose - The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty....... Patients and methods - From the NARA, we extracted data on reverse hybrid THAs from January 1, 2000 until December 31, 2013. 38,415 such hips were studied and compared with cemented THAs. The Kaplan-Meier method and Cox regression analyses were used to estimate the prosthesis survival and the relative risk...

  6. Total knee arthroplasty in ochronosis

    Directory of Open Access Journals (Sweden)

    Vaibhav G. Patel, MBBS

    2015-09-01

    Full Text Available Alkaptonuria is disorder of tyrosine metabolism due to deficiency of homogentisic oxidase characterized by excretion of homogentisic acid in urine, deposition of oxidized homogensitate pigments in connective tissues and articular cartilages (ochronosis. The result is dark pigmentation and weakening of the tissues resulting in chronic inflammation and osteoarthritis. Management of alkaptonuric ochronic osteoarthritis is usually symptomatic and replacements have comparable outcomes to osteoarthritis in patients without ochronosis. I report a case of a patient with ochronosis of knee treated with total knee replacement and report operative pearls for surgery in this rare disorder.

  7. Total filmless digital radiology service

    International Nuclear Information System (INIS)

    Mun, S.K.; Goeringer, F.; Benson, H.; Horii, S.C.

    1989-01-01

    The completion of a comprehensive picture archiving and communication system (PACS) at Georgetown University Hospital has allowed us to identify a number of technical, administrative, personnel, and operational issues that will affect a total digital radiology service. With a hospital-wide digital imaging network system, computer simulation of communications and storage options, and economic modeling, we have developed a feasibility study and implementation strategy for the smooth transition to a nearly filmless radiology service over the next several years. This paper describes the technical and operational requirements for various database operations, workstations (used in diagnosis, review, and education), and communications. Site and installation planning, personnel training, and transition operations are discussed

  8. Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Dolmatov, Valerii Yu [Federal State Unitary Enterprise Special Design-Technology Bureau (FSUE SDTB) ' ' Tekhnolog' ' at the St Petersburg State Institute of Technology (Technical University) (Russian Federation)

    2007-04-30

    The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

  9. Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

    International Nuclear Information System (INIS)

    Dolmatov, Valerii Yu

    2007-01-01

    The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

  10. Qualidade total: Um novo paradigma?

    Directory of Open Access Journals (Sweden)

    Suzana da Rosa Tolfo

    1999-01-01

    Full Text Available Nos últimos anos, o movimento para a implantação da Gestão da Qualidade Total vem crescendo ao redor do mundo. Em razão disso, há uma diversidade de ações realizadas com o nome de "Qualidade Total'. Uma revisão da teoria é complexa, porque existem muitos autores que tratam da questão. Eles escolhem diferentes perspectivas de análises (teóricas e empíricas e há dificuldades em se identificar um corpo conceitual. Há uma ampla difusão de modelos, ferramentas, técnicas, mercado e consultores. Essa popularidade, muitas vezes, faz com que determinadas organizações adotem essa forma de gestão do trabalho sem o conhecimento necessário das implicações que um modelo dessa ordem representa; especialmente no caso brasileiro, suscetível a proposições importadas. O presente artigo propõe um exame daquilo que os fundadores têm articulado sobre TQM, as principais críticas nesta direção e a avaliação de como vem sendo aplicadono nosso país.

  11. Testing EDM of Total Stations

    Directory of Open Access Journals (Sweden)

    Cirbus Ján

    2001-03-01

    Full Text Available The paper is devoted to testing electrooptical distance measuring devices (EDM built in total stations, than can be used for various tasks in the contemporary geodetic works. A rich market offer and availability of these universal measuring systems with satisfying distance range, excellent accuracy and other parameters, make total stations as dominant terrestrial geodetic instruments.For succesfully applying these instruments, above all for relliable distance measurements, the stability of the modulation frequency is the most important pre-condition. In the article, therefore, there are given some methods to verify the modulation frequency stability. In addition, some ways for determining the EDM distance constant and periodical corrections of the phase measuring unit are introduced for 4 types of EDM : LEICA 1700L, TOPCON GTS6A, TOPCON GTS2, C.ZEISS ELTA50. It were also investigated their possibilities for precise distance survey. Values of the determined constants and periodical corrections are presented in Tab. 2.Based on the investigation results of the 4 EDM types and using the values m obtained for different distances S, equations of the a posteriori standard deviations in form : m = (a+b.S were derived too.

  12. Total Value of Phosphorus Recovery.

    Science.gov (United States)

    Mayer, Brooke K; Baker, Lawrence A; Boyer, Treavor H; Drechsel, Pay; Gifford, Mac; Hanjra, Munir A; Parameswaran, Prathap; Stoltzfus, Jared; Westerhoff, Paul; Rittmann, Bruce E

    2016-07-05

    Phosphorus (P) is a critical, geographically concentrated, nonrenewable resource necessary to support global food production. In excess (e.g., due to runoff or wastewater discharges), P is also a primary cause of eutrophication. To reconcile the simultaneous shortage and overabundance of P, lost P flows must be recovered and reused, alongside improvements in P-use efficiency. While this motivation is increasingly being recognized, little P recovery is practiced today, as recovered P generally cannot compete with the relatively low cost of mined P. Therefore, P is often captured to prevent its release into the environment without beneficial recovery and reuse. However, additional incentives for P recovery emerge when accounting for the total value of P recovery. This article provides a comprehensive overview of the range of benefits of recovering P from waste streams, i.e., the total value of recovering P. This approach accounts for P products, as well as other assets that are associated with P and can be recovered in parallel, such as energy, nitrogen, metals and minerals, and water. Additionally, P recovery provides valuable services to society and the environment by protecting and improving environmental quality, enhancing efficiency of waste treatment facilities, and improving food security and social equity. The needs to make P recovery a reality are also discussed, including business models, bottlenecks, and policy and education strategies.

  13. Enantioselective Synthesis of (-)-Vallesine: Late-Stage C17-Oxidation via Complex Indole Boronation.

    Science.gov (United States)

    Antropow, Alyssa H; Garcia, Nicholas R; White, Kolby L; Movassaghi, Mohammad

    2018-06-04

    The first enantioselective total synthesis of (-)-vallesine via a strategy that features a late-stage regioselective C17-oxidation followed by a highly stereoselective transannular cyclization is reported. The versatility of this approach is highlighted by the divergent synthesis of the archetypal alkaloid of this family, (+)-aspidospermidine, and an A-ring-oxygenated derivative, (+)-deacetylaspidospermine, the precursor to (-)-vallesine, from a common intermediate.

  14. A Safer and Convenient Synthesis of Sulfathiazole for Undergraduate Organic and Medicinal Chemistry Classes

    Science.gov (United States)

    Boyle, Jeff; Otty, Sandra; Sarojini, Vijayalekshmi

    2012-01-01

    A safer method for the synthesis of the sulfonamide drug sulfathiazole, for undergraduate classes, is described. This method improves upon procedures currently followed in several undergraduate teaching laboratories for the synthesis of sulfathiazole. Key features of this procedure include the total exclusion of pyridine, which has potential…

  15. Studies toward the synthesis of Amaryllidaceae alkaloids from Morita-Baylis-Hillman adducts: a straightforward synthesis of functionalized dihydroisoquinoline-5(6H)-one core

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Elizandra C.S.; Coelho, Fernando [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica]. E-mail: coelho@iqm.unicamp.br

    2007-07-01

    We disclose herein our results concerning a study aiming at the synthesis of the highly substituted carbon skeleton of alkaloids isolated from plants of the Amaryllidaceae family. The total synthesis of the functionalized dihydroisoquinoline-5(6H)-one core, which is the bottom part of the structure of alkaloids isolated from this botanic family, is described, using Morita-Baylis-Hillman adducts as substrate. This compound should be a useful and valuable intermediate for the total synthesis of alkaloids isolated from Amaryllidaceae. (author)

  16. Studies toward the synthesis of Amaryllidaceae alkaloids from Morita-Baylis-Hillman adducts: a straightforward synthesis of functionalized dihydroisoquinoline-5(6H)-one core

    International Nuclear Information System (INIS)

    Lopes, Elizandra C.S.; Coelho, Fernando

    2007-01-01

    We disclose herein our results concerning a study aiming at the synthesis of the highly substituted carbon skeleton of alkaloids isolated from plants of the Amaryllidaceae family. The total synthesis of the functionalized dihydroisoquinoline-5(6H)-one core, which is the bottom part of the structure of alkaloids isolated from this botanic family, is described, using Morita-Baylis-Hillman adducts as substrate. This compound should be a useful and valuable intermediate for the total synthesis of alkaloids isolated from Amaryllidaceae. (author)

  17. Total employment effect of biofuels

    International Nuclear Information System (INIS)

    Stridsberg, S.

    1998-08-01

    The study examined the total employment effect of both direct production of biofuel and energy conversion to heat and electricity, as well as the indirect employment effect arising from investments and other activities in conjunction with the production organization. A secondary effect depending on the increased capital flow is also included in the final result. The scenarios are based on two periods, 1993-2005 and 2005-2020. In the present study, the different fuels and the different applications have been analyzed individually with regard to direct and indirect employment within each separate sector. The greatest employment effect in the production chain is shown for logging residues with 290 full-time jobs/TWh, whereas other biofuels range between 80 and 280 full-time jobs/TWh. In the processing chain, the corresponding range is 200-300 full-time jobs per each additional TWh. Additionally and finally, there are secondary effects that give a total of 650 full-time jobs/TWh. Together with the predicted increase, this suggests that unprocessed fuel will provide an additional 16 000 annual full-time jobs, and that fuel processing will contribute with a further 5 000 full-time jobs. The energy production from the fuels will provide an additional 13 000 full-time jobs. The total figure of 34 000 annual full-time jobs must then be reduced by about 4000 on account of lost jobs, mainly in the oil sector and to some extent in imports of biofuel. In addition, the anticipated increase in capital turnover that occurs within the biofuel sector, will increase full-time jobs up to year 2020. Finally, a discussion is given of the accomplishment of the programmes anticipated by the scenario, where it is noted that processing of biofuel to wafers, pellets or powder places major demands on access to raw material of good quality and that agrarian fuels must be given priority if they are to enter the system sufficiently fast. Straw is already a resource but is still not accepted by

  18. Noncovalent synthesis of protein dendrimers

    NARCIS (Netherlands)

    Lempens, E.H.M.; Baal, van I.; Dongen, van J.L.J.; Hackeng, T.M.; Merkx, M.; Meijer, E.W.

    2009-01-01

    The covalent synthesis of complex biomolecular systems such as multivalent protein dendrimers often proceeds with low efficiency, thereby making alternative strategies based on noncovalent chemistry of high interest. Here, the synthesis of protein dendrimers using a strong but noncovalent

  19. Survival of adult neurons lacking cholesterol synthesis in vivo.

    Science.gov (United States)

    Fünfschilling, Ursula; Saher, Gesine; Xiao, Le; Möbius, Wiebke; Nave, Klaus-Armin

    2007-01-02

    Cholesterol, an essential component of all mammalian plasma membranes, is highly enriched in the brain. Both during development and in the adult, brain cholesterol is derived from local cholesterol synthesis and not taken up from the circulation. However, the contribution of neurons and glial cells to total brain cholesterol metabolism is unknown. Using conditional gene inactivation in the mouse, we disrupted the squalene synthase gene (fdft1), which is critical for cholesterol synthesis, in cerebellar granule cells and some precerebellar nuclei. Mutant mice showed no histological signs of neuronal degeneration, displayed ultrastructurally normal synapses, and exhibited normal motor coordination. This revealed that these adult neurons do not require cell-autonomous cholesterol synthesis for survival or function. We conclude that at least some adult neurons no longer require endogenous cholesterol synthesis and can fully meet their cholesterol needs by uptake from their surrounding. Glia are a likely source of cholesterol in the central nervous system.

  20. Survival of adult neurons lacking cholesterol synthesis in vivo

    Directory of Open Access Journals (Sweden)

    Möbius Wiebke

    2007-01-01

    Full Text Available Abstract Background Cholesterol, an essential component of all mammalian plasma membranes, is highly enriched in the brain. Both during development and in the adult, brain cholesterol is derived from local cholesterol synthesis and not taken up from the circulation. However, the contribution of neurons and glial cells to total brain cholesterol metabolism is unknown. Results Using conditional gene inactivation in the mouse, we disrupted the squalene synthase gene (fdft1, which is critical for cholesterol synthesis, in cerebellar granule cells and some precerebellar nuclei. Mutant mice showed no histological signs of neuronal degeneration, displayed ultrastructurally normal synapses, and exhibited normal motor coordination. This revealed that these adult neurons do not require cell-autonomous cholesterol synthesis for survival or function. Conclusion We conclude that at least some adult neurons no longer require endogenous cholesterol synthesis and can fully meet their cholesterol needs by uptake from their surrounding. Glia are a likely source of cholesterol in the central nervous system.

  1. Conversion total hip arthroplasty: Primary or revision total hip arthroplasty

    Science.gov (United States)

    Schwarzkopf, Ran; Baghoolizadeh, Mahta

    2015-01-01

    Total hip arthroplasty (THA) is an increasingly common procedure among elderly individuals. Although conversion THA is currently bundled in a diagnosis related group (DRG) with primary THA, there is a lack of literature supporting this classification and it has yet to be identified whether conversion THA better resembles primary or revision THA. This editorial analyzed the intraoperative and postoperative factors and functional outcomes following conversion THA, primary THA, and revision THA to understand whether the characteristics of conversion THA resemble one procedure or the other, or are possibly somewhere in between. The analysis revealed that conversion THA requires more resources both intraoperatively and postoperatively than primary THA. Furthermore, patients undergoing conversion THA present with poorer functional outcomes in the long run. Patients undergoing conversion THA better resemble revision THA patients than primary THA patients. As such, patients undergoing conversion THA should not be likened to patients undergoing primary THA when determining risk stratification and reimbursement rates. Conversion THA procedures should be planned accordingly with proper anticipation of the greater needs both in the operating room, and for in-patient and follow-up care. We suggest that conversion THA be reclassified in the same DRG with revision THA as opposed to primary THA as a step towards better allocation of healthcare resources for conversion hip arthroplasties. PMID:26601055

  2. Instability after total hip arthroplasty

    Science.gov (United States)

    Werner, Brian C; Brown, Thomas E

    2012-01-01

    Instability following total hip arthroplasty (THA) is an unfortunately frequent and serious problem that requires thorough evaluation and preoperative planning before surgical intervention. Prevention through optimal index surgery is of great importance, as the management of an unstable THA is challenging even for an experienced joints surgeon. However, even after well-planned surgery, a significant incidence of recurrent instability still exists. Non-operative management is often successful if the components are well-fixed and correctly positioned in the absence of neurocognitive disorders. If conservative management fails, surgical options include revision of malpositioned components; exchange of modular components such as the femoral head and acetabular liner; bipolar arthroplasty; tripolar arthroplasty; use of a larger femoral head; use of a constrained liner; soft tissue reinforcement and advancement of the greater trochanter. PMID:22919568

  3. A total safety management model

    International Nuclear Information System (INIS)

    Obadia, I.J.; Vidal, M.C.R.; Melo, P.F.F.F.

    2002-01-01

    In nuclear organizations, quality and safety are inextricably linked. Therefore, the search for excellence means reaching excellence in nuclear safety. The International Atomic Energy Agency, IAEA, developed, after the Chernobyl accident, the organizational approach for improving nuclear safety based on the safety culture, which requires a framework necessary to provide modifications in personnel attitudes and behaviors in situations related to safety. This work presents a Total Safety Management Model, based on the Model of Excellence of the Brazilian Quality Award and on the safety culture approach, which represents an alternative to this framework. The Model is currently under validation at the Nuclear Engineering Institute, in Rio de Janeiro, Brazil, and the results of its initial safety culture self assessment are also presented and discussed. (author)

  4. Demand: a total nuclear disarmament

    International Nuclear Information System (INIS)

    Hessel, Stephane; Jacquard, Albert

    2012-01-01

    This bibliographical note presents a book, in which the authors make a plea for a total nuclear disarmament. They think that humanity cannot be found in competition, but in emulation, and examine how we can get rid of the nuclear bomb. They discuss the background of nuclear energy, state that nuclear weapons have always been useless and extremely dangerous, consider arms race as crazy and as a crime against humanity, recall that nuclear weapons already made numerous victims (Hiroshima, Nagasaki, nuclear tests), that they are a sword of Damocles over 7 billions human beings, that nuclear winter would be an apocalypse, that the Non Proliferation Treaty is a decoy. They discuss the political role of nuclear weapons, and outline that the only solution is their abolition. They discuss what has already been done and what is still to be done, and formulate a strategy for the future

  5. Total quality management implementation guidelines

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-01

    These Guidelines were designed by the Energy Quality Council to help managers and supervisors in the Department of Energy Complex bring Total Quality Management to their organizations. Because the Department is composed of a rich mixture of diverse organizations, each with its own distinctive culture and quality history, these Guidelines are intended to be adapted by users to meet the particular needs of their organizations. For example, for organizations that are well along on their quality journeys and may already have achieved quality results, these Guidelines will provide a consistent methodology and terminology reference to foster their alignment with the overall Energy quality initiative. For organizations that are just beginning their quality journeys, these Guidelines will serve as a startup manual on quality principles applied in the Energy context.

  6. Total quality management program planning

    Energy Technology Data Exchange (ETDEWEB)

    Thornton, P.T.; Spence, K.

    1994-05-01

    As government funding grows scarce, competition between the national laboratories is increasing dramatically. In this era of tougher competition, there is no for resistance to change. There must instead be a uniform commitment to improving the overall quality of our products (research and technology) and an increased focus on our customers` needs. There has been an ongoing effort to bring the principles of total quality management (TQM) to all Energy Systems employees to help them better prepare for future changes while responding to the pressures on federal budgets. The need exists for instituting a vigorous program of education and training to an understanding of the techniques needed to improve and initiate a change in organizational culture. The TQM facilitator is responsible for educating the work force on the benefits of self-managed work teams, designing a program of instruction for implementation, and thus getting TQM off the ground at the worker and first-line supervisory levels so that the benefits can flow back up. This program plan presents a conceptual model for TQM in the form of a hot air balloon. In this model, there are numerous factors which can individually and collectively impede the progress of TQM within the division and the Laboratory. When these factors are addressed and corrected, the benefits of TQM become more visible. As this occurs, it is hoped that workers and management alike will grasp the ``total quality`` concept as an acceptable agent for change and continual improvement. TQM can then rise to the occasion and take its rightful place as an integral and valid step in the Laboratory`s formula for survival.

  7. Instability following total knee arthroplasty.

    Science.gov (United States)

    Rodriguez-Merchan, E Carlos

    2011-10-01

    Background Knee prosthesis instability (KPI) is a frequent cause of failure of total knee arthroplasty. Moreover, the degree of constraint required to achieve immediate and long-term stability in total knee arthroplasty (TKA) is frequently debated. Questions This review aims to define the problem, analyze risk factors, and review strategies for prevention and treatment of KPI. Methods A PubMed (MEDLINE) search of the years 2000 to 2010 was performed using two key words: TKA and instability. One hundred and sixty-five initial articles were identified. The most important (17) articles as judged by the author were selected for this review. The main criteria for selection were that the articles addressed and provided solutions to the diagnosis and treatment of KPI. Results Patient-related risk factors predisposing to post-operative instability include deformity requiring a large surgical correction and aggressive ligament release, general or regional neuromuscular pathology, and hip or foot deformities. KPI can be prevented in most cases with appropriate selection of implants and good surgical technique. When ligament instability is anticipated post-operatively, the need for implants with a greater degree of constraint should be anticipated. In patients without significant varus or valgus malalignment and without significant flexion contracture, the posterior cruciate ligament (PCL) can be retained. However, the PCL should be sacrificed when deformity exists particularly in patients with rheumatoid arthritis, previous patellectomy, previous high tibial osteotomy or distal femoral osteotomy, and posttraumatic osteoarthritis with disruption of the PCL. In most cases, KPI requires revision surgery. Successful outcomes can only be obtained if the cause of KPI is identified and addressed. Conclusions Instability following TKA is a common cause of the need for revision. Typically, knees with deformity, rheumatoid arthritis, previous patellectomy or high tibial osteotomy, and

  8. Systematic review: Do patient expectations influence treatment outcomes in total knee and total hip arthroplasty?

    Directory of Open Access Journals (Sweden)

    Haanstra Tsjitske M

    2012-12-01

    Full Text Available Abstract Objective This systematic review aims to summarise all the available evidence related to the association between pre-operative patient expectations (outcome expectations, process expectations and self efficacy expectations and 5 different treatment outcomes (overall improvement, pain, function, stiffness and satisfaction in patients with total knee or total hip arthroplasty at three different follow-op periods (>6 weeks; >6 weeks- ≤6 months; >6 months. Methods English and Dutch language articles were identified through PubMed, EMBASE.com, PsycINFO, CINAHL and The Cochrane Library from inception to September 2012. Articles assessing the association between pre-operative patient expectations and treatment outcomes for TKA/THA in either adjusted or unadjusted analysis were included. Two reviewers, working independently, determined eligibility, rated methodological quality and extracted data on study design, population, expectation measurements, outcome measurements and strength of the associations. Methodological quality was rated by the same reviewers on a 19 item scale. The scores on the quality assessment were taken into account when drawing final conclusions. Results The search strategy generated 2252 unique references, 18 articles met inclusion criteria. Scores on the methodological quality assessment ranged between 6% and 79%. Great variety was seen in definitions and measurement methods of expectations. No significant associations were found between patient expectations and overall improvement, satisfaction and stiffness. Both significant positive and non-significant associations were found for the association between expectations and pain and function. Conclusions There was no consistency in the association between patients’ pre-operative expectations and treatment outcomes for TKA and THA indentified in this systematic review. There exists a need for a sound theoretical framework underlying the construct of

  9. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    This thesis presents a method for behavioral synthesis of asynchronous circuits, which aims at providing a synthesis flow which uses and tranfers methods from synchronous circuits to asynchronous circuits. We move the synchronous behavioral synthesis abstraction into the asynchronous handshake...... is idle. This reduces unnecessary switching activity in the individual functional units and therefore the energy consumption of the entire circuit. A collection of behavioral synthesis algorithms have been developed allowing the designer to perform time and power constrained design space exploration...

  10. Click synthesis of PET radiopharmaceuticals

    International Nuclear Information System (INIS)

    Xu Mei; Kuang Chunxiang

    2009-01-01

    Increasing attention has been focused on synthesis radiopharmaceuticals for positron emission tomography (PET). The recent years witnessed applications of click chemistry to PET radiopharmaceutical synthesis,because of its distinctive advantages including high speed,yield and stereospecificity under mild conditions. Synthesis of 18 F-labeled and 11 C-labeled radiopharmaceuticals and intermediates via click chemistry are reviewed. The future trend of click chemistry for the synthesis of PET radiopharmaceutical is prospected. (authors)

  11. Predictors of muscle protein synthesis after severe pediatric burns.

    Science.gov (United States)

    Diaz, Eva C; Herndon, David N; Lee, Jinhyung; Porter, Craig; Cotter, Matthew; Suman, Oscar E; Sidossis, Labros S; Børsheim, Elisabet

    2015-04-01

    Following a major burn, skeletal muscle protein synthesis rate increases but is often insufficient to compensate for massively elevated muscle protein breakdown rates. Given the long-term nature of the pathophysiologic response to burn injury, we hypothesized that muscle protein synthesis rate would be chronically elevated in severely burned children. The objectives of this study were to characterize muscle protein synthesis rate of burned children over a period of 24 months after injury and to identify predictors that influence this response. A total of 87 children with 40% or greater total body surface area (TBSA) burned were included. Patients participated in stable isotope infusion studies at 1, 2, and approximately 4 weeks after burn and at 6, 12, and 24 months after injury to determine skeletal muscle protein fractional synthesis rate. Generalized estimating equations with log link normal distribution were applied to account for clustering of patients and control for patient characteristics. Patients (8 ± 6 years) had large (62, 51-72% TBSA) and deep (47% ± 21% TBSA third degree) burns. Muscle protein fractional synthesis rate was elevated throughout the first 12 months after burn compared with established values from healthy young adults. Muscle protein fractional synthesis rate was lower in boys, in children older than 3 years, and when burns were greater than 80% TBSA. Muscle protein synthesis is elevated for at least 1 year after injury, suggesting that greater muscle protein turnover is a component of the long-term pathophysiologic response to burn trauma. Muscle protein synthesis is highly affected by sex, age, and burn size in severely burned children. These findings may explain the divergence in net protein balance and lean body mass in different populations of burn patients. Prognostic study, level III.

  12. Supercritical Synthesis of Biodiesel

    Directory of Open Access Journals (Sweden)

    Michel Vaultier

    2012-07-01

    Full Text Available The synthesis of biodiesel fuel from lipids (vegetable oils and animal fats has gained in importance as a possible source of renewable non-fossil energy in an attempt to reduce our dependence on petroleum-based fuels. The catalytic processes commonly used for the production of biodiesel fuel present a series of limitations and drawbacks, among them the high energy consumption required for complex purification operations and undesirable side reactions. Supercritical fluid (SCF technologies offer an interesting alternative to conventional processes for preparing biodiesel. This review highlights the advances, advantages, drawbacks and new tendencies involved in the use of supercritical fluids (SCFs for biodiesel synthesis.

  13. Toleration, Synthesis or Replacement?

    DEFF Research Database (Denmark)

    Holtermann, Jakob v. H.; Madsen, Mikael Rask

    2016-01-01

    , in order to answer is not yet another partisan suggestion, but rather an attempt at making intelligible both the oppositions and the possibilities of synthesis between normative and empirical approaches to law. Based on our assessment and rational reconstruction of current arguments and positions, we...... therefore outline a taxonomy consisting of the following three basic, ideal-types in terms of the epistemological understanding of the interface of law and empirical studies: toleration, synthesis and replacement. This tripartite model proves useful with a view to teasing out and better articulating...

  14. Robotic synthesis of [carbon-11]methionine

    International Nuclear Information System (INIS)

    Korsakov, M.V.; Kisselev, M.Y.; Solovyov, D.; Horti, A.G.; Vasilev, A.; Nilsson, L.E.; Ulin, J.

    1992-01-01

    [ 11 C]Methionine was prepared in a fully automated robotic synthesis, using the SCANDITRONIX robotic system starting from [ 11 C]I and homocysteine thiolactone. The product was purified using solid phase extraction on anionic exchange cartridges. The decay corrected yield was 60% based on CH 3 I and 16 min synthesis time. The radiochemical purity was 98-99% and the chemical impurities were: homocysteine 0.05-0.07 mg/ml, homocystine 0.005 mg/ml, 'cold' methionine 0.03-0.05 mg/ml, and homocysteine thiolactone 0.0008-0.002 mg/ml. The total procedure takes 30 min from EOB. (author) 6 figs., 3 tabs

  15. Synthesis of peptide .alpha.-thioesters

    Science.gov (United States)

    Camarero, Julio A [Livermore, CA; Mitchell, Alexander R [Livermore, CA; De Yoreo, James J [Clayton, CA

    2008-08-19

    Disclosed herein is a new method for the solid phase peptide synthesis (SPPS) of C-terminal peptide .alpha. thioesters using Fmoc/t-Bu chemistry. This method is based on the use of an aryl hydrazine linker, which is totally stable to conditions required for Fmoc-SPPS. When the peptide synthesis has been completed, activation of the linker is achieved by mild oxidation. The oxidation step converts the acyl-hydrazine group into a highly reactive acyl-diazene intermediate which reacts with an .alpha.-amino acid alkylthioester (H-AA-SR) to yield the corresponding peptide .alpha.-thioester in good yield. A variety of peptide thioesters, cyclic peptides and a fully functional Src homology 3 (SH3) protein domain have been successfully prepared.

  16. Process synthesis and intensification of hybrid separations

    DEFF Research Database (Denmark)

    Errico, Massimiliano

    2017-01-01

    Hybrid flowsheets are defined, in the context of process intensification, as alternatives suitable for replacing energy-intensive separation methods through the combination of more than one unit operation. Distillation is one of the first options considered for achieving a required separation...... and commented on. The corresponding distillation-based processes are considered for comparison. Synthesis of the possible hybrid flowsheets appears to be important, especially when multicomponent mixtures are considered. This aspect is discussed for the combination of liquid-liquid extraction and distillation...... as applied to the separation of biobutanol from its fermentation broth. The synthesis of alternative hybrid flowsheets is reported, showing that one configuration can realize a 43% reduction in the total annual cost. Bioalcohol production by fermentation perfectly represents the casewhere distillation alone...

  17. Synthesis of [13N]cisplatin

    International Nuclear Information System (INIS)

    Haber, M.T.; Risenspire, K.C.

    1985-01-01

    A method for the ''carrier-added'' synthesis of [ 13 N]cisplatin is described. Yields were approx.1-4 mCi from 20-40 mCi of [ 13 N]ammonia with a total synthesis time of 19-28 minutes. The product was approx.96% radiochemically pure as judged by HPLC analysis and had a specific activity of approx.100 mCi/mmole in 1.0 ml of saline. [ 13 N)Cisplatin was administered intraperitoneally to mice. Of the tissues investigated, concentration of label was highest in kidneys. At 10 min, considerable label in the blood, liver, and kidney was in a form other than cisplatin. However, no evidence was obtained that [ 13 N]ammonia was released from [ 13 N]cisplatin in vivo. [ 13 N]Cisplatin may be used to assess drug delivery to primary and metastatic brain tumors in patients receiving intravenous or intraarterial cisplatin chemotherapy. (author)

  18. Ready access to functionally embellished cis-hydrindanes and cis-decalins: protecting group-free total syntheses of (±)-Nootkatone and (±)-Noreremophilane.

    Science.gov (United States)

    Handore, Kishor L; Seetharamsingh, B; Reddy, D Srinivasa

    2013-08-16

    A simple and efficient synthesis of functionalized cis-hydrindanes and cis-decalins was achieved using a sequential Diels-Alder/aldol approach in a highly diastereoselective manner. The scope of this method was tested with a variety of substrates and was successfully applied to the synthesis of two natural products in racemic form. The highlights of the present work provide ready access to 13 new cis-hydrindanes/cis-decalins, a protecting group-free total synthesis of an insect repellent Nootkatone, and the first synthesis of a Noreremophilane using the shortest sequence.

  19. Synthesis imaging in radio astronomy

    International Nuclear Information System (INIS)

    Perley, R.A.; Schwab, F.R.; Bridle, A.H.

    1989-01-01

    Recent advances in techniques and instrumentation for radio synthesis imaging in astronomy are discussed in a collection of review essays. Topics addressed include coherence in radio astronomy, the interferometer in practice, primary antenna elements, cross correlators, calibration and editing, sensitivity, deconvolution, self-calibration, error recognition, and image analysis. Consideration is given to wide-field imaging (bandwidth and time-average smearing, noncoplanar arrays, and mosaicking), high-dynamic-range imaging, spectral-line imaging, VLBI, solar imaging with a synthesis telescope, synthesis imaging of spatially coherent objects, noise in images of very bright sources, synthesis observing strategies, and the design of aperture-synthesis arrays

  20. Perspective: Toward "synthesis by design": Exploring atomic correlations during inorganic materials synthesis

    Science.gov (United States)

    Soderholm, L.; Mitchell, J. F.

    2016-05-01

    Synthesis of inorganic extended solids is a critical starting point from which real-world functional materials and their consequent technologies originate. However, unlike the rich mechanistic foundation of organic synthesis, with its underlying rules of assembly (e.g., functional groups and their reactivities), the synthesis of inorganic materials lacks an underpinning of such robust organizing principles. In the latter case, any such rules must account for the diversity of chemical species and bonding motifs inherent to inorganic materials and the potential impact of mass transport on kinetics, among other considerations. Without such assembly rules, there is less understanding, less predictive power, and ultimately less control of properties. Despite such hurdles, developing a mechanistic understanding for synthesis of inorganic extended solids would dramatically impact the range of new material discoveries and resulting new functionalities, warranting a broad call to explore what is possible. Here we discuss our recent approaches toward a mechanistic framework for the synthesis of bulk inorganic extended solids, in which either embryonic atomic correlations or fully developed phases in solutions or melts can be identified and tracked during product selection and crystallization. The approach hinges on the application of high-energy x-rays, with their penetrating power and large Q-range, to explore reaction pathways in situ. We illustrate this process using two examples: directed assembly of Zr clusters in aqueous solution and total phase awareness during crystallization from K-Cu-S melts. These examples provide a glimpse of what we see as a larger vision, in which large scale simulations, data-driven science, and in situ studies of atomic correlations combine to accelerate materials discovery and synthesis, based on the assembly of well-defined, prenucleated atomic correlations.

  1. One-Pot Two-Step Organocatalytic Asymmetric Synthesis of Spirocyclic Piperidones via Wolff Rearrangement–Amidation–Michael–Hemiaminalization Sequence

    Directory of Open Access Journals (Sweden)

    Yanqing Liu

    2017-02-01

    Full Text Available A highly enantioselective organocatalytic Wolff rearrangement–amidation–Michael–hemiaminalization stepwise reaction is described involving a cyclic 2-diazo-1,3-diketone, primary amine and α,β-unsaturated aldehyde. Product stereocontrol can be achieved by adjusting the sequence of steps in this one-pot multicomponent reaction. This approach was used to synthesize various optically active spirocyclic piperidones with three stereogenic centers and multiple functional groups in good yields up to 76%, moderate diastereoselectivities of up to 80:20 and high enantioselectivities up to 97%.

  2. Asymmetric Ugi 3CR on isatin-derived ketimine: synthesis of chiral 3,3-disubstituted 3-aminooxindole derivatives

    Directory of Open Access Journals (Sweden)

    Giordano Lesma

    2014-06-01

    Full Text Available An efficient Ugi three-component reaction of a preformed chiral ketimine derived from isatin with various isonitrile and acid components has been developed. The reactions proceeded smoothly and in a stereocontrolled manner with regard to the new center of the Ugi products due to the stereoinduction of the amine chiral residue. A wide variety of novel chiral 3,3-disubstituted 3-aminooxindoles were obtained, a selection of which were subjected to post-Ugi transformations, paving the way to application as peptidomimetics.

  3. The Chemical Synthesis of Discodermolide

    Science.gov (United States)

    Paterson, I.; Florence, G. J.

    The marine sponge-derived polyketide discodermolide is a potent antimitotic agent that represents a promising natural product lead structure in the treatment of cancer. Discodermolide shares the same microtubule-stabilising mechanism of action as Taxol®, inhibits the growth of solid tumours in animal models and shows synergy with Taxol. The pronounced cytotoxicity of discodermolide, which is maintained against cancer cell lines that display resistance to Taxol and other drugs, combined with its scarce availability from its natural source, has fuelled significant academic and industrial interest in devising a practical total synthesis as a means of ensuring a sustainable supply for drug development. This chapter surveys the various total syntheses of discodermolide that have been completed over the period 1993-2007, focusing on the strategies employed for introduction of the multiple stereocentres and achieving control over the alkene geometry, along with the various methods used for realising the pivotal fragment couplings to assemble progressively the full carbon skeleton. This dedicated synthetic effort has triumphed in removing the supply problem for discodermolide, providing sufficient material for extensive biological studies and enabling its early stage clinical development, as well as facilitating SAR studies for lead optimisation.

  4. Stellar population synthesis

    International Nuclear Information System (INIS)

    Pickles, A.J.

    1989-01-01

    The techniques used to derive astrophysically useful information from observations of the integrated light of composite stellar systems are briefly reviewed. A synthesis technique, designed to separate and describe on a standard system the competing effects of age and metallicity variations is introduced, and illustrated by its application to the study of the history of star formation in bright elliptical galaxies in clusters. (author)

  5. Enzymatic synthesis of vanillin

    NARCIS (Netherlands)

    van den Heuvel, RHH; Fraaije, MW; Laane, C; van Berkel, WJH; Heuvel, Robert H.H. van den; Berkel, Willem J.H. van

    Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated

  6. Enzymatic synthesis of vanillin

    NARCIS (Netherlands)

    Heuvel, van den R.H.H.; Fraaije, M.W.; Laane, C.; Berkel, van W.J.H.

    2001-01-01

    Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated

  7. Synthesis de 1-dotriacotanol

    International Nuclear Information System (INIS)

    Hernandez, L.; Gonzalez, J.C.

    1996-01-01

    In order to prepare isotopic labeled long chain aliphatic primary alcohol's, the synthesis overall yielding and chemical purity of 1-dotriacotanol were 41% and 98%, respectively. This procedure is very useful for carbon-14 and tritium labeling at Beta position of saturated fatty alcohol's

  8. Synthesis of acrylic prepolymer

    International Nuclear Information System (INIS)

    Hussin bin Mohd Nor; Dahlan bin Haji Mohd; Mohamad Hilmi bin Mahmood.

    1988-04-01

    An acrylic prepolymer was synthesized from glycidyl methacrylate (GMA), butyl methacrylate (BMA), methyl methacrylate (MMA) and acrylic acid (AA). Butyl acetate (BAc), benzoyl peroxide (BzO), 4-methoxyphenol (MPh) and triethylamine (TEA) were used as solvent, initiator, inhibitor and catalyst respectively. Observations of the synthesis leading to the formation of acrylic prepolymer are described. (author)

  9. Synthesis of new radiotracers

    International Nuclear Information System (INIS)

    Chahed, Ahlem

    2008-01-01

    The brain's sensibility besides to the rigorous selectivity of changes taking place on brain's barriers leads us to synthesis specifics radiotracers based on diamine ethylene and marked with technetium radioisotope to form a radiotracer able to pass these barriers and diagnose illnesses in an early stage. These radiotracers are tested by a biodistribution on a small animal to be ratified. (Author)

  10. Synthesis of arabinoxylan fragments

    DEFF Research Database (Denmark)

    Underlin, Emilie Nørmølle; Böhm, Maximilian F.; Madsen, Robert

    , or production of commercial chemicals which are mainly obtained from fossil fuels today.The arbinoxylan fragments have a backbone of β-1,4-linked xylans with α-L-arabinose units attached at specific positions. The synthesis ultilises an efficient synthetic route, where all the xylan units can be derived from D...

  11. [Synthesis of new nitrosoureas].

    Science.gov (United States)

    Papadaki-Valiraki, A; Siatra-Papastaikoudi, T; Skaltsounis, A L; Roussakis, C

    1989-01-01

    Two chemical pathways were used for the synthesis of three new N'-(2-chloroethyl)-N-[2-(4-alkoxyphenylthio)ethyl]-N'-nitrosoureas and two new N'-(2-chloroethyl)-N)[2-(4-alkoxyphenyl-thio)ethyl]-N-nitrosoureas . The study of the cytotoxicity of the three N'-nitrosoureas, was carried out in two experimental models (P 388 and NSCLCN6).

  12. MICROWAVES IN ORGANIC SYNTHESIS

    Science.gov (United States)

    The effect of microwaves, a non-ionizing radiation, on organic reactions is described both in polar solvents and under solvent-free conditions. The special applications are highlighted in the context of solventless organic synthesis which involve microwave (MW) exposure of neat r...

  13. SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ...

    African Journals Online (AJOL)

    Preferred Customer

    In the present study, synthesis, and biological evaluation of some novel ... Then slowly cooled and resultant mixture was basified with aqueous sodium hydroxide ... mol), anhydrous potassium carbonate (5.52 g, 0.04 mol) in acetone (25 mL), ...

  14. Synthesis, characterization and properties

    Indian Academy of Sciences (India)

    Unknown

    work, we report herein the synthesis, structural cha- racterization and properties of a chiral Mn(IV) mononuclear ... atmosphere with a platinum disc working electrode, a platinum wire auxiliary electrode and a Ag/AgCl ... SMART APEX CCD area detector system [λ(Mo-. Kα) = 0⋅71073 Å], graphite monochromator, 2400.

  15. A General Approach to the Basiliolide/Transtaganolide Natural Products: Total Syntheses of Basiliolide B, epi-8-Basiliolide B, Transtaganolide C, and Transtaganolide D

    KAUST Repository

    Nelson, Hosea M.; Murakami, Kei; Virgil, Scott C.; Stoltz, Brian M.

    2011-01-01

    (Figure Presented) In a flash: The total synthesis of transtaganolide and basiliolide natural products is achieved in three steps from achiral, monocyclic esters (see scheme). Featured in the syntheses are an Ireland-Claisen/Diels- Alder cascade

  16. Industrial scale gene synthesis.

    Science.gov (United States)

    Notka, Frank; Liss, Michael; Wagner, Ralf

    2011-01-01

    The most recent developments in the area of deep DNA sequencing and downstream quantitative and functional analysis are rapidly adding a new dimension to understanding biochemical pathways and metabolic interdependencies. These increasing insights pave the way to designing new strategies that address public needs, including environmental applications and therapeutic inventions, or novel cell factories for sustainable and reconcilable energy or chemicals sources. Adding yet another level is building upon nonnaturally occurring networks and pathways. Recent developments in synthetic biology have created economic and reliable options for designing and synthesizing genes, operons, and eventually complete genomes. Meanwhile, high-throughput design and synthesis of extremely comprehensive DNA sequences have evolved into an enabling technology already indispensable in various life science sectors today. Here, we describe the industrial perspective of modern gene synthesis and its relationship with synthetic biology. Gene synthesis contributed significantly to the emergence of synthetic biology by not only providing the genetic material in high quality and quantity but also enabling its assembly, according to engineering design principles, in a standardized format. Synthetic biology on the other hand, added the need for assembling complex circuits and large complexes, thus fostering the development of appropriate methods and expanding the scope of applications. Synthetic biology has also stimulated interdisciplinary collaboration as well as integration of the broader public by addressing socioeconomic, philosophical, ethical, political, and legal opportunities and concerns. The demand-driven technological achievements of gene synthesis and the implemented processes are exemplified by an industrial setting of large-scale gene synthesis, describing production from order to delivery. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Lipid synthesis in the aorta of chick and other species

    International Nuclear Information System (INIS)

    Rao, A.R.

    1976-01-01

    The relative rate of fatty acid biosynthesis from labelled acetate in the adipose tissue of chicken is much lower than that in the rat (O'Hea and Leveille, 1968). To determine similar species differences in lipid synthesis in the aortas of cock, rat, rabbit and monkey, thoracic and abdominal segments of fresh aortas were incubated in vitro with (1- 14 C)-acetate for 3 h. Total lipids and their fractions (free and total cholesterol, free fatty acids, triglycerides and phospholipids) were counted for radioactivity. Incorporation of radioactivity into total as well as all classes of lipids was several times greater in chicken than in other species. Significant and consistent incorporation into cholesterol occurred only in chicks. Synthesis into total lipids and triglycerides was greater in the thoracic segment of chicks. These findings (Rao and Rao, 1968) are consistent with the ready susceptibility of chicken to atherosclerosis. (author)

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

    Indian Academy of Sciences (India)

    Unknown

    An efficient synthesis of quinolines under solvent-free conditions. 201 was then irradiated with microwaves in a microwave oven (Samsung model# CE118KF) at 1050W (70% of total power) for 5 minutes (3 + 2 with an inter- mission of 5 minutes). The reaction mixture was cooled at room temperature and rendered basic (pH.

  19. Measuring Quality in Online Education: A Meta-Synthesis

    Science.gov (United States)

    Esfijani, Azam

    2018-01-01

    This article presents a meta-synthesis review of quality of online education (QOE) measurement approaches. In order to survey the existing body of knowledge, a qualitative method was employed to investigate what quality of online education is comprised of and how the concept has been measured through the literature. To achieve this, a total of 112…

  20. Novel Synthesis of 1-Oxo-10-epi-α-cyperone

    Institute of Scientific and Technical Information of China (English)

    CHEN Jin-Chun; ZHENG Guo-Jun; FANG Li-Jing; LI Yu-Lin

    2003-01-01

    @@ In the sesquiterpenic family, β-dihydroagarofuran and a large number of eudesmanes have an oxygenated func tional group at C1. [1] Although considerable efforts have been devoted to the total synthesis of eudesmane β-dihydroagarofuran and some germacrane sesquiterpenoids starting from the corresponding eudesmane over the pastdecades, the introduction of C1 oxygenated functional group still represents significant challenge.

  1. Using product driven process synthesis in the biorefinery

    NARCIS (Netherlands)

    Kiskini, A.; Zondervan, E.; Wierenga, P.A.; Poiesz, E.; Gruppen, H.

    2015-01-01

    In this work, we propose the use of the product-driven process synthesis (PDPS) methodology for the product and process design stage in biorefinery. The aim of the biorefinery is to optimize the total use of the whole feedstock – with focus being on various products simultaneously – rather than to

  2. Synthesis and characterization of thermally oxidized ZnO films

    Indian Academy of Sciences (India)

    Administrator

    Synthesis and characterization of thermally oxidized ZnO films. A P RAMBU1,* and N IFTIMIE2 .... R. −. Δ. = = (1) where Ra is the sensor resistance in the air and Rg is the .... ple, Aida and coworkers (2006) reported that the total oxidation is ...

  3. Synthesis of BiFeO3 by carbonate precipitation

    Indian Academy of Sciences (India)

    tional ceramic synthesis approach of mixing and heating the oxides of Bi and Fe ... −1 . Phase identification was carried out by X-ray powder diffraction using a PAN analytic ... of the total Fe ions in the starting solution have entered the. Bi2CO5 ...

  4. Optimization of process parameters for synthesis of silica–Ni ...

    Indian Academy of Sciences (India)

    The synthesis and characterization of nanostructured mate- rials has found importance .... 2, 3 such that xj = +1, −1 and 0, respectively representing the upper level, lower level ... N is the total number of experiments. In this case N is equal to 8.

  5. Modelling of flame temperature of solution combustion synthesis of ...

    Indian Academy of Sciences (India)

    Administrator

    The basis of combustion synthesis technique comes from the ... of oxidizer to fuel is calculated using the total oxidizing ..... +. −. ∑. (4) where S/Nm is the mean S/N ratio of all the experimental ..... Minitab Inc., User manual of MINITAB. TM.

  6. Total Petroleum Hydrocarbons (TPH): ToxFAQs

    Science.gov (United States)

    ... a state: This map displays locations where Total Petroleum Hydrocarbons (TPH) is known to be present. On ... I get more information? ToxFAQs TM for Total Petroleum Hydrocarbons (TPH) ( Hidrocarburos Totales de Petróleo (TPH) ) August ...

  7. Inhibition of chloroplast protein synthesis following light chilling of tomato

    International Nuclear Information System (INIS)

    Kent, J.; Ort, D.

    1989-01-01

    In the present study we looked at the effects of a high light chill on the pulsed incorporation of 35 S methionine into total, stromal, and thylakoid proteins of lightly abraded leaflets of 18-21 day old tomato (Lycopersicon esculentum Mill ca. Floramerica) seedlings. Based on gel fluorographic patterns of marker proteins that are indicative of the net rates of chloroplast and cytoplasmic protein synthesis, there appears to be a nearly complete cessation of chloroplastic protein synthesis. No labeling is observed for either the stromal large subunit of Rubisco or the thylakoid-bound alpha and beta subunits of the coupling factor. One notable exception, however, appears to be the 32 kd, D1 protein. Its net synthetic rate remains high despite the inhibition of other chloroplastically synthesized proteins. The small subunit of Rubicso, LHCP-II, as well as several other proteins of known cytoplasmic origin, were still synthesized, albeit, at lower than control rates. Light chilling of chill-insensitive spinach produced a similar, but less dramatic differential behavior between chloroplastic and cytoplasmic protein synthesis. It appears, in chilling-sensitive plants, that chloroplast protein synthesis exhibits a greater sensitivity to low temperature inhibition than does cytoplasmic protein synthesis and that recovery of chloroplast protein synthesis may play an important role in recovery of photosynthetic activity following chilling

  8. Stimulation of prostacyclin synthesis in rats by phenobarbital treatment

    International Nuclear Information System (INIS)

    Pynadath, T.I.; Haghighi, A.Z.

    1986-01-01

    Prostacyclin (PGI 2 ), synthesized in the endothelial cells of arteries, is known to inhibit the aggregation of platelets and hence thrombosis in blood. Low levels of PGI 2 have been observed in coronary heart disease which is associated with low levels of HDL in blood. Recently, it has been shown that synthesis of PGI 2 in vitro, is stimulated by HDL. Hence it seems likely that higher level of HDL in blood would increase the level of PGI 2 in blood. Since phenobarbital treatment is known to increase blood HDL levels in humans and animals, this study was undertaken to determine the effect of phenobarbital treatment on the synthesis of PGI 2 . Coronary vascular microsomes were prepared from Sprague Dawley rats treated with phenobarbital for two days. The PGI 2 synthesizing activity was assayed by incubating these microsomes with 1- 14 C-arachidonic acid and by determining the 14 C-activity recovered in 6-ketoprostaglandin F/sub 1α/, the stable decomposition product of PGI 2 . Phenobarbital treatment increased the synthesis of PGI 2 nearly 2-fold. Addition of phenobarbital did not increase PGI 2 synthesis in control microsomes; however, the synthesis was increased by HDL. Thus, it appears that the observed increase in PGI 2 synthesis resulting from phenobarbital treatment was partly, if not totally, due to the increase in blood HDL level

  9. Synthesis and applications of radiolabelled drugs in pharmaceutical development

    International Nuclear Information System (INIS)

    Landvatter, S.W.; Heys, J.R.; Garner, K.T.; Mack, J.F.; Senderoff, S.G.; Shu, A.Y.; Villani, A.J.; Saunders, D.

    1994-01-01

    Radiolabelled drugs play a vital role in the development of new pharmaceuticals including application in drug discovery, pre-clinical development and clinical development. The synthesis of these pharmaceuticals in tritium or carbon-14 labelled form poses many challenges for the synthetic organic chemist. The actual choice of synthetic route must take into account the small scale, limited choice and high cost of labelled precursors, and the positioning of the label into a metabolically stable position. There are, however, a number of synthetic strategies available for overcoming these constraints. Although in some C-14 syntheses the requisite labelled raw material can be purchased and the existing synthesis adapted for labelling, frequently the synthetic challenge is the synthesis of a structurally simple, yet commercially unavailable, labelled precursor (e.g., γ-butyrolactone-[2- 14 C], cyclohexanone-[ 3 H], CuCN-[ 14 C], 2-furancarboxaldehyde-[ 14 C]). Another useful strategy in C-14 synthesis is the conversion of an advanced intermediate, or perhaps the unlabelled product itself, into a precursor which can then be reconverted into the labelled version of the intermediate. Occasionally, a new total synthesis must be developed. In addition to these strategies, tritium labelling can uniquely take advantage of exchange labelling techniques, synthesis and reduction of unsaturated precursors, or tritium-halogen replacement reactions. Examples of these strategies and use of the labelled products are discussed

  10. Lutetium-177 DOTATATE Production with an Automated Radiopharmaceutical Synthesis System.

    Science.gov (United States)

    Aslani, Alireza; Snowdon, Graeme M; Bailey, Dale L; Schembri, Geoffrey P; Bailey, Elizabeth A; Pavlakis, Nick; Roach, Paul J

    2015-01-01

    Peptide Receptor Radionuclide Therapy (PRRT) with yttrium-90 ((90)Y) and lutetium-177 ((177)Lu)-labelled SST analogues are now therapy option for patients who have failed to respond to conventional medical therapy. In-house production with automated PRRT synthesis systems have clear advantages over manual methods resulting in increasing use in hospital-based radiopharmacies. We report on our one year experience with an automated radiopharmaceutical synthesis system. All syntheses were carried out using the Eckert & Ziegler Eurotope's Modular-Lab Pharm Tracer® automated synthesis system. All materials and methods used were followed as instructed by the manufacturer of the system (Eckert & Ziegler Eurotope, Berlin, Germany). Sterile, GMP-certified, no-carrier added (NCA) (177)Lu was used with GMP-certified peptide. An audit trail was also produced and saved by the system. The quality of the final product was assessed after each synthesis by ITLC-SG and HPLC methods. A total of 17 [(177)Lu]-DOTATATE syntheses were performed between August 2013 and December 2014. The amount of radioactive [(177)Lu]-DOTATATE produced by each synthesis varied between 10-40 GBq and was dependant on the number of patients being treated on a given day. Thirteen individuals received a total of 37 individual treatment administrations in this period. There were no issues and failures with the system or the synthesis cassettes. The average radiochemical purity as determined by ITLC was above 99% (99.8 ± 0.05%) and the average radiochemical purity as determined by HPLC technique was above 97% (97.3 ± 1.5%) for this period. The automated synthesis of [(177)Lu]-DOTATATE using Eckert & Ziegler Eurotope's Modular-Lab Pharm Tracer® system is a robust, convenient and high yield approach to the radiolabelling of DOTATATE peptide benefiting from the use of NCA (177)Lu and almost negligible radiation exposure of the operators.

  11. Prebiotic synthesis of histidine

    Science.gov (United States)

    Shen, C.; Yang, L.; Miller, S. L.; Oro, J.

    1990-01-01

    The prebiotic formation of histidine (His) has been accomplished experimentally by the reaction of erythrose with formamidine followed by a Strecker synthesis. In the first step of this reaction sequence, the formation of imidazole-4-acetaldehyde took place by the condensation of erythrose and formamidine, two compounds that are known to be formed under prebiotic conditions. In a second step, the imidazole-4-acetaldehyde was converted to His, without isolation of the reaction products by adding HCN and ammonia to the reaction mixture. LC, HPLC, thermospray liquid chromatography-mass spectrometry, and tandem mass spectrometry were used to identify the product, which was obtained in a yield of 3.5% based on the ratio of His/erythrose. This is a new chemical synthesis of one of the basic amino acids which had not been synthesized prebiotically until now.

  12. Voice synthesis application

    Science.gov (United States)

    Lightstone, P. C.; Davidson, W. M.

    1982-04-01

    The military detection assessment laboratory houses an experimental field system which assesses different alarm indicators such as fence disturbance sensors, MILES cables, and microwave Racons. A speech synthesis board which could be interfaced, by means of a computer, to an alarm logger making verbal acknowledgement of alarms possible was purchased. Different products and different types of voice synthesis were analyzed before a linear predictive code device produced by Telesensory Speech Systems of Palo Alto, California was chosen. This device is called the Speech 1000 Board and has a dedicated 8085 processor. A multiplexer card was designed and the Sp 1000 interfaced through the card into a TMS 990/100M Texas Instrument microcomputer. It was also necessary to design the software with the capability of recognizing and flagging an alarm on any 1 of 32 possible lines. The experimental field system was then packaged with a dc power supply, LED indicators, speakers, and switches, and deployed in the field performing reliably.

  13. Synthesis of quantum dots

    Science.gov (United States)

    McDaniel, Hunter

    2017-10-17

    Common approaches to synthesizing alloyed quantum dots employ high-cost, air-sensitive phosphine complexes as the selenium precursor. Disclosed quantum dot synthesis embodiments avoid these hazardous and air-sensitive selenium precursors. Certain embodiments utilize a combination comprising a thiol and an amine that together reduce and complex the elemental selenium to form a highly reactive selenium precursor at room temperature. The same combination of thiol and amine acts as the reaction solvent, stabilizing ligand, and sulfur source in the synthesis of quantum dot cores. A non-injection approach may also be used. The optical properties of the quantum dots synthesized by this new approach can be finely tuned for a variety of applications by controlling size and/or composition of size and composition. Further, using the same approach, a shell can be grown around a quantum dot core that improves stability, luminescence efficiency, and may reduce toxicity.

  14. Benzoylurea Chitin Synthesis Inhibitors.

    Science.gov (United States)

    Sun, Ranfeng; Liu, Chunjuan; Zhang, Hao; Wang, Qingmin

    2015-08-12

    Benzoylurea chitin synthesis inhibitors are widely used in integrated pest management (IPM) and insecticide resistance management (IRM) programs due to their low toxicity to mammals and predatory insects. In the past decades, a large number of benzoylurea derivatives have been synthesized, and 15 benzoylurea chitin synthesis inhibitors have been commercialized. This review focuses on the history of commercial benzolyphenylureas (BPUs), synthetic methods, structure-activity relationships (SAR), action mechanism research, environmental behaviors, and ecotoxicology. Furthermore, their disadvantages of high risk to aquatic invertebrates and crustaceans are pointed out. Finally, we propose that the para-substituents at anilide of benzoylphenylureas should be the functional groups, and bipartite model BPU analogues are discussed in an attempt to provide new insight for future development of BPUs.

  15. Phase contrast image synthesis

    DEFF Research Database (Denmark)

    Glückstad, J.

    1996-01-01

    A new method is presented for synthesizing arbitrary intensity patterns based on phase contrast imaging. The concept is grounded on an extension of the Zernike phase contrast method into the domain of full range [0; 2 pi] phase modulation. By controlling the average value of the input phase funct...... function and by choosing appropriate phase retardation at the phase contrast filter, a pure phase to intensity imaging is accomplished. The method presented is also directly applicable in dark field image synthesis....

  16. synthesis and structures

    Indian Academy of Sciences (India)

    Priya Saxena

    2017-08-29

    Aug 29, 2017 ... to a single crystal X-ray diffraction study for 1, 2 and 4-7. Keywords. Sterically .... 2.2b Mono-Schiff base 2: A suspension of I (1.00 g,. 2.27 mmol) and ...... bridge Crystallographic Data Centre, CCDC, 12 Union. Road, Cambridge .... H-C 2014 Rational design and synthesis of porous poly- mer networks: ...

  17. Synthesis of stress proteins in winter wheat seedlings under gamma-radiation

    International Nuclear Information System (INIS)

    Gudkova, N.V.; Kosakovskaya, I.V.; Major, P.S.

    2001-01-01

    A universal cellular response to a number of diverse stresses is the synthesis of a set of stress proteins. Most of them are heat shock proteins (HSP). We show that both heat shock and gamma-radiation enhance the synthesis of HSP70 in the total protein fractions of winter wheat seedlings. It is found that a dose of 15 Gy induced the synthesis of 35 and 45 kD proteins after 5 h of irradiation in both total and mitochondrial protein fractions. On the second day after exposure, both 35 and 45 kD proteins were not observed, but new total proteins with a molecular weight of 90 and 92 kD appeared. The synthesis of 35 and 45 kD proteins after gamma-irradiation is revealed for the first time, their function being now unknown

  18. Retinal protein synthesis in relationship to environmental lighting

    International Nuclear Information System (INIS)

    Hollyfield, J.G.; Anderson, R.E.

    1982-01-01

    A series of in vivo and in vitro experiments using Xenopus laevis juvenile toads was conducted to probe the relationship between environmental lighting and protein synthesis in the retina. Autoradiographic and biochemical analyses indicated that measurable changes in protein synthesis did not occur during a normal diurnal cycle when animals were conditioned to 12 hr light followed by 12 hr darkness each day (LD). However, when retinas from animals maintained in continuous darkness (DD) for 3 days were incubated with 3 H-leucine, there was a 40% reduction in the specific radioactivity of total retinal proteins compared with retinas from animals maintained in continuous light (LL) for 3 days or on the LD cycle. Retinas from DD animals injected with 3 H-leucine showed a 48% reduction in protein synthesis compared with retinas of LL animals. In autoradiographs of retinas from in vivo or in vitro experiments, grain counts were 40% lower in the total retinas of the DD animals compared with retinas of LL animals. This reduction occurred throughout the entire retina and was not restricted to any specific cell type. There was also a 35% reduction in the rate of radioactive band displacement in the rod outer segments of DD animals, although the percent of 3 H-leucine incorporated into opsin relative to total retinal protein was the same for both groups. We conclude from these studies that fluctuations in the rate of protein synthesis during the normal light-dark cycle are not detectable. However, major differences in protein synthesis are evident when animals are stressed with continuous darkness for several days. This effect is not restricted to any particular retinal layer but occurs throughout the entire retina. Moreover, prolonged darkness affects protein synthesis in extraocular tissues as well

  19. Distributed PROMPT-LTL Synthesis

    Directory of Open Access Journals (Sweden)

    Swen Jacobs

    2016-09-01

    Full Text Available We consider the synthesis of distributed implementations for specifications in Prompt Linear Temporal Logic (PROMPT-LTL, which extends LTL by temporal operators equipped with parameters that bound their scope. For single process synthesis it is well-established that such parametric extensions do not increase worst-case complexities. For synchronous systems, we show that, despite being more powerful, the distributed realizability problem for PROMPT-LTL is not harder than its LTL counterpart. For asynchronous systems we have to consider an assume-guarantee synthesis problem, as we have to express scheduling assumptions. As asynchronous distributed synthesis is already undecidable for LTL, we give a semi-decision procedure for the PROMPT-LTL assume-guarantee synthesis problem based on bounded synthesis.

  20. Integrated methanol synthesis

    International Nuclear Information System (INIS)

    Jaeger, W.

    1982-01-01

    This invention concerns a plant for methanol manufacture from gasified coal, particularly using nuclear power. In order to reduce the cost of the hydrogen circuits, the methanol synthesis is integrated in the coal gasification plant. The coal used is gasified with hydration by means of hydrogen and the crude gas emerging, after cooling and separating the carbon dioxide and hydrogen sulphide, is mixed with the synthetic gas leaving the methane cracking furnace. This mixture is taken to the methanol synthesis and more than 90% is converted into methanol in one pass. The gas mixture remaning after condensation and separation of methanol is decomposed into three fractions in low temperature gas decomposition with a high proportion of unconverted carbon monoxide. The flow of methane is taken to the cracking furnace with steam, the flow of hydrogen is taken to the hydrating coal gasifier, and the flow of carbon monoxide is taken to the methanol synthesis. The heat required for cracking the methane can either be provided by a nuclear reactor or by the coke left after hydrating gasification. (orig./RB) [de

  1. Gold Nanoparticle Microwave Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Krantz, Kelsie E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Christian, Jonathan H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coopersmith, Kaitlin [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Washington, II, Aaron L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-07-27

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  2. Chemistry of Ammonothermal Synthesis

    Directory of Open Access Journals (Sweden)

    Theresia M. M. Richter

    2014-02-01

    Full Text Available Ammonothermal synthesis is a method for synthesis and crystal growth suitable for a large range of chemically different materials, such as nitrides (e.g., GaN, AlN, amides (e.g., LiNH2, Zn(NH22, imides (e.g., Th(NH2, ammoniates (e.g., Ga(NH33F3, [Al(NH36]I3 · NH3 and non-nitrogen compounds like hydroxides, hydrogen sulfides and polychalcogenides (e.g., NaOH, LiHS, CaS, Cs2Te5. In particular, large scale production of high quality crystals is possible, due to comparatively simple scalability of the experimental set-up. The ammonothermal method is defined as employing a heterogeneous reaction in ammonia as one homogenous fluid close to or in supercritical state. Three types of milieus may be applied during ammonothermal synthesis: ammonobasic, ammononeutral or ammonoacidic, evoked by the used starting materials and mineralizers, strongly influencing the obtained products. There is little known about the dissolution and materials transport processes or the deposition mechanisms during ammonothermal crystal growth. However, the initial results indicate the possible nature of different intermediate species present in the respective milieus.

  3. Gold Nanoparticle Microwave Synthesis

    International Nuclear Information System (INIS)

    Krantz, Kelsie E.; Christian, Jonathan H.; Coopersmith, Kaitlin; Washington II, Aaron L.; Murph, Simona H.

    2016-01-01

    At the nanometer scale, numerous compounds display different properties than those found in bulk material that can prove useful in areas such as medicinal chemistry. Gold nanoparticles, for example, display promise in newly developed hyperthermia therapies for cancer treatment. Currently, gold nanoparticle synthesis is performed via the hot injection technique which has large variability in final particle size and a longer reaction time. One underdeveloped area by which these particles could be produced is through microwave synthesis. To initiate heating, microwaves agitate polar molecules creating a vibration that gives off the heat energy needed. Previous studies have used microwaves for gold nanoparticle synthesis; however, polar solvents were used that partially absorbed incident microwaves, leading to partial thermal heating of the sample rather than taking full advantage of the microwave to solely heat the gold nanoparticle precursors in a non-polar solution. Through this project, microwaves were utilized as the sole heat source, and non-polar solvents were used to explore the effects of microwave heating only as pertains to the precursor material. Our findings show that the use of non-polar solvents allows for more rapid heating as compared to polar solvents, and a reduction in reaction time from 10 minutes to 1 minute; this maximizes the efficiency of the reaction, and allows for reproducibility in the size/shape of the fabricated nanoparticles.

  4. Feature-aware natural texture synthesis

    KAUST Repository

    Wu, Fuzhang; Dong, Weiming; Kong, Yan; Mei, Xing; Yan, Dongming; Zhang, Xiaopeng; Paul, Jean Claude

    2014-01-01

    This article presents a framework for natural texture synthesis and processing. This framework is motivated by the observation that given examples captured in natural scene, texture synthesis addresses a critical problem, namely, that synthesis

  5. A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

    Directory of Open Access Journals (Sweden)

    Arno Verlee

    2017-02-01

    Full Text Available For the synthesis of m-sulfamoylbenzamide analogues, small molecules which are known for their bioactivity, a chemoselective procedure has been developed starting from m-(chlorosulfonylbenzoyl chloride. Although a chemoselective process in batch was already reported, a continuous-flow process reveals an increased selectivity at higher temperatures and without catalysts. In total, 15 analogues were synthesized, using similar conditions, with yields ranging between 65 and 99%. This is the first automated and chemoselective synthesis of m-sulfamoylbenzamide analogues.

  6. A divergent synthesis of the delta(13)-9-isofurans.

    Science.gov (United States)

    Taber, Douglass F; Gu, Peiming; Li, Rui

    2009-08-07

    A stereodivergent total synthesis of the Delta(13)-9-isofurans has been developed. The four core substituted tetrahydrofurans were prepared by the Sharpless asymmetric epoxidation and Sharpless asymmetric dihydroxylation followed by cascade cyclization. The relative configuration at C-8 was inverted by oxidation followed by immediate L-Selectride reduction. The relative configuration of the C-15 diastereomers was assigned by (S)-Binol/LAH/EtOH reduction of the corresponding enone. This synthesis of the Delta(13)-9-isofurans will provide sufficient material for further investigation of their biological activity.

  7. A Divergent Synthesis of the Δ13-9-Isofurans

    Science.gov (United States)

    Taber, Douglass F.; Gu, Peiming; Li, Rui

    2009-01-01

    A stereodivergent total synthesis of the Δ13-9-isofurans has been developed. The four core substituted tetrahydrofurans were prepared by the Sharpless asymmetric epoxidation and Sharpless asymmetric dihydroxylation followed by cascade cyclization. The relative configuration at C-8 was inverted by oxidation followed by immediate L-selectride reduction. The relative configuration of the C-15 diastereomers were assigned by (S)-Binol/LAH/EtOH reduction of the corresponding enone. This synthesis of the Δ13-9-isofurans will provide sufficient material for further investigation of their biological activity. PMID:19572754

  8. Robotic synthesis of L-[1-11C]tyrosine

    International Nuclear Information System (INIS)

    Luurtsema, Gert; Medema, Jitze; Elsinga, P.H.; Visser, G.M.; Vaalburg, Willem

    1994-01-01

    L-[1- 11 C]tyrosine promises to become an important tracer for determination of the protein synthesis rate (PSR) in tumor tissue and brain. The commercially available Anatech RB-86 robotic system is utilized for the automation of the L-[1- 11 C]tyrosine production via the isocyanide method as reported by Bolster et al. (Eur. J. Nucl. Med. 12, 321-324, 1986). The total synthesis time, including HPLC-purification and enantiomeric separation is 60 min. With a practical yield of 20 mCi L-[1- 11 C]tyrosine at a specific activity > 1000 Ci/mmol. (author)

  9. Structure elucidation and stereoselective total synthesis of pavettamine, the causal agent of gousiekte

    CSIR Research Space (South Africa)

    Bode, ML

    2010-03-01

    Full Text Available resolution fast atom bombardment (FAB) mass spectra were recorded by Dr. L. Fourie, University of Potchefstroom, on a VG 7070-E spectrometer (Xe beam, m-nitrobenzyl alcohol matrix, detection of positive ions with m/z>99). Electrospray-mass spectrometry (ES...), 45.46T (C-1), 31.46T and 31.16T (C-3), 30.00Q ((CH3)2C), 28.44Q (C(CH3)3), 19.87Q and 19.71Q ((CH3)2C). HRMS (FAB): m/z 631.4042 (M+); calcd for C31H57N3O10: 631.4044. 3.5 Diethyl (2S)-malate (4) (2S)-Malic acid (100 g, 0.746 mol) was suspended...

  10. A concise total synthesis of (R)-fluoxetine, a potent and selective serotonin reuptake inhibitor

    International Nuclear Information System (INIS)

    Fatima, Angelo de; Lapis, Alexandre Augusto M.; Pilli, Ronaldo A.

    2005-01-01

    (R)-Fluoxetine, potent and selective serotonin reuptake inhibitor, has been synthesized in six steps, 50% overall yield and 99% ee from benzaldehyde via catalytic asymmetric allylation with Maruoka's catalyst. (author)

  11. A concise total synthesis of (R)-fluoxetine, a potent and selective serotonin reuptake inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Fatima, Angelo de; Lapis, Alexandre Augusto M.; Pilli, Ronaldo A. [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica]. E-mail: pilli@iqm.unicamp.br

    2005-05-15

    (R)-Fluoxetine, potent and selective serotonin reuptake inhibitor, has been synthesized in six steps, 50% overall yield and 99% ee from benzaldehyde via catalytic asymmetric allylation with Maruoka's catalyst. (author)

  12. Total Synthesis of ent-Pregnanolone Sulfate and Its Biological Investigation at the NMDA Receptor

    Czech Academy of Sciences Publication Activity Database

    Kapras, Vojtěch; Vyklický, Vojtěch; Buděšínský, Miloš; Císařová, I.; Vyklický ml., Ladislav; Chodounská, Hana; Jahn, Ullrich

    2018-01-01

    Roč. 20, č. 4 (2018), s. 946-949 ISSN 1523-7060 R&D Projects: GA ČR(CZ) GBP304/12/G069; GA TA ČR(CZ) TE01020028; GA MZd(CZ) NV15-29370A Grant - others:AV ČR(CZ) MSM200111601 Program:Program na podporu mezinárodní spolupráce začínajících výzkumných pracovníků Institutional support: RVO:61388963 ; RVO:67985823 Keywords : Wieland-Miescher ketone * palladium-catalyzed reduction * neuroactive steroids Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 6.579, year: 2016

  13. Total synthesis of haterumalides NA and NC via a chromium-mediated macrocyclization.

    Science.gov (United States)

    Schomaker, Jennifer M; Borhan, Babak

    2008-09-17

    The syntheses of haterumalides NA and NC were accomplished via the macrocyclization of a chlorovinylidene chromium carbenoid onto a pendant aldehyde to generate the C8-C9 bond with the desired stereoisomer as the major product. Utilizing the latter chemistry enables access to both C9 hydroxylated (haterumalides NC and ND) and C9 deoxygenated forms (haterumalides NA, NB, and NE; via deoxygenation of the C9-hydroxyl).

  14. Enantioselective total synthesis of (+)-brefeldin A and 7-epi-brefeldin A.

    Science.gov (United States)

    Wu, Yikang; Shen, Xin; Yang, Yong-Qing; Hu, Qi; Huang, Jia-Hui

    2004-05-28

    A convergent enantioselective route to brefeldin A (BFA) and 7-epi-BFA was developed. The key C-4/C-5 chiral centers were established by using chiral auxiliary induced intermolecular asymmetric aldolization in the presence of TiCl(4) and TMEDA. The results with the thiazolidinethione/TiCl(4) mediated intermolecular asymmetric aldolization added some new information about the scope and limitations to the existing knowledge of that type of reactions (which so far was essentially limited to the reactions with N-propionyl thiazolidinethiones). During the course a method for protecting the liable aldol hydroxyl groups by using inexpensive TBSCl in DMF with 2,6-lutidine as the base was developed to replace the otherwise unavoidable TBSOTf procedure. Due to the excessive steric hindrance, removal of the auxiliary was much more difficult than most literature cases. Cleavage of the oxazolidinone by reduction was almost impossible. The thiazolidinethione auxiliary was relatively easier to remove. However, several reactions reported for facile removal of thiazolidinethione auxiliaries in the literature still failed. Reductive removal of the thiazolidinethione auxiliary was most effectively realized with LiBH(4) in diethyl ether in the presence of 1 equiv of MeOH (a modification of a literature procedure for removal of oxazolidinone auxiliaries in less hindered substrates). Apart from the auxiliary removal, oxidation of the alcohol into aldehyde and the deprotection of the dithiolane protecting group were also rather difficult in the present context. A range of methods were screened before final solutions were found. The five-membered ring was constructed by employing an intramolecular Mukaiyama reaction after many attempts with the intramolecular aldolization under a variety of conditions failed. The rate of elimination of the alkoxyl to form the alpha,beta-double bond of the key intermediate cyclopentenone 49 with DBU was highly solvent dependent (very sluggish in CH(2)Cl(2) but rather fast in MeOH). Introduction of the lower chain (which was synthesized by using a Jacobsen KHR to establish the C-15 chirality) was achieved through a Michael addition similar to the precedents in the literature. It has not been noticed before that the yield of this Michael reaction could be dramatically raised by using 3 equiv of the copper-lithium reagent 55. Reduction of the C-7 carbonyl was apparently more difficult than similar cases in the literature. After examination of many reagents under various conditions, it was found that the best reagent for yielding the alpha-isomer was (S)-2-methyl-CBS-borolidine/BH(3) and that for the beta-isomer was L-Selectride. The alpha- and beta-isomers were then further elaborated into (+)-brefeldin A and 7-epi-BFA, respectively. An unexpected yet very interesting solubility difference between BFA and 7-epi-BFA was also observed.

  15. Total synthesis and related studies of large, strained, and bioactive natural products

    Science.gov (United States)

    HIRAMA, Masahiro

    2016-01-01

    Our chemical syntheses and related scientific investigations of natural products with complex architectures and powerful biological activities are described, focusing on the very large 3 nm-long polycyclic ethers called the ciguatoxins, highly strained and labile chromoprotein antitumor antibiotics featuring nine-membered enediyne cores, and extremely potent anthelmintic macrolides called the avermectins. PMID:27725470

  16. Tandem ring-closing metathesis/isomerization reactions for the total synthesis of violacein

    DEFF Research Database (Denmark)

    Petersen, Mette Terp; Nielsen, Thomas Eiland

    2013-01-01

    A series of 5-substituted 2-pyrrolidinones was synthesized through a one-pot ruthenium alkylidene-catalyzed tandem RCM/isomerization/nucleophilic addition sequence. The intermediates resulting from RCM/isomerization showed reactivity toward electrophiles in aldol condensation reactions which...

  17. Enantioselective Allylation of Thiophene-2-carbaldehyde: Formal Total Synthesis of Duloxetine

    Czech Academy of Sciences Publication Activity Database

    Motloch, P.; Valterová, Irena; Kotora, M.

    2014-01-01

    Roč. 356, č. 1 (2014), s. 199-204 ISSN 1615-4150 Grant - others:GA ČR(CZ) GAP207/11/0587 Institutional support: RVO:61388963 Keywords : aldehydes * allylation * Lewis bases * organocatalysis * synthetic methods Subject RIV: CC - Organic Chemistry Impact factor: 5.663, year: 2014

  18. Scalable total synthesis and comprehensive structure-activity relationship studies of the phytotoxin coronatine.

    Science.gov (United States)

    Littleson, Mairi M; Baker, Christopher M; Dalençon, Anne J; Frye, Elizabeth C; Jamieson, Craig; Kennedy, Alan R; Ling, Kenneth B; McLachlan, Matthew M; Montgomery, Mark G; Russell, Claire J; Watson, Allan J B

    2018-03-16

    Natural phytotoxins are valuable starting points for agrochemical design. Acting as a jasmonate agonist, coronatine represents an attractive herbicidal lead with novel mode of action, and has been an important synthetic target for agrochemical development. However, both restricted access to quantities of coronatine and a lack of a suitably scalable and flexible synthetic approach to its constituent natural product components, coronafacic and coronamic acids, has frustrated development of this target. Here, we report gram-scale production of coronafacic acid that allows a comprehensive structure-activity relationship study of this target. Biological assessment of a >120 member library combined with computational studies have revealed the key determinants of potency, rationalising hypotheses held for decades, and allowing future rational design of new herbicidal leads based on this template.

  19. Scalable total synthesis and comprehensive structure–activity relationship studies of the phytotoxin coronatine

    OpenAIRE

    Littleson, Mairi M.; Baker, Christopher M.; Dalençon, Anne J.; Frye, Elizabeth C.; Jamieson, Craig; Kennedy, Alan R.; Ling, Kenneth B.; McLachlan, Matthew M.; Montgomery, Mark G.; Russell, Claire J.; Watson, Allan J. B.

    2018-01-01

    The authors thank the EPSRC UK National Mass Spectrometry Facility at Swansea University for analyses, the University of Strathclyde for PhD studentship (M.M.L), and Syngenta for financial and chemical support. Natural phytotoxins are valuable starting points for agrochemical design. Acting as a jasmonate agonist, coronatine represents an attractive herbicidal lead with novel mode of action, and has been an important synthetic target for agrochemical development. However, both restricted a...

  20. A Phylogenetic Synthesis for Oceanic Dolphins: Total Evidence, Cytonuclear Discordance, and Possible Introgressive Hybridization

    OpenAIRE

    Haisten, David

    2016-01-01

    Introgressive hybridization is increasingly being detected in vertebrate taxa but was thought to be rare in mammals. Recent evidence suggests that this view might not correct and cetaceans may be pre-disposed for the capacity to hybridize. Numerous instances of cetacean (dolphins, whales, and porpoises) hybridization have been reported both in captivity and in the wild, many of which occurred in oceanic dolphins: family Delphinidae. The rapid radiation of Delphinidae commenced during the Mio...

  1. Asymmetric total synthesis of 6-Tuliposide B and its biological activities against tulip pathogenic fungi.

    Science.gov (United States)

    Shigetomi, Kengo; Omoto, Shoko; Kato, Yasuo; Ubukata, Makoto

    2011-01-01

    The structure-activity relationship was investigated to evaluate the antifungal activities of tuliposides and tulipalins against tulip pathogenic fungi. 6-Tuliposide B was effectively synthesized via the asymmetric Baylis-Hillman reaction. Tuliposides and tulipalins showed antifungal activities against most of the strains tested at high concentrations (2.5 mM), while Botrytis tulipae was resistant to tuliposides. Tulipalin formation was involved in the antifungal activity, tulipalin A showed higher inhibitory activity than 6-tuliposide B and tulipalin B. Both the tuliposides and tulipalins showed pigment-inducing activity against Gibberella zeae and inhibitory activity against Fusarium oxysporum f. sp tulipae. These activities were induced at a much lower concentration (0.05 mM) than the antifungal MIC values.

  2. A facile and rapid automated synthesis of 3'-deoxy-3'-[18F]fluorothymidine

    International Nuclear Information System (INIS)

    Tang Ganghua; Tang Xiaolan; Wen Fuhua; Wang Mingfang; Li Baoyuan

    2010-01-01

    Aim: To develop a simplified and fully automated synthesis procedure of 3'-deoxy-3'-[ 18 F]fluorothymidine ([ 18 F]FLT) using PET-MF-2V-IT-I synthesis module. Methods: Synthesis of [ 18 F]FLT was performed using PET-MF-2V-IT-I synthesis module by one-pot two-step reaction procedure, including nucleophilic fluorination of 3-N-t-butoxycarbonyl-1-[5'-O-(4,4'-dimethoxy triphenylmethyl)-2'-deoxy-3'-O-(4-nitrobenzenesulfonyl) -β-D-threopentofuranosyl]thymine (15 mg) as the precursor molecule with [ 18 F]fluoride, and subsequent hydrolysis of the protecting group with 1.0 M HCl at the same reaction vessel and purification with SEP PAK cartridges instead of the HPLC system. Results: The automated synthesis of [ 18 F]FLT with SEP PAK purification gave corrected radiochemical yield of 23.2±2.6% (n=6, uncorrected yield: 16-22%) and radiochemical purity of >97% within the total synthesis time of 35 min. Conclusion: The fully one-pot automated synthesis procedure with SEP PAK purification can be applied to the fully automated synthesis of [ 18 F]FLT using commercial [ 18 F]FDG synthesis module.

  3. RNA synthesis during germination of UV-irradiated Dictyostelium discoideum spores

    International Nuclear Information System (INIS)

    Okaichi, Kumio

    1987-01-01

    UV irradiation to the spores of Dictyostelium discoideum NC4 resulted in a more prolonged delay of amoeba-emergence from swollen spores with increasing UV fluence. During the germination, an inhibition of total RNA synthesis and a shift of stage of maximum RNA synthesis to the later period were observed. The maximum poly(A) + RNA synthetic activity was found on an early stage of amoeba-emergence prior about 1 h to the beginning of rRNA synthesis in unirradiated spore germination; but, in UV-irradiated spore germination, the stage of maximum poly(A) + RNA synthesis shifted to the later stage of germination with increasing UV fluence. A decreased synthesis of poly(A) + RNA and a severe inhibition of rRNA synthesis were observed on UV-irradiated and germinated spores, but no significant inhibition of 4 - 5 S RNA synthesis was detected. Actinomycin D suppressed almost completely the rRNA synthesis of emerged amoebae but the drug apparently did not affect the emergence of amoebae at any stage of germination. It was postulated that the delay of amoeba-emergence in UV-irradiated spore must be mainly due to the shift of the stage of maximum synthesis of poly(A) + RNA to the later stage of germination. (author)

  4. Effects of toluene on protein synthesis and the interaction with ethanol in hepatocytes isolated from fed and fasted rats

    International Nuclear Information System (INIS)

    Smith-Kielland, A.; Ripel, Aa.; Gadeholt, G.

    1989-01-01

    The effects of three different concentrations (about 20, 100 and 1000 μM) of toluene on protein synthesis were studied in hepatocytes isolated from fed and fasted rats after 60 and 120 min. of incubation. The interaction between ethanol (60 mM) and the low and high toluene concentrations were also tested. To measure protein synthesis, 14 C-valine was used as the precursor amino acid. Total valine concentration was 2 mM to ensure near-constant specific radioactivity of precursor. Toluene concentrations were measured by head-space gas chromatography. Protein synthesis was unchanged in the presence of low toluene concentrations. Intermediate toluene concentration decreased protein synthesis by about 20% and high toluene concentration decreased protein synthesis by about 60%. Protein synthesis was similar in cells from fed and fasted rats. Ethanol alone inhibited protein synthesis by 20-30%, more in fasted than in fed rats. Toluene and ethanol in combination inhibited protein synthesis additively. The high toluene concentration with or without ethanol appeared to inhibit synthesis/secretion of export proteins in hepatocytes from fasted rats. In conclusion, our study indicates that toluene in relatively high concentrations inhibits general protein synthesis in isolated rat hepatocytes. Toluene and ethanol seems to inhibit protein synthesis additively. (author)

  5. Effects of toluene on protein synthesis and the interaction with ethanol in hepatocytes isolated from fed and fasted rats

    Energy Technology Data Exchange (ETDEWEB)

    Smith-Kielland, A.; Ripel, Aa.; Gadeholt, G.

    1989-01-01

    The effects of three different concentrations (about 20, 100 and 1000 ..mu..M) of toluene on protein synthesis were studied in hepatocytes isolated from fed and fasted rats after 60 and 120 min. of incubation. The interaction between ethanol (60 mM) and the low and high toluene concentrations were also tested. To measure protein synthesis, /sup 14/C-valine was used as the precursor amino acid. Total valine concentration was 2 mM to ensure near-constant specific radioactivity of precursor. Toluene concentrations were measured by head-space gas chromatography. Protein synthesis was unchanged in the presence of low toluene concentrations. Intermediate toluene concentration decreased protein synthesis by about 20% and high toluene concentration decreased protein synthesis by about 60%. Protein synthesis was similar in cells from fed and fasted rats. Ethanol alone inhibited protein synthesis by 20-30%, more in fasted than in fed rats. Toluene and ethanol in combination inhibited protein synthesis additively. The high toluene concentration with or without ethanol appeared to inhibit synthesis/secretion of export proteins in hepatocytes from fasted rats. In conclusion, our study indicates that toluene in relatively high concentrations inhibits general protein synthesis in isolated rat hepatocytes. Toluene and ethanol seems to inhibit protein synthesis additively.

  6. Theses of the reports of the XXXI Zvenigorod conference on the plasma physics and controlled thermonuclear synthesis

    International Nuclear Information System (INIS)

    Kovrizhnykh, L.M.; Ivanov, V.A.; Nagaeva, M.L.; Aleksandrov, A.F.; Vorob'ev, V.S.; Ivanenkov, G.V.; Meshcheryakov, A.I.

    2004-01-01

    Theses of the reports of the 31th Zvenigorod Conference on the physics and controlled thermonuclear synthesis, presented by Russian and foreign scientists, are published. The total number of reports is 258, namely, summarizing ones 16, magnetic confinement of high temperature plasma - 98, inertial thermonuclear synthesis - 44, physical processes in low temperature plasma - 58, physical bases of plasma and beam technologies - 42 [ru

  7. Synthesis of (+)-dumetorine and congeners by using flow chemistry technologies.

    Science.gov (United States)

    Riva, Elena; Rencurosi, Anna; Gagliardi, Stefania; Passarella, Daniele; Martinelli, Marisa

    2011-05-23

    An efficient total synthesis of the natural alkaloid (+)-dumetorine by using flow technology is described. The process entailed five separate steps starting from the enantiopure (S)-2-(piperidin-2-yl)ethanol 4 with 29% overall yield. Most of the reactions were carried out by exploiting solvent superheating and by using packed columns of immobilized reagents or scavengers to minimize handling. New protocols for performing classical reactions under continuous flow are disclosed: the ring-closing metathesis reaction with a novel polyethylene glycol-supported Hoveyda catalyst and the unprecedented flow deprotection/Eschweiler-Clarke methylation sequence. The new protocols developed for the synthesis of (+)-dumetorine were applied to the synthesis of its simplified natural congeners (-)-sedamine and (+)-sedridine. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Viscous polysaccharide and starch synthesis in Rhodella reticulata (Porphyridiales, Rhodophyta)

    International Nuclear Information System (INIS)

    Kroen, W.K.; Ramus, J.

    1990-01-01

    Rhodella reticulata Deason, Butler and Rhyne produces copious amounts of a viscous polysaccharide (VP) during growth in batch cultures. The VPs accumulated on the cell surface and in the culture medium once cells ceased growth; starch concurrently accumulated within the cells. Light-saturated 14 C-uptake declined steadily as the cells aged. Net synthesis rates for starch and mucilage were two- and four-fold lower, respectively, in non-growing cells than in growing cells, while the relative partitioning of newly-fixed carbon into these materials was not different. These data suggest that total photosynthetic loading, rather than partitioning into one specific pool, controls cellular synthesis rates. No preferential synthesis of VPs occurred during the stationary phase. The findings have important implications for the commercial production of VPs

  9. Viscous polysaccharide and starch synthesis in Rhodella reticulata (Porphyridiales, Rhodophyta)

    Energy Technology Data Exchange (ETDEWEB)

    Kroen, W.K.; Ramus, J. (Duke Univ., Beaufort, NC (USA))

    1990-06-01

    Rhodella reticulata Deason, Butler and Rhyne produces copious amounts of a viscous polysaccharide (VP) during growth in batch cultures. The VPs accumulated on the cell surface and in the culture medium once cells ceased growth; starch concurrently accumulated within the cells. Light-saturated {sup 14}C-uptake declined steadily as the cells aged. Net synthesis rates for starch and mucilage were two- and four-fold lower, respectively, in non-growing cells than in growing cells, while the relative partitioning of newly-fixed carbon into these materials was not different. These data suggest that total photosynthetic loading, rather than partitioning into one specific pool, controls cellular synthesis rates. No preferential synthesis of VPs occurred during the stationary phase. The findings have important implications for the commercial production of VPs.

  10. Formal total syntheses of classic natural product target molecules via palladium-catalyzed enantioselective alkylation

    Directory of Open Access Journals (Sweden)

    Yiyang Liu

    2014-10-01

    Full Text Available Pd-catalyzed enantioselective alkylation in conjunction with further synthetic elaboration enables the formal total syntheses of a number of “classic” natural product target molecules. This publication highlights recent methods for setting quaternary and tetrasubstituted tertiary carbon stereocenters to address the synthetic hurdles encountered over many decades across multiple compound classes spanning carbohydrate derivatives, terpenes, and alkaloids. These enantioselective methods will impact both academic and industrial settings, where the synthesis of stereogenic quaternary carbons is a continuing challenge.

  11. Global Drought Total Economic Loss Risk Deciles

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Drought Total Economic Loss Risk Deciles is a 2.5 minute grid of global drought total economic loss risks. A process of spatially allocating Gross Domestic...

  12. Chinese National Strategy of Total War

    National Research Council Canada - National Science Library

    Good, Michael J

    2008-01-01

    ... concept of total warfare. This research seeks to determine if China is currently engaged in a total war with the United States across nontraditional forms of conflict including economic, political, information, financial...

  13. Totally optimal decision trees for Boolean functions

    KAUST Repository

    Chikalov, Igor; Hussain, Shahid; Moshkov, Mikhail

    2016-01-01

    We study decision trees which are totally optimal relative to different sets of complexity parameters for Boolean functions. A totally optimal tree is an optimal tree relative to each parameter from the set simultaneously. We consider the parameters

  14. Global Landslide Total Economic Loss Risk Deciles

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Landslide Total Economic Loss Risk Deciles is a 2.5 minute grid of global landslide total economic loss risks. A process of spatially allocating Gross...

  15. Radiochemical synthesis of etomoxir

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, Hafiz G. [Institute of Nuclear Medicine and Oncology (INMOL), New Campus Road, Lahore (Pakistan); Yunus, M. [University of the Punjab, New Campus Road, Lahore (Pakistan); Feinendegen, Ludwig E., E-mail: feinendegen@gmx.ne [Department of Nuclear Medicine, Heinrich-Heine University Duesseldorf, Wannental 45, 88131 Lindau (Germany)

    2011-02-15

    Sodium 2-{l_brace}6-(4-chlorophenoxy)hexyl{r_brace}oxirane-2-carboxylate (Etomoxir) inhibits transport of fatty acids via the carnitine shuttle into mitochondria of muscle cells and prevents long chain fatty acids from providing energy through {beta}-oxidation especially for muscle contraction. The objective of this synthesis is to develop a method for radioiodination of Etomoxir in order to explore its potential in diagnostic metabolic studies and molecular imaging. Thus, a method is described for the radiochemical synthesis and purification of ethyl 2-{l_brace}6-(4-[{sup 131}I]iodophenoxy)hexyl{r_brace}oxirane-2-carboxylate (3) and 2-{l_brace}6-(4-[{sup 131}I]iodo-phenoxy)hexyl{r_brace}oxirane-2-carboxylic acid (4). For the synthesis of these new agents, ethyl 2-{l_brace}6-(4-bromophenoxy)hexyl{r_brace}oxirane-2-carboxylate (1) and 2-{l_brace}6-(4-bromophenoxy)hexyl{r_brace}oxirane-2-carboxylic acid (2) were refluxed with [{sup 131}I]NaI in the presence of anhydrous acetone at a temperature of 80 {sup o}C and 90 {sup o}C for a period of 3-4 hours, respectively. The method of radiolabeling, based on the nucleophilic exchange reaction, resulted in a radiochemical yield of 43% and 67% for compounds 3 and 4, respectively. This paper reports on the labeling of etomoxir with radioiodine as {sup 124}I labeled etomoxir may be of great importance in molecular imaging.

  16. Evidence synthesis software.

    Science.gov (United States)

    Park, Sophie Elizabeth; Thomas, James

    2018-06-07

    It can be challenging to decide which evidence synthesis software to choose when doing a systematic review. This article discusses some of the important questions to consider in relation to the chosen method and synthesis approach. Software can support researchers in a range of ways. Here, a range of review conditions and software solutions. For example, facilitating contemporaneous collaboration across time and geographical space; in-built bias assessment tools; and line-by-line coding for qualitative textual analysis. EPPI-Reviewer is a review software for research synthesis managed by the EPPI-centre, UCL Institute of Education. EPPI-Reviewer has text mining automation technologies. Version 5 supports data sharing and re-use across the systematic review community. Open source software will soon be released. EPPI-Centre will continue to offer the software as a cloud-based service. The software is offered via a subscription with a one-month (extendible) trial available and volume discounts for 'site licences'. It is free to use for Cochrane and Campbell reviews. The next EPPI-Reviewer version is being built in collaboration with National Institute for Health and Care Excellence using 'surveillance' of newly published research to support 'living' iterative reviews. This is achieved using a combination of machine learning and traditional information retrieval technologies to identify the type of research each new publication describes and determine its relevance for a particular review, domain or guideline. While the amount of available knowledge and research is constantly increasing, the ways in which software can support the focus and relevance of data identification are also developing fast. Software advances are maximising the opportunities for the production of relevant and timely reviews. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise

  17. TUW at the First Total Recall Track

    Science.gov (United States)

    2015-11-20

    TUW AT THE FIRST TOTAL RECALL TRACK MIHAI LUPU Abstract. For the first participation in the TREC Total Recall track, we set out to try some basic...significantly and consistently outperformed it. 1. Introduction As the organizers point out, the focus of the Total Recall Track is to evaluate methods to...TUW AT THE FIRST TOTAL RECALL TRACK 3 The only change we made was at a higher level. The Sofia ML library provides 5 more ML algorithms. The following

  18. Lactobacillusassisted synthesis of titanium nanoparticles

    Directory of Open Access Journals (Sweden)

    Jha Anal

    2007-01-01

    Full Text Available AbstractAn eco-friendlylactobacillussp. (microbe assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

  19. Organic synthesis with stable isotopes

    International Nuclear Information System (INIS)

    Blazer, R.M.; Daub, G.H.; Kerr, V.N.; Williams, D.L.; Whaley, T.W.

    1982-01-01

    Described is a scheme for the synthesis of L-arginine-1- 13 C utilizing methods developed for the synthesis of L-ornithine-1- 13 C from L-ornithine-2- 13 C and then converting ornithine into arginine with the enzyme acylase

  20. A novel synthesis of hemispherands

    NARCIS (Netherlands)

    Ostaszewski, Ryszard; Verboom, Willem; Reinhoudt, David

    1992-01-01

    A novel, flexible synthesis of hemispherands {2,5,8-trioxa[9](3,3″) m-terphenylophanes 5a-d} with different central aromatic groups is described. The key step comprises the introduction of the central aromatic ring in the last step of the synthesis via a Suzuki cross-coupling reaction using

  1. Chemical synthesis on SU-8

    DEFF Research Database (Denmark)

    Qvortrup, Katrine; Taveras, Kennedy; Thastrup, Ole

    2011-01-01

    In this paper we describe a highly effective surface modification of SU-8 microparticles, the attachment of appropriate linkers for solid-supported synthesis, and the successful chemical modification of these particles via controlled multi-step organic synthesis leading to molecules attached...

  2. Learning via Query Synthesis

    KAUST Repository

    Alabdulmohsin, Ibrahim Mansour

    2017-05-07

    Active learning is a subfield of machine learning that has been successfully used in many applications. One of the main branches of active learning is query synthe- sis, where the learning agent constructs artificial queries from scratch in order to reveal sensitive information about the underlying decision boundary. It has found applications in areas, such as adversarial reverse engineering, automated science, and computational chemistry. Nevertheless, the existing literature on membership query synthesis has, generally, focused on finite concept classes or toy problems, with a limited extension to real-world applications. In this thesis, I develop two spectral algorithms for learning halfspaces via query synthesis. The first algorithm is a maximum-determinant convex optimization method while the second algorithm is a Markovian method that relies on Khachiyan’s classical update formulas for solving linear programs. The general theme of these methods is to construct an ellipsoidal approximation of the version space and to synthesize queries, afterward, via spectral decomposition. Moreover, I also describe how these algorithms can be extended to other settings as well, such as pool-based active learning. Having demonstrated that halfspaces can be learned quite efficiently via query synthesis, the second part of this thesis proposes strategies for mitigating the risk of reverse engineering in adversarial environments. One approach that can be used to render query synthesis algorithms ineffective is to implement a randomized response. In this thesis, I propose a semidefinite program (SDP) for learning a distribution of classifiers, subject to the constraint that any individual classifier picked at random from this distributions provides reliable predictions with a high probability. This algorithm is, then, justified both theoretically and empirically. A second approach is to use a non-parametric classification method, such as similarity-based classification. In this

  3. Dibutylphosphoric acid synthesis

    International Nuclear Information System (INIS)

    Elias, H.; Boumaout, R.; Kellou, N.; Amedjkouh, A.; Hamidi, A.

    1995-09-01

    This work consists on the synthesis of dibutylphosphoric acis (DBP) by reaction of butanol with phosphorus pentoxid and on its separation by liquid-liquid extraction. It also deals with the characterization of DBP by some physicochemical analysis methods such as : chromatography, pH-metry and infrared and ultraviolet spectrophotometries. this study showed essentialy, that DBP can be formed in an appreciable amount (55%) when the reaction is realised with butanol/pentoxid molar ratio upper than 3 at temperature of 95 C

  4. Microemulsion Synthesis of Nanoparticles

    Directory of Open Access Journals (Sweden)

    Gotić, M.

    2013-11-01

    Full Text Available Nanoparticles and nanomaterials have wide applications in electronics, physics, material design, being also utilized as sensors, catalysts, and more and more in biomedicine. Microemulsions are an exceptionally suitable medium for the synthesis of nanoparticles due to their thermodynamical stability, great solubility of both polar and nonpolar components, as well as their ability to control the size, dispersity and shape of the particles. This review presents microemulsion techniques for the synthesis of inorganic nanoparticles. It takes place in water-in-oil microemulsions by mixing one microemulsion with a cationic precursor, and the other with a precipitating or reducing agent, or by direct addition of reducing agents or gas (O2, NH3 ili CO2 into microemul sion (Fig. 1. Metal nanoparticles are used as catalysts, sensors, ferrofluids etc. They are produced by reducing the metal cation with a suitable reducing agent. In a similar way, one can prepare nanoparticles of alloys from the metal salts, provided that the metals are mutually soluble. The microemulsion technique is also suitable for depositing nanoparticles onto various surfaces. Highly active catalysts made from nanoparticles of Pt, Pd, Rh and other noble metals may be obtained in this way. Metal oxides and hydroxides may be prepared by hydrolysis or precipitation in the water core of microemulsion. Precipitation can be initiated by adding the base or precipitating agent into the microemulsion with water solution of metal ions. Similarly, nanoparticles may be prepared of sulphides, halogenides, cyanides, carbonates, sulphates and other insoluble metal salts. To prevent oxidation of nanoparticles, especially Fe, the particles are coated with inert metals, oxides, various polymers etc. Coating may provide additional functionality; e.g. coating with gold allows subsequent functionalization with organic compounds containing sulphur, due to the strong Au–S bond. Polymer coatings decrease

  5. Sustained improvement of intractable rheumatoid arthritis after total lymphoid irradiation

    International Nuclear Information System (INIS)

    Field, E.H.; Strober, S.; Hoppe, R.T.

    1983-01-01

    Total lymphoid irradiation (TLI) was administered to 11 patients who had intractable rheumatoid arthritis that was unresponsive to conventional medical therapy, including aspirin, multiple nonsteroidal antiinflammatory drugs, gold salts, and D-penicillamine. Total lymphoid irradiation was given as an alternative to cytotoxic drugs such as azathioprine and cyclophosphamide. After radiotherapy, 9 of the 11 patients showed a marked improvement in clinical disease activity as measured by morning stiffness, joint tenderness, joint swelling, and overall functional abilities. The mean improvement of disease activity in all patients ranged from 40-70 percent and has persisted throughout a 13-28 month followup period. This improvement permitted the mean daily steroid dose to be reduced by 54%. Complications included severe fatigue and other constitutional symptoms during radiotherapy, development of Felty's syndrome in 1 patient, and an exacerbation of rheumatoid lung disease in another. After therapy, all patients exhibited a profound T lymphocytopenia, and a reversal in their T suppressor/cytotoxic cell to helper cell ratio. The proliferative responses of peripheral blood mononuclear cells to phytohemagglutinin, concanavalin A, and allogeneic leukocytes (mixed leukocyte reaction) were markedly reduced, as was in vitro immunoglobulin synthesis after stimulation with pokeweed mitogen. Alterations in T cell numbers and function persisted during the entire followup period, except that the mixed leukocyte reaction showed a tendency to return to normal values

  6. Defense meteorological satellite measurements of total ozone

    International Nuclear Information System (INIS)

    Lovill, J.E.; Ellis, J.S.; Luther, F.M.; Sullivan, R.J.; Weichel, R.L.

    1992-01-01

    A multichannel filter radiometer (MFR) on Defense Meteorological Satellites (DMS) that measured total ozone on a global-scale from March 1977 - February 1980 is described. The total ozone data measured by the MFR were compared with total ozone data taken by surfaced-based Dobson spectrophotometers. When comparisons were made for five months, the Dobson spectrophotometer measured 2-5% more total ozone than the MFR. Comparisons between the Dobson spectrophotometer and the MFR showed a reduced RMS difference as the comparisons were made at closer proximity. A Northern Hemisphere total ozone distribution obtained from MFR data is presented

  7. Synthesis of Lipidated Proteins.

    Science.gov (United States)

    Mejuch, Tom; Waldmann, Herbert

    2016-08-17

    Protein lipidation is one of the major post-translational modifications (PTM) of proteins. The attachment of the lipid moiety frequently determines the localization and the function of the lipoproteins. Lipidated proteins participate in many essential biological processes in eukaryotic cells, including vesicular trafficking, signal transduction, and regulation of the immune response. Malfunction of these cellular processes usually leads to various diseases such as cancer. Understanding the mechanism of cellular signaling and identifying the protein-protein and protein-lipid interactions in which the lipoproteins are involved is a crucial task. To achieve these goals, fully functional lipidated proteins are required. However, access to lipoproteins by means of standard expression is often rather limited. Therefore, semisynthetic methods, involving the synthesis of lipidated peptides and their subsequent chemoselective ligation to yield full-length lipoproteins, were developed. In this Review we summarize the commonly used methods for lipoprotein synthesis and the development of the corresponding chemoselective ligation techniques. Several key studies involving full-length semisynthetic lipidated Ras, Rheb, and LC3 proteins are presented.

  8. Ethylene and protein synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Osborne, D J

    1973-01-01

    Ethylene reduces the rate of expansion growth of cells and it is suggestive that the rate of expansion is controlled at least in part by the synthesis of hydroxyproline rich glycopeptides that are secreted with other polysaccharide material through the plasmalemma into the cell wall, thereby enhancing the thickness of the cell wall and also rendering it poorly extensible. In combination, auxin would appear to counteract the effect of ethylene in this respect, for although auxin enhances the synthesis of protein and the content in the cell walls, as well as causing some increase in wall thickness, it reduces the amount of hydroxyproline reaching the wall. Such effects may be instrumental in enhancing wall plasticity, the rate of expansion and the final cell size. These results indicate that ethylene and auxin together afford a dual regulatory system exerted through a control of a specific part of the protein synthetic pathway, the products of which regulate the rate of expansion, and the potential for expansion, of the plant cell wall. 38 references, 3 figures, 8 tables.

  9. Gold-Catalyzed Cyclizations of Alkynol-Based Compounds: Synthesis of Natural Products and Derivatives

    Directory of Open Access Journals (Sweden)

    Pedro Almendros

    2011-09-01

    Full Text Available The last decade has witnessed dramatic growth in the number of reactions catalyzed by gold complexes because of their powerful soft Lewis acid nature. In particular, the gold-catalyzed activation of propargylic compounds has progressively emerged in recent years. Some of these gold-catalyzed reactions in alkynes have been optimized and show significant utility in organic synthesis. Thus, apart from significant methodology work, in the meantime gold-catalyzed cyclizations in alkynol derivatives have become an efficient tool in total synthesis. However, there is a lack of specific review articles covering the joined importance of both gold salts and alkynol-based compounds for the synthesis of natural products and derivatives. The aim of this Review is to survey the chemistry of alkynol derivatives under gold-catalyzed cyclization conditions and its utility in total synthesis, concentrating on the advances that have been made in the last decade, and in particular in the last quinquennium.

  10. Exploring and Implementing Participatory Action Synthesis

    Science.gov (United States)

    Wimpenny, Katherine; Savin-Baden, Maggi

    2012-01-01

    This article presents participatory action synthesis as a new approach to qualitative synthesis which may be used to facilitate the promotion and use of qualitative research for policy and practice. The authors begin by outlining different forms of qualitative research synthesis and then present participatory action synthesis, a collaborative…

  11. How students process equations in solving quantitative synthesis problems? Role of mathematical complexity in students’ mathematical performance

    Directory of Open Access Journals (Sweden)

    Bashirah Ibrahim

    2017-10-01

    Full Text Available We examine students’ mathematical performance on quantitative “synthesis problems” with varying mathematical complexity. Synthesis problems are tasks comprising multiple concepts typically taught in different chapters. Mathematical performance refers to the formulation, combination, and simplification of equations. Generally speaking, formulation and combination of equations require conceptual reasoning; simplification of equations requires manipulation of equations as computational tools. Mathematical complexity is operationally defined by the number and the type of equations to be manipulated concurrently due to the number of unknowns in each equation. We use two types of synthesis problems, namely, sequential and simultaneous tasks. Sequential synthesis tasks require a chronological application of pertinent concepts, and simultaneous synthesis tasks require a concurrent application of the pertinent concepts. A total of 179 physics major students from a second year mechanics course participated in the study. Data were collected from written tasks and individual interviews. Results show that mathematical complexity negatively influences the students’ mathematical performance on both types of synthesis problems. However, for the sequential synthesis tasks, it interferes only with the students’ simplification of equations. For the simultaneous synthesis tasks, mathematical complexity additionally impedes the students’ formulation and combination of equations. Several reasons may explain this difference, including the students’ different approaches to the two types of synthesis problems, cognitive load, and the variation of mathematical complexity within each synthesis type.

  12. Synthesis of Calystegine A(3) from Glucose by the Use of Ring-Closing Metathesis

    DEFF Research Database (Denmark)

    Monrad, Rune Nygaard; Pipper, Charlotte Bressen; Madsen, Robert

    2009-01-01

    A synthesis of the nortropane alkaloid calystegine A(3) is described from D-glucose. The key step employs a zinc-mediated tandem reaction where a benzyl-protected methyl 6-iodo glucoside is fragmented to give an unsaturated aldehyde, which is then transformed into the corresponding benzylimine...... affords calystegine A(3). The synthesis uses a total of 13 steps from glucose and confirms the absolute configuration of the natural product....

  13. An Expeditious Stereoselective Synthesis of (−)-Pinidinone from Ethyl Acetoacetate

    International Nuclear Information System (INIS)

    Damodar, Kongara; Jun, Jong-Gab

    2016-01-01

    An expeditious stereoselective synthesis of a naturally occurring 2,6-disubstituted piperidine alkaloid, (−)-pinidinone, has been accomplished with an overall yield of 31% in total eight steps. The synthesis involves ethyl acetoacetate as the starting material and the stereoselective α-aminoallylation of aldehyde with (S)-tert-butanesulfinamide, allyl bromide, and indium and Grubbs' olefin cross-metathesis as the pivotal steps.

  14. Action of ionizing radiation on catalase synthesis in the rat liver

    International Nuclear Information System (INIS)

    Komov, V.P.; Strelkova, M.A.

    1975-01-01

    3-amino-1,2,4-triazole was used to study the effect of total-body X-ray irradiation on the rates of catalase synthesis and breakdown in rat liver. It was found that in the interval between hour 22 and hour 144 of radiation sickness, the average rate of catalase synthesis in the liver was 2.6 times lower in rats that received a dose of 800 rads than in control rats

  15. The rate of synthesis and decomposition of tissue proteins in hypokinesia and increased muscular activity

    Science.gov (United States)

    Fedorov, I. V.; Chernyy, A. V.; Fedorov, A. I.

    1978-01-01

    During hypokinesia and physical loading (swimming) of rats, the radioactivity of skeletal muscle, liver, kidney, heart, and blood proteins was determined after administration of radioactive amino acids. Tissue protein synthesis decreased during hypokinesia, and decomposition increased. Both synthesis and decomposition increased during physical loading, but anabolic processes predominated in the total tissue balance. The weights of the animals decreased in hypokinesia and increased during increased muscle activity.

  16. Investigation of Prins reaction for the synthesis of 2, 4- disubstituted ...

    Indian Academy of Sciences (India)

    (a) Nicolaou K C and Sorensen E J 1996 Classics in Total Synthesis, VCH, Weinheim; (b) Molinski T F. 1996 Tetra. Lett. 37 7879; Fusetani N, Shimoda K and. Matsunaga S 1993 J. Am. Chem. Soc. 115 3977. 5. (a) Yadav J S, Reddy B V S, Sekhar K C and Gunasekar. D 2001 Synthesis 6 885; (b) Zhang W-C and Li C-J 2000.

  17. Synthesis of milligram quantities of proteins using a reconstituted in vitro protein synthesis system.

    Science.gov (United States)

    Kazuta, Yasuaki; Matsuura, Tomoaki; Ichihashi, Norikazu; Yomo, Tetsuya

    2014-11-01

    In this study, the amount of protein synthesized using an in vitro protein synthesis system composed of only highly purified components (the PURE system) was optimized. By varying the concentrations of each system component, we determined the component concentrations that result in the synthesis of 0.38 mg/mL green fluorescent protein (GFP) in batch mode and 3.8 mg/mL GFP in dialysis mode. In dialysis mode, protein concentrations of 4.3 and 4.4 mg/mL were synthesized for dihydrofolate reductase and β-galactosidase, respectively. Using the optimized system, the synthesized protein represented 30% (w/w) of the total protein, which is comparable to the level of overexpressed protein in Escherichia coli cells. This optimized reconstituted in vitro protein synthesis system may potentially be useful for various applications, including in vitro directed evolution of proteins, artificial cell assembly, and protein structural studies. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

    International Nuclear Information System (INIS)

    Horst, M.N.

    1990-01-01

    Chitin synthesis in crustaceans involves the deposition of a protein-polysaccharide complex at the apical surface of epithelial cells which secrete the cuticle or exoskeleton. The present study involves an examination of in vivo incorporation of radiolabeled amino acids and amino sugars into the cuticle of postmolt blue crabs, Callinectes sapidus. Rates of incorporation of both 3H leucine and 3H threonine were linear with respect to time of incubation. Incorporation of 3H threonine into the endocuticle was inhibited greater than 90% in the presence of the protein synthesis inhibitor, puromycin. Linear incorporation of 14C glucosamine into the cuticle was also demonstrated; a significant improvement of radiolabeling was achieved by using 14C-N-acetylglucosamine as the labeled precursor. Incorporation of 3H-N-acetylglucosamine into the cuticle of postmolt blue crabs was inhibited 89% by puromycin, indicating that concurrent protein synthesis is required for the deposition of chitin in the blue crab. Autoradiographic analysis of control vs. puromycin-treated crabs indicates that puromycin totally blocks labeling of the new endocuticle with 3H glucosamine. These results are consistent with the notion that crustacean chitin is synthesized as a protein-polysaccharide complex. Analysis of the postmolt and intermolt blue crab cuticle indicates that the exoskeleton contains about 60% protein and 40% chitin. The predominant amino acids are arginine, glutamic acid, alanine, aspartic acid, and threonine

  19. Synthesis of All Stereoisomers of Eudesm-11-en-4-ol. 2. Total Synthesis of Selin-11-en-4α-ol, Intermedeol, Neointermedeol, and Paradisiol. First Total Synthesis of Amiteol

    NARCIS (Netherlands)

    Kesselmans, Ronald P.W.; Wijnberg, Joannes B.P.A.; Minnaard, Adriaan J.; Walinga, Robert E.; Groot, Aede de

    1991-01-01

    The syntheses of (±)-selin-11-en-4α-ol (5), (±)-intermedeol (6), (±)-neointermedeol (7), (±)-amiteol (9), and the four remaining unnatural stereoisomers (±)-paradisiol (8), (±)-7-epi-amiteol (10), (±)-5-epi-neointermedeol (11), and (±)-5-epi-paradisiol (12) are described. In addition, the related

  20. Crystal morphology modification by the addition of tailor-made stereocontrolled poly(N-isopropyl acrylamide)

    DEFF Research Database (Denmark)

    Munk, Tommy; Baldursdottir, Stefania; Hietala, Sami

    2012-01-01

    . One such additive is the thermosensitive polymer poly(N-isopropyl acrylamide) (PNIPAM). The use of PNIPAM as a crystallization additive provides a possibility to affect viscosity at separation temperatures and nucleation and growth rates at higher temperatures. In this study, novel PNIPAM derivatives......; the morphology of crystals changed from needle to dendritic shape. Additionally, the amphiphilic nature of PNIPAM increased the solubility of nitrofurantoin in water. PNIPAMs with varying molecular weights and stereoregularities resulted in similar changes in the crystal habit of the drug regardless of whether...