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Sample records for pyridazines

  1. A case study of Copper Pyridazine Halides

    Indian Academy of Sciences (India)

    In this paper, therefore, we demonstrate a retrosynthetic analysis to interpret the occurrence of isostructures and supramolecular isomers and predict the possibility of new phases in copperhalide-pyridazine- H₂O system. A significant feature of this paper is the use of crystal engineering tools, namely, synthons and tectons ...

  2. Synthesis and biological activity of pyridazine amides, hydrazones and hydrazides.

    Science.gov (United States)

    Buysse, Ann M; Yap, Maurice Ch; Hunter, Ricky; Babcock, Jonathan; Huang, Xinpei

    2017-04-01

    Optimization studies on compounds initially designed to be herbicides led to the discovery of a series of [6-(3-pyridyl)pyridazin-3-yl]amides exhibiting aphicidal properties. Systematic modifications of the amide moiety as well as the pyridine and pyridazine rings were carried out to determine if these changes could improve insecticidal potency. Structure-activity relationship (SAR) studies showed that changes to the pyridine and pyridazine rings generally resulted in a significant loss of insecticidal potency against green peach aphids [Myzus persicae (Sulzer)] and cotton aphids [(Aphis gossypii (Glover)]. However, replacement of the amide moiety with hydrazines, hydrazones, or hydrazides appeared to be tolerated, with small aliphatic substituents being especially potent. A series of aphicidal [6-(3-pyridyl)pyridazin-3-yl]amides were discovered as a result of random screening of compounds that were intially investigated as herbicides. Follow-up studies of the structure-activity relationship of these [6-(3-pyridyl)pyridazin-3-yl]amides showed that biosteric replacement of the amide moiety was widely tolerated suggesting that further opportunities for exploitation may exist for this new area of insecticidal chemistry. Insecticidal efficacy from the original hit, compound 1, to the efficacy of compound 14 produced greater than 10-fold potency improvement against Aphis gossypii and greater than 14-fold potency improvement against Myzus persicae. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  3. Synthesis and characterization of novel substituted 3,6-bis(2-pyridyl)pyridazine metal-coordinating ligands

    NARCIS (Netherlands)

    Hoogenboom, R.; Kickelbick, G.; Schubert, U.S.

    2003-01-01

    The synthesis of novel functionalized 3,6-di(2-pyridyl)pyridazines via an inverse electron demand Diels-Alder reaction between the corresponding 3,6-di(2-pyridyl)-1,2,4,5-tetrazine and various alkynes is reported. The resulting 3,6-di(2-pyridyl)pyridazines were investigated using X-ray

  4. Bulk Inclusions of Pyridazine-Based Molecular Rotors in Tris(o-phenylenedioxy)cyclotriphosphazene (TPP)

    Czech Academy of Sciences Publication Activity Database

    Dron, P. I.; Zhao, K.; Kaleta, Jiří; Shen, Y.; Wen, J.; Shoemaker, R. K.; Rogers, C. T.; Michl, Josef

    2016-01-01

    Roč. 26, č. 31 (2016), s. 5718-5732 ISSN 1616-301X EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY Institutional support: RVO:61388963 Keywords : dielectric spectroscopy * inclusion compounds * molecular rotors * pyridazine * solid-state NMR Subject RIV: CC - Organic Chemistry Impact factor: 12.124, year: 2016

  5. Potassium Hydroxide Impregnated Alumina (KOH-Alumina) as a Recyclable Catalyst for the Solvent-Free Multicomponent Synthesis of Highly Functionalized Substituted Pyridazines and/or Substituted Pyridazin-3(2H)-ones under Microwave Irradiation.

    Science.gov (United States)

    Mecadon, Hormi; Myrboh, Bekington

    2011-01-01

    The work described herein employs potassium hydroxide impregnated alumina (KOH-alumina) as a mild, efficient, and recyclable catalyst for a one-pot solvent-free and environmentally safer synthesis of 3,4,6-triarylpyridazines and some substituted pyridazines from active methylene carbonyl species, 1,2-dicarbonyls, and hydrazine hydrate by microwave (MW) irradiation. The method offers highly convergent, inexpensive, and functionality-tolerable procedure for rapid access to important pyridazine compounds in good yields.

  6. A Pyridazine-Based Fluorescent Probe Targeting Aβ Plaques in Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Yong Dae Park

    2018-01-01

    Full Text Available Accumulation of β-amyloid (Aβ plaques comprising Aβ40 and Aβ42 in the brain is the most significant factor in the pathogenesis of Alzheimer’s disease (AD. Thus, the detection of Aβ plaques has increasingly attracted interest in the context of AD diagnosis. In the present study, a fluorescent pyridazine-based dye that can detect and image Aβ plaques was designed and synthesized, and its optical properties in the presence of Aβ aggregates were evaluated. An approximately 34-fold increase in emission intensity was exhibited by the fluorescent probe after binding with Aβ aggregates, for which it showed high affinity (KD = 0.35 µM. Moreover, the reasonable hydrophobic properties of the probe (log P = 2.94 allow it to penetrate the blood brain barrier (BBB. In addition, the pyridazine-based probe was used in the histological costaining of transgenic mouse (APP/PS1 brain sections to validate the selective binding of the probe to Aβ plaques. The results suggest that the pyridazine-based compound has the potential to serve as a fluorescent probe for the diagnosis of AD.

  7. Isomeric signatures in the fragmentation of pyridazine and pyrimidine induced by fast ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Montenegro, Eduardo C. [Instituto de Física, Universidade Federal do Rio de Janeiro, 21941-972 Rio de Janeiro, RJ (Brazil)

    2015-07-28

    We present fast proton impact induced fragmentations of pyrimidine and pyridazine as an experimental resource to investigate isomeric signatures. Major isomeric imprints are identified for few fragment ions and differences of more than an order of magnitude for the cross sections of fragments of the same mass were measured. The observation of the molecular structure of these isomers gives no apparent indication for the reasons for such substantial differences. It is verified that the simple displacement of the position of one nitrogen atom strongly inhibits or favors the production of some ionic fragment species. The dependency of the fragmentation cross sections on the proton impact energy, investigated by means of time of flight mass spectroscopy and of a model calculation based in first order perturbation theory, allows us to disentangle the complex collision dynamics of the ionic fragments. The proton-induced fragmentation discriminates rather directly the association between a molecular orbital ionization and the fragment-ions creation and abundance, as well as how the redistribution of the energy imparted to the molecules takes place, triggering not only single but also double vacancy and leads to specific fragmentation pathways.

  8. Ultrasound-assisted green synthesis of pyrroles and pyridazines in water via three-component condensation reactions of arylglyoxals

    Directory of Open Access Journals (Sweden)

    Bagher Eftekhari-Sis

    2013-04-01

    Full Text Available A green and efficient method for the preparation of 5-aryl-4-hydroxy-2-methyl-1H-pyrrole-3-carboxylic acid esters and 6-aryl-3-methylpyridazine-4-carboxylic acid esters via three-component reaction of arylglyoxal hydrates with β-dicarbonyl compounds in the presence of ammonium acetate and hydrazine hydrate using water as solvent under ultrasonic irradiation was reported. The reactions proceeded rapidly and afforded the corresponding pyrroles and pyridazines in good to high yields in very short reaction time.

  9. Helical self-organization and hierarchical self-assembly of an oligoheterocyclic pyridine-pyridazine strand into extended supramolecular fibers.

    Science.gov (United States)

    Cuccia, Louis A; Ruiz, Eliseo; Lehn, Jean-Marie; Homo, Jean-Claude; Schmutz, Marc

    2002-08-02

    The synthesis and characterization of an alternating pyridine-pyridazine strand comprising thirteen heterocycles are described. Spontaneous folding into a helical secondary structure is based on a general molecular self-organization process enforced by the conformational information encoded within the primary structure of the molecular strand itself. Conformational control based on heterocyclic "helicity codons" illustrates a strategy for designing folding properties into synthetic oligomers (foldamers). Strong intermolecular interactions of the highly ordered lock-washer subunits of compound 3 results in hierarchical supramolecular self-assembly into protofibrils and fibrils. Compound 3 also forms mechanically stable two-dimensional Langmuir-Blodgett and cast thin films.

  10. General study of pyridazine compounds against cyclooxygenase enzyme and their relation with analgesic, anti-inflammatory and anti-arthritic activities

    Directory of Open Access Journals (Sweden)

    Mohammad Asif

    2010-01-01

    Full Text Available There is increased focus on developed non-steroidal anti-inflammatory drugs (NSAIDs containing a pyridazine nucleus. The NSAIDs are one of the most commonly used medications worldwide to inhibit cyclooxygenase (COX-1 and COX-2 enzyme in varying extent by inhibiting prostaglandin (PGEs synthesis for the treatment of pain, inflammation, arthritis and edema. Their routine and long-term use causes gastrointestinal (GIT and renal toxicities. In order to minimize these side-effects, selective COX-2 inhibitors are prepared with an improved GIT and renal safety profile relative to other NSAIDs. The recent development toward the effective NSAIDs agents causes dual COX and lipooxygenase inhibitory effects because COX-2 inhibitors cause cardiovascular problems. The literature stimulated these above findings. Our attention has been focused on the series of pyridazine or other derivatives that were reported or will be reported in the future as anti-inflammatory, analgesic, anti-arthritic as well as anti-edemic agent.

  11. Synthesis of [123I]iodine labelled imidazo[1,2-b] pyridazines as potential probes for the study of peripheral benzodiazepine receptors using SPECT

    International Nuclear Information System (INIS)

    Katsifis, A.; Mattner, F.; Dikic, B.; Barlin, G.

    2004-01-01

    The pyridazines 3-acetamidomethyl-6-chloro-2-(4'-iodophenyl)imidazo[1,2-b]pyridazine 1 (IC 50 = 1.6 nM) and 3-benzamidomethyl-6-iodo-2-(4'-t-butylphenyl)imidazo[1,2-b] pyridazine 2 (IC 50 = 4.2 nM), are high affinity and selective ligands for the peripheral benzodiazepine receptors (PBR) compared to the central benzodiazepine counterparts. The [ 123 I]1 and [ 123 I]2 labelled analogues of these compounds were subsequently synthesised for the potential study of the PBR in vivo using SPECT. Radioiodination of [ 123 I]1 was achieved by iododestannylation of the corresponding tributyl tin precursor with Na[ 123 I] in the presence of peracetic acid or chloramine-T and the product isolated by C-18 RP HPLC. Radioiodination of [ 123 I]2 was achieved by copper assisted bromine [ 123 I]iodine exchange of the corresponding bromo precursor in the presence of acetic acid and sodium bisulfate as reducing agent at 200 C. Purification of the crude products were achieved by semi-preparative C-18 RP HPLC to give the products in radiochemical yields > 90%. The products were obtained in > 97% chemical and radiochemical purity and with specific activities > 180 GBq/μmol. (orig.)

  12. Synthesis of [{sup 123}I]iodine labelled imidazo[1,2-b] pyridazines as potential probes for the study of peripheral benzodiazepine receptors using SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Katsifis, A.; Mattner, F.; Dikic, B. [Radiopharmaceuticals Div. ANSTO, Menai, NSW (Australia); Barlin, G. [Div. of Neurosciences, John Curtin School of Medical Research, Australian National Univ., Canberra (Australia)

    2004-07-01

    The pyridazines 3-acetamidomethyl-6-chloro-2-(4'-iodophenyl)imidazo[1,2-b]pyridazine 1 (IC{sub 50} = 1.6 nM) and 3-benzamidomethyl-6-iodo-2-(4'-t-butylphenyl)imidazo[1,2-b] pyridazine 2 (IC{sub 50} = 4.2 nM), are high affinity and selective ligands for the peripheral benzodiazepine receptors (PBR) compared to the central benzodiazepine counterparts. The [{sup 123}I]1 and [{sup 123}I]2 labelled analogues of these compounds were subsequently synthesised for the potential study of the PBR in vivo using SPECT. Radioiodination of [{sup 123}I]1 was achieved by iododestannylation of the corresponding tributyl tin precursor with Na[{sup 123}I] in the presence of peracetic acid or chloramine-T and the product isolated by C-18 RP HPLC. Radioiodination of [{sup 123}I]2 was achieved by copper assisted bromine [{sup 123}I]iodine exchange of the corresponding bromo precursor in the presence of acetic acid and sodium bisulfate as reducing agent at 200 C. Purification of the crude products were achieved by semi-preparative C-18 RP HPLC to give the products in radiochemical yields > 90%. The products were obtained in > 97% chemical and radiochemical purity and with specific activities > 180 GBq/{mu}mol. (orig.)

  13. Synthesis and reactions of 4-(p-methoxybenzyl-6-[5,6,7,8-tetrahydro-2-naphthyl]-pyridazin-3(2H-one

    Directory of Open Access Journals (Sweden)

    NAGWA M.S. EL-DIN HARB

    1999-11-01

    Full Text Available The condensation of 4-(p-methoxybenzyl-6-[5,6,7,8-tetrahydro-2-naphthyl]-pyridazin-3(2H-one (3, prepared by the reaction of 6-[5,6,7,8-tetrahydro-2-naphthyl]-4,5-dihydropyridazin-3(2H-one (1 and anisaldehyde, with dimethyl sulphate, formaldehyde and acrylonitrile, and also the formation of the Mannich base, proceeded smoothly at the 2-position to give compounds 4,5,6,7, respectively. 4-p-Methoxybenzyl-3-chloro-6-[5,6,7,8-tetrahydro-2-naphthyl]-pyridazine (9 was prepared in law yield by the action of phosphorus oxychloride on 3. The reaction of 9 with benzylamine, aniline and piperidine gave 10a,b,c, respectively. 4-p-Methoxybenzyl-6-[5,6,7,8-tetrahydro-2-napthyl]pyridazine-3(2H-thione (12 was prepared either by the action of thiourea on 9, or by the reaction of 3 with phosphorus pentasulphide. The reaction of these thiones with acrylonitrile, morpholine and piperidine to give 13 and 14 a,b, respectively, were also investigated.

  14. Exploiting the Electrophilic and Nucleophilic Dual Role of Nitrile Imines: One-Pot, Three-Component Synthesis of Furo[2,3-d]pyridazin-4(5H)-ones.

    Science.gov (United States)

    Giustiniano, Mariateresa; Mercalli, Valentina; Amato, Jussara; Novellino, Ettore; Tron, Gian Cesare

    2015-08-21

    An expeditious multicomponent reaction to synthesize tetrasubstituted furo[2,3-d]pyridazin-4(5H)-ones is reported. In brief, hydrazonoyl chlorides react with isocyanoacetamides, in the presence of TEA, to give 1,3-oxazol-2-hydrazones which, without being isolated, can react with dimethylacetylene dicarboxylate to afford furo[2,3-d]pyridazin-4(5H)-ones with an unprecedented level of complexity in a triple domino Diels-Alder/retro-Diels-Alder/lactamization reaction sequence.

  15. Aspartic protease inhibitory and nematocidal activity of phenyl-4-(2-phenylhydrazonohexahydrofuro[3,2-c]pyridazin-7-ol (Percival dianhydroosazone

    Directory of Open Access Journals (Sweden)

    El Sayed H. El Ashry

    2014-04-01

    Full Text Available We synthesized Phenyl-4-(2-phenylhydrazonohexahydrofuro[3,2-c]pyridazin-7-ol (compound 3. The structure compound 3 was elucidated with IR, 1H NMR, 13C NMR and EIMS spectra. Compound 3 showed potent inhibitory activity against aspartic proteases, human cathepsin D and Plasmodium falciparum plasmepsin-II with IC50 = 20 μM. Enzyme-inhibitor complexes were predicted to stabilize by electrostatic and hydrophobic interactions between the side chains of amino acid residues at the active center and compound 3. Moreover, compound 3 displayed good nematocidal activity against all developmental stages of C. elegans.

  16. ZrOCl2.8H2O as a green and efficient catalyst for the expeditious synthesis of substituted 3-arylpyrimido[4,5-c]pyridazines in water

    Directory of Open Access Journals (Sweden)

    Mehdi Rimaz

    2015-09-01

    Full Text Available A new and simple synthetic methodology for the preparation of 3-arylpyrimido[4,5-c]pyridazine-5,7(6H,8H-diones and 3-aryl-5-oxo-7-thioxo-7,8-dihydropyrimido[4,5-c]pyridazin-5(6H-ones by a one-pot three component reaction of barbituric acid or thiobarbituric acid with arylglyoxals in the presence of catalytic amount of ZrOCl2∙8H2O as green Lewis acid and hydrazine hydrate at ambient temperature in water was reported. All of these pyrimidopyridazines derivatives have one clustered water molecule in their molecular structure. The use of ZrOCl2∙8H2O catalyst is feasible because of its easy availability, convenient handling, high stability, simple recovery, reusability, good activity and eco-friendly.

  17. TETRACYANONICKELATE(II) PYRIDAZINE COMPLEXES

    African Journals Online (AJOL)

    B. S. Chandravanshi

    and therefore they have been attracting increasing attention from scientists [1]. .... in the spectra of the complexes studied are listed in Table 1, together with free ..... Raman spectra were recorded at Anadolu University, Department of Physics.

  18. pyridines and imidazo[1,2-b]pyridazines

    Indian Academy of Sciences (India)

    Hongli Fan

    2018-05-07

    May 7, 2018 ... School of Chemistry and Chemical Engineering, Heze University, 2269 Daxue ... approach to the synthesis of 3-substituted imidazo[1,2- ...... and Sharratt A P 1991 Chemistry of amidines. Part. 1. Determination of the site of ...

  19. Bis(μ-pyridazine-3-carboxylato-κ2O:O′bis[aquadioxido(pyridazine-3-carboxylato-κ2N2,Ouranium(VI] dihydrate

    Directory of Open Access Journals (Sweden)

    Janusz Leciejewicz

    2009-01-01

    Full Text Available The structure of the binuclear title complex, [U2(C5H3N2O24O4(H2O2]·2H2O, is composed of centrosymmetric dimers in which each UO22+ ion is coordinated by two ligand molecules. One donates its N,O-bonding group and the other donates both carboxylate O atoms. Each of the latter bridges adjacent uranyl ions. The coordination environment of the metal center is a distorted pentagonal bipyramid. The dimers are interconnected by O—H...O hydrogen bonds between coordinated and uncoordinated water molecules and carboxylate O atoms. An intramolecular O—H...N interaction is also present.

  20. Synthesis of Some New Pyridazine Derivatives for Anti-HAV Evaluation

    Directory of Open Access Journals (Sweden)

    Eman M. Flefel

    2017-01-01

    Full Text Available 4-(2-(4-Halophenylhydrazinyl-6-phenylpyridazin-3(2H-ones 1a,b were prepared and treated with phosphorus oxychloride, phosphorus pentasulphide and ethyl chloroformate to give the corresponding chloropyridazine, pyridazinethione, oxazolopyridazine derivatives 2–4, respectively. Compound 2 reacted with hydrazine hydrate to afford hydrazinylpyridazine 7. The reaction of 4-(2-(4-chlorophenylhydrazinyl-3-hydrazinyl-6-phenylpyridazine (7 with acetic anhydride, p-chlorobenzaldehyde and carbon disulphide gave the corresponding pyridazinotriazine derivatives 8–10. On the other hand, 5-(4-chlorophenylamino-7-(3,5-dimethoxybenzylidene-3-phenyl-5H-pyridazino[3,4-b][1,4]thiazin-6(7H-one (11 was prepared directly from the reaction of compound 3 with chloroacetic acid in presence of p-chlorobenzaldehyde. Compound 11 reacted with nitrogen nucleophiles (hydroxylamine hydrochloride, hydrazine hydrate and active methylene group-containing reagents (malononitrile, ethyl cyanoacetate to afford the corresponding fused compounds 12–15, respectively. Pharmacological screening for antiviral activity against hepatitis A virus (HAV was performed for the new compounds. 4-(4-Chlorophenylamino-6-phenyl-1,2-dihydropyridazino[4,3-e][1,2,4]triazine-3(4H-thione (10 showed the highest effect against HAV.

  1. Poly[aqua(μ3-pyridazine-4-carboxylato-κ2O:O:O′lithium

    Directory of Open Access Journals (Sweden)

    Wojciech Starosta

    2011-04-01

    Full Text Available The structure of the title compound, [Li(C5H3N2O2(H2O]n, is composed of centrosymmetric dimers in which two LiI ions are bridged by a carboxylate O atom, each donated by a ligand, acting in a bidentate mode. The second carboxylato O atoms bridge the dimers to LiI ions in adjacent dimers, forming molecular layers parallel to (001. Each LiI ion is coordinated by two bridging carboxylate O atoms, a bridging carboxylate O atom donated by the adjacent dimer and an aqua O atom, resulting in a distorted tetrahedral coordination geometry. The layers are held together by O—H...N hydrogen bonds in which coordinated water O atoms act as donors and ligand hetero-ring N atoms as acceptors.

  2. 3,6-bis-(2-pyridyl)-pyridazine as supramolecular (CO)initiator for DL-lactide polymerization

    NARCIS (Netherlands)

    Hoogenboom, R.; Schubert, U.S.

    2003-01-01

    The synthesis of a new hydroxy functionalized dipyridylpyridazine by a Diels-Alder reaction between 5-hexyn-1-ol and dipyridyltetrazine was reported. An aluminum alkoxide was generated in situ from this functional ligand to initiate the controlled ring opening polymn. of of DL-lactide resulting in a

  3. 3,6-Bis(2'-pyridyl)pyridazine (L) and its deprotonated form (L-H+)- as ligands for (acac)2Run+ or (bpy)2Rum+: Investigation of mixed valency in [{(acac)2Ru}2(.mu.-L-H+)] and [{(bpy)2Ru}2 (.mu.-L-H+)]4+ by spectroelectrochemistry and EPR

    Czech Academy of Sciences Publication Activity Database

    Ghumaan, S.; Sarkar, B.; Patra, S.; Parimal, K.; van Slageren, J.; Fiedler, Jan; Kaim, W.; Lahiri, G. K.

    -, č. 4 (2005), s. 706-712 ISSN 1477-9226 R&D Projects: GA MŠk 1P05OC068; GA AV ČR IAA400400505 Institutional research plan: CEZ:AV0Z40400503 Keywords : Creutz-Taube ions * electrochemical properties * electrochemistry Subject RIV: CG - Electrochemistry Impact factor: 3.003, year: 2005

  4. 4-oxobutenoic acid towards nitrogen-containing nucleophiles

    Indian Academy of Sciences (India)

    Abstract. A series of novel amino acid derivatives has been synthesized by the reaction of 4-[4-methoxy-. 3-methylphenyl]-4-oxobutenoic acid with primary and secondary amines. The treatment of amino acids with hydrazine afforded pyridazine. Phenylhydrazone was obtained from the reaction of the acid with phenyl.

  5. Oriented crystalline monolayers and bilayers of 2 x 2 silver(1) grid architectures at the air-solution interface: Their assembly and crystal structure elucidation

    DEFF Research Database (Denmark)

    Weissbuch, J.; Baxter, P.N.W.; Kuzmenko, I.

    2000-01-01

    Oriented crystalline monolayers, similar to 14 Angstrom thick, of a 2 x 2 Ag+ grid complex, self-assembled at the air-solution interface starting from an water-insoluble ligand 3,6-bis[2-(6-phenylpyridine)]pyridazine spread on silver-ion-containing solutions,were examined by grazing-incidence X...

  6. 3-aminopyridazine derivatives with atypical antidepressant, serotonergic, and dopaminergic activities.

    Science.gov (United States)

    Wermuth, C G; Schlewer, G; Bourguignon, J J; Maghioros, G; Bouchet, M J; Moire, C; Kan, J P; Worms, P; Biziere, K

    1989-03-01

    Minaprine [3-[(beta-morpholinoethyl)amino]-4-methyl-6-phenylpyridazine dihydrochloride] is active in most animal models of depression and exhibits in vivo a dual dopaminomimetic and serotoninomimetic activity profile. In an attempt to dissociate these two effects and to characterize the responsible structural requirements, a series of 47 diversely substituted analogues of minaprine were synthesized and tested for their potential antidepressant, serotonergic, and dopaminergic activities. The structure-activity relationships show that dopaminergic and serotonergic activities can be dissociated. Serotonergic activity appears to be correlated mainly with the substituent in the 4-position of the pyridazine ring whereas the dopaminergic activity appears to be dependent on the presence, or in the formation, of a para-hydroxylated aryl ring in the 6-position of the pyridazine ring.

  7. Convergence problems and energetic regions in π excited states of certain conjugated molecules

    International Nuclear Information System (INIS)

    Giambiagi, M.S. de; Giambiagi, M.; Barros, H.G. de P.L. de.

    1980-01-01

    When calculating π bond orders of excited and superexcited states of conjugated molecules, difficulties arise in applying the variation method; besides, the convergence problems involved are well known. For pyridazine, chosen for discussion, 27 states are considered; the convergence problem is envisaged through two criteria in the choice of a parameter introduced in the compromise Hamiltonian. This convergence parameter is related to the variation method. There exist three particular solutions for bond orders, which divide the 27 states into energetical regions. (Author) [pt

  8. Kinetic Re-Evaluation of Fuel Neutralization by AKGA

    Science.gov (United States)

    Oropeza Cristina; Kosiba, Mike; Davis, Chuck

    2010-01-01

    Baseline characterization testing previously identified alpha-ketoglutaric acid (AKGA) cis a potential alternative to the current standard hydrazine (HZ) family fuel neutralization techniques in use at Kennedy Space Center (KSC). Thus far, the reagent shows promise for use in hardware decontamination operations and as a drop-in replacement for the scrubber liquor currently used in KSC four tower vapor scrubbers. Implementation of AKGA could improve process safety and reduce or eliminate generation of hydrazine-Iaden waste streams. This paper focuses on evaluation of the kinetics of these decontamination reactions in solution. Pseudo first order reaction rate constants with respect to the pyridazine products (6-oxo-4,5-dihydro-1H-pyridazine-3-carboxylic acid, (PCA) and 1-methyl-6-oxo-4,5-dihydro-pyridazine-3-carboxylic acid (mPCA)) in the presence of excess AKGA were determined by monitoring product formation using a ultra-violet visible absorption spectroscopy method. The results are presented here in comparison to previous data obtained by monitoring reactant depletion by gas chromatography with nitrogen phosphorus detector (GC-NPD).

  9. 5,6-Dipropylphthalazino[2,3-a]cinnoline-8,13-dione

    Directory of Open Access Journals (Sweden)

    G. Vimala

    2016-04-01

    Full Text Available In the title compound, C22H22N2O2, the two central fused pyridazine rings have screw-boat conformations and the dihedral angle between their mean planes is 36.22 (8°. The mean plane of the cinnoline ring system makes a dihedral angle of 46.56 (5° with the mean plane of the phthalazine ring to which it is fused. In the crystal, molecules are linked via C—H...O hydrogen bonds, forming chains along the b axis. The chains are reinforced by C—H...π interactions.

  10. Synthesis and Antibacterial Evaluation of Novel Heterocyclic Compounds Containing a Sulfonamido Moiety

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    Eman A. El-Bordany

    2013-01-01

    Full Text Available Aiming for the synthesis of new heterocyclic compounds containing a sulfonamido moiety suitable for use as antibacterial agents, the precursor ethyl {[4-N-(4,6-dimethylpyrimidin-2-ylsulfamoyl]phenylazo}cyanoacetate was reacted with a variety of active methylene compounds producing pyran, pyridine and pyridazine derivatives. Also, the reactivity of the precursor hydrazone towards hydrazine derivatives to give pyrazole and oxazole derivatives was studied. On the other hand, treatment of the same precursor with urea, thiourea and/or guanidine hydrochloride furnished pyrimidine and thiazine derivatives, respectively. The newly synthesized compounds were tested for antibacterial activity, whereby eight compounds were found to have high activities.

  11. The selective alpha7 nicotinic acetylcholine receptor agonist A-582941 activates immediate early genes in limbic regions of the forebrain

    DEFF Research Database (Denmark)

    Thomsen, M S; Mikkelsen, J D; Timmermann, D B

    2008-01-01

    to study whether alpha7 nAChR stimulation activates brain regions involved in cognition in juvenile as well as adult individuals. Here, we compared the effects of the novel and selective alpha7 nAChR agonist 2-methyl-5-(6-phenyl-pyridazin-3-yl)-octahydro-pyrrolo[3,4-c]pyrrole (A-582941) in the juvenile...... regions critically involved in working memory and attention. Furthermore, this effect is more pronounced in juvenile than adult rats, indicating that the juvenile forebrain is more responsive to alpha7 nAChR stimulation. This observation may be relevant in the treatment of juvenile-onset schizophrenia....

  12. SYNTHESIS, CHARACTERIZATION AND ANTI-BACTERIAL ACTIVITY OF CERTAIN 2,3,4,5-TETRAHYDROPYRIDAZINONE ANALOGUES

    Directory of Open Access Journals (Sweden)

    Gaurav ALANG

    2011-04-01

    Full Text Available In the present study, six new derivatives of PYridazinone were synthesized and evaluate their anti-bacterial activity. The experimental work involves the synthesis of benzoyl propionic acid (a, then 6-phenyl-2,3,4,5-tetrahydro pyridazin-3-one (b which was then condensed with various, aldehydes to form respective derivatives, AH the synthesized compounds were identified by IR, 1HNMR and antimicrobial activity was performed on the compounds synthesized against Staphylococcus aureus (MTCC 737, Staphylococcus epidermidis (MTCC 3615, Pseudomonas aeruginosa (MTCC 424 and Escherichia coli (MTCC 1687

  13. Challenges in the development of an M4 PAM in vivo tool compound: The discovery of VU0467154 and unexpected DMPK profiles of close analogs.

    Science.gov (United States)

    Wood, Michael R; Noetzel, Meredith J; Poslusney, Michael S; Melancon, Bruce J; Tarr, James C; Lamsal, Atin; Chang, Sichen; Luscombe, Vincent B; Weiner, Rebecca L; Cho, Hyekyung P; Bubser, Michael; Jones, Carrie K; Niswender, Colleen M; Wood, Michael W; Engers, Darren W; Brandon, Nicholas J; Duggan, Mark E; Conn, P Jeffrey; Bridges, Thomas M; Lindsley, Craig W

    2017-01-15

    This letter describes the chemical optimization of a novel series of M 4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core, developed via iterative parallel synthesis, and culminating in the highly utilized rodent in vivo tool compound, VU0467154 (5). This is the first report of the optimization campaign (SAR and DMPK profiling) that led to the discovery of VU0467154, and details all of the challenges faced in allosteric modulator programs (steep SAR, species differences in PAM pharmacology and subtle structural changes affecting CNS penetration). Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Direct calculation of self-consistent π bond orders in conjugated systems and pairing relations

    International Nuclear Information System (INIS)

    Castro, A.F.

    1982-01-01

    Pairing relations in excited states of conjugated systems which satisfy to a given symmetry with a Pariser-Parr-Pople-like (PPP) calculation are studied. Six π - electron systems are considered having a symmetry axis which does not cross π centers following a treatment which permits the direct obtainment of the bond order matrix based on Hall's method. Pairing relations are looked for, too, using particular solutions when U(3) groups is applied. Pyridazine molecules are used in order to test the results. (L.C.) [pt

  15. Reactivity and Synthetic Applications of 4,5-Dicyanopyridazine: An Overview

    Directory of Open Access Journals (Sweden)

    Donatella Giomi

    2010-03-01

    Full Text Available Despite the poor reputation of electron-deficient pyridazines in intermolecular Hetero Diels-Alder (HDA reactions, 4,5-dicyanopyridazine (DCP showed a surprising reactivity as a heterocyclic azadiene in inverse electron-demand HDA processes with different dienophiles. The use of alkenes, alkynes and enamines as 2p electron counterparts afforded dicyanocyclohexa-1,3-dienes and substituted phthalonitriles, respectively, while the use of suitable bis-dienophiles provides a general strategy for the one-pot synthesis of polycyclic carbo- and hetero-cage systemsthrough pericyclic three-step homodomino processes. HDA reactions with heterocyclic dienophiles allowed direct benzoannelation: in particular, pyrrole and indole derivatives were converted to dicyano-indoles and -carbazoles. In addition an unprecedented reactivity of DCP as a very reactive heterocyclic electrophile at the C-4 carbon was also evidenced: by changing the experimental conditions, cyanopyrrolyl- and cyanoindolyl-pyridazines were obtained through reactions of pyrrole and indole systems as carbon nucleophiles in formal SNAr2 processes where a CN group of DCP acts as leaving group. Thus, careful control of the reaction conditions allows exploitation of both pathways for the synthesis of different classes of heterocyclic derivatives.

  16. A spectroscopic study of the molecular interactions of harmane with pyrimidine and other diazines.

    Science.gov (United States)

    Muñoz, M A; Guardado, P; Galán, M; Carmona, C; Balón, M

    2000-01-17

    FTIR, UV-vis, steady state and time-resolved fluorescence measurements show that harmane (1-methyl-9H-pyrido/3,4-b/indole) interacts with pyrimidine and its isomers pyrazine and pyridazine in its ground and lowest singlet states. The mechanisms of interaction are dependent on both the structure of the diazine and the nature of the solvent. Thus, in a low polar solvent such as toluene, harmane forms ground state 1:1 hydrogen-bonded complexes with all the diazines. These complexes quench the fluorescence of harmane and diminish its fluorescence lifetime. Conversely, in buffered (pH 8.7) aqueous solutions, pyrimidine behaves differently from the other diazines. Thus, whereas pyrimidine only interacts with harmane in its ground state, pyrazine and pyridazine also interact in the excited state. The harmane-pyrimidine ground state interaction is an entropic controlled process. Therefore, we propose the formation of pi-pi stacked 1:1 complexes between these substrates. Association constants for the different types of complexes and quenching parameters are reported.

  17. Clastogenic adaption of Vicia faba root tip meristem cells after consecutive treatments with S-phase dependent and S-phase independent agents

    International Nuclear Information System (INIS)

    Heindorff, K.; Schubert, I.; Rieger, R.; Michaelis, A.

    1987-01-01

    Pretreatment of Vicia faba root tip meristems with low doses of S-phase independent clastogens, such as X-rays or bleomycin, prior to a high (challenge) dose of S-phase dependent clastogens, such as alkylating agents (TEM, Trenimon) or the pyridazine derivative MH, led to decreased challenge treatment-induced aberration frequencies, i.e., clastogenic adaptation. Using the inverse treatment sequence bleomycin and MH proved to be able to substitute for each other in provoking clastogenic (cross) adaptation while bleomycin and alkylating agents were unable to do so. The data support the assumption of inducible cellular functions that become triggered by low clastogen doses and additionally describe some particular properties of bleomycin when used for conditioning. Bleomycin proved to be capable to exert protection independent of the agent used for challenge treatment. (author)

  18. Synthesis of new derivatives of 1-(3-aminophenyl-4-benzoyl-5-phenyl-1H-pyrazole-3-carboxylic acid

    Directory of Open Access Journals (Sweden)

    RAHMI KASIMOGULLAR

    2010-12-01

    Full Text Available 1-(3-Aminophenyl-4-benzoyl-5-phenyl-1H-pyrazole-3-carboxylic acid (1 was synthesized according to the literature. 2-(3-Aminophenyl-2,6-dihydro-3,4-diphenyl-7H-pyrazolo[3,4-d]pyridazin-7-one (5 was obtained by the cyclocondensation reaction of 1 with hydrazine hydrate. New pyrazole derivatives of compounds 1 and 5 were synthesized by their reaction with β-diketones, β-ketoesters, β-naphthol, phenol and various other reagents. The structures of the synthesized compounds were characterized by 1H-NMR, 13C-NMR, IR and mass spectroscopy, as well as elemental analysis.

  19. N-Substituted 5-Chloro-6-phenylpyridazin-3(2H-ones: Synthesis, Insecticidal Activity Against Plutella xylostella (L. and SAR Study

    Directory of Open Access Journals (Sweden)

    Song Yang

    2012-08-01

    Full Text Available A series of N-substituted 5-chloro-6-phenylpyridazin-3(2H-one derivatives were synthesized based on our previous work; all compounds were characterized by spectral data and tested for in vitro insecticidal activity against Plutella xylostella. The results showed that the synthesized pyridazin-3(2H-one compounds possessed good insecticidal activities, especially the compounds 4b, 4d, and 4h which showed > 90% activity at 100 mg/L. The structure-activity relationships (SAR for these compounds were also discussed.

  20. Comprehensive and Facile Synthesis of Some Functionalized Bis-Heterocyclic Compounds Containing a Thieno[2,3-b]thiophene Motif

    Science.gov (United States)

    Mabkhot, Yahia N.; Barakat, Assem; Al-Majid, Abdullah M.; Alshahrani, Saeed A.

    2012-01-01

    A comprehensive and facile method for the synthesis of new functionalized bis-heterocyclic compounds containing a thieno[2,3-b]thiophene motif is described. The hitherto unknown bis-pyrazolothieno[2,3-b]thiophene derivatives 2a–c, bis-pyridazin othieno[2,3-b]thiophene derivatives 4, bis-pyridinothieno[2,3-b]thiophene derivatives 6a,b, and to an analogous bis-pyridinothieno[2,3-b]thiophene nitrile derivatives 7 are obtained. Additionally, the novel bis-pyradazinonothieno[2,3-b]thiophene derivatives 9, and nicotinic acid derivatives 10, 11 are obtained via bis-dienamide 8. The structures of all newly synthesized compounds have been elucidated by 1H, 13C NMR, GCMS, and IR spectrometry. These compounds represent a new class of sulfur and Nitrogen containing heterocycles that should also be of interest as new materials. PMID:22408452

  1. Structure-activity relationship (SAR) study and design strategies of nitrogen-containing heterocyclic moieties for their anticancer activities.

    Science.gov (United States)

    Akhtar, Jawaid; Khan, Ahsan Ahmed; Ali, Zulphikar; Haider, Rafi; Shahar Yar, M

    2017-01-05

    The present review article offers a detailed account of the design strategies employed for the synthesis of nitrogen-containing anticancer agents. The results of different studies describe the N-heterocyclic ring system is a core structure in many synthetic compounds exhibiting a broad range of biological activities. Benzimidazole, benzothiazole, indole, acridine, oxadiazole, imidazole, isoxazole, pyrazole, triazoles, quinolines and quinazolines including others drugs containing pyridazine, pyridine and pyrimidines are covered. The following studies of these compounds suggested that these compounds showed their antitumor activities through multiple mechanisms including inhibiting protein kinase (CDK, MK-2, PLK1, kinesin-like protein Eg5 and IKK), topoisomerase I and II, microtubule inhibition, and many others. Our concise representation exploits the design and anticancer potency of these compounds. The direct comparison of anticancer activities with the standard enables a systematic analysis of the structure-activity relationship among the series. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  2. Challenges in the development of an M4 PAM preclinical candidate: The discovery, SAR, and in vivo characterization of a series of 3-aminoazetidine-derived amides.

    Science.gov (United States)

    Tarr, James C; Wood, Michael R; Noetzel, Meredith J; Bertron, Jeanette L; Weiner, Rebecca L; Rodriguez, Alice L; Lamsal, Atin; Byers, Frank W; Chang, Sichen; Cho, Hyekyung P; Jones, Carrie K; Niswender, Colleen M; Wood, Michael W; Brandon, Nicholas J; Duggan, Mark E; Conn, P Jeffrey; Bridges, Thomas M; Lindsley, Craig W

    2017-07-01

    This letter details the continued chemical optimization of a novel series of M 4 positive allosteric modulators (PAMs) based on a 5-amino-thieno[2,3-c]pyridazine core by incorporating a 3-amino azetidine amide moiety. The analogs described within this work represent the most potent M 4 PAMs reported for this series to date. The SAR to address potency, clearance, subtype selectivity, CNS exposure, and P-gp efflux are described. This work culminated in the discovery of VU6000918, which demonstrated robust efficacy in a rat amphetamine-induced hyperlocomotion reversal model at a minimum efficacious dose of 0.3mg/kg. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Challenges in the development of an M4 PAM preclinical candidate: The discovery, SAR, and biological characterization of a series of azetidine-derived tertiary amides.

    Science.gov (United States)

    Tarr, James C; Wood, Michael R; Noetzel, Meredith J; Melancon, Bruce J; Lamsal, Atin; Luscombe, Vincent B; Rodriguez, Alice L; Byers, Frank W; Chang, Sichen; Cho, Hyekyung P; Engers, Darren W; Jones, Carrie K; Niswender, Colleen M; Wood, Michael W; Brandon, Nicholas J; Duggan, Mark E; Jeffrey Conn, P; Bridges, Thomas M; Lindsley, Craig W

    2017-12-01

    Herein we describe the continued optimization of M 4 positive allosteric modulators (PAMs) within the 5-amino-thieno[2,3-c]pyridazine series of compounds. In this letter, we disclose our studies on tertiary amides derived from substituted azetidines. This series provided excellent CNS penetration, which had been challenging to consistently achieve in other amide series. Efforts to mitigate high clearance, aided by metabolic softspot analysis, were unsuccessful and precluded this series from further consideration as a preclinical candidate. In the course of this study, we found that potassium tetrafluoroborate salts could be engaged in a tosyl hydrazone reductive cross coupling reaction, a previously unreported transformation, which expands the synthetic utility of the methodology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Crystal structures of eight 3D molecular adducts derived from bis-imidazole, bis(benzimidazole), and organic acids

    Science.gov (United States)

    Ding, Aihua; Jin, Shouwen; Jin, Shide; Hu, KaiKai; Lin, Zhihao; Liu, Hui; Wang, Daqi

    2018-01-01

    Cocrystallization of the bis(imidazole)/bis(benzimidazole) with a series of organic acids gave a total of eight molecular adducts with the compositions: (3,6-bis(imidazole-1-yl)pyridazine): (trichloroacetic acid)2(1) [(H2L1)2+ · (tca-)2, L1 = 3,6-bis(imidazole-1-yl)pyridazine, tca- = trichloroacetate], (bis(N-imidazolyl)methane): (suberic acid) (2) [(L2) · (H2suba), L2 = bis(N-imidazolyl)methane, H2suba = suberic acid], bis(N-imidazolyl)methane: (3-nitrophthalic acid): 3H2O (3) [(H2L2)2+ · (3-Hnpa-)2 · 3H2O, 3-Hnpa- = 3-nitro hydrogenphthalate], (bis(N-imidazolyl)butane)0.5: (4-nitrophthalic acid): H2O (4) [(H2L3)0.5+ · (4-Hnpa-)- · H2O, L3 = bis(N-imidazolyl)butane, 4-Hnpa- = 4-nitro hydrogenphthalate], (1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole): (3,5-dinitrosalicylic acid) (5) [(HL4) · (3,5-dns-), L4 = 1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole, 3,5-dns- = 3,5-dinitrosalicylate], (1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole): (3-nitrophthalic acid) (6) [(H2L4) · (3-npa2-), L4 = 1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole, 3-npa2-=3-nitrogenphthalate], (bis(N-imidazolyl)butane): (pamoic acid) (7) [(H2L3) · (pam), pam = pamoate], and (3,6-bis(imidazole-1-yl)pyridazine): (1,5-naphthalenedisulfonic acid) [(H2L1)2+ · (npda)2- = 1,5-naphthalenedisulfonate] (8). The eight adducts have been characterized by X-ray diffraction technique, infrared spectrum, and elemental analysis, and the melting points of all adducts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the eight investigated crystals both the end ring N in the bis(imidazole) moieties are protonated when the organic acids are deprotonated except 2, and 5, and the crystal packing is interpreted in terms of the strong ionic Nsbnd H⋯O H-bond between the imidazolium and the deprotonated acidic groups. Except the Nsbnd H⋯O H-bond, the Osbnd H⋯O H-bonds were also found at the salts 3, 4

  5. Inhibition of allergic dermal inflammation by the novel imidazopyridazine derivative TAK-427 in a guinea pig experimental model of eczema.

    Science.gov (United States)

    Fukuda, Shigeru; Midoro, Katsuo; Kamei, Takayuki; Gyoten, Michiyo; Kawano, Yasuhiko; Ashida, Yasuko; Nagaya, Hideaki

    2002-12-01

    Antigen challenge by patch ovalbumin emulsion induced an eczema-like skin lesion in epicutaneously sensitized guinea pigs. Diseased skin sites were macroscopically characterized by manifestations of dermatitis, such as erythema, edema, and papules, and microscopically characterized by acanthosis, spongiosis, and dermal infiltration by eosinophils. Using such lesions as a model of eczema, we evaluated the potential value of TAK-427 [2-[6-[[3-[4-(diphenylmethoxy)piperidino]propyl]amino] imidazo[1,2-b]pyridazin-2-yl]-2-methylpropionic acid dihydrate] as a therapeutic agent for atopic dermatitis by comparing it with dexamethasone and antihistamines. TAK-427 (0.3-30 mg/kg, p.o.) and dexamethasone (3 and 10 mg/kg, p.o.) inhibited eosinophil infiltration into the skin and ameliorated the dermatitis manifestations and epidermal damage. By contrast, none of the antihistamines tested (azelastine, ketotifen, terfenadine, and cetirizine) suppressed the eosinophil infiltration or dermatitis manifestations. To elucidate the mechanism by which TAK-427 inhibited the development of eczema, we investigated cytokine expression in the affected skin. Both TAK-427 and dexamethasone suppressed the increased mRNA expression of interleukin (IL)-13, granulocyte-macrophage colony-stimulating factor, IL-1alpha, tumor necrosis factor-alpha, interferon-gamma, and IL-8, but not IL-10, suggesting that TAK-427 inhibits allergic inflammation of the skin leading to the development of eczema by inhibiting the expression of proinflammatory cytokines after antigen challenge.

  6. Fabrication and evaluation of polymeric early-warning fire-alarm devices. [combustion products

    Science.gov (United States)

    Senturia, S. D.

    1975-01-01

    The electrical resistivities were investigated of some polymers known to be enhanced by the presence of certain gases. This was done to make a device capable of providing early warning to fire through its response with the gases produced in the early phases of combustion. Eight polymers were investigated: poly(phenyl acetylene), poly(p-aminophenyl acetylene), poly(p-nitrophenyl acetylene), poly(p-formamidophenyl acetylene), poly(ethynyl ferrocene), poly(ethynyl carborane), poly(ethynyl pyridine), and the polymer made from 1,2,3,6 tetramethyl pyridazine. A total of 40 usable thin-film sandwich devices and a total of 70 usable interdigitated-electrode lock-and-key devices were fabricated. The sandwich devices were used for measurements of contact linearity, polymer conductivity, and polymer dielectric constant. The lock-and-key devices were used to determine the response of the polymers to a spectrum of gases that included ammonia, carbon nonoxide, carbon dioxide, sulfur dioxide, ethylene, acrolein, water vapor, and normal laboratory air. Strongest responses were to water vapor, ammonia, and acrolein, and depending on the polymer, weaker responses to carbon dioxide, sulfur dioxide, and carbon monoxide were observed. A quantitative theory of device operation, capable of accounting for observed device leakage current and sensitivity, was developed. A prototype detection/alarm system was designed and built for use in demonstrating sensor performance.

  7. Installing an additional emission quenching pathway in the design of iridium(III)-based phosphorogenic biomaterials for bioorthogonal labelling and imaging.

    Science.gov (United States)

    Li, Steve Po-Yam; Yip, Alex Man-Hei; Liu, Hua-Wei; Lo, Kenneth Kam-Wing

    2016-10-01

    We report the synthesis, characterization, photophysical and electrochemical behaviour and biological labelling applications of new phosphorogenic bioorthogonal probes derived from iridium(III) polypyridine complexes containing a 1,2,4,5-tetrazine moiety. In contrast to common luminescent cyclometallated iridium(III) polypyridine complexes, these tetrazine complexes are almost non-emissive due to effective Förster resonance energy transfer (FRET) and/or photoinduced electron transfer (PET) from the excited iridium(III) polypyridine unit to the appended tetrazine moiety. However, they exhibited significant emission enhancement upon reacting with (1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethanol (BCN-OH) (ca. 19.5-121.9 fold) and BCN-modified bovine serum albumin (BCN-BSA) (ca. 140.8-1133.7 fold) as a result of the conversion of the tetrazine unit to a non-quenching pyridazine derivative. The complexes were applied to image azide-modified glycans in live cells using a homobifunctional crosslinker, 1,13-bis((1R,8S,9s)-bicyclo[6.1.0]non-4-yn-9-ylmethyloxycarbonylamino)-4,7,10-trioxatridecane (bis-BCN). Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

    Directory of Open Access Journals (Sweden)

    Rita M. Borik

    2007-08-01

    Full Text Available The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction of 6a,b,d-f,h with glycine and hippuric acid in acetic anhydride afforded pyridazinone derivatives 17a-f. Synthesis of pyridazine carboxylic acid derivatives 22a,b from the reaction of 6b,e with dimethyl acetylenedicarboxylate (DMAD in the presence of triphenylphosphine at room temperature is also reported. Most of these reactions were conducted under irradiation in a microwave oven in the absence of solvent in an attempt to improve the product yields and to reduce the reaction times.

  9. Facile synthesis and antimicrobial evaluation of some new heterocyclic compounds incorporating a biologically active sulfamoyl moiety.

    Science.gov (United States)

    Darwish, Elham S

    2014-01-01

    A facile and convenient synthesis of new heterocyclic compounds containing a sulfamoyl moiety suitable for use as antimicrobial agents was reported. The precursor 3-oxo-3-phenyl-N-(4-sulfamoylphenyl)propionamide was coupled smoothly with arenediazonium salt producing hydrazones which reacted with malononitrile or triethylorthoformate affording pyridazine and triazine derivatives, respectively. Also, the reactivity of the same precursor with DMF-DMA was followed by aminotriazole; aromatic aldehydes was followed by hydrazine hydrate, triethylorthoformate, or thiourea affording triazolo[1,5-a]pyrimidine, pyrazole, acrylamide, and dihydropyrimidine derivatives, respectively. On the other hand, treatment of the precursor propionamide with phenyl isothiocyanate and KOH in DMF afforded the intermediate salt which was treated with dilute HCl followed by 2-bromo-1-phenylethanone affording carboxamide derivative. While the same intermediate salt reacted in situ with chloroacetone, ethyl 2-chloroacetate, 3-(2-bromoacetyl)-2H-chromen-2-one, methyl iodide, or 2-oxo-N-phenylpropane hydrazonoyl chloride afforded the thiophene, ketene N,S-acetal, and thiadiazole derivatives, respectively. The structure of the new products was established based on elemental and spectral analysis. Antimicrobial evaluation of some selected examples from the synthesized products was carried out whereby four compounds were found to have moderate activities and one compound showed the highest activity.

  10. EXPERIMENTAL AND COMPUTATIONAL STUDIES OF THE FORMATION MECHANISM OF PROTONATED INTERSTELLAR DIAZINES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhe-Chen; Cole, Callie A.; Bierbaum, Veronica M. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309 (United States); Snow, Theodore P., E-mail: zhwa4666@colorado.edu [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2015-01-10

    Studies of interstellar chemistry have grown in number and complexity by both observations and laboratory measurements, and nitrogen-containing aromatics have been implicated as important interstellar molecules. In this paper, the gas-phase collision induced dissociation (CID) processes of protonated pyridazine (1,2-diazine), pyrimidine (1,3-diazine), and pyrazine (1,4-diazine) cations (C{sub 4}H{sub 5}N{sub 2} {sup +}) are investigated in detail both experimentally and theoretically. The major neutral loss for all three CID processes is HCN, leading to the formation of C{sub 3}H{sub 4}N{sup +} isomers; our density functional theory (DFT) calculations support and elucidate our experimental results. The formation of C{sub 3}H{sub 4}N{sup +} isomers from the reaction of abundant interstellar acrylonitrile (CH{sub 2}CHCN) and H{sup +}is also studied employing DFT calculations. Our results lead to a novel mechanism for interstellar protonated diazine formation from the consecutive reactions of CH{sub 2}CHCN+ H{sup +} + HCN. Moreover, our results motivate the continuing search for interstellar C{sub 3}H{sub 4}N{sup +} isomers as well as polycyclic aromatic N-containing hydrocarbons (PANHs)

  11. CM 40907: a structurally novel anticonvulsant in mice, rats and baboons

    International Nuclear Information System (INIS)

    Chambon, J.P.; Brochard, J.; Hallot, A.; Heaulme, M.; Brodin, R.; Roncucci, R.; Biziere, K.

    1985-01-01

    CM 40907 [3-(4-hydroxypiperidyl)-6-(2'-chlorophenyl)-pyridazine] is a chemically original compound which possesses the pharmacological properties of a potent, p.o. active anticonvulsant. The anticonvulsant activity of CM 40907 was examined in mice, rats and photosensitive Papio-papio baboons and compared to that of phenobarbital, diphenylhydantoin, carbamazepine, sodium valproate and ethosuximide. In mice, CM 40907 antagonized electroconvulsive shock and chemically induced seizures with an overall potency comparable to that of carbamazepine and a therapeutic ratio (ED50 rotorod/ED50 electroshock) superior to that of ethosuximide, sodium valproate, phenobarbital and carbamazepine. In the rat CM 40907 suppressed completed kindled amygdaloid seizures and was approximately as active as phenobarbital. In naturally photosensitive Senegalese Papio-papio baboons CM 40907 antagonized myoclonus and cortical paroxysmal discharges. In this model CM 40907 was approximately one-fourth as potent as phenobarbital, twice as potent as carbamazepine and 6 times more potent than sodium valproate. In mice CM 40907, at anticonvulsant doses, increased the affinity of [ 3 H]flunitrazepam for its central receptor site. Based on these results it is postulated that CM 40907 is a potent and relatively nonsedative anticonvulsant and may be of therapeutic benefit in epileptic disorders

  12. Synthesis and biological activity of a new class of insecticides: the N-(5-aryl-1,3,4-thiadiazol-2-yl)amides.

    Science.gov (United States)

    Eckelbarger, Joseph D; Parker, Marshall H; Yap, Maurice Ch; Buysse, Ann M; Babcock, Jonathan M; Hunter, Ricky; Adelfinskaya, Yelena; Samaritoni, Jack G; Garizi, Negar; Trullinger, Tony K

    2017-04-01

    Optimization studies on a high-throughput screening (HTS) hit led to the discovery of a series of N-(6-arylpyridazin-3-yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4-thiadiazole ring could lead to more potent biological activity and/or a broader sap-feeding pest spectrum. The resulting N-(5-aryl-1,3,4-thiadiazol-2-yl)amides were explored as a new class of insecticides. Several methods for 2-amino-1,3,4-thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid) and Bemisia tabaci (Gennadius) (sweetpotato whitefly). Structure-activity relationship (SAR) studies on both the amide tail and the aryl A-ring of novel N-(5-aryl-1,3,4-thiadiazol-2-yl)amides led to a new class of insecticidal molecules active against sap-feeding insect pests. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Recent Developments of C-Aryl Glucoside SGLT2 Inhibitors.

    Science.gov (United States)

    Zhang, Yang; Liu, Zhao-Peng

    2016-01-01

    Sodium-glucose cotransporter 2 (SGLT2) is almost exclusively expressed in the proximal renal tubules. It is responsible for about 90% of the glucose reabsorption from tubular fluid. Selective inhibition of SGLT2 is expected to favor in the normalization of plasma glucose levels in T2DM patients through the prevention of renal glucose reabsorption and the promotion of glucose excretion from urine. Selective SGLT2 inhibitors have the merits to minimize the gastrointestinal side effects associated with SGLT1 inhibition, and selective SGLT2 inhibition may have a low risk of hypoglycemia. Since the C-aryl glucosides are metabolically more stable than the O-glucosides, numerous efforts have been made in the development of potent and selective C-aryl glucoside SGLT2 inhibitors, and a number of them are now used as anti-diabetes drugs in clinic or at various stages of clinical developments. Based on their structural features, in this review, these SGLT2 inhibitors are classified as three types: the phenyl/arylmethylphenyl C-glucosides, with an emphasis on the modifications on the proximal and/or the distal phenyl ring, and the spacer; the heteroarylmethylphenyl Cglucosides, with a replacement of the distal phenyl ring by a heterocycle like pyridazine, pyrimidine, thiophene and benzothiophene, thiazole, 1,3,4-thiadiazole, and triazolopyridinone; and the glucose-modified Caryl glucosides, including the glucose C-1 derived O-spiroketals, C-4 gem-difluoro analogues, C-5 and C-6 modified derivatives, dioxa-bicyclo[3.2.1]octane bridged ketals, the thioglucosides, and carbasugars. The structure-activity relationships (SARs) of each type along with their inhibitory potency against human SGLT2 and selectivity over human SGLT1 are discussed.

  14. Rubrolides as model for the development of new lactones and their aza analogs as potential photosynthesis inhibitors.

    Science.gov (United States)

    Pereira, Ulisses A; Barbosa, Luiz C A; Demuner, Antônio J; Silva, Antônio A; Bertazzini, Michele; Forlani, Giuseppe

    2015-07-01

    Natural phytotoxins and their synthetic analogs are a potential source of new bioactive compounds for agriculture. Analogs of rubrolides, a class of γ-alkylidene-γ-lactones isolated from different ascidians, have been shown to interfere with the photosynthetic electron-transport chain, yet their activity needs to be improved. With this aim, ten 5-aryl-6-benzyl-4-bromopyridazin-3(2H)-ones were prepared in yields ranging from 44 to 88% by reaction of their correspondent γ-alkylidene-γ-lactones with NH2 NH2 . The structures of these rubrolide analogs were determined by (1) H- and (13) C-NMR, 2D-NMR (COSY and HETCOR), NOE difference, and MS techniques. These compounds were evaluated for their abilities of interfering with the light-driven reduction of ferricyanide by isolated spinach chloroplasts. Lactones with electron-withdrawing substituents in the para-position of the benzylidene ring were the most effective inhibitors. Characterization of the activity of 11b/11b' suggested a mechanism based on the interaction with the plastoquinone binding site of photosystem II. Addition of several compounds to the culture medium of a cyanobacterial model strain was found to inhibit algal growth. However, the relative effectiveness was not consistent with their activity in vitro, suggesting the occurrence of multiple targets and/or detoxyfication mechanisms. Indeed, the compounds showed differential effects on the heterotrophic growth of some crop species, Cucumis sativus and Sorghum bicolor. Pyridazin-3(2H)-ones 12e, 12i, and 12j, which have been found poorly active against the photosynthetic electron transport, were the most effective in inhibiting the growth of some weeds, Ipomoea grandifolia and Brachiaria decumbens, under greenhouse conditions. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

  15. Comparative metabonomics of differential hydrazine toxicity in the rat and mouse

    International Nuclear Information System (INIS)

    Bollard, Mary E.; Keun, Hector C.; Beckonert, Olaf; Ebbels, Tim M.D.; Antti, Henrik; Nicholls, Andrew W.; Shockcor, John P.; Cantor, Glenn H.; Stevens, Greg; Lindon, John C.; Holmes, Elaine; Nicholson, Jeremy K.

    2005-01-01

    Interspecies variation between rats and mice has been studied for hydrazine toxicity using a novel metabonomics approach. Hydrazine hydrochloride was administered to male Sprague-Dawley rats (30 mg/kg, n = 10 and 90 mg/kg, n = 10) and male B6C3F mice (100 mg/kg, n = 8 and 250 mg/kg, n = 8) by oral gavage. In each species, the high dose was selected to produce the major histopathologic effect, hepatocellular lipid accumulation. Urine samples were collected at sequential time points up to 168 h post dose and analyzed by 1 H NMR spectroscopy. The metabolites of hydrazine, namely diacetyl hydrazine and 1,4,5,6-tetrahydro-6-oxo-3-pyridazine carboxylic acid (THOPC), were detected in both the rat and mouse urine samples. Monoacetyl hydrazine was detected only in urine samples from the rat and its absence in the urine of the mouse was attributed to a higher activity of N-acetyl transferases in the mouse compared with the rat. Differential metabolic effects observed between the two species included elevated urinary β-alanine, 3-D-hydroxybutyrate, citrulline, N-acetylcitrulline, and reduced trimethylamine-N-oxide excretion unique to the rat. Metabolic principal component (PC) trajectories highlighted the greater degree of toxic response in the rat. A data scaling method, scaled to maximum aligned and reduced trajectories (SMART) analysis, was used to remove the differences between the metabolic starting positions of the rat and mouse and varying magnitudes of effect, to facilitate comparison of the response geometries between the rat and mouse. Mice followed 'biphasic' open PC trajectories, with incomplete recovery 7 days after dosing, whereas rats followed closed 'hairpin' time profiles, indicating functional reversibility. The greater magnitude of metabolic effects observed in the rat was supported by the more pronounced effect on liver pathology in the rat when compared with the mouse

  16. Light at the end of the tunnel in radiation therapy: molecular imaging in radiation research

    International Nuclear Information System (INIS)

    Rao, V.L. Papineni

    2013-01-01

    Accurate dose delivery to malignant tissue in radiotherapy is quite important for enhancing the treatment efficacy while minimizing morbidity of surrounding normal tissues. Advances in therapeutic strategies and diagnosis technologies along with our understanding of the biology of tumor response to radiation therapy have paved way to allow nearly 60% of current cancer patients to be treated with Radiation Therapy. The confluence of molecular imaging and nanotechnology fields are bridging physics and medicine and are quickly making strides in opening new avenues and therapeutic strategies that complement radiation therapy - with a distinct footprint in immunotherapy, adoptive cell therapy, and targeted chemotherapy. Incorporating optical imaging in radiation therapy in my laboratory, we demonstrated that molecular probes can monitor radiation-induced physiological changes at the target and off-target sites using in vivo molecular imaging approaches. Further we show endogenous bioluminescence resulting from whole body irradiation, which is distinct from the Cherenkov radiation. Mice without anesthesia were held in ventilated mouse pie cage and subjected to 5 Gy X-ray irradiation using commercially available X-RAD320 irradiator (1 Gy/min; F2 beam hardening filter 1.5 mm Al, 0.25 mm Cu, 0.75 mm Sn,). The endogenous bioluminescence from the subjects was captured using cooled CCD camera. Significant increase (up to 100 fold) in the amounts of photons released as bioluminescence was detected during 5 min capture from the mice subjected to irradiation compared to that of the control. To determine the early inflammatory response, the reactive oxygen species (ROS) activity was monitored using L-012 (8-amino-5-chloro-7-phenylpyridol (3,4-d)pyridazine-1,4(2H,3H) dione), a chemiluminescence reporter. L-012 was administered (i.p) after 15 min of irradiation. Chemiluminescence resulting from the irradiation induced ROS activity, possible through the action of the

  17. In vitro pharmacological characterization of a novel selective alpha7 neuronal nicotinic acetylcholine receptor agonist ABT-107.

    Science.gov (United States)

    Malysz, John; Anderson, David J; Grønlien, Jens H; Ji, Jianguo; Bunnelle, William H; Håkerud, Monika; Thorin-Hagene, Kirten; Ween, Hilde; Helfrich, Rosalind; Hu, Min; Gubbins, Earl; Gopalakrishnan, Sujatha; Puttfarcken, Pamela S; Briggs, Clark A; Li, Jinhe; Meyer, Michael D; Dyhring, Tino; Ahring, Philip K; Nielsen, Elsebet Ø; Peters, Dan; Timmermann, Daniel B; Gopalakrishnan, Murali

    2010-09-01

    Enhancement of alpha7 nicotinic acetylcholine receptor (nAChR) activity is considered a therapeutic approach for ameliorating cognitive deficits present in Alzheimer's disease and schizophrenia. In this study, we describe the in vitro profile of a novel selective alpha7 nAChR agonist, 5-(6-[(3R)-1-azabicyclo[2,2,2]oct-3-yloxy]pyridazin-3-yl)-1H-indole (ABT-107). ABT-107 displayed high affinity binding to alpha7 nAChRs [rat or human cortex, [(3)H](1S,4S)-2,2-dimethyl-5-(6-phenylpyridazin-3-yl)-5-aza-2-azoniabicyclo[2.2.1]heptane (A-585539), K(i) = 0.2-0.6 nM or [(3)H]methyllycaconitine (MLA), 7 nM] that was at least 100-fold selective versus non-alpha7 nAChRs and other receptors. Functionally, ABT-107 did not evoke detectible currents in Xenopus oocytes expressing human or nonhuman alpha3beta4, chimeric (alpha6/alpha3)beta4, or 5-HT(3A) receptors, and weak or negligible Ca(2+) responses in human neuroblastoma IMR-32 cells (alpha3* function) and human alpha4beta2 and alpha4beta4 nAChRs expressed in human embryonic kidney 293 cells. ABT-107 potently evoked human and rat alpha7 nAChR current responses in oocytes (EC(50), 50-90 nM total charge, approximately 80% normalized to acetylcholine) that were enhanced by the positive allosteric modulator (PAM) 4-[5-(4-chloro-phenyl)-2-methyl-3-propionyl-pyrrol-1-yl]-benzenesulfonamide (A-867744). In rat hippocampus, ABT-107 alone evoked alpha7-like currents, which were inhibited by the alpha7 antagonist MLA. In dentate gyrus granule cells, ABT-107 enhanced spontaneous inhibitory postsynaptic current activity when coapplied with A-867744. In the presence of an alpha7 PAM [A-867744 or N-[(3R)-1-azabicyclo[2.2.2]oct-3-yl]-4-chlorobenzamide hydrochloride (PNU-120596)], the addition of ABT-107 elicited MLA-sensitive alpha7 nAChR-mediated Ca(2+) signals in IMR-32 cells and rat cortical cultures and enhanced extracellular signal-regulated kinase phosphorylation in differentiated PC-12 cells. ABT-107 was also effective in protecting rat

  18. Evaluation of {sup 18}F-BCPP-EF for mitochondrial complex 1 imaging in the brain of conscious monkeys using PET

    Energy Technology Data Exchange (ETDEWEB)

    Tsukada, Hideo; Ohba, Hiroyuki; Kanazawa, Masakatsu; Kakiuchi, Takeharu; Harada, Norihiro [Hamamatsu Photonics K.K., Central Research Laboratory, Hamamatsu, Shizuoka (Japan)

    2014-04-15

    We have reported on the development of a novel PET probe, {sup 18}F-2-tert-butyl-4-chloro-5-{6-[2-(2-fluoroethoxy)-ethoxy] -pyridin-3-ylmethoxy}-2H-pyridazin-3-one ({sup 18}F-BCPP-EF), for quantitative imaging of mitochondrial complex 1 (MC-1) activity in the brain of the living rat. For clinical application in humans, translational research in the monkey was conducted. PET measurements with {sup 18}F-BCPP-EF were performed in young and old monkeys (Macaca mulatta) in a conscious state with arterial blood sampling. The binding specificity of {sup 18}F-BCPP-EF was evaluated with rotenone, a specific MC-1 inhibitor, in young animals. The binding (total distribution volume, V{sub T}) of {sup 18}F-BCPP-EF was calculated using Logan graphical analysis, and one-tissue compartment model (1-TC) and two-tissue compartment model (2-TC) analyses using a metabolite-corrected plasma input function. F-BCPP-EF was rapidly taken up into the brain just after intravenous injection, peaked between 10 and 20 min after injection, and was then gradually eliminated. The 2-TC analysis provided a better fit than the 1-TC analysis, and the V{sub T} values from the 2-TC analysis correlated well with those from the Logan plot. With predosing with rotenone, {sup 18}F-BCPP-EF showed a higher uptake peak in the brain, followed by more rapid elimination thereafter than in the vehicle condition, resulting in significant reductions in 2-TC V{sub T} values in all regions. In old animals, the kinetics of {sup 18}F-BCPP-EF were slightly slower with lower peak levels than in young animals, resulting age-related reductions in {sup 18}F-BCPP-EF binding in all brain regions. The present study demonstrated that {sup 18}F-BCPP-EF may be a potential PET probe for quantitative imaging MC-1 activity in the living brain using PET. (orig.)

  19. Synthesis and carbon-11-labeling of p-MeO-SSR180575, a novel indoleacetamide-based candidate for PET imaging of the peripheral benzodiazepine receptor (TSPO 18 kDa)

    International Nuclear Information System (INIS)

    Damont, A.L.; Le Helleix, St.; Kuhnast, B.; Boisgard, R.; Tavitian, B.; Dolle, F.; Marguet, F.; Puech, F.

    2011-01-01

    Complete text of publication follows: Objectives: The 3-iso-quinolinecarboxamide [ 11 C]PK11195, despite its low brain uptake and high level of nonspecific binding, is still the most widely used PET-radioligand for the in vivo imaging of the peripheral benzodiazepine receptor (PBR or TSPO 18 kDa). Several new PBR radioligands are currently developed to replace [ 11 C]PK11195 [1], e.g the pyrazolo[1, 5-a]pyrimidine-acetamides [ 11 C]DPA-713 and [ 18 F]DPA-714, the imidazo[1, 2-a]pyridine-acetamides [ 11 C]CLINME and [ 18 F]PBR111 and the N-benzyl-N-(2-phenoxy-aryl)- acetamides [ 11 C]PBR28 and [ 18 F]FEDAA1106. Another attractive newly identified chemical class of structures are the indole-acetamides and notably compounds derived from the lead compound SSR180575 [2]. Herein are reported the synthesis and the labelling with the positron-emitter carbon-11 (half-life: 20.38 min) of a novel derivative of SSR180575, bearing a para methoxy function on its phenyl ring. Methods: p-MeO-SSR180575 (1) was synthesized from commercially available 4-chloro-2-nitrotoluene in 10 steps. O-demethylation, performed with a boron tribromide solution in dichloromethane at low temperature, afforded the free phenol derivative 2. Carbon-11 labeling of p-MeO-SSR180575 (1) was performed using a TRACERLab FX-C Pro synthesizer (GEMS) and comprised (1) trapping of [ 11 C]MeOTf at -10 C in acetone (0.3 mL) containing the nor-derivative 2 (O-demethylated, 0.6-0.9 mg) and aq. 3N NaOH (8 μL); (2) heating at 110 C for 2 min; (3) concentration to dryness and taking up the residue in 1.0 mL of the HPLC mobile phase; (4) purification using semi-preparative reversed-phase HPLC (Waters Symmetry R C-18 - eluent: CH 3 CN / H 2 O / TFA: 50 / 50 / 0.1 (v:v:v) - flow rate: 5 mL/min - detection at 254 nm) and (5) SepPak Plus R C-18-based formulation for i.v. injection approach was the pyridazine ring formation reaction that proceeded partially: the maximum conversion of the intermediate diester-indole reacting

  20. Synthesis and carbon-11-labeling of p-MeO-SSR180575, a novel indoleacetamide-based candidate for PET imaging of the peripheral benzodiazepine receptor (TSPO 18 kDa)

    International Nuclear Information System (INIS)

    Damont, A.; Le Helleix, St.; Kuhnast, B.; Boisgard, R.; Tavitian, B.; Dolle, F.; Marguet, F.; Puech, F.

    2011-01-01

    Complete text of publication follows: Objectives: The 3-iso-quinolinecarboxamide [ 11 C]PK11195, despite its low brain uptake and high level of nonspecific binding, is still the most widely used PET-radioligand for the in vivo imaging of the peripheral benzodiazepine receptor (PBR or TSPO 18 kDa). Several new PBR radioligands are currently developed to replace [ 11 C]PK11195, e.g the pyrazolo[1, 5-a]pyrimidine-acetamides [ 11 C]DPA-713 and [ 18 F]DPA-714, the imidazo[1, 2-a]pyridine-acetamides [ 11 C]CLINME and [ 18 F]PBR111 and the N-benzyl-N-(2-phenoxy-aryl)- acetamides [ 11 C]PBR28 and [ 18 F]FEDAA1106. Another attractive newly identified chemical class of structures are the indole-acetamides and notably compounds derived from the lead compound SSR180575. Herein are reported the synthesis and the labelling with the positron-emitter carbon-11 (half-life: 20.38 min) of a novel derivative of SSR180575, bearing a para methoxy function on its phenyl ring. Methods: p-MeO-SSR180575 (1) was synthesized from commercially available 4-chloro-2-nitrotoluene in 10 steps. O-demethylation, performed with a boron tribromide solution in dichloromethane at low temperature, afforded the free phenol derivative 2. Carbon-11 labeling of p-MeO-SSR180575 (1) was performed using a TRACERLab FX-C Pro synthesizer (GEMS) and comprised (1) trapping of [ 11 C]MeOTf at -10 C in acetone (0.3 mL) containing the nor-derivative 2 (O-demethylated, 0.6-0.9 mg) and aq. 3N NaOH (8 μL); (2) heating at 110 C for 2 min; (3) concentration to dryness and taking up the residue in 1.0 mL of the HPLC mobile phase; (4) purification using semi-preparative reversed-phase HPLC (Waters Symmetry C-18 - eluent: CH 3 CN / H 2 O / TFA: 50 / 50 / 0.1 (v:v:v) - flow rate: 5 mL/min - detection at 254 nm) and (5) SepPak R Plus C-18-based formulation for i.v. injection. Results: p-MeO-SSR180575 (1) was obtained in 10% overall yield. The tricky and low-yielding step in our approach was the pyridazine ring formation

  1. Copper-organic/octamolybdates: structures, bandgap sizes, and photocatalytic activities.

    Science.gov (United States)

    Luo, Lan; Lin, Haisheng; Li, Le; Smirnova, Tatyana I; Maggard, Paul A

    2014-04-07

    The structures, optical bandgap sizes, and photocatalytic activities are described for three copper-octamolybdate hybrid solids prepared using hydrothermal methods, [Cu(pda)]4[β-Mo8O26] (I; pda = pyridazine), [Cu(en)2]2[γ-Mo8O26] (II; en = ethylenediamine), and [Cu(o-phen)2]2[α-Mo8O26] (III; o-phen = o-phenanthroline). The structure of I consists of a [Cu(pda)]4(4+) tetramer that bridges to neighboring [β-Mo8O26](4-) octamolybdate clusters to form two-dimensional layers that stack along the a axis. The previously reported structures of II and III are constructed from [Cu2(en)4Mo8O26] and [Cu2(o-phen)4Mo8O26] clusters. The optical bandgap sizes were measured by UV-vis diffuse reflectance techniques to be ∼1.8 eV for I, ∼3.1 eV for II, and ∼3.0 eV for III. Electronic structure calculations show that the smaller bandgap size of I originates primarily from an electronic transition between the valence and conduction band edges comprised of filled 3d(10) orbitals on Cu(I) and empty 4d(0) orbitals on Mo(VI). Both II and III contain Cu(II) and exhibit larger bandgap sizes. Accordingly, aqueous suspensions of I exhibit visible-light photocatalytic activity for the production of oxygen at a rate of ∼90 μmol O2 g(-1) h(-1) (10 mg samples; radiant power density of ∼1 W/cm(2)) and a turnover frequency per calculated surface [Mo8O26](4-) cluster of ∼36 h(-1). Under combined ultraviolet and visible-light irradiation, I also exhibits photocatalytic activity for hydrogen production in 20% aqueous methanol of ∼316 μmol H2 g(-1) h(-1). By contrast, II decomposed during the photocatalysis measurements. The molecular [Cu2(o-phen)4(α-Mo8O26)] clusters of III dissolve into the aqueous methanol solution under ultraviolet irradiation and exhibit homogeneous photocatalytic rates for hydrogen production of up to ∼8670 μmol H2·g(-1) h(-1) and a turnover frequency of 17 h(-1). The clusters of III can be precipitated out by evaporation and redispersed into solution with