19 research outputs found

    1-[(2-Chloro-8-methyl­quinolin-3-yl)­meth­yl]pyridin-2(1H)-one

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    In the title compound, C16H13ClN2O, the quinoline ring system is approximately planar [maximum deviation 0.021 (2) Å] and forms a dihedral angle of 85.93 (6)° with the pyridone ring. Inter­molecular C—H⋯O hydrogen bonding, together with weak C—H⋯π and π–π inter­actions [centroid-to-centroid distances 3.5533 (9) and 3.7793 (9) Å], characterize the crystal structure

    Nucleophile-Catalyzed Additions to Activated Triple Bonds. Protection of Lactams, Imides, and Nucleosides with MocVinyl and Related Groups

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    Additions of lactams, imides, (S)-4-benzyl-1,3-oxazolidin-2-one, 2-pyridone, pyrimidine-2,4-diones (AZT derivatives), or inosines to the electron-deficient triple bonds of methyl propynoate, tert-butyl propynoate, 3-butyn-2-one, N-propynoylmorpholine, or N-methoxy-N-methylpropynamide in the presence of many potential catalysts were examined. DABCO and, second, DMAP appeared to be the best (highest reaction rates and E/Z ratios), while RuCl3, RuClCp*(PPh3)2, AuCl, AuCl(PPh3), CuI, and Cu2(OTf)2 were incapable of catalyzing such additions. The groups incorporated (for example, the 2-(methoxycarbonyl)ethenyl group that we name MocVinyl) serve as protecting groups for the above-mentioned heterocyclic CONH or CONHCO moieties. Deprotections were accomplished via exchange with good nucleophiles: the 1-dodecanethiolate anion turned out to be the most general and efficient reagent, but in some particular cases other nucleophiles also worked (e.g., MocVinyl-inosines can be cleaved with succinimide anion). Some structural and mechanistic details have been accounted for with the help of DFT and MP2 calculations

    Carbohydrate based formal synthesis of stemoamide using ring-closing metathesis

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    A synthesis of stemoamide has been achieved from D-glucose. The stereocontrolled allylation under Barbier reaction conditions led to the installation of the 2-pyrrolidinone ring at C-3 followed by a ring-closing metathesis approach to construct the azepine ring system

    A new route to prepare 6-chloro-5-(2-chloroethyl)oxindole

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    6-Chloro-5-(2-chloroethyl)oxindole, a key intermediate in the manufacturing of the antipsychotic drug, ziprasidone, has been synthesized by a new route. The salient features of the synthesis are (1) bis-dialkylation of 2,4-difluoro-5-chloronitrobenzene with sodium diethyl malonate, (2) decarboxylative hydrolysis to obtain the oxindole derivative, and (3) reduction and chlorination of acetic ester side chain

    Diastereoselective reformatsky reaction of methyl 4-bromocrotonate with 1,2:5, 6-di-O-isopropylidene-[α]-D-ribo-hexofuranos-3-ulose: application to novel

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    This paper describes an efficient synthetic route for novel bicyclic nucleosides. The stereochemistry of the targeted bicyclic nucleosides was successfully achieved by vinylogous Reformatsky reaction and ring closing metathesis reaction on a carbohydrate backbone

    Enzymatic Strategy for the Resolution of New 1-Hydroxymethyl Tetrahydro-β-carboline Derivatives in Batch and Continuous-Flow Systems

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    Many alkaloids containing a tetrahydro-β-carboline skeleton have well-known therapeutic effects, leading to increased interest in the synthesis of these natural products. Enantiomers of N-Boc-protected 1-hydroxymethyl-1,2,3,4-tetrahydro-β-carboline [(±)-7], 1-hydroxymethyl-6-methoxy-1,2,3,4-tetrahydro-β-carboline [(±)-8], and 1-hydroxymethyl-6-fluoro-1,2,3,4-tetrahydro-β-carboline [(±)-9] were prepared through enzymecatalyzed asymmetric acylation of their primary hydroxyl group. The preliminary experiments were performed in a continuous-flow system, while the preparative-scale resolutions were done as batch reactions. Excellent enantioselectivities (E>200) were obtained with Candida antarctica lipase B (CAL-B) and acetic anhydride in toluene at 60°C. The recovered alcohols and the produced esters were obtained with high enantiomeric excess values (ee≥96%). The O-acylated enantiomers [(S)-10-(S)-12)] were transformed into the corresponding amino alcohols [(S)-7-(S)-9)] with methanolysis. Microwave-assisted Boc removals were also performed and resulted in the corresponding compounds (R)-4-(R)-6 and (S)-4-(S)-6 without a drop in the enantiomeric excess values (ee≥96%). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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