共查询到20条相似文献,搜索用时 15 毫秒
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E. A. Dikusar V. I. Potkin S. K. Pyatkevich 《Russian Journal of General Chemistry》2014,84(9):1701-1705
Preparative method for the synthesis of lithium, sodium, cesium, and calcium salts of (E)-4-(5-arylisoxazol-3-yl)methyleneaminobutanoic, (E)-6-(5-arylisoxazol-3-yl)methyleneaminohexanoic, (E,S)-3-methyl-2-(5-arylisoxazol-3-yl)methyleneaminobutanoic, (E,S)-4-methyl-2-(5-arylisoxazol-3-yl)methyleneaminopentanoic and (E,2S,3S)-3-methyl-2-(5-arylisoxazol-3-yl)methyleneaminopentanoic acids was developed by reacting 5-phenyl(4-tolyl)isoxazole-3-carbaldehydes with amino acids like 4-aminobutyric and 6-aminocaproic acids, L-valine, L-leucine or L-isoleucine in the presence of lithium hydride, sodium methoxide, cesium carbonate or calcium hydride in boiling methanol. 相似文献
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J. W. Bats T. Heinrich M. Reggelin 《Acta Crystallographica. Section C, Structural Chemistry》1999,55(10):IUC9900121-IUC9900121
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《Tetrahedron: Asymmetry》2005,16(6):1135-1140
Stereoselective synthesis of pharmaceutically interesting chiral tetrahydrofurans starting from mannose diacetonide is reported. A 1,4-diol system derived from mannose diacetonide, through a Mitsunobu reaction was stereospecifically cyclized to give chiral tetrahydrofurans. Both the C-1 and C-4 centers of d-mannose are successfully exploited to install the requisite side chains. 相似文献
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Syntheses of (2S,4S)- and (2S,4R)-5-fluoroleucine, and, and of (2S,4S)-[5,5-(2)H(2)]-5-fluoroleucine, have been completed. The methodology allows these compounds to be prepared in sufficient quantities for incorporation by solid-state protein synthesis into strategic sites in proteins for folding studies. X-ray structures of the epimers and have been obtained and show the presence of conformational isomerism. The torsion angles between the F-C bond and the main chain are compared with values found in a mutant of the protein ubiquitin in which (2S,4S)-5-fluoroleucine replaces leucine residues 50 and 67 in the native protein. 相似文献
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《Tetrahedron letters》1987,28(27):3059-3060
The synthesis of mevalonolactone stereospecifically labeled at carbon 5 is described combining chemical reactions with an enzymatic reduction step. 相似文献
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(4S,5S)-4-Formyl-5-vinyl-2-oxazolidinone (4b), which is readily obtained via a zinc-silver-mediated reductive elimination of alpha-d-lyxofuranosyl phenyl sulfone (3b), is successfully converted to the naturally occurring, nonproteinogenic amino acid (2S,3R)-3-amino-2-hydroxydecanoic acid (2). Also in this study, a facile "oxazolidinone rearrangement" reaction is uncovered during the attempted formation of the (methylthio)thiocarbonate derivative of the oxazolidinone alcohol 7. 相似文献
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A convenient approach for the preparation of (2S,3R,4R,5S,6R)-2-(3-(4-ethylbenzyl)-4-chlorophenyl)-6-(hydroxymethyl)- tetrahydro-2H-pyran-3,4,5-triol I is developed. The target compound via four steps is synthesized from 4-bromo-2-(bromomethyl)- 1-chlorobenzene and the isomers of undesired ortho-products were avoided during the preparation. 相似文献
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Biserka Koji-Prodi
Iva Rui-Toro Vitomir unji Enio Decorte Flavio Moimas 《Helvetica chimica acta》1984,67(3):916-926
Resolution of racemic cis-3-(2-aminophenylthio)-2-hydroxy-3-(4-methoxyphenyl) propionic acid ( 2 ) via the cinchonidine salt 3 , and brucine salt 4 , isolation of the calcium salts (+)- and (?)- 5 , as well as their cyclization to enantiomeric 1,5-benzothiazepines (+)- and (?)- 1 , are described. X-Ray single-crystal analysis reveals (2S, 3S) absolute configuration of (+)- 1 on the basis of tentative comparison of CD data with those for the 1,4-benzodiazepine derivative (+)- 8 of known absolute configuration. 相似文献
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《结构化学》2017,(9)
The title compound(2S,3S,E)-4-(3,4-dihydroxybenzylidene)-3-(3,4-dihydroxyphenyl)-5-oxotetrahydrofuran-2-carboxylic acid was synthesized and the 2D structure was characterized by ~1H-NMR ~(13)C-NMR and LCMS. The absolute configuration was determined by single-crystal X-ray diffraction of the key intermediate(2S,3S,E)-ethyl 4-(3,4-dimethoxybenzylidene)-3-(3,4-dimethoxyphenyl)-5-oxotetrahydrofuran-2-carboxylate. The crystal belongs to tetragonal system, space group P4_1 with a = 13.0665(2), b = 13.0665(2), c = 13.4735(2) ?, V = 2300.4(6) ?~3, Z = 4, D_c = 1.278 g/cm~3, μ(CuKα) = 0.801 mm~(-1), F(000) = 936, S = 1.050, R = 0.0364 and wR(I 2σ(I)) = 0.1071. X-ray diffraction results showed that the molecular structure is stabilized totally by Van der Waals force. The antibacterial activity tests showed that the title compound possesses slight synergistic effect against MRSA and Acinetobacter baumanii. 相似文献
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Davies SG Rodriguez-Solla H Tamayo JA Cowley AR Concellon C Garner AC Parkes AL Smith AD 《Organic & biomolecular chemistry》2005,3(8):1435-1447
The highly diastereoselective samarium diiodide and D(2)O-promoted conjugate reduction of homochiral (E)- and (Z)-benzylidene and isobutylidene diketopiperazines (E)-5,7 and (Z)-6,8 has been demonstrated. This methodology allows the asymmetric synthesis of methyl (2S,3R)-dideuteriophenylalanine 27 in > or = 95% de and >98% ee, and (2S,3R)- or (2S,3S)-dideuterioleucine-(S)-phenylalanine dipeptides 37 and 38 in moderate de, 66% and 74% respectively. A mechanism is proposed to account for this process. 相似文献
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The fluorinated amino acid, (2S,3S)-3'-fluoroisoleucine 3, has been synthesised by a route involving stereoselective cuprate or photochemical addition to the compound 4, derived in turn from (2S)-pyroglutamic acid. This provides a reporter group for the hydrophobic amino acid (2S)-isoleucine for use in protein studies. 相似文献