- Method for producing chiral mercapto amino acids
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The invention relates to a method for producing chiral mercapto amino acids of formula (I) wherein R1, R2 and R3 can represent hydrogen, C6-C12 aryl, C1-C6-alkyl-C6-C12-aryl, C6-C12-aryl-C1-C6-alkyl, C1-C18-alkyl or C2-C18-alkenyl, R2 and R3 forming a saturated or unsaturated ring. According to said method, a) an oxo compound of formula (II), wherein X represents a leaving group, is reacted in the presence of ammonia or ammonium hydroxide and a sulfide, optionally under phase transfer catalysis or addition of a solubiliser, with a ketone or an aldehyde of formula (III) wherein R4 and R5 can represent a C1-C12 alkyl radical or a C6-C20 aryl radical or one of the two radicals H, or R4 and R5 together form a C4-C7 ring, to form the compound of formula (IV), that b) reacts with HCN to form the corresponding nitrile, whereupon c) the crystallised nitrile is converted, by selective hydrolysis by means of a mineral acid, into the corresponding amide of formula (VI), and d) is then converted into the corresponding chiral amide of formula (VI*) by means of an L amidase or a chiral dissociating acid, whereupon by reaction with an acid, the desired chiral mercapto amino acid of formula (I) is obtained, or e) first the reaction with an acid is carried out, and then the conversion into the chiral mercapto amino acid takes place.
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- Heterocyclic compounds, pharmaceutical compositions comprising same, and methods for inhibiting β-amyloid peptide release and/or its synthesis by use of such compounds
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Disclosed are compounds which inhibit β-amyloid peptide release and/or its synthesis, and, accordingly, have utility in treating Alzheimer's disease. Also disclosed are pharmaceutical compositions comprising a compound which inhibits β-amyloid peptide release and/or its synthesis as well as methods for treating Alzheimer's disease both prophylactically and therapeutically with such pharmaceutical compositions.
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- Mechanistic Studies on Thiazolidine Formation in Aldehyde/Cysteamine Model Systems
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A mechanism was proposed to elucidate the formation of a thiazolidine in aldehyde/cysteamine model systems. Buffer dramatically promotes thiazolidine formation from formaldehyde and cysteamine. Phosphate tends to stabilize the primary carbocation formed, and this may lead to completion of the cyclization by attack of the amino nitrogen on the activated carbon. Protic solvent, by removing the water molecule, further enhances thiazolidine formation. Redox reaction catalyzed by phosphate ions results in the conversion of thiazolidine to the corresponding thiazoline through hydride transfer.
- Huang, Tzou-Chi,Huang, Lee-Zen,Ho, Chi-Tang
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p. 224 - 227
(2007/10/03)
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- Chemical prevention or reversal of cataract by phase separation inhibitors
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The present invention relate to methods and pharmaceutical reagents for decreasing the phase separation temperature and inhibiting the formation of high molecular with aggregates in eye lenses, thereby inhibiting or reversing cataract formation.
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- Antiatherosclerotic and antithrombotic 2-amino-6-phenyl-4H-pyran-4-ones
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This invention relates to compounds of Formula I STR1 which are useful as antiatherosclerotic agents and inhibitors of cell proliferation for the treatment of proliferative diseases. In addition, various compounds of Formula I are useful inhibitors of platelet aggregation.
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- Research on radioprotective agents: Δ-2 Thiazolines and homologous derivatives
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Compounds derived from Δ-2 thiazoline, Δ-2 thiazolinium iodoalkylate and 4,5-dihydro-1,3 thiazine have been prepared and evaluated as potential antiradiation agents in mice. They generally have a low toxicity and significant radioprotective activity.
- Robbe,Fernandez,Chapat,et al.
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- A DIRECT TRANSFORMATION OF BICYCLIC KETO ESTERS TO N-FORMIMIDOYL THIENAMYCIN
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A convenient direct transformation of p-nitrobenzyl 6-(1'-hydroxyethyl)-azabicyclo-(3.2.0)heptane-3,7-dione-2-carboxylate to N-formimidoyl thienamycin utilizing the silylated derivative of N-formimidoyl cysteamine is described.
- Shinkai, I.,Reamer, R. A.,Hartner, F. W.,Liu, T.,Sletzinger, M.
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p. 4903 - 4906
(2007/10/02)
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