Merck + Co., Inc.

Donald F Reinhold

Torleif Utne

Gary H Rasmusson

David B Johnston

Ronald B Jobson

Newton L Abramson

Michael C Vander Zwan

A process for the preparation of (S)- or L-3-(3,4-dihydroxyphenyl)alanine (L-dopa) is described. The process utilizes water as reaction process solvent and proceeds via formation of an intermediate which can be kinetically resolved in a polar solvent to a precursor of the desired isomer and in which the undesired isomer can be efficiently racemized for reuse.

Process for L-dopa

A method of preparing a compound of the formula: ##STR1## where Formula (I) may also have the structure of partial Formula (III); wherein, ##STR2## R' is hydrogen or methyl; R' is hydrogen or .beta.-methyl;

Preparation of 4-aza-17-substituted-5.alpha.-androstan-3-ones useful as

Process for resolving enantiomers of 1-t-butylamino-2,3-dihydroxypropane using a pyroglutamic acid or a tartaric acid as resolving agent. The enantiomers of 1-t-butylamino-2,3-dihydroxypropane are useful in preparing .beta.-adrenergic blocking agents.

Pyroglutamic acid salts of t-butylamino-2,3-dihydroxypropane

The present invention relates to a novel and useful process for preparing 4,6-diamino-5-arylazopyrimidine from an arylazomalononitrile in the presence of ammonium chloride and formamide. If desired, the 4,6-diamino-5-arylazopyrimidine may then be hydrogenated to form 4,5,6-triaminopyrimidine which, when the hydrogenation is carried out in the presence of formic acid or its derivative, gives adenine.

Preparation of 4,6-diamino-5-arylazopyrimidines and adenine compounds

3-Fluoro-D-alanine and its deutero analogs, which are potent antibacterial agents, are prepared from fluoropyruvic acid by asymmetric synthesis using an optically active amine such as D-.alpha.-methyl-benzylamine.

Process for preparing 3-fluoro-D-alanine and its deutero analogs

3-Fluoro-L-alanine is transformed by asymmetric conversion, via an intermediate L-2-(halo)-3-fluoropropionic acid, to 3-fluoro-D-alanine. The 3-fluoro-D-alanine thus obtained is a potent antibacterial agent.

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North Plainfield, NJ, United States of America

Donald F Reinhold