F.i.s. Fabbrica Italiana Sintetici S.p.a.

Roberto Bortolaso

Mariano Stivanello

Siro Serafini

The present invention relates to a process for preparing the cyclohexylamine salt of (+)-threo-2-hydroxy-3-(2'-aminophenylthio)-3-(4'-methoxyphenyl)-propionic acid and of its optical (-)-antipode, by starting from the racemate acid by means of a first crystallization from a suitable chiral base and a second crystallization from a cyclohexylamine-containing solvent. Said salt is an intermediate in the synthesis of diltiazem, a well-known calcium-antagonist drug.

Process for preparing the cyclohexylamine salt of (+) -

The present invention relates to a process for preparing [R-(R*,R*)]-5-(3-chlorophenyl)-3-[2-(3,4-dimethoxyphenyl)-1-methyl-ethyl]- oxazolidin-2-one of Formula (1), characterized in that said process comprises the step of reacting (R)-3, 4-methoxy-amphetamine of Formula (3), with (R)-3-chloro-mandelic acid, of Formula (9): ##STR1##

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Vicenza, Italy

Roberto Bortolaso