Synthelabo

Antonio Ugolini

Guy Rossey

Alexander E Wick

Isaac Chekroun

Andre Bourbon

Abkar Vartanian

Jean-Baptiste Graux

Bernard Gerin

2-Aminothiophenol is reacted with methyl (-)-(2R,3S)-2,3-epoxy-3-(4-methoxyphenyl)propionate, and the intermediate methyl (2S,3S)-3-[(2-aminophenyl)thio]-2-hydroxy-3-(4-methoxyphenyl)propionate is cyclized in the presence of methanesulfonic acid, in the same vessel and without isolating said intermediate product, using e.g. chlorobenzene as a solvent.

Method for preparing

Process for the preparation of compounds of the general formula (I) ##STR1## wherein R is hydrogen or (C.sub.1-4)alkyl.

Process for the preparation of propionic acid derivatives

2-Aminothiophenol is reacted with (-)-(2R,3S)-2,3-epoxy-3-(4-methoxyphenyl) methylpropionate, and the intermediate (2S,3S)-3-[(2-aminophenyl)thio]-2-hydroxy-3-(4-methoxyphenyl) methylpropionate is then cyclized in the presence of methane sulfonic acid, in the same container and without isolating said intermediate product, using chlorobenzene as a solvent.

Method of preparing

A process for the preparation of a methyl (+)-(2S,3S)-3-[(2-aminophenyl)thio]-2-hydroxy-3-(4-methoxyphenyl)propionat e of the formula (I): ##STR1## in which X denotes hydrogen or chlorine, which process comprises reacting a 2-aminothiophenol of formula (II): ##STR2## in which X is as defined above, with methyl (-)-(2R,3S)-2,3-epoxy-3-(4-methoxyphenyl)propionate, in a 1,2-dichloroethane solvent.

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Le Pecq, France

Antonio Ugolini