Lipoic acid → alpha Lipoic acid

Participants

Reaction Conditions

Reaction Steps

A solution which contained 3.0 g R-(+)-thioctic acid and 7.0 g S-(-)-thioctic acid in a mixture of 135 ml cyclohexane and 15 ml ethyl acetate was cooled off from 35 to 40° C. down to -5 to -10° C., filtered and dried. 8.5 g thioctic acid were obtained in the novel modification as first crystallizate. The S-(-)-thioctic acid content was 67.8% with a melting range of 53 to 58° C.

Provenance & Evidence