Lipoic acid → alpha Lipoic acid

Participants

Reaction Conditions

Reaction Steps

A solution which contained 20.0 g R-(+)-thioctic acid and 5.0 g S-(-)-thioctic acid in a mixture of 225 ml cyclohexane and 25 ml ethyl acetate was cooled off from 35 to 40° C. down to -5 to -10° C., filtered and dried. 17.3 g thioctic acid were obtained in the novel modification as first crystallizate. The R-(+)-thioctic acid content was 75.6% with a melting range of 49 to 54° C.

Provenance & Evidence