合成路线1

The reduction of N-(benzyloxycarbonyl)-L-phenylalanine (XVI) gives the corresponding aldehyde (XVII), which is cyclized with 2-sulfanylethylamine (XVIII) to yield the thiazolidine (XIX). The dehydrogenation of (XIX) by means of MnO2 affords the thiazole derivative (XX). Finally, the amino group of (XX) is deprotected with HBr to afford the desired intermediate, 2-phenyl-1(S)-(2-thiazolyl)ethylamine (XXI). Alternatively, N-(benzyloxycarbonyl)-L-phenylalanine (XVI) can be converted into the corresponding amide (XXII), which is treated with the Lawesson's reagent to yield the thioamide (XXIII). Finally, the cyclization of (XXIII) with 2-bromoacetaldehyde (XXIV) gives already reported thiazole derivative (XX) (partial racemization occurs during the synthetic process). Enantiomeric separation takes place in a later stage.