2-Hydroxypropylmercapturic acid, i.e. N-acetyl-S-(2-hydroxypropyl)-l-cysteine, has been isolated, as the dicyclohexylammonium salt, from the urine of rats dosed with 1-bromopropane. 2. The formation of the same metabolite from 1-chloropropane, 1-iodopropane, 1,2-epoxypropane and 1-chloropropan-2-ol has been demonstrated by chromatographic examination of the urine excreted by rats after they had been dosed with these compounds. 3. (+)- and (-)-Dicyclohexylammonium 2-hydroxypropylmercapturate have been prepared by fractional crystallization of the mixture of isomers obtained by two methods: the reaction of 1,2-epoxypropane with l-cysteine followed by acetylation, and the reduction of 2-oxopropylmercapturic acid. 4. The following compounds have also been prepared: S-(3-hydroxypropyl)-l-cysteine, (+)- and (-)-S-(2-hydroxypropyl)-l-cysteine, dicyclohexylammonium 3-hydroxypropylmercapturate, (+)- and (-)-dicyclohexylammonium 2-hydroxy-1-methylethylmercapturate, and (+)- and (-)-dicyclohexylammonium 1-(ethoxycarbonyl)ethylmercapturate.
