Epoxides as obligatory intermediates in the metabolism of alpha-halohydrins

1. The metabolism of several dihalopropanols has been studied in the rat. Irrespective of their structure, each compound produced the same two mercapturic acids, excreted as urinary metabolites. 2. The mercapturic acid metabolites of the dihalopropanols were identified as N-acetyl-S-(2,3-dihydroxypropyl)cysteine and N,N'-bis-acetyl-S,S'-(1,3-bis-cysteinyl)propan-2-ol. Depending on the halogen present, each dihalopropanol produced beta-chlorolactate or beta-bromolactate as oxidative metabolites. 3. From the metabolic pathway of these compounds, it is inferred that an epoxide is an intermediate in their metabolism. 4. The metabolism of 2-chloropropane-1,3-diol has been investigated in the rat and the isolation of one mercapturic acid, N-acetyl-S-(2,3-dihydroxypropyl)cysteine, confirms that an epoxide intermediate is involved.