Urinary metabolites of clomethiazole. Detection and structural analysis by gas chromatography-mass spectrometry.

As the result of a renewed extensive investigation of clomethiazole (Distraneurin) metabolism five previously unknown metabolites could be isolated from human urine. Their structures were elucidated by mass spectrometry. Whereas previous investigations on the metabolism of clomethiazole had demonstrated changes only of the ethyl group, we now found metabolites attached to the methyl group, too. The newly isolated compounds 5-(1-hydroxy-2-chloroethyl)-4-methylthiazole (9) and 5-(2-hydroxyethyl)-4-thiazole carboxylic acid lactone (5) were found to be more abundant in human urine than 4-methyl-5-thiazole acetic acid previously considered as the main metabolite.