Abstract

The urine from dogs which had received S(-)-pentobarbital yielded two crystalline metabolites from fractions obtained by partition column chromatography. The structures of the two major metabolites were found to be 5-ethyl-5-[3'-(S)-hydroxy-1'(S) methylbutyl] and 5-ethyl-5-[3'(R)-hydroxy-1'(S) methylbutyl] barbituric acids with the latter compound present in larger amounts. The significance of the larger amounts of the latter metabolite present in relation to the conformation of S(-)-and R(+)-pentobarbitals is discussed.