The 2-benzazepine 9-chloro-7-(2-chlorophenyl)-5H-pyrimido[5,4-d] [2]benzazepine (1) has been selected for development as an anxiolytic agent. In support of this program, we have confirmed by chemical synthesis the structures of three in vitro (rat liver homogenate) metabolites of 1 and confirmed the structure of the major in vivo (dog and man) metabolite of 1, compound 2. Two of the metabolites, arising from hydroxylation of the pyrimidobenzazepine ring at the 5-position (2) and N-oxide formation at the 3-position of the pyrimidobenzazepine ring (3), were found to be as active as 1 in a series of pharmacological tests. The third metabolite, formed by hydroxylation of the 7-phenyl group in the 4-position (4), was found to be inactive in the same pharmacological screens.