Several drugs (clozapine, chlorpromazine, imipramine, buspirone, diltiazem, and propranolol) were subjected to modified Udenfriend conditions (Fe2+/Mn2+/EDTA/ascorbic acid/O2). From each reaction, one to four oxidation products were obtained in 1–8% overall yield. Many of these products (9 out of 14) have been reported to be metabolites of the parent drugs in vivo. The products resulted mainly from aromatic hydroxylation, and are ...