Optical resolution of (+/-)-2,5-dimethyl-2'-hydroxy-9alpha- and -9beta-propyl-6,7-benzomorphans and their pharmacological properties.

The levo and dextro isomers of 2,5-dimethyl-2'-hydroxy-9alpha- and -9beta-propyl-6,7-benzomorphans have been prepared. The analgesic potency and physical dependence capacity of the optical isomers and their racemic parents were determined. The 9alpha-propyl levo isomer was analgesically equipotent with morphine; the 9beta-propyl levo isomer was considerably more potent subcutaneously and equipotent orally. None of the optical isomers suppressed the withdrawal syndrome; the 9beta-propyl levo isomer exacerbated the withdrawal syndrome.