Improved resolution of (±)-trans-2'-hydroxy-5,9-dimethyl-6,7-benzomorphans

An efficient resolution of (±)-trans-2'-hydroxy-5,9-dimethyl-6,7-benzomorphan has been developed employing (—)-(R)- and (+)-(S)-O-acetylmandelic acids. Measurement of optical rotations on the resolved bases, NMR analyses of diastereomeric urea derivatives, as well as gas chromatographic analyses of diastereomeric amide derivatives indicate a net improvement over previous resolution methodology and an enantiomeric excess ≥ 99%. © 1992 Wiley-Liss, Inc.