Four optical isomers of nipradilol (NIP) were prepared from (3R)-or (3S)-3, 4-dihydro-8- hydroxy-3-nitroxy-2H-1-benzopyran by glycidylation and amination, and evaluated for β- blocking and vasodilating activities. The order of potency of β-blocking activity was S, R- NIP>> S, S-NIP> R, R-NIP>> R, S-NIP. As regards vasodilating activity, S, R-NIP and R, R- NIP were more potent than S, S-NIP and R, S-NIP.
