Absolute Configurations of Four Isomers of 3-Formamido-4-hydroxy-α-[[N-(p-methoxy-α-methylphenethyl) amino] methyl] benzyl Alcohol, a Potent β-Adrenoreceptor Stimulant

抄録

The two pairs of enantiomers (1A and 1B) of 3-formamido-4-hydroxy-α-[[N-(p-methoxy-α-methylphenethyl) amino] methyl] benzyl alcohol (1) were resolved into four isomers ((-)-1A, (+)-1A, (-)-1B and (+)-1B). Two isomers ((-)-1A and (-)-1B) were also obtained from (-)-N-(p-methoxy-α-methylphenethyl) amine (5) and 4'-benzyloxy-3'-nitro-2-bromoacetophenone by several steps. The configurations of the enantiomers of 5 were determined by chemical correlation with those of N-(p-hydroxy-α-methylphenethyl)-amine, whose configuration is known. The configurations of the asymmetric carbon (α) carrying the OH group and the asymmetric carbon (β) located in the amine moiety of (+)-1A were respectively determined by correlation with (+)-4-methoxy-3-nitrobenzoic acid (7) and (+)-5, whose configurations are known, through (+)-3-amino-4-methoxy-α-[[N-(p-methoxy-α-methylphenethyl) amino] methyl] benzyl alcohol (12). On the basis of these experiments the configurations of the four isomers were shown as follows : (-)-1A=αR, βR, (+)-1A=αS, βS, (-)-1B=αS, βR and (+)-1B=αR, βS. Bronchodilator activity of these compounds was found to decrease in the order (-)-1A>(+)-1B>(+)-1A>(-)-1B.