Stereoselectivity of a Potent Calcium Antagonist, 1-Benzyl-3-pyrrolidinyl Methyl 2,6-Dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate

Article abstract of DOI:10.1021/jm00162a013

Four enantiomers (3a-d) of the title compound, YM-09730 (3), were synthesized by the reaction of (-)- or (+)-5-(methoxycarbonyl)-2,6-dimethyl-4-(m-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid (1a or 1b) with (S)- or (R)-1-benzyl-3-pyrrolidinol (2a or 2b). <3H>Nitrendipine binding affinity and coronary vasodilating activity of these compounds were evaluated.The absolute configuration of the most potent enantiomer (3a) with the longest duration was unequivocally determined to be (S)-1,4-dihydropyridine-C4 and (S)-pyrrolidine-C3 (S,S) by X-ray crystallographic study on 3a*HBr as well as 3a*HCl.The configuration of 1a corresponds to R, and the other enantiomers of 3 were respectively determined by chemical correlation.The potency order of the four enantiomers was (S,S)-3a > (S,R)-3b > (R,R)-3d > (R,S)-3c.Latent chiral characters of nifedipine derivatives with the identical ester groups were assigned by comparison of their puckering modes of 1,4-dihydropyridine (DHP) rings with those found in 3a*HCl or 3a*HBr.On the basis of the assignment, it has been revealed that the (S)-DHP nifedipine derivatives possess the synperiplanar carbonyl group at C5.The conformational restriction may be a factor causing stereoselectivity of antagonism.