Abstract

The α1a-antagonistic activity of dihydropyrimidinone C-5 amides is analyzed through the Fujita- Ban and Hansch approaches. The analyses have helped to ascertain the role of different substituents in explaining the observed antagonistic activity of these analogues. From both approaches, it is predicted that the more hydrophobic X-substituents and the phenyl or P-cyanophenyl substituents at the 4-position of the piperidine ring are beneficial in raising the α1a-receptor antagonist action of a compound. Likewise, the presence of Fat R4 (the para-position of either phenyl or 2-cyanophenyl ring) further helps in augmenting it. The positions R1 and R3, of the dihydropyrimidinone ring are in favour of Me and H respectively. In addition, a non hydrogenbond acceptor substituent at R3 is least preferred. Substituents at position R6 of this ring, however, by either H or CH2OMe leads to better potency compounds.