Design and synthesis of novel alpha(1a) adrenoceptor-selective antagonists. 4. Structure-activity relationship in the dihydropyrimidine series

We have previously disclosed dihydropyridines such as 1a,b as selective alp ha(1a) antagonists as a potential treatment for benign prostatic hyperplasi a (BPH). The propensity of dihydropyridines toward an oxidation led us to f ind suitable replacements of the core unit. The accompanying papers describ e the structure-activity relationship (SAR) of dihydropyrimidinones 2a,b as selective alpha(1a) antagonists. We report herein the SAR of dihydropyrimi dines such as 4 and highlight the similarities and differences between the dihydropyrimidine and dihydropyrimidinone series of compounds.