Bronchodilator and antiulcer phenoxypyrimidinones.

Series of 5-phenoxy-2(1H)-pyrimidinones, 5-phenoxy-4(3H)-pyrimidinones, and related compounds were prepared in a follow-up of a lead prepared as a potential cyclic nucleotide regulating agent. Compounds were evaluated for bronchodilator activity in histamine-challenged guinea pigs and for anticulcer activity in a cold-restraint, stressed rat ulcer model. Bronchodilator activity comparable to, or greater than, that of theophylline was found in both the 2(1H)- and 4(3H)-pyrimidinone series and was most prominent in analogues containing either an electron-withdrawing or -donating substituent in the para position of the phenoxy ring. Significant antiulcer activity was observed only in the 2(1H)-pyrimidinone series among three closely related analogues. One of these, 5-(m-methylphenoxy)-2(1H)-pyrimidinone (3), exhibited more potent antiulcer effects than the clinically useful antiulcer agent carbenoxolone, without demonstrating bronchodilator activity.