Synthesis and beta-blocking activity of (R,S)-(E)-oximeethers of 2, 3-dihydro-1,8-naphthyridine and 2,3-dihydrothiopyrano[2, 3-b]pyridine:potential antihypertensive agents - part IX.

The synthesis of oximeethers of 2,3-dihydro-1,8-naphthyridine and 2, 3-dihydrothiopyrano[2,3-b]pyridine is described. These compounds exhibit a selective beta-blocking activity, with a selectivity towards beta(2)-receptors. Groups in the N(1) position giving rise to a considerable steric hindrance led to a higher beta(2)-blocking selectivity, whereas groups creating a moderate hindrance caused a weak but significant decrease in beta(2)-antagonist potency. Substitution of the N(1)-R group with a sulfur atom led to compounds possessing beta(1)-, beta(2)- and beta(3)-blocking properties. Compounds 9c(1) and 10a(1) showed a beta(3)-antagonist activity slightly lower than that of propranolol.