Synthesis and antiallergy activity of 4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidines

Abstract
A series of 4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidines with substitutions in the 2, 3 and 7 positions was prepared. The compounds were evaluated in the rat passive cutaneous anaphylaxis test for antiallergy activity. Several compounds had potent oral activity and were superior to disodium cromoglycate and doxanthrazole. Structure-activity relationships are discussed.