Synthesis and antiallergy activity of 10-oxo-10H-pyrido[1,2-a]thieno[3,2-d]pyrimidines and 10-oxo-10H-pyrido[1,2-a]thieno[3,4-d]pyrimidines

Synthesis and antiallergy activity of 10-oxo-10H-pyrido[1,2-a]thieno[3,2-d]pyrimidines (2 and 3) and 10-oxo-10H-pyrido[1,2-a]thieno[3,4-d]pyrimidines (4 and 5) are described. The activity, shown by these compounds in the rat passive cutaneous anaphylaxis (PCA) test, is compared to the PCA data previously reported for a series of 4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidines. 10-Oxo-N-1H-tetrazol-5-yl-10H-pyrido[1,2-a]thieno[3,4-d]pyri midine (2b), 10-oxo-7-(1H-tetrazol-5-yl)-10H-pyrido[1,2-a]thieno[3,4-d]py rimidine (4e), and 3,10-dihydro-10-oxo-7-(1H-tetrazol-5-yl)-1H-pyrido[1,2-a]thieno[3, 4-d] pyrimidine (7e) gave a 100% inhibition in the rat PCA test at a dose of 5 mg/kg. The activity displayed by these compounds is comparable to that of the most active compounds in the 4-oxo-4H-pyrido[1,2-a]thieno[2,3-d]pyrimidine series.

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

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 found to be superior to disodium cromoglycate and doxantrazole. Structure-activity relationships are discussed.

Antiallergy activity of 10-oxo-10-H-pyridazino[6,1-b]quinazoline-2-carboxylic acids

A series of substituted 10-oxo-10H-pyridazino[6,1-b]quinazoline-2-carboxylic acids was prepared and evaluated as antiallergy agents. The 8-chloro and unsubstituted analogues were more potent that cromolyn sodium and doxantrazole intravenously in the rat PCA test. None of the analogues possessed significant oral activity.