Studies on 1,2,3-triazoles. 10. Synthesis and antiallergic properties of 9-oxo-1H,9H-benzothiopyrano[2,3-d]-1,2,3-triazoles and their S-oxides.

Selected derivatives of 9-oxo-1H,9H-benzothiopyrano[2,3-d]-1,2,3-triazole, a new heterocyclic ring system, and their S-oxides have been prepared and evaluated for antiallergic activity in the rat passive cutaneous anaphylaxis screen. Several of the compounds show intravenous potencies similar to or greater than that of disodium cromoglycate, the most potent being 6,7-dimethyl-9-oxo-1H,9H-benzothiopyrano[2,3-d]-1,2,3-triazole and its 4,4-dioxide.