Synthesis and xanthine oxidase inhibitory analysis of 1H-pyrrolo[3,2-c]pyridine-4,6(5H,7H)-dione (3,7-dideazaxanthine) and two of its derivatives.

The synthesis of 1H-pyrrolo[3,2-c]pyridine-4,6(5H,7H)-dione (3,7-dideazaxanthine) (1), 5-methyl-1H-pyrrolo-[3,2-c]pyridine-4,6(5H,7H)-dione (1-methyl-3,7-dideazaxanthine) (2), and 1,7-dihydropyrano[4,3-b]pyrrole-4,6-dione (1-oxa-1,3,7-trideazaxanthine) (3) has been accomplished from 3-alkoxycarbonylpyrrole-2-acetates (4, 11, and 12 for 1 and 2) and from 3-carboxypyrrole-2-acetic acid (6 for 3). Compounds 1 and 2 have been found to be weak inhibitors of the noncompetitive type for xanthine oxidase while 3 showed no inhibitory properties toward this enzyme.