S. Schneller, A. Ibay, W. Christ
May 1, 1984
Citations
0
Influential Citations
7
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
Commencing with 7-chloro-3-methylquinazoline-2,4(1H,3H)-dione (9a), a five step synthesis of 7-methylpyrimido[5,4-g]-1,2,4-benzotriazine-6,8(7H,9H)-dione (lin-benzoreumycin, 6) has been accomplished. A synthesis of 1,7-dimethylpyrimido[5,4-g]-1,2,4-benzotriazine-6,8(1H,7H)-dione (lin-benzotoxoflavin, 5) employing an intermediate from the preparation of 6 (i.e., 7-chloro-3-methyl-6-nitroquinazoline-2,4(1H,3H)-dione, 9b) was attempted but could not be accomplished beyond the dihydro precursor of 5 (i.e., 12). Compound 9b did lead to successful preparations of 7-methylimidazo[4,5-g]quinazoline-6,8(5H,7H)-dione (lin-benzo-1-methylxanthine, 7) and 3,7-dimethylimidazo[4,5-g]quinazoline-6,8(5H,7H)-dione (lin-benzo-1,9-dimethylxanthine, 8) by first reacting 9b with ammonia (for 7) or methylamine (for 8) followed by reductive cyclization in formic acid.