1984 Volume 32 Issue 6 Pages 2160-2164
Two novel ring systems, 12-methyl-6H-isoquino [2, 1-a] quinazolin-6-one (2) and 6-methyl-13H-quinazolino [3, 4-a] quinazolin-13-one (3a), were synthesized. Reaction of 3-methylisocoumarin (4) with 2-cyanoaniline gave 2-(2-cyanophenyl)-3-methylisocarbostyril (5), which was converted to 2-(2-carbamoylphenyl)-3-methylisocarbostyril (6) by treatment with alkaline hydrogen peroxide. The cyclization of 6 with boron trifluoride etherate afforded 2. Compound 3a was prepared by the reaction of 2-methyl-4H-3, 1-benzoxazin-4-one (8a) with 2-cyanoaniline in one step. Some derivatives (3b-g) were also prepared by this method. The reaction mechanism is discussed.
