One-pot syntheses of fused quinazolines by reaction of N-(2-cyanophenyl) chloromethanimidoyl chloride. I. A new synthesis of 1,3-oxazolo- and 1,3-oxazino[2,3-b]quinazolines

Abstract

12H-Benzo[1,3]oxazolo[2,3-b]quinazolin-12-imine (5a), 9-chloro-12H-benzo[1, 3]oxazolo[2,3-b]quinazolin-12-imine (5b), 2,3-dihydro-5H-[1,3]oxazolo[2,3-b] quinazolin-5-imine (5c), 2,3-dihydro-3,3-dimethyl-5H-[1,3]oxazolo[2,3-b] quinazolin-5-imine (5d) and 3,4-dihydro-2H,6H-[1,3]oxazino[2,3-b]quinazolin-6- imine (5e) were synthesized in a one-pot reaction of N-(2-cyanophenyl) chloromethanimidoyl chloride (1) with 2-aminophenols, 2-aminoethanol, and 3-aminopropanol in the presence of a base. The course of the reaction was controlled by the temperature and the amount of base used. N-(2-Cyanophenyl)-(2- hydroxyanilino)methanimidoyl chloride (3a), 2-chloro-3-(2-hydroxy-phenyl)-3,4- dihydroquinazolin-4-imine (4a) and 6-imino-2H, 3H, 4H, 6H, 11H-1,3-oxazino[2,3- b]-5-quinazolinium chloride (6) were identified as intermediates of the one-pot process.