Ring Fission of Quinazolines by Means of the Reissert Reaction

抄録

Under the Reissert reaction conditions, quinazoline (1a) afforded 2'-formylbenzanilide (2a), o-aminobenzaldehyde (3a), and N-formylbenzamide (4). Similarly, 4-methyl-(1b) and 4-ethoxyquinazoline (1c) gave the corresponding benzanilides 2b and 2c, respectively, o-aminoacetophenone (3b, from 1b), and benzamide (5). It was confirmed that the same results were obtained in the absence of the cyanide ion. A substituent at the 2-position prevented the ring fission, and only the corresponding N³-benzoyl pseudo-base (14) was obtained. The generality of the ring fission was shown by the reactions of 1-phenyl-1H-pyrazolo [3, 4-d] pyrimidine (6) and 3-phenyl-3H-1, 2, 3-triazolo [4, 5-d] pyrimidine (8), giving 5-amino-1-phenyl-1H-pyrazole-4-carbaldehyde (7) and 5-amino-1-phenyl-1H-1, 2, 3-triazole-4-carbaldehyde (9), respectively.