Studies on 4(1H)-quinazolinones. III. Some derivatizations of 2-ethoxycarbonylalkyl-1-substituted-4(1H)-quinazolinones.

Reactions of 2-(substituted-amino) benzamide (1) with ethyl chloroformylformate (2), ethyl chloroformylacetate (3), and ethyl 2-chloroformylpropionate (4) gave 1-substituted 4 (1H)-quinazolinones (5, 6, and 7, respectively) having an ethoxycarbonyl group on the substituent at position 2. 2-Ethoxycarbonyl-1-methyl-4 (1H)-quinazolinone (5b) was converted to the carboxylic acid 14, the hydroxamic acid 16, the amide 18, and the nitrile 19. The nitrile 19 was allowed to react with various nucleophiles to give 1-methyl-4 (1H)-quinazolinones (17, 20, 21, and 22) having a substituted heteroatom at position 2. The reaction of 19 with sodium azide gave 1, 2-dihydro-4-hydroxy-1-methyl-2-(5H-tetrazol-5-ylidene)-quinazoline (25) which is the 1, 3-dipolar addition product to the cyano group. The intramolecular ring closures of 5, 6, and 7 having an alkoxycarbonylalkyl or chloroalkyl group at position 1 proceeded by using an appropriate base or heating to give the corresponding pyrrolo- or pyrido [1, 2a] quinazolinones (27, 28, 29, 31, and 32).