SYNTHESIS OF 1-AROYL-1,2-DIHYDRO-3H-INDOL-3-ONES VIA CYCLIZATION OF N-2-(2-CHLOROACETYL)PHENYLBENZAMIDES WITH TRIETHYLAMINE IN THE PRESENCE OF DI-tert-BUTYL DICARBONATE

摘要

1-Aroyl-1,2-dihydro-3H-indo1-3-ones can now be conveniently obtained from 2-aryl-4-(Z)-(chloromethylidene)-4H-3,1-benzoxazines using an easy operated three-step sequence under mild conditions. Thus, the starting materials are hydrolyzed with dilute hydrochloric acid at 0 degrees C to N-2-(2-chloroacetyl)phenylbenzamides, of which treatment with triethylamine in the presence of di-tert-butyl dicarbonate at room temperature, followed by deprotection with trifluoroacetic acid at room temperature, provides the desired products.