Sham S. Gandhi

Synthetic routes to 1,5-dihydro-5-oxo-4,1-benzoxazepines and to 5-oxooxazolo[3,2-a]quinolines

Abstract The literature concerning phenacyl anthranilate, N- phenacylanthranilic acid and phenacyl N-phenacylanthranilate is clarified. Phenacyl anthranilate is dehydrated to 1,5-dihydro-5-oxo-2-pheny 1-4,1-benzoxazepine by treatment with phosphoryl chloride; other examples of this reaction are described. A preparation of 4-methyl-5-oxo-2-phenyloxazolo[3,2-a]quinoline from N-phenacylanthranilic acid and propionic anhydride is reported.

Acylation of N′-arylbenzothiohydrazides and of their N′-acyl-derivatives; 2-acylalkylidene-3-aryl-5-phenyl-2H-1,3,4-thiadiazolenes and related compounds

Reactions of N′-arylbenzothiohydrazides and of their N-acyl-derivatives with carboxylic anhydrides under various sets of conditions are shown to lead to 2-acylalkylidene-3-aryl-5-phenyl-2H-1,3,4-thiadiazolenes. The probable mechanism of formation of these compounds via the corresponding 2-alkylidenethiadiazolene as intermediate is discussed.