Studies on the Syntheses of Heterocyclic Compounds. CDXVII. Syntheses of 1, 2-Benzoxazepine, Oxindole and Furanoquinolone Derivatives by Cyclization of Hydroxamic Acid with Polyphosphoric Acid

Abstract

Cyclization of 3-(2, 3, 4-trimethoxyphenyl) propionohydroxamic acid (II), 2-(3, 4-dimethoxyphenyl) acetohydroxamic acid (VI) and 3-(α-diethoxybenzyl)-2, 3, 4, 5-tetrahydro-1-hydroxy-2-ketopyrrole (X) with polyphosphoric acid gave 4, 5-dihydro-3-oxo-[2H]-1, 2-benzoxazepine (IV), 5, 6-dimethoxyoxindole (VII) and 2, 3, 4, 9-tetrahydro-4-oxo-furo [2, 3-b] quinoline (XI), respectively.