Studies on the Syntheses of Heterocyclic Compounds. CCIV. Ring Contraction in the Catalytic Hydrogenation of 3-Oximino-4-oxoisocarbostyril.

Abstract

One of two compounds, which were obtained by catalytic hydrogenation of VII in dry methanol using one molar equivalent of dry hydrochloride gas in the presence of platinum oxide, was separated after recrystallization from water. The structure of the above compound was characterized to be XV by acetylation and hydrolysis. In the latter case, the carboxylic acid (X) was obtained and found to be identical with an authentic sample, which was obtained by ring contraction of IX.