Azomalonic Ester Syntheses. Part I. One‐Step Synthesis of Triazolo[1,4]benzodiazepines from Azomalonates. Preparation of Novel Polyaza Tricycles from Diethyl (2‐Chloroacetamido)malonate

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Abstract
A useful synthetic principle for the preparation of N‐heterocycles consists in the base treatment of azoma‐lonates carrying electrophilic centers in the side chain. Thus, pharmacologically active triazolo[1,4]benzodiazepine‐carboxamides can be prepared in one step from azomalonates derived from 2‐aminobenzophenones and diethyl (2‐chloroacetamido)malonate. The same malonate coupled with diazotized 3‐amino‐2‐chloropyridine leads in 2 steps to 3 novel pyridotriazoloazines. Similarly, N‐protected 2‐amino‐diphenylamine derivatives are converted into triazoloquinoxaline‐carboxylic acids. The heteocycles are further characterized by functional‐group inter‐conversion. Some mechanistic aspects of the azomalonic‐ester synthesis are discussed.