Reaction of β-cyano esters with hydrazine hydrate. Unexpected formation of dipyrrolo[1,2-b:1′,2′-e][1,2,4,5]tetrazine, a novel ring system

✍ Scribed by Krystyna Wejroch; Jerzy Lange; Aneta Wesołowska; Tadeusz Jagodzi Ski; Maja Sadowska; Janina Karolak-Wojciechowska

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2005
• Tongue: English
• Weight: 130 KB
• Volume: 42
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570420525

✦ Synopsis

Abstract

Some intermediates and by‐products of the title reaction, known to yield 6‐hydrazinopyridazine‐3‐one derivatives, were isolated or detected when the amount of hydrazine hydrate used to react with two model β‐cyano esters was reduced to less than two equivalents. N'‐(1‐amino‐4‐hydrazino‐4‐oxo‐2‐phenylbutyli‐dene)‐4‐hydrazino‐4‐oxo‐2‐phenylbutanehydrazonamide and 3,3,8,8‐tetramethyl‐2,3,7,8‐tetrahydro‐1__H__,6__H__‐dipyrrolo[1,2‐b:1′,2′‐e][1,2,4,5]tetrazine‐1,6‐dione were isolated as the terminal products of side‐reactions; they were unreactive to hydrazine. The latter compound is a derivative of a novel ring system. Mechanism of the reaction was proposed.