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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
Author(s) -
Wejroch Krystyna,
Lange Jerzy,
Wesołowska Aneta,
Ski Tadeusz Jagodzi,
Sadowska Maja,
KarolakWojciechowska Janina
Publication year - 2005
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570420525
Subject(s) - chemistry , hydrazine (antidepressant) , hydrate , tetrazine , ring (chemistry) , yield (engineering) , medicinal chemistry , derivative (finance) , organic chemistry , chromatography , materials science , economics , financial economics , metallurgy
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.