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Reactions of 3‐chloro‐6‐hydrazinopyridazine with michael‐retro‐michael reagents
Author(s) -
Sunder Shyam,
Peet Norton P.
Publication year - 1980
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.5570170734
Subject(s) - chemistry , pyrazole , michael reaction , pyridazine , reagent , yield (engineering) , salt (chemistry) , organic chemistry , medicinal chemistry , ethyl cyanoacetate , malononitrile , catalysis , materials science , metallurgy
Although pyrazole formation results from treatment of 3‐chloro‐6‐hydrazinopyridazine ( 2 ) with both ethoxymethylenemalononitrile and ethyl (ethoxymethylene)cyanoacetate, 6‐chlorotriazolo[4,3‐ b ]pyridazine ( 5 ) was produced (75% yield) when 2 was treated with diethyl ethoxymethylenemalonate. Treatment of 2 with diethyl acetylmalonate ( 8 ) gave both 6‐chloro‐3‐methyltriazolo[4,3‐ b ]pyridazine ( 10 ) and 5‐hydroxy‐3‐methyl‐1‐(6‐chloro‐3‐pyridazinyl)‐1 H ‐pyrazole‐4‐carboxylic acid ethyl ester ( 12 ). Pyrazole 12 was initially isolated as a salt of triazolopyridazine 10 .