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Facile access to some new 3,3′‐bipyrazole‐ester derivatives utilizing bis‐hydrazonoyl chlorides
Author(s) -
Dawood Kamal M.,
Elassar AbdelZaher A.,
AlFulaij Othman A.
Publication year - 2020
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.3787
Subject(s) - chemistry , cycloaddition , organic chemistry , dimethyl acetylenedicarboxylate , aniline , hydrazine (antidepressant) , medicinal chemistry , catalysis , chromatography
The 1,3‐dipolar cycloaddition reaction of bis‐hydrazonoyl chlorides with ethyl propiolate and dimethyl acetylenedicarboxylate afforded diethyl 1,1′‐aryl‐3,3′‐bipyrazole‐4,4′‐dicarboxylate and tetramethyl 1,1′‐diaryl‐3,3′‐bipyrazole‐4,4′,5,5′‐tetracarboxylate esters, respectively. Heating the latter two compounds with a mixture of HCl/AcOH furnished the same product: 3,3′‐bipyrazole‐5,5′‐dicarboxylic acid. Reaction of the tetracarboxylate ester with aniline derivatives and with hydrazine gave the corresponding bipyrazole‐fused heterocycles. Heating the dicarboxylic acid with 2‐aminothiazole gave the corresponding bis‐amide derivative. The structures of the products were established by elemental analysis, spectral data, and single‐crystal X‐ray crystallography.