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Synthesis of novel heterocycles using 1,2,3‐triazole‐4‐carbohydrazides as precursors
Author(s) -
Mohamed Hanan A.,
Khidre Rizk E.,
Kariuki Benson M.,
ElHiti Gamal 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.3840
Subject(s) - chemistry , hydrazine (antidepressant) , triazole , reagent , hydrate , yield (engineering) , acrylate , acetic acid , pyrazole , ethanol , carbon disulfide , organic chemistry , combinatorial chemistry , chromatography , materials science , metallurgy , monomer , polymer
Herein, we report the synthesis of various heterocyclic ring systems containing 1,2,3‐triazole from the reactions of acid hydrazides and commercially available reagents, using efficient and simple procedures. Reactions of certain 1,2,3‐triazole‐4‐carbohydrazides and α‐bromoketones in boiling ethanol afforded the corresponding hydrazones rather than the expected triazines. The hydrazones could also be synthesized in 85‐90% yield via an alternative pathway that involved the reaction of 1,2,3‐triazole‐4‐carbohydrazides and 4‐acetyl‐1,2,3‐triazoles in boiling ethanol containing glacial acetic acid. Reaction of one of the 4‐carbohydrazides with carbon disulfide, followed by the reaction with hydrazine hydrate, gave 4 H ‐1,2,4‐triazole‐3‐thiol in 73% yield, which further reacted with other α‐bromoketones in boiling ethanol to afford 7 H ‐[1,2,4]triazolo[3,4‐ b ][1,3,4]thiadiazines in 82‐84% yields. Additionally, reactions of certain carbohydrazides with ethyl 2‐cyano‐3,3‐bis(methylthio)acrylate gave 1‐aryl‐1 H ‐1,2,3‐triazole‐4‐carbohydrazides rather than the expected 1 H ‐pyrazole‐4‐carboxylates.