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A selective synthesis of 1‐aryl‐3‐quinoxalinyl‐1,2,4‐triazole and furo[2,3‐ b ]quinoxaline
Author(s) -
Kim Ho Sik,
Kurasawa Yoshihisa,
Takada Atsushi
Publication year - 1989
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.5570260442
Subject(s) - chemistry , tautomer , quinoxaline , hydrazine (antidepressant) , acetic acid , medicinal chemistry , hydrate , hydrazone , enamine , imine , aryl , sodium nitrite , organic chemistry , triazole , nitrite , dicamba , catalysis , agronomy , alkyl , chromatography , weed control , biology , nitrate
The reaction of the ester 1 with ethyl benzoate‐2‐diazonium chloride gave the α‐arylhydrazonoester 2b , whose reaction with hydrazine hydrate afforded the α‐arylhydrazonoacylhydrazide 3b. The reaction of 3b with sodium nitrite in water/acetic acid under heating on a boiling water bath provided the 1‐aryl‐3‐quin‐oxalinyl‐1,2,4‐triazole 5b , presumably via the α‐arylhydrazonoacylazide 4b , while the isolation of 4b and then its refluxing in dioxane/water furnished the furo[2,3‐ b ]quinoxaline 6. The tautomeric behavior of 2b and 3b between the hydrazone imine and diazenyl enamine forms was described together with the tautomer ratio determined by the nmr spectral data.