Convenient one-pot syntheses of pyrazoles from imines, a vilsmeier type reagent and hydrazine

Autor:	Anna Denisenko, Sergey N. Denisenko, Alan R. Katritzky, Michael Arend
Rok vydání:	2000
Předmět:	Steric effects chemistry.chemical_compound chemistry Reagent Organic Chemistry Hydrazine Regioselectivity Combinatorial chemistry Tautomer Tetrahydrofuran
Zdroj:	Journal of Heterocyclic Chemistry. 37:1309-1314
ISSN:	1943-5193 0022-152X
DOI:	10.1002/jhet.5570370548
Popis:	A simple one-pot procedure for the regioselective synthesis of pyrazoles from readily available starting materials is described. Vilsmeier type reagent 1 reacts with imines 10 (via the corresponding tautomeric secondary enamines) in tetrahydrofuran to give enaminoimine hydrochlorides 11. Nonsymmetrical imines generally react preferentially with 1 at the sterically less hindered α-position. The enaminoimine hydrochlorides 11 are transformed in situ to the corresponding pyrazoles 12 in moderate to high yields by the addition of hydrazine.
Databáze:	OpenAIRE
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