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Highly Regioselective One‐Pot, Three‐Component Synthesis of 1‐Aryl‐3,4‐Substituted/Annulated‐5‐(Cycloamino)/(Alkylamino)pyrazoles from β‐Oxodithioesters
Author(s) -
Nandi Ganesh C.,
Singh Maya S.,
Ila Hiriyakkanavar,
Junjappa Hiriyakkanavar
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201101397
Subject(s) - chemistry , regioselectivity , thioamide , hydrazine (antidepressant) , acetic acid , catalysis , organic chemistry , amine gas treating , aryl , one pot synthesis , combinatorial chemistry , ethanol , pyrazole , alkyl , chromatography
An efficient, highly regioselective protocol for the synthesis of the title compounds is reported. The reaction involves a one‐pot, three‐component cyclocondensation of β‐oxodithioester, amine, and hydrazine in ethanol at reflux in the presence of a catalytic amount of acetic acid. Densely functionalized pyrazoles were constructed through the cyclization of a thioamide intermediate generated in situ from the β‐oxodithioester. This method allows a rapid and general synthesis of previously inaccessible pyrazoles and synthetically demanding pyrazoles containing fused rings.