An efficient synthesis of isomeric 1-(1-Alkyl-1H-pyrazolyl) ethanones

A simple and versatile general method for the preparation of N-substituted 3-, 4-, or 5-acetylpyrazoles from corresponding acids via hydrolysis and decarboxylation of substituted diethyl [(1-alkyl-1H-pyrazolyl)carbonyl]malonates was developed. Title compounds were prepared in three steps without isolation of intermediates in 48-82% overall yield. © 2012 HeteroCorporation.