Vilsmeier Formylation of Hydrazones and Semicarbazones Derived from Alkyl, Benzyl, and Cycloalkyl Methyl Ketones

Formylation of ten accessible phenylhydrazones and semicarbazones derived from alkyl, benzyl, and cycloalkyl methyl ketones with the complex of POCl₃ with dimethylformamide was studied. Depending on the electronic and steric structure of the substrates, the reaction yields 1-phenyl- or 1-unsubstituted 3,4-dialkyl-, 3-alkyl-4-aryl-, or 3-alkyl-4-formylpyrazoles. These compounds can be readily oxidized into the corresponding carboxylic acids.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 3, 2005, pp. 448–452.Original Russian Text Copyright © 2005 by Lebedev, Lebedeva, Sheludyakov, Kovaleva, Ustinova, Kozhevnikov.