Vilsmeier Formylation of Hydrazones and Semicarbazones Derived from Alkyl, Benzyl, and Cycloalkyl Methyl Ketones
作者:A. V. Lebedev、A. B. Lebedeva、V. D. Sheludyakov、E. A. Kovaleva、O. L. Ustinova、I. B. Kozhevnikov
DOI:10.1007/s11176-005-0241-y
日期:2005.3
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
An efficient and simple procedure for conversion of different classes of aldehydes and ketones into the corresponding semicarbazones with semicarbazide hydrochloride using basicalumina is studied.
norephedrine, ephedrine, norpseudoephedrine, and pseudoephedrine, in growing plants of Ephedragerardiana. This finding serves to identify pyruvate as the elusive precursor of the aliphatic C2 terminus of the skeleton of the alkaloids. In earlier experiments with C-labelled substrates, label from [3-14C]pyruvic acid was incorporated mainly, but not exclusively, into the C-methyl group of ephedrine, and label