B. Cross, Robert L. Arotin, Charles F. Ruopp
Jul 1, 1980
Citations
0
Influential Citations
6
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
A rapid, convenient conversion of 1,2-dimethylpyrazolium salts (1) to 1-methylpyrazoles (2) is accomplished in piperidine or 3-methylpiperidine at temperatures ≥ 106°. This demethylation represents a particularly useful procedure for the synthesis of 3- and 5-substituted aminopyrazoles, which are not readily obtainable by other methods. The 50:50 mixture of piperidinopyrazole isomers 2b can be obtained directly by treating 3-chloro-1,2-dimethyl-5-phenylpyrazolium iodide (3b) with piperidine in ethanol at 106°.