SYNTHESIS OF 3-FLUOROPYRAZOLO[1,5-a]PYRIDINES BY FLUORINATION OF METHYL PYRAZOLO[1,5-a]PYRIDINE-3-CARBOXYLATES

Abstract

The reaction of methyl esters of pyrazolo[1,5-a]pyridine-2,3-dicarboxylic and 2-phenylpyrazolo[1,5-a]pyridine-3-carboxylic acids with the fluorinating reagent Selectfluor gave 3-fluoropyrazolo[1,5-a]pyridine-2-carboxylic acid methyl ester and 3-fluoro-2-phenylpyrazolo[1,5-a]pyridine. Monitoring the progress of the reaction by 1H NMR spectroscopy showed the formation of an intermediate fluorinecontaining σ-complex.

Authors: Sabina V. Alieva, Aleksey Yu. Vorob'ev*