H. Ochi, T. Miyasaka, Kiyoshi Kanada
Jul 1, 1976
Citations
0
Influential Citations
16
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
2-Hydroxypyrazolo[1,5-a]pyridine (I) was synthesized by reaction of ethyl 2-pyridylacetate (IV) with hydroxylamine-O-sulfonic acid. I was shown to undergo nitrosation, nitration and bromination at C-3 position. Methylation of I with diazomethane gave 2-methoxypyrazolo[1,5-a]pyridine (V), while methylation of I with dimethyl sulfate gave a mixture of V and 1-methyl-1,2-dihydropyrazolo[1,5-a]pyridin-2-one (VI). The enol form was found to be predominant tautomeric species of I in solution. Treatment of I with acetic anhydride afforded 2-acetoxypyrazolo[1,5-a]pyridine (XIII) exclusively. 1-Acetyl-1,2-dihydropyrazolo[1,5-a]pyridin-2-one (XIV) dose not seem to intervene in the formation of thermally stable O-acetylated product (XIII).