The pyrolytic rearrangement of 1-alkynoyl-3-methylpyrazoles: synthesis of pyrazolo [1, 5-a] pyridin-5-ols and related compounds

…, FW Eastwood, GD Fallon, SC Lee, RP Mcgeary

Index: Brown, Roger F. C.; Eastwood, Frank W.; Fallon, Gary D.; Lee, Swee Choo; McGeary, Ross P. Australian Journal of Chemistry, 1994 , vol. 47, # 6 p. 991 - 1008

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Citation Number: 13

Abstract

Abstract Flash vacuum pyrolysis of 1-(alkyn-2′-oyl)-3-methylpyrazoles at 650/0.03 mm forms pyrazolo [1, 5-a] pyridin-5-ols, often in high yield, which may bear substituents at C2, C3 or C7. In the absence of a 3-methyl group in the precursor, N-ethynylpyrazoles are formed in low yield. The formation of both types of product is interpreted as involving 3-(N- pyrazolyl) propadienones formed by N1→ N2 migration of the N-alkynoyl group with ...