
%0 Journal Article
%A Brown, RFC 
%A Eastwood, FW 
%A Fallon, GD 
%A Lee, SC 
%A Mcgeary, RP 
%T The Pyrolytic Rearrangement of 1-Alkynoyl-3-methylpyrazoles: Synthesis of Pyrazolo[1,5-a]pyridin-5-ols and Related Compounds
%J Australian Journal of Chemistry
%D 1994/06/01
%V 47
%N 6
%P 991-1007
%K 
%R https://doi.org/10.1071/CH9940991
%U https://www.publish.csiro.au/paper/CH9940991 
%X Flash vacuum pyrolysis of 1-(alkyn-2&#8242;-oyl)-3-methylpyrazoles at 650&#176;/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 &#8594; N2 migration of the N-alkynoyl group with inversion of the three-carbon chain. The fused-ring structure of 2-methylpyrazolo[1,5-a]pyridin-5-ol (25) was established by X-ray crystallography of the O-benzoyl derivative (27). 
