Concise routes to pyrazolo[1,5-a]pyridin-3-yl pyridazin-3-ones
作者:Karen A. Johnston、Robert W. Allcock、Zhong Jiang、Ian D. Collier、Haakon Blakli、Georgina M. Rosair、Patrick D. Bailey、Keith M. Morgan、Yasushi Kohno、David R. Adams
DOI:10.1039/b713638b
日期:——
Cycloaddition of pyridine N-imine with 6-alkyl-4-oxohex-5-ynoates followed by condensation with hydrazine provides concise access to pharmacologically active 6-(pyrazolo[1,5-a]pyridin-3-yl)pyridazinones. For the first time alkynyl heterocycles are also shown to be effective dipolarophiles for pyridine N-imine, and analogous compounds can be accessed directly in modest yields through the reaction of 6-(alkyn-1-yl)pyridazin-3-one derivatives.