Beilstein journal of organic chemistry2009Vol. 5pp. 64-
204
gorja2009pdcmediatedbeilstein
Abstract
Pd/C-mediated alkynylation of 5-iodo-pyrazole-4-carboxylic acid, involving the first regioselective construction of α-pyrone ring on a pyrazol moiety via tandem coupling–cyclization process, has been developed to afford pyrano[4,3-c]pyrazol-4(1H)-one in a single pot.