One-pot activation–alkynylation–cyclization synthesis of 1,5-diacyl-5-hydroxypyrazolines in a consecutive three-component fashion (Beilstein Journal of Organic Chemistry)

Abstract A consecutive three-component activation–alkynylation–cyclization reaction of (hetero)aryl glyoxylic acids, oxalyl chloride, arylacetylenes, and hydrazides efficiently forms 1,5-diacyl-5-hydroxypyrazolines in moderate to good yields. The structures were unambiguously corroborated by comprehensive NMR spectroscopy and X-ray structure analyses of selected derivatives. Beilstein J. Org. Chem. 2019, 15, 1360–1370. doi:10.3762/bjoc.15.136