Facile one-pot synthesis of 3,5-disubstituted 1 h -pyrazoles from propargylic alcohols via propargyl hydrazides

摘要

A new and efficient metal-free, two-component, one-pot approach to a variety of 3,5-disubstituted 1H-pyrazoles has been developed from propargylic alcohols. This transformation proceeds via an acid-catalyzed propargylation of N,N-diprotected hydrazines followed by base-mediated 5-endo-dig cyclization leading to 3,5-disubstituted 1H-pyrazoles in good overall yields.? Georg Thieme Verlag Stuttgart. New York.