A general application of 1-acyl-3-hydroxy-1H-pyrazoles 5 as useful acylatin
g agents for alcohols or phenols, amines and hydrazines is described. The u
se of a hydrazide for a direct acylation of an alcohol in the presence of 4
-ethoxymethylene-2-phenyl-5( 4H)-oxazolone (1) is also discussed.