Formal [4+1] cyclization of (thio/imido)hydrazides and ethyl 3,3,3-trifluoropropanoate: unified synthesis of 1,3,4-oxadiazoles, 1,3,4-thiadiazoles and 1,2,4-triazoles

We have developed a unified approach to 1,3,4-oxadiazoles, 1,3,4-thiadiazoles and 1,2,4-triazoles with ethyl acetate decoration by treating hydrazides, thiohydrazides and imidohydrazide with ethyl 3,3,3-trifluoropropanoate in the presence of a suitable base.