摘要:
Structural modification of some (pyrimidin-2-yl)hydrazones derived from ethyl acetoacetate via methylation at the N-3 atom promotes anomalous cyclization to give [1,2,4]triazolo[1,5-a]pyrimidine derivatives. The mechanism of this transformation includes specific cleavage of the aliphatic fragment in the substrate with subsequent rearrangement of carbene-like intermediate.