Abstract It has been shown from X-ray structural analytical data that the reaction of 2- ethoxycarbonylmethyl-1, 4, 6-trimethylpyrimidinium iodide with carboxylic acid hydrazides gives pyrazolo [1, 5-a] pyrimidine derivatives and not the isomeric triazolo [4, 3-a] pyridines previously reported. This novel and previously unreported rearrangement of 1, 2- dialkylpyrimidinium salts occurs via recyclization of the pyrimidine ring with inclusion of a ...
