A new synthetic route to 7H-imidazo[1,2-b][1,2,4]triazoles

The reaction of benzil 1-ureidoethylidene hydrazones 8 with a mixture of triphenylphosphine, carbon tetrachloride, and triethylamine provides a general route to 7H-imidazo1,2-b]1,2,4]triazoles 18 via the thermal reaction of the expected keto azine carbodiimide intermediates 13, and the structure of 18 was confirmed by X-ray crystallographic analysis.