1.4 ml of triethylamine, then 3 g of the product of Step B were introduced into a solution of 1.76 g of propionic acid hydrazide in 160 ml of toluene, this latter having been brought to reflux and then cooled. After refluxing for 1 hour, the toluene was eliminated under reduced pressure and the residue was taken up in 50 ml of chloroform and 50 ml of water. The aqueous phase was extracted with chloroform and the organic extracts were dried and concentrated to obtain an oil which was purified by chromatography on silica and elution with ethyl acetate and cyclohexane (8-2) to obtain 3 g of 3-ethyl-4-(4-methoxyphenyl)-5-(4-nitro-3-methylphenyl)-4H-1,2,4-triazole in the form of an oil which had an Rf of 0.6 on thin film chromatography (eluent:chloroformethanol 9-1).
