Aniline → N,N'-Diphenylformamidine

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Reaction Steps

Thus, a mixture of triethyl orthoformate (1 equ.) and aniline (2 equ.) is heated at reflux for 2 hours. The ethanol evolved during the reaction is then distilled through a fractionating column. The reaction mixture is then allowed to cool, whereupon it solidifies. Recrystallisation of the solid from toluene yields N,N′-diphenyl formamidine in 80% yield. N,N′-diphenyl formamidine (1 equ.) and triethyl orthoformate (2 equ.) are mixed and a catalytic amount of dry aniline hydrochloride is then added. The mixture is heated and ethanol is seen to reflux within a few minutes. The mixture is heated at reflux for 1 hour and then the ethanol is distilled. Following the distillation, anhydrous potassium carbonate is added. The mixture is shaken and then allowed to stand for 2 hours. The reaction mixture is then distilled under reduced pressure. At 93 mmHg, excess triethyl orthoformate is collected at 83-85° C. The pressure is then reduced to 40 mmHg and ethyl N-phenylimdioformate is collected at 117° C. in 95% yield.

Provenance & Evidence