Addition of Halides to Cyanamides and Carbodiimides

The addition of hydrogen halides to cyanamide which in its tautomeric form can be written as carbodiimide (XX) was reported by Drechsel in 1875. The author obtained both the dihydrochloride XXI (X = Cl), and the dihydrobromide XXI (X = Br) of cyanamide. 

The dihydrohalides of cyanamide have been obtained by other investigators (24-,46,49,56 structure w as recognized only recently 

Chloroformamidine hydrochlorides were also obtained by addition of hydrogen chloride to dicyano imide ( ), and to mono- (39.48,7 disubstituted cyanamides. 

By addition of hydrogen chloride to diphenylcarbodiimide, Lengfeld and Stieglitz synthesized l-chloro-N,N -diphenylformamidine hydrochloride (XXII) in 1895. The reaction is not limited to diarylcarbodiimides, and from dialkylcarbodiimides the corresponding chloroformamidine hydrochlorides can be obtained in quantitative yield 

N -Di n -butylchloroformamidine hydrochloride ( ). To a solution of 15.9 g (0.1 mole) of di- -butylcarbodiimide in 100 ml of chloroform gaseous hydrogen chloride is added until the exothermic reaction ceases. Excess hydrogen chloride is removed with nitrogen and evaporation of the solvent affords N,N -di-n-butylchloroformamidine hydrochloride as a colorless oil. 

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