Addition of Halogen to Isocyanides

The addition of halogen to isocyanides to produce carbonimidoyl dichlorides was demonstrated by Nef (io8.io9j Guillemard ( ). 

The reaction proceeds in chloroform at room temperature however, no yields are reported. In the aliphatic series it is sometimes advantageous to conduct the reaction in diethyl ether, using sulfuryl chloride as the chlorinating agent. Thus, ethylcarbonimidoyl dichloride VIII is obtained in the reaction of ethyl isocyanide with sulfuryl chloride However, addition of chlorine to long-chain aliphatic isocyanides does not produce the corresponding carbonimidoyl dichlorides ( ). 

Similarly, addition of bromine and iodine to phenyl isocyanide yields the corresponding crude carbonimidoyl dihalides however, Nef 

N 3-Dimethylaminopropyl)carbonimidoyl dichloride To a solution of 1.44 g of 3-dimethylaminopropyl isocyanide in 11ml of chloroform chlorine is added with ice-cooling until a yellow color is observed. The precipitated 1.45 g (62%) of N-(3-dimethylaminopropyl)carbonimidoyl dichloride, m.p. 130.5-132°C, is collected and dried in vacuo. The compound is very hygroscopic. 

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