Isocyanide dichlorides are organic compounds containing the RN=CCl2 functional group. Classically they are obtained by chlorination of isocyanides. Phenylcarbylamine chloride is a well-characterized example.
Preparation Chlorination of organic isothiocyanates is also well established: RN=C=S + 2Cl2 → RN=CCl2 + SCl2 Alkylisocyanates are chlorinated by phosphorus pentachloride: RN=C=O + PCl5 → RN=CCl2 + POCl3
Cyanogen chloride also chlorinates to give the isocyanide dichloride: ClCN + Cl2 → ClN=CCl2
Reactions Isocyanide dichlorides participate in Friedel-Crafts-like reactions, leading, after hydrolysis, to benzamides: RN=CCl2 + ArH → RN=C(Cl)Ar + HCl RN=C(Cl)Ar + H2O → R(H)NC(O)Ar + HCl
The N=C bond is relatively inert.Ulrich, H. The Chemistry of Imidoyl Halides; Plenum Press: New York, 1968.
Hydrogen fluoride displaces the chlorides to give the isocyanide difluoride.
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