Chemical Properties of Isocyanides

(1) HYDROLYSIS: unlike cyanides, alkyl isocyanides are NOT hydrolysed by alkalies; dilute MINERAL acids, however, hydrolyse them to a primary amine + formic acid, e.g. methyl isocyanide + 2H2O (acid) gives methylamine + HCOOH -- a hydrolysis route back to the same primary amine the isocyanide was made from, closing the loop with the carbylamine reaction. (2) REDUCTION: catalytic reduction (Na/C2H5OH, or Ni/H2) gives a SECONDARY amine, e.g. methyl isocyanide + 4[H] gives dimethylamine -- contrast this with cyanide reduction, which instead gives a PRIMARY amine. (3) ISOMERISATION: heating an alkyl isocyanide at 250 C converts it into the more thermodynamically stable, isomeric cyanide, e.g. methyl isocyanide rearranges to methyl cyanide. (4) ADDITION REACTIONS: the isocyanide's divalent, lone-pair-bearing carbon adds across a halogen, sulphur or oxygen atom: with X2, it forms an i …