ISOCYANIDE SYNTHESIS

Methyl, n-butyl, sec-butyl, and tert-butyl isocyanides were prepared by reacting p-toluenesulfonyl chloride, quinoline, and the corresponding N-alkyl formamide in a rotary evaporator at 1.5-mm. Hg pressure. The isocyanides distill upon formation and were collected in a dry ice trap. One distillation without a fractionating column gave a 50 to 75 yield of chromatographically GLC pure product. The simplicity of the procedure and facility of obtaining large quantities of high purity aliphatic isocyanides is a distinct improvement over published procedures. This procedure is recommended for the synthesis of all isocyanides having a boiling point of 150-175C760 mm or less. Optimum yields will be obtained when a reaction flask size of no less than 2 liters, a formamide charge of no more than 25 gm, and a pressure of no greater than 2.0 mm are used.