Research On Synthesis Of Isocyanides Via Formylation

The wide applications of isocyanides in the organic synthesis have resulted in the quickly development of isocyanides related chemistry. At present, the isocyanides functional group has been in the top list of the applied functional groups.Metallic cyanides and alkyl iodides were convert to complex, which was decomposed to isocyanides and metallic iodides. The maximum yield of isocyanides is lower than55%. Hoffman method for synthesis of isocyanides is often applied to the identification of primary amine and it is less practical in the synthesis of isocyanides. Compared with other synthetic approaches, formylation method for synthesis of isocyanides is more easily and widely useful and the mono-N-substituted formamide proves to be a better material for dehydrating to isocyanides within a better yield. Therefore, formylation method has been studied for the preparation of isocyanides in this paper.Research on synthesis of methyl a-isocyanophenyl acetate was made. Methyl aminophenyl acetate hydrochloride and triethylamine were convert to free amino compounds. Then the formic acid and acetic anhydride was added into reaction to synthesize methyl formylaminophenyl acetate. Methyl a-isocyanophenyl acetate was provided from methyl formylaminophenyl acetate in the presence of POC13and Et3N. The conditions of all three steps were optimized.We also focused on the research for synthesis of tosylbenzyl isocyanide. N-(a-tosylbenzyl) formamide was synthesized from sodium p-toluenesulfinate, benzaldehyde, formic acid and formamide via one-pot process. Then N-(a-tosylbenzyl) formamide was dehydrated into tosylbenzyl isocyanide in the presence of POCl3and Et3N. The conditions of the protocol were optimized.The synthesis of Benzyl isocyanide was investigated. Formic acid and acetic anhydride were added to benzyl amine to synthesize N-benzylformamide. Then benzyl isocyanide was synthesized from N-benzylformamide in the presence of POCl3and Et3N. The optimized conditions were obtained by studying the formylation and dehydration processes.