Utilization of a Methoxy Group in Lignin to Prepare Amides by the Carbonylation of Amines

The synthesis of valuable chemicals from lignin is of great significance. However, there is still no suitable route to produce chemicals with excellent yield. Here, we reported a new method to synthesize amides by the carbonylation of amines directly. Lignin was used as a source of methyl by cleaving the methoxy group using LiI. Different amines were employed to investigate the amide bond formation. The corresponding amides were obtained with good to excellent yields. Several methyl ethers were also used as a methyl source. Excellent conversion of N-methylaniline and selectivity of N-methylacetanilide were obtained. More importantly, lignin monomer compounds and lignin were used as a source of methyl. Satisfactory results were received. A possible mechanism based on the controlled experiments was proposed. This method may provide a potential way for the transformation of lignin into valuable chemicals.