Copper‐(II) Catalyzed N‐Formylation and N‐Acylation of Aromatic, Aliphatic, and Heterocyclic Amines and a Preventive Study in the C‐N Cross Coupling of Amines with Aryl Halides

A Cu‐(II) catalyzed N‐formylation and N‐acylation of amines with moderate to excellent yields, using N, N‐dimethyl formamide (DMF) and N, N‐dimethyl acetamide (DMA) as a formyl and acylating sources in the presence of 1,2,4‐triazole is reported. This novel, highly efficient and simple protocol shows broad substrate scope for aliphatic, aromatic, and heterocyclic amines. In addition, the conditions to prevent N‐formylation and N‐acylation impurities in the C−N cross coupling of amines and aryl halides are described typically when DMF and DMA are used as solvents, with various catalysts, ligands, and bases. It's a fair cop! The efficiency of cheaper and convenient Cu‐(II) catalytic system, for N‐formylation and N‐acylation of wide range of amines in presence of 1,2,4‐triazole as base, as well as N‐formyl and N‐acyl carrier has been investigated, Though 1,2,4‐triazole is known as N‐acyl carrier, while N‐formyl carrier is not reported earlier. Ironically, in addition, a significant preventive study to avoid these by‐products during the C−N bond cross coupling reactions using DMF and DMA as solvents is reported for the first time, that will help the correct planning of many future syntheses.