Organophosphoric Acid Promoted Transamidation: Using N,N‐Dimethylformamide and N,N‐Dimethylacetamide as the Acyl Sources

Abstract

A new and efficient protocol for the transamidation promoted by organophosphoric acid has been reported. The protocol was applied for the N‐formylation of amines including aromatic, aliphatic and heterocyclic amines, affording moderate to excellent yields (54‐98 %) via the transamidation of N,N‐dimethylformamide (DMF). Similarly, the protocol was used for the N‐acylation of a range of amines, moderate yields via transamidation of N,N‐dimethylacetamide (DMA) were obtained. Moreover, the protocol could be easily performed on a multigram scale.

Environmentally Benign Transamidation Protocol for Weakly Nucleophilic Aromatic Amines with N‐Acyl‐2‐piperidinones: Catalyst‐, Additive‐, Base‐ and Solvent‐Free Condition

“…This adds to the synthesis cost and generation of metal waste and resources [27] . Subsequently, several metal‐free transamidation protocols have been developed that employ DTBP, [28] TBHP, [8] proline, [29] KO t Bu, [30] benzoic acid, [31] NH 2 OH.HCl, [32] Et 3 N, [12] B(OH) 3 , [33] TMSCl, [34] organophosphoric acid, [35] chitosan, [36] hypervalent iodine, [37] benztriazole [38] or NaHMDS [39] to effect transamidation. Thus far the developed protocols [27,30,40] for transamidation of amides with anilines have at least one or more of the following shortcomings: limited to primary amides, formylation/acetylation, low yield, limited substrate scope, heavy metal catalyst, microwave irradiation, high temperature, requires additive, uses strong base, requires peroxide activator, excessive use of anilines/reagents/additive, long reaction time, or requires inert atmosphere.…”