Direct amidation of carboxylic acids with amines under microwave irradiation using silica gel as a solid support

Abstract

A highly improved methodology for the direct amidation of carboxylic acids with amines using silica gel as a solid support and catalyst is described. Several examples using aliphatic, aromatic, unsaturated and fatty acids combined with primary and secondary amines are shown.

Unexpected Reactivity of N‐Acyl‐Benzotriazoles with Aromatic Amines in Acidic Medium (ABAA Reaction)

“…The data were obtained in a scan mode ranging from 100 to 1000 m/z or 250 to 1500 m/z to in 0.7 sec intervals. 13 C and 1 H NMR spectra in [D 6 ]DMSO were collected on a Bruker AVANCE 600 MHz spectrometer equipped with a BBFO helium cryoprobe at 298 K. Chemical shifts (δ) are reported in parts per million using residual nondeuterated solvents as internal references. Spectra were processed and visualized with Topspin 3.2 (Bruker Biospin).…”

“…However, despite the efficiency of these methods, the coupling of aromatic amines is still problematic due to their low nucleophile character. Aromatic amines are usually reacted with acyl chlorides, and the use of high temperatures and microwaves is often required to obtain an acceptable coupling, which according to the principle of “green chemistry” needs to be improved . The problem is even more tedious when less reactive substituted aromatic amines are used.…”

“…Aromatic amines are usually reacted with acyl chlorides, [4][5][6] and the use of high temperatures and microwaves is often required to obtain an acceptable coupling, which according to the principle of "green chemistry" needs to be improved. [13] The problem is even more tedious when less reactive substituted aromatic amines are used. In this study, we report on the unexpected synthesis of aromatic amides from benzotriazole-activated carboxylic acids (Bt-carboxylic acids), and a variety of aromatic amines, in acidic medium.…”

Ultrasound Promoted Oxamate Synthesis: A Chemoselective and Direct Approach from Amines

“…Amide bond is the most important functionality as it finds numerous applications in pharmaceuticals, dyes, bioactive natural products, agrochemicals etc . Protection of amines by the formation of amide linkage plays a crucial role in organic synthesis . In the same way the oxalyl (1, 2‐dicarbonyl) group is one of the significant functionality in several biologically active species.…”

“…[3,4] Protection of amines by the formation of amide linkage plays a crucial role in organic synthesis. [5][6][7] In the same way the oxalyl (1, 2-dicarbonyl) group is one of the significant functionality in several biologically active species. Organic molecules with oxamate groups exhibit significant activity such as antimalarial, [8] antiallergy, [9,10] and most notably anticancer [11,12] as it is a metabolic inhibitor of LDH.…”