Amidation Of Esters Research Articles

ChemInform Abstract: ZrCl4 as a New Catalyst for Ester Amidation: An Efficient Synthesis of h‐P2X7R Antagonists.

AbstractIt is shown that the catalytic activity of ZrCl4 is higher for the amidation of methyl‐pyroglutamate derivatives compared to conventional catalysts (PTSA or HCl).

ZrCl4 as a new catalyst for ester amidation: an efficient synthesis of h-P2X7R antagonists

The catalytic activity of zirconium (IV) chloride (ZrCl4) versus conventional catalysts (PTSA or HCl) for the amidation of methyl-pyroglutamate derivatives was investigated. In this study of the synthesis of P2X7 receptor (P2X7R) antagonists, ZrCl4 was the best catalyst for the synthesis of pyroglutamides substituted in position 1. Four new pyroglutamides have shown good antagonistic properties on the human P2X7 receptor (h-P2X7R).

ChemInform Abstract: A Heterogeneous Niobium(V) Oxide Catalyst for the Direct Amidation of Esters.

AbstractThe first example of a heterogeneously catalyzed direct amidation of esters with amines is reported.

Heterogeneous recyclable nano-palladium catalyzed amidation of esters using formamides as amine sources

Catalyzed by supported palladium nanoparticles, a decarbonylative amidation reaction between various aryl esters and formamides by C–O bond activation has been developed for the synthesis of amides.

ChemInform Abstract: Microwave‐Promoted Direct Amidation of Unactivated Esters Catalyzed by Heteropolyanion‐Based Ionic Liquids under Solvent‐Free Conditions.

Abstract A simple and efficient procedure for the synthesis of amides directly from unactivated esters and amines catalyzed by heteropolyanion-based ionic liquids under microwave-promoted and solvent-free conditions has been reported. The practical protocol was found to be compatible with different structurally diverse substrates. Moderate to excellent yields, solvent-free media, and operational simplicity are the main highlights. Furthermore, the heteropolyanion-based ionic liquids were easily reusable for this amidation.

ChemInform Abstract: N‐Heterocyclic Carbene‐Catalyzed Amidation of Vinyl Esters with Aromatic Amines.

AbstractA novel method is elaborated for the synthesis of amides (III) and (V) by NHC‐catalyzed direct amidation of vinyl esters with anilines.

ChemInform Abstract: Ammonium Nitrate: A Biodegradable and Efficient Catalyst for the Direct Amidation of Esters under Solvent‐Free Conditions.

AbstractA simple, metal‐free, and environment‐friendly procedure for amidation of esters with amines using ammonium nitrate as catalyst is developed.

Pharmaceuticals and Surfactants from Alga-Derived Feedstock: Amidation of Fatty Acids and Their Derivatives with Amino Alcohols.

Amidation of renewable feedstocks, such as fatty acids, esters, and Chlorella alga based biodiesel, was demonstrated with zeolites and mesoporous materials as catalysts and ethanolamine, alaninol, and leucinol. The last two can be derived from amino acids present in alga. The main products were fatty alkanol amides and the corresponding ester amines, as confirmed by NMR and IR spectroscopy. Thermal amidation of technical-grade oleic acid and stearic acid at 180 °C with ethanolamine were non-negligible; both gave 61% conversion. In the amidation of stearic acid with ethanolamine, the conversion over H-Beta-150 was 80% after 3 h, whereas only 63% conversion was achieved for oleic acid; this shows that a microporous catalyst is not suitable for this acid and exhibits a wrinkled conformation. The highest selectivity to stearoyl ethanolamide of 92% was achieved with mildly acidic H-MCM-41 at 70% conversion in 3 h at 180 °C. Highly acidic catalysts favored the formation of the ester amine, whereas the amide was obtained with a catalyst that exhibited an optimum acidity. The conversion levels achieved with different fatty acids in the range C12-C18 were similar; this shows that the fatty acid length does not affect the amidation rate. The amidation of methyl palmitate and biodiesel gave low conversions over an acidic catalyst, which suggested that the reaction mechanism in the amidation of esters was different.

Zirconium-catalyzed direct amide bond formation between carboxylic esters and amines

Development of catalytic amide bond formation reactions from readily available starting materials remains a challenging task for modern organic chemistry. Herein, we report that unactivated carboxylic esters and amines react in the presence of 10 mol% of zirconocene dichloride (Cp2ZrCl2) in toluene at 110 °C to afford amides in very good to excellent conversions. The Zr-catalyzed reaction is amenable for the amidation of aliphatic and aromatic carboxylic esters with primary and secondary amines. The reaction proceeds with almost complete retention of configuration for chiral esters and chiral amines.

Microwave-promoted direct amidation of unactivated esters catalyzed by heteropolyanion-based ionic liquids under solvent-free conditions

A simple and efficient procedure for the synthesis of amides directly from unactivated esters and amines catalyzed by heteropolyanion-based ionic liquids under microwave-promoted and solvent-free conditions has been reported. The practical protocol was found to be compatible with different structurally diverse substrates. Moderate to excellent yields, solvent-free media, and operational simplicity are the main highlights. Furthermore, the heteropolyanion-based ionic liquids were easily reusable for this amidation.

ChemInform Abstract: Synthesis of β‐Hydroxyacetamides from Unactivated Ethyl Acetates under Base‐Free Conditions and Microwave Irradiation.

Abstract The amidation of unactivated ethyl esters with achiral and chiral 1,2-amino alcohols under microwave irradiation and base-free conditions is described. This procedure provides a convenient method for the synthesis of β-hydroxyacetamides bearing pyrazole, imidazole, and benzimidazole groups in high yields and without racemization. The protocol described herein is environmentally friendly and allows for the preparation of a wide variety of β-hydroxyacetamides, which are key intermediates in the synthesis of oxazolines and other derivatives of biological interest.

N-Heterocyclic carbene-catalysed amidation of vinyl esters with aromatic amines

A novel amide bond formation reaction was developed via N-heterocyclic carbene (NHC)-catalysed direct amidation of vinyl esters. In the presence of 5.0 mol % NHC catalyst, a variety of aromatic amines undergo acylation reaction with different vinyl esters to produce amides in 51% to quantitative yields.

Novel polyamidoamine dendrimer-functionalized palygorskite adsorbents with high adsorption capacity for Pb2 + and reactive dyes

Novel polyamidoamine (PAMAM) dendrimer-functionalized palygorskite (Pal) adsorbents, up to generation 4.0, with high adsorption capacity, were designed and efficiently synthesized by grafting PAMAM onto 3-aminopropyltriethoxysilane-modified palygorskite (NH2-Pal) surfaces. This was carried out using a divergent method including the Michael addition of methyl acrylate (MA) and amidation of the resultant ester moieties with ethylenediamine (EDA). The optimal conditions for Michael addition were achieved using 88.8mmol MA (relative to 4.0g NH2-Pal) at 323K for 24h. The optimal conditions for amidation of the resultant esters were achieved using 179.3mmol EDA (relative to 2.1g Pal-PAMAM G0.5) at 323K for 48h. All of the amino-terminated Pal-PAMAM G(n) (n=0, 1, 2, 3 and 4) adsorbents exhibited very high density amino-terminated groups and adsorption capacities for both Pb2+ and Reactive Red 3BS, which increased with increasing generation number. The maximum adsorption capacity for Pb2+ at 293K was 68.5±3.3, 151.1±5.7, 196.5±6.1, 389.1±9.6 and 694.4±12.9mg/g for Pal-PAMAM G(n) (n=0, 1, 2, 3 and 4), respectively. The maximum adsorption capacity for Reactive Red 3BS at 293K was 34.2±2.7, 69.9±4.3, 122.0±6.4, 242.7±7.1 and 322.6±6.9mg/g for Pal-PAMAM G(n) (n=0, 1, 2, 3 and 4), respectively.

Efficient Production of Alkanolamides from Microalgae

Fatty acid alkanolamides (FAAA) are lipid derivatives with industrial applications as biosurfactants and biolubricants. Although conventionally produced from vegetable oils, use of alternative renewable sources that do not compete with the food supply chain, such as microalgae, is desirable. We studied the production of FAAA through direct in situ amidation of algal biomass or by amidation of fatty acid methyl esters (FAME) recovered from in situ transesterification of algae. In situ transesterification resulted in spontaneous formation of a distinct FAME phase, which could be easily recovered and converted to FAAA. With this two-step transesterification-followed-by-amidation method, >95% of algal lipids were recovered as FAAA products. In situ amidation did not result in a separate product phase, likely because of the amphiphilic nature of the product. However, extraction with ethyl acetate allowed recovery of nearly 90% of the biomass lipids as FAAA after in situ amidation.

Catalytic amidation of unactivated ester derivatives mediated by trifluoroethanol.

A catalytic amidation method has been developed, employing 2,2,2-trifluoroethanol to facilitate condensation of unactivated esters and amines, enabling the synthesis of a range of amide products in good to excellent yields. Mechanistic studies indicate the reaction proceeds through a trifluoroethanol-derived active ester intermediate.

Chemoselective calcium-catalysed direct amidation of carboxylic esters

Cheap, non-toxic and environmentally benign CaI2 catalyses direct amide bond formation between unactivated carboxylic esters and primary amines in excellent yields.

Synthesis of β-hydroxyacetamides from unactivated ethyl acetates under base-free conditions and microwave irradiation

The amidation of unactivated ethyl esters with achiral and chiral 1,2-amino alcohols under microwave irradiation and base-free conditions is described. This procedure provides a convenient method for the synthesis of β-hydroxyacetamides bearing pyrazole, imidazole, and benzimidazole groups in high yields and without racemization. The protocol described herein is environmentally friendly and allows for the preparation of a wide variety of β-hydroxyacetamides, which are key intermediates in the synthesis of oxazolines and other derivatives of biological interest.

Ammonium Nitrate: A Biodegradable and Efficient Catalyst for the Direct Amidation of Esters under Solvent-free Conditions

Abstract A simple, metal-free, and environment-friendly procedure is developed for the direct conversion of esters to amides using ammonium nitrate as a catalyst under solvent-free conditions. Aryls, heteroaryls, and aliphatic esters are easily converted to the corresponding amides in excellent isolated yields (85–99%). An enantiopure ester and amine were both shown to react without racemization. The methodology has been successfully applied to preparation of procainamide.

Amidation of esters with amino alcohols using organobase catalysis.

A catalytic protocol for the base-mediated amidation of unactivated esters with amino alcohol derivatives is reported. Investigations into mechanistic aspects of the process indicate that the reaction involves an initial transesterification, followed by an intramolecular rearrangement. The reaction is highly general in nature and can be extended to include the synthesis of oxazolidinone systems through use of dimethyl carbonate.

ChemInform Abstract: Lanthanum(III) Triflate Catalyzed Direct Amidation of Esters.

Lanthanum trifluoromethanesulfonate is an effective single-component catalyst for synthesizing a variety of amides directly from esters and amines under mild conditions. Highly selective amidation of esters and amines, as well as catalyst-controlled amidation of esters, demonstrated the effectiveness of the catalyst system.