AL2O3 GAUSSIAN SOFTWARE SOFTWARE

27 However, the trouble with the presence of an acidic N–H bond in amides causes this reaction to grow from the intrinsic strength of the amide C–N bond together. 26 Examples of transamidation reaction is occasional, and it's application is finite in organic synthesis, and mostly used in intermolecular reactions. Most of them pass through from low activity, low selectivity, or narrow scope. 22 For straight amidation, 23 at present, most researchers are focusing on heterogeneous 24 catalysis from carboxylic acids 25 with amines. 19,20 Amide bond formation 21 via unconventional methods has been reviewed, and some substitutes were obtainable to carry out acylation on nitrogen. 17,18 Another example is metal-free transamidation by direct nucleophilic addition to the amide bond.

15,16 The most successful example of direct amide synthesis is the coupling of carboxylic acids with amines flourished by boric acids. 13,14 Therefore, the ACS Green Chemistry Institute has evaluated the amide bond formation with well atom economy as one of the biggest challenges for organic chemists. 12 Also, a greener procedure for direct amide bond formation has been investigated. 10,11 However, there are boundaries such as the lability of the activated acid derivatives and exhausting procedures. 7–9Ī consecutive scheme for the synthesis of amides has emerged on amides and the coupling of activated carboxylic acid derivatives. 3–6 The world's leading pharmaceutical companies GSK, AstraZeneca and Pfizer conducted a small survey of 128 drug candidate molecules, and from which, they found that around 10% of the reactions used in their synthesis involved an amide bond formation reaction.

Amidation reactions are the most accomplished chemical processes in the pharmaceutical industry and drug discovery activities. The amide bond is an inevitable ingredient of synthetic and biological polymers 1,2 and is a significant functional group in organic chemistry, particularly in synthetic organic chemistry. This catalytic method is effective for the simultaneous activation of the carbonyl group and N–H bond by using the Al 2O 3 catalyst. The products were purified by recrystallization and column chromatography techniques. The catalyst was reused several times with no significant loss in its catalytic activity. In this study, five successful compounds were synthesized by the transamidation of secondary amides with amines using a reusable Al 2O 3 catalyst.

AL2O3 GAUSSIAN SOFTWARE SOFTWARE

Moreover, using the Gaussian09 software at the DFT level, HUMO, LUMO and the intrinsic reaction coordinates (IRCs) have also been calculated to find out the transition state of the reaction and energy. Several aliphatic and aromatic amines were used for the transamidation of N-methylbenzamide in the presence of the Al 2O 3 catalyst. By using the concepts of amphoteric properties of Al 2O 3, amides were synthesized from secondary amides and amines in the presence of triethylamine solvent. Al 2O 3 is an amphoteric catalyst that activates the carbonyl carbon of the secondary amide group and helps the C–N cleavage of the reactant amide group by attacking the N–H hydrogen. Unfortunately, the traditional synthesis of amides suffers from some important drawbacks, including low atom efficiency, high catalyst loading, separation of products from the reaction mixture and production of byproducts. Amides are the most extensively used substances in both synthetic organic and bioorganic chemistry.

Al2o3 gaussian software