• In the present era, the biological process of producing long peptides is known as protein biosynthesis & synthetic peptides are used either as drugs or in the diagnosis of disease.
• Based on the prior arts literature survey, it is noted that though the reagents provide excellent yields & low racemization for the coupling reaction, but they are relatively expensive & the guanidium by product has to be removed by column chromatography. Further it is noted in different scenario of Benzotraizol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP) reagents which liberate hexamethylphosphoramide (HMPA), which is highly carcinogenic.
• Hence, there is a need to develop cheap, efficient, non-toxic & non-carcinogenic coupling reagents for peptide synthesis & present invention has addressed the issues efficiently.

Present invention describes a process for synthesizing amides in one-pot via in-situ formation of anhydride in presence of a coupling reagent.

The process comprising the steps of:

• preparing a solution of 1.2 equivalent part of acid in THF;
• adding equivalents part of coupling reagent to the mixture
• allowing the resulting mixture to stir at room temperature for 30 min;
• subsequently, adding 1 equivalent part of amine, equivalent part of base , & equivalent part of catalyst to the resultant mixture;
• extracting the mixture with Ethyl cetate (EtOAc) and sequentially washing the mixture with saturated bicarbonate solution, 10% HCl solution and saturated Sodium Chloride (NaCl) solution
• drying the organic layer formed over anhydrous Sodium sulfate (Na2SO4);
• Filtering & Concentrating the filtrate in vacuo; &
• purifying and isolating the desired amide using column chromatography, wherein negligible by-product formation or minimal racemization occurs.

Further, one-pot in reaction between the carboxylic acid & amine takes place in presence of 4 equivalent P2O5 & in presence of 3 equivalent part of diisopropylethylamine & 0.2 equivalent part of catalytic amounts of DMAP.