Sustainable Amidation Reactions – Recent Advances

Abstract

Due to the widespread occurrence of amides in modern pharmaceuticals and biologically active compounds, amidation reaction is one of the most important reactions in organic chemistry. Traditional methods to form amide bonds involve the coupling of a carboxylic acid with an amine and require the pre-activation of the carboxylic acid moiety. Sustainable routes are replacing these existing methods since large amounts of waste are produced. Recently, novel reagents and

A new outlook in oxidative transformations and coupling reactions via in situ generation of organic chloramines

“…[ 6 ] Because of the high reactivity of N–Cl compounds [ 7 ] (amides or amines), one can use milder reaction conditions toward these organic transformations for the construction of a variety of bonds like C–Cl, S–Cl, C–O, C=O, C–N, N–N, CSONR(S–N), and CONHR. [ 8–12 ] The trivial preparation of N ‐chloro compounds (amines and amides) and the use of substrate as the coupling reagent in all cases aid well for the applications in organic synthesis.…”

“…Owing to the high activity of the N–Cl bond scientist utilized N ‐chloramines (Scheme 2b) [ 26 ] for the construction of C–N bond (amination reactions), in which N ‐chloramines are acting as electrophiles for the synthesis of a wide range of diarylamines. Due to the high activity N–Cl bond, Wu developed for the first time palladium‐catalyzed carbonylative cross‐coupling (Scheme 2c) [ 12b ] between N ‐chloramines and organoboronic acids via electrophilic aminocarbonylation reactions for the synthesis of a vast range of organic materials. First time, Watkins developed (Scheme 2d) [ 27 ] a metal‐free regioselective selective C‐5 chlorination of a broad range of 8‐substituted quinolines using trichloroisocyanuric acid ( N ‐chloramide) as an atom‐efficient halogen source, which led to the synthesis of a broad range of chlorinated quinoline derivatives.…”

Silicon compounds as stoichiometric coupling reagents for direct amidation

“…Accordingly many efficient and inventive protocols have been developed to form this bond that have been reviewed many times. [3][4][5][6][7][8][9][10] Notwithstanding this state of affairs, it is surprising that amidation is still a reaction considered non-ideal, as outlined by the 2007 ACS Green Chemistry Institute (GCI) Pharmaceutical Roundtable, which voted that an aim to develop amide formation avoiding poor atom economy reagents should be the top priority for the chemical research community. 11 In 2018, the ACS GCI Pharmaceutical Roundtable redefined the goal to develop general methods for catalytic/sustainable (direct) amide or peptide formation, reflecting the unsolved nature of sustainable amidation.…”

Recent Advancement in the Copper Mediated Synthesis of Heterocyclic Amides as Important Pharmaceutical and Agrochemicals

“…There are some reports in the literature reviews for the catalytic and enzymetic routes for amidation reactions [24–33] . Furthermore, there are few reports on the application of heterocyclic amides in medicine and agriculture [34–36] .…”