1664-52-4Relevant articles and documents
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Yamazaki et al.
, (1954)
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Water-removable ynamide coupling reagent for racemization-free syntheses of peptides, amides, and esters
Liu, Tao,Zhang, Xue,Peng, Zejun,Zhao, Junfeng
supporting information, p. 9916 - 9921 (2021/12/24)
A novel ynamide coupling reagent, the by-product of which can be removed by water, was reported. It promotes the direct coupling between carboxylic acids and amines, alcohols or thiols to provide amides, peptides, esters and thioesters, respectively. No detectable racemization was observed for all the coupling reactions of carboxylic acids containing an α-chiral center. Importantly, a simple acidic aqueous work-up removed the by-product readily to afford pure coupling products in good to excellent yields without the use of column chromatography, thus making this method more environmentally benign, user friendly and cost-effective. The robustness of the water-removable ynamide coupling reagent was further exemplified by the racemization/epimerization-free synthesis of carfilzomib, in which no column chromatography purification was involved for the entire 12-step synthesis.
Tetramethyl Orthosilicate (TMOS) as a Reagent for Direct Amidation of Carboxylic Acids
Braddock, D. Christopher,Lickiss, Paul D.,Rowley, Ben C.,Pugh, David,Purnomo, Teresa,Santhakumar, Gajan,Fussell, Steven J.
supporting information, p. 950 - 953 (2018/02/23)
Tetramethyl orthosilicate (TMOS) is shown to be an effective reagent for direct amidation of aliphatic and aromatic carboxylic acids with amines and anilines. The amide products are obtained in good to quantitative yields in pure form directly after workup without the need for any further purification. A silyl ester as the putative activated intermediate is observed by NMR methods. Amidations on a 1 mol scale are demonstrated with a favorable process mass intensity.