78172-94-8Relevant articles and documents
Tungsten-Catalyzed Transamidation of Tertiary Alkyl Amides
Feng, Fang-Fang,Liu, Xuan-Yu,Cheung, Chi Wai,Ma, Jun-An
, p. 7070 - 7079 (2021/06/30)
Transamidation has recently emerged as a straightforward and convenient means to diversify amides. However, the kinetically and thermodynamically demanding transamidation of notoriously robust, fully alkyl-substituted tertiary amides still remains a longstanding challenge. Here, we describe a method for the activation of tertiary alkyl amides to streamline transamidation using simple tungsten(VI) chloride as a catalyst and chlorotrimethylsilane as an additive. The highly electrophilic and oxophilic tungsten catalyst enables the selective scission of a C-N bond of tertiary alkyl amides to effect transamidation of a myriad of structurally and electronically diverse tertiary alkyl amides and amines. Mechanistic study implies that the synergistic effect of the catalyst and the additive could pronouncedly induce the nucleophilic acyl substitution of tertiary alkyl amide with amine to realize transamidation.
New boron(III)-catalyzed amide and ester condensation reactions
Maki, Toshikatsu,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 8645 - 8657 (2008/02/08)
In 1996, we reported that benzeneboronic acids bearing electron-withdrawing groups at the meta- or para-position are highly effective catalysts for the amide condensation reaction in less-polar solvents. In this paper, we report that N-alkyl-4-boronopyridinium halides are more effective catalysts than the previous ones in more polar solvents. N-Alkyl-4-boronopyridinium halides are effective not only for amide condensation between equimolar mixtures of carboxylic acids and amines but also for the esterification of α-hydroxycarboxylic acids in alcohol solvents. Furthermore, perchlorocatecholborane is more effective than areneboronic acids for the amide condensation of sterically demanding carboxylic acids. In addition, Lewis acid-assisted Br?nsted acid (LBA), which is prepared from a 1:2 M mixture of boric acid and tetrachlorocatechol, is effective for the Ritter reaction from alcohols and nitriles to amides.
A CONVENIENT METHOD FOR THE SYNTHESIS OF CARBOXAMIDES AND PEPTIDES BY THE USE OF TETRABUTYLAMMONIUM SALTS
Watanabe, Yutaka,Mukaiyama, Teruaki
, p. 285 - 288 (2007/10/02)
Various carboxamides and peptides are prepared in good yields by treatment of free acids and amines in H2O-dichloromethane or aqueous THF with bis(o-nitrophenyl) phenylphosphonate in the presence of tetrabutylammonium hydrogen sulfate or bromide.Carboxylic esters are also successfully converted to amides via carboxylate salts in one-pot.
