78172-94-8Relevant academic research and scientific papers
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.
Oxidative Amidation of Nitroalkanes with Amine Nucleophiles using Molecular Oxygen and Iodine
Li, Jing,Lear, Martin J.,Kawamoto, Yuya,Umemiya, Shigenobu,Wong, Alice R.,Kwon, Eunsang,Sato, Itaru,Hayashi, Yujiro
supporting information, p. 12986 - 12990 (2015/11/02)
The formation of amides and peptides often necessitates powerful yet mild reagent systems. The reagents used, however, are often expensive and highly elaborate. New atom-economical and practical methods that achieve such goals are highly desirable. Ideally, the methods should start with substrates that are readily available in both chiral and non-chiral forms and utilize cheap reagents that are compatible with a wide variety of functional groups, steric encumberance, and epimerizable stereocenters. A direct oxidative method was developed to form amide and peptide bonds between amines and primary nitroalkanes simply by using I2 and K2CO3 under O2. Contrary to expectations, a 1:1 halogen-bonded complex forms between the iodonium source and the amine, which reacts with nitronates to form α-iodo nitroalkanes as precursors to the amides.
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.
N-alkyl-4-boronopyridinium salts as thermally stable and reusable amide condensation catalysts
Maki, Toshikatsu,Ishihara, Kazuaki,Yamamoto, Hisashi
, p. 5043 - 5046 (2007/10/03)
(Chemical Equation Presented) N-Alkyl-4-boronopyridinium salts are highly effective and reusable catalysts for the dehydrative amide condensation reaction between equimolar mixtures of carboxylic acids and amines. N- Alkylboronopyridinium salts are thermally stabilized in the order N-alkyl-2-boronopyridinium salt ? N-alkyl-3-boronopyridinium salt N-alkyl-4-boronopyridinium salt. Homogeneous catalysts, such as 4-borono-N-methylpyridinium iodide, are more effective in the presence of ionic liquid and can be recovered by extraction with ionic liquid. In contrast, heterogeneous catalysts, such as polystyrene-bound 4-boronopyridinium salts, are effective even in the absence of ionic liquid and can be recovered by filtration.
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.
