20172-29-6Relevant academic research and scientific papers
Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
, p. 15890 - 15895 (2021/05/19)
A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
Organocatalytic and enantioselective [4+2] cyclization between hydroxymaleimides and: Ortho -hydroxyphenyl para -quinone methide-selective preparation of chiral hemiketals
Xiang, Min,Li, Chen-Yi,Song, Xiang-Jia,Zou, Ying,Huang, Zhi-Cheng,Li, Xia,Tian, Fang,Wang, Li-Xin
supporting information, p. 14825 - 14828 (2020/12/07)
A cinchona alkaloid squaramide promoted enantioselective [4+2] cyclization between hydroxymaleimides and ortho-hydroxyphenyl p-QMs has been disclosed, and a wide range of chiral hemiketals containing chromane and succinimide frameworks with two adjacent quaternary stereogenic centers have been prepared for the first time with excellent results (up to 99% yield, up to 99?:?1 dr, up to >99% ee) under mild conditions. This journal is
Switching from biaryl formation to amidation with convoluted polymeric nickel catalysis
Sen, Abhijit,Dhital, Raghu N.,Sato, Takuma,Ohno, Aya,Yamada, Yoichi M.A.
, p. 14410 - 14418 (2020/12/21)
A stable, reusable, and insoluble poly(4-vinyl-pyridine) nickel catalyst (P4VP-NiCl2) was prepared through the molecular convolution of poly(4-vinylpyridine) (P4VP) and nickel chloride. We proposed a coordination structure of the Ni center in the precatalyst based on elemental analysis and Ni K-edge XANES, and we confirmed that it is consistent with Ni K-edge EXAFS. The Suzuki?Miyaura-type coupling of aryl halides and arylboronic esters proceeded using P4VP-NiCl2 (0.1 mol % Ni) to give the corresponding biaryl compounds in up to 94% yield. Surprisingly, when the same reaction of aryl halides and arylboronic acid/ester was carried out in the presence of amides, the amidation proceeded predominantly to give the corresponding arylamides in up to 99% yield. In contrast, the reaction of aryl halides and amides in the absence of arylboronic acid/ester did not proceed. P4VP-NiCl2 successfully catalyzed the lactamization for preparing phenanthridinone. P4VP-NiCl2 was reused five times without significant loss of catalytic activity. Pharmaceuticals, natural products, and biologically active compounds were synthesized efficiently using P4VPNiCl2 catalysis. Nickel contamination in the prepared pharmaceutical compounds was not detected by ICP-MS analysis. The reaction was scaled to multigrams without any loss of chemical yield. Mechanistic studies for both Suzuki?Miyaura and amidation were performed.
Palladium-Catalyzed α-Arylation of Carboxylic Acids and Secondary Amides via a Traceless Protecting Strategy
He, Zhi-Tao,Hartwig, John F.
supporting information, p. 11749 - 11753 (2019/08/26)
A novel traceless protecting strategy is presented for the long-standing challenge of conducting the palladium-catalyzed α-arylation of carboxylic aids and secondary amides with aryl halides. Both of the presented coupling processes occur with a variety of carboxylic acids and amides and with a variety of aryl bromides containing a broad range of functional groups, including base-sensitive functionality like acyl, alkoxycarbonyl, nitro, cyano, and even hydroxyl groups. Five commercial drugs were prepared through this method in one step in 81-96% yield. Gram-scale synthesis of medication Naproxen and Flurbiprofen with low palladium loading further highlights the practical value of this method.
Au(i)/Au(iii)-Catalyzed C-N coupling
Rodriguez, Jessica,Adet, Nicolas,Saffon-Merceron, Nathalie,Bourissou, Didier
supporting information, p. 94 - 97 (2019/12/25)
Cycling between Au(i) and Au(iii) is challenging, so gold-catalyzed cross-couplings are rare. The (MeDalphos)AuCl complex, which we showed was prone to undergo oxidative addition, is reported here to efficiently catalyze the C-N coupling of aryl iodides and amines. The transformation does not require an external oxidant or a directing group. It is robust and works with a wide scope of aryl iodides and N-nucleophiles under mild conditions. Mechanistic studies, including the NMR and MS characterization of a key aryl amido Au(iii) complex, strongly support a 2e redox cycle in which oxidative addition precedes transmetalation and reductive elimination is the rate-determining step.
Convenient metal-free direct oxidative amidation of aldehyde using dibromoisocyanuric acid under mild conditions
Kang, Soosung,La, Minh Thanh,Kim, Hee-Kwon
supporting information, p. 3541 - 3546 (2018/08/29)
A facile method for the direct synthesis of amides from aldehydes is described. Amide bonds were synthesized by an oxidative amidation in the presence of dibromoisocyanuric acid (DBI). Treatment of aromatic and aliphatic aldehydes with dibromoisocyanuric acid generated acyl bromide intermediates, which were employed to react with a variety of secondary and primary amines to give amides. Through this reaction method, various amides were synthesized directly from aldehydes under mild conditions in high yields and short times. This facile and efficient procedure provides potential strategy for the direct synthesis of amides from aldehydes.
Organocatalytic Asymmetric Annulation between Hydroxymaleimides and Nitrosoarenes: Stereoselective Preparation of Chiral Quaternary N-Hydroxyindolines
Yang, Yu,Ren, Hong-Xia,Chen, Feng,Zhang, Zheng-Bing,Zou, Ying,Chen, Chao,Song, Xiang-Jia,Tian, Fang,Peng, Lin,Wang, Li-Xin
supporting information, p. 2805 - 2808 (2017/06/07)
An unusual and highly effective asymmetric annulation of nitrosoarenes with hydroxymaleimides catalyzed by a chiral bifunctional amine squaramide catalyst has been disclosed. A wide range of highly fused chiral N-hydroxyindolines with two consecutive quaternary stereocenters and multifunctional groups were directly and effectively prepared in excellent yields (up to >99%) with complete regioselective cyclization and excellent stereoselectivities (up to >99:1 dr and >99% ee). The efficiency and potentials of the new reaction and the target chiral entities were well demonstrated by delicate transformations into a series of new chiral indolines.
N-Acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides: Highly selective and efficient reagents for acylation of amines in water
Ebrahimi, Sara,Saiadi, Safoura,Dakhilpour, Simin,Mirsattari, Seyed Nezamoddin,Massah, Ahmad Reza
, p. 95 - 104 (2016/04/26)
A variety of N-acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides (1a-e) were synthesized in one pot from 4-chloroaniline under solvent-free conditions and have been developed as chemoselective N-acylation reagents. Selective protection of primary amines in the presence of secondary amines, acylation of aliphatic amines in the presence of aryl amines, and monofunctionalization of primary-secondary diamines as well as selective N-acylation of amino alcohols using these reagents are described. All of the acylation reactions were carried out in water as a green solvent. High stability and easy preparation of these acylating reagents are other advantages of this method.
One pot preparation of amides from azo compounds by Sm/TiCl4
Li, Xue,Zhang, Yong-Min
, p. 1219 - 1222 (2007/10/03)
Azo compounds were conveniently reduced by a system consisting of Sm/TiCl4 to produce aniline anions. This anion species reacted smoothly with aliphatic acyl chlorides or acid anhydrides to afford corresponding amides under mild and neutral conditions.
