Semi-catalytic reduction of secondary amides to imines and aldehydes
作者:Sun-Hwa Lee、Georgii I. Nikonov
DOI:10.1039/c4dt00372a
日期:——
Ruthenium catalyzed reduction of iminoyl chlorides by HSiMe2Ph allows for a two-step conversion of secondary amides into imines and aldehydes.
钌催化的HSiMe2Ph还原亚胺酰氯,实现了将二级酰胺转化为亚胺和醛的两步反应。
METHOD FOR THE CATALYTIC REDUCTION OF ACID CHLORIDES AND IMIDOYL CHLORIDES
申请人:Nikonov Georgii
公开号:US20140228579A1
公开(公告)日:2014-08-14
The present application relates to methods for the catalytic reduction of acid chlorides and/or imidoyl chlorides. The methods comprise reacting the acid chloride or imidoyl chloride with a silane reducing agent in the presence of a catalyst such as [Cp(Pr
i
3
P)Ru(NCMe)
2
]
+
[PF
6
]
−
.
Photochemical Activation of Aromatic Aldehydes: Synthesis of Amides, Hydroxamic Acids and Esters
作者:Nikolaos F. Nikitas、Mary K. Apostolopoulou、Elpida Skolia、Anna Tsoukaki、Christoforos G. Kokotos
DOI:10.1002/chem.202100655
日期:2021.5.20
the activation of aromatic aldehydes has been developed. Utilizing thioxanthen-9-one as the photocatalyst and cheap household lamps as the light source, a variety of aromatic aldehydes have been activated and subsequently converted in a one-pot reaction into amides, hydroxamic acids and esters in good to high yields. The applicability of this method was highlighted in the synthesis of Moclobemide, a
The α-Effect in Hydrazinolysis of 4-Chloro-2-Nitrophenyl X-Substituted-Benzoates: Effect of Substituent X on Reaction Mechanism and the α-Effect
作者:Min-Young Kim、Tae-Eun Kim、Jieun Lee、Ik-Hwan Um
DOI:10.5012/bkcs.2014.35.8.2271
日期:2014.8.20
Second-order rate constants ($k_N$) have been measured spectrophotometrically for the reaction of 4-chloro-2-nitrophenyl X-substituted-benzoates (6a-6h) with a series of primary amines including hydrazine in 80 mol % $H_2O$/20 mol % DMSO at $25.0^\circ}C$. The Br$\o}$nsted-type plot for the reaction of 4-chloro-2-nitrophenyl benzoate (6d) is linear with $\beta}_nuc}$ = 0.74 when hydrazine is excluded from the correlation. Such a linear Br$\o}$nsted-type plot is typical for reactions reported previously to proceed through a stepwise mechanism in which expulsion of the leaving group occurs in the rate-determining step (RDS). The Hammett plots for the reactions of 6a-6h with hydrazine and glycylglycine are nonlinear. In contrast, the Yukawa-Tsuno plots exhibit excellent linear correlations with $\rho}_X$ = 1.29-1.45 and r = 0.53-0.56, indicating that the nonlinear Hammett plots are not due to a change in RDS but are caused by resonance stabilization of the substrates possessing an electron-donating group (EDG). Hydrazine is ca. 47-93 times more reactive than similarly basic glycylglycine toward 6a-6h (e.g., the $\alpha}$-effect). The $\alpha}$-effect increases as the substituent X in the benzoyl moiety becomes a stronger electron-withdrawing group (EWG), indicating that destabilization of the ground state (GS) of hydrazine through the repulsion between the nonbonding electron pairs on the two N atoms is not solely responsible for the substituent-dependent $\alpha}$-effect. Stabilization of transition state (TS) through five-membered cyclic TSs, which would increase the electrophilicity of the reaction center or the nucleofugality of the leaving group, contributes to the $\alpha}$-effect observed in this study.
Sulfur-Fluoride Exchange (SuFEx)-Mediated Synthesis of Sterically Hindered and Electron-Deficient Secondary and Tertiary Amides via Acyl Fluoride Intermediates
作者:Christopher J. Smedley、Andrew S. Barrow、Christian Spiteri、Marie-Claire Giel、Pallavi Sharma、John E. Moses
DOI:10.1002/chem.201701552
日期:2017.7.26
Amide bond formation is one of the most executed reactions in chemistry and biology. This is largely due to the ubiquity of the amide functional group in biological molecules, natural products and pharmaceutically important drugs. We report here the development of “SuFExAmide”: a new sulfur–fluoride exchange (SuFEx) click chemistry based protocol for the efficient amidation of carboxylic acids via