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1.
Sourav Jana Sadhanendu Samanta Avik K. Bagdi Valerii Z. Shirinian Alakananda Hajra 《RSC advances》2018,8(22):12360
A simple and efficient metal-free arylation of imidazo[1,2-a]pyridines at the C-3 position with arylhydrazine has been achieved at room temperature under ambient air conditions. Various 2,3-disubstituted imidazopyridines and imidazothiazoles were synthesized with high yields. The present methodology demonstrates the usefulness of commercially available aryl hydrazine as an arylating agent.Metal-free C–H arylation of imidazo[1,2-a]pyridines at C-3 position with arylhydrazines in presence of DBU has been developed at room temperature under ambient air. 相似文献
2.
In this study, Cp*Co(iii)-catalyzed site-selective amidation of pyridones and isoquinolones using oxazolones as the amidation reagent is reported. This approach features mild conditions, high efficiency and good functional tolerance. Furthermore, gram-scale preparation and preliminary mechanism experiments were carried out. It provides a straightforward approach for the direct modification of pyridone derivatives.In this study, Cp*Co(iii)-catalyzed site-selective amidation of pyridones and isoquinolones using oxazolones as the amidation reagent is reported. 相似文献
3.
A site-selective ruthenium-catalyzed keto group assisted C–H bond activation of 2-aryl tetrahydroquinoline (azaflavanone) derivatives has been achieved with a variety of alkenes for the first time. A wide range of substrates was utilized for the synthesis of a wide variety of alkenylated azaflavanones. This simple and efficient protocol provides the C5-substituted azaflavanone derivatives in high yields with a broad range of functional group tolerance. Further, the C5-alkenylated products were converted into substituted 2-aryl quinoline derivatives in good yields.A site-selective ruthenium-catalyzed keto group assisted C–H bond activation of 2-aryl tetrahydroquinoline (azaflavanone) derivatives has been achieved with a variety of alkenes for the first time. 相似文献
4.
A visible-light-mediated method for the construction of N-monoalkylated products from easily available benzamides and benzyl alcohol in the presence of eosin Y has been developed. The reaction proceeded smoothly, for a wide range of derivatives of benzamides and benzyl alcohols, to give the desired products in good to excellent yields. Biological studies, such as those on drug-likeness and molecular docking, are carried out on the molecules.A visible-light-mediated method for the construction of N-monoalkylated products from easily available benzamides and benzyl alcohol in the presence of eosin Y has been developed. 相似文献
5.
Xiuling Chen Siying Hu Rongxing Chen Jian Wang Minghu Wu Haibin Guo Shaofa Sun 《RSC advances》2018,8(9):4571
An efficient Fe-catalyzed esterification of primary, secondary, and tertiary amides with various alcohols for the preparation of esters was performed. The esterification process was accomplished with FeCl3·6H2O, which is a stable, inexpensive, environmentally friendly catalyst with high functional group tolerance.An efficient Fe-catalyzed esterification of primary, secondary, and tertiary amides with various alcohols was performed. Esterification was accomplished with inexpensive, environmentally friendly FeCl3·6H2O, and with high functional group toleranceThe amide bond is not only employed as an important natural peptide skeleton in biological systems, but also as a versatile functional group in organic transformations.1,2 Among amide transformations,3,4 transamidation and esterification of amides have attracted widespread attention from organic chemists.5–11 In contrast to transamidation of amides, esterification of amides is relatively difficult because of the low nucleophilicity of alcohols compared with amines.12 To overcome this shortcoming, various processes for the esterification of amides have been developed, such as using an activating agent,6 employing twisted amides,7 and forming intramolecular assisted groups.8 For increasing the synthetic flexibility of esterification of amides, new catalytic systems Zn(OTf)2 and Sc(OTf)3 were developed by Mashima and Williams for the esterification of amides.9 Shimizu et al. reported CeO2 catalyzed esterification of amides.10 Off late, progress of the significant Ni-catalyzed esterification of amides has gained precedence.11 Although this approach produces satisfactory yield, the drawbacks such as the use of an expensive catalyst, generation of reagent waste, high temperature and the limited scope of the substrate still persists. Herein, under mild reaction conditions, we report a novel and efficient Fe-catalyzed esterification of amides for the synthesis of esters (eqn (1)). Compared to conventional methods, this esterification procedure is distinguished by using a stable, inexpensive, environment-friendly catalyst, i.e., FeCl3·6H2O with a low toxicity solvent. The catalytic system has wide functional group compatibility. The reactions of several primary, secondary, and tertiary amides with various alcohols have been well tolerated in this process. Moreover, esters were also as effective as esterification reagents for the esterification of amides by the acyl–acyl exchange process. In the course of our present study, a Co-catalyzed amide C–N cleavage to form esters was reported by Danoun et al.13 However, an additional additive (Bipy) and Mn (3 equiv.) were needed and the scope of the reaction was limited to only tertiary amides; primary or secondary amides were not compatible with this catalytic oxidation system.1We initially selected benzamide 1a and ethanol 2a as model substrates to screen the reaction conditions, and the results are summarized in Entry Catalyst (20%) Additive (40%) Yieldb 1 FeCl2 — 31 2 FeCl3 — 31 3 FeBr3 — 25 4 FeSO4·7H2O — 20 5 Fe(NO3)3·9H2O — 20 6 FeCl3·6H2O — 35 7 CuCl2 — Trace 8 PdCl2 — Trace 9 Ni2Cl·6H2O — Trace 10 — — — 12 FeCl3·6H2O Pyridine Trace 13 FeCl3·6H2O 1,10-Phenanthroline Trace 14 FeCl3·6H2O Formic acid Trace 15 FeCl3·6H2O l-Proline Trace 16 FeCl3·6H2O H2SO4 22 17 FeCl3·6H2O HNO3 25 18 FeCl3·6H2O HCl 91 19 — HCl 35 20c FeCl3·6H2O HCl Trace 21d FeCl3·6H2O HCl 36 22e FeCl3·6H2O HCl 28 23f FeCl3·6H2O HCl 40