Synthesis of 3-Sulfenylindoles from Indoles and Various Sulfenylation Agents through Aerobic Oxidative C–S Bond Coupling

Synlett ◽  
2018 ◽  
Vol 29 (14) ◽  
pp. 1914-1920 ◽  
Author(s):  
Meichao Li ◽  
Zhenlu Shen ◽  
Chaorong Xu ◽  
Shanli Yi ◽  
Xinquan Hu ◽  
...  

A novel aerobic catalytic oxidation system for the sulfenylation of indoles with a variety of sulfenylation agents through oxidative C–S bond coupling has been successfully developed. The reactions were performed with potassium iodide as the catalyst, sodium nitrite as the co-catalyst, and molecular oxygen as the terminal oxidant in the presence of acetic acid. Under the optimal reaction conditions, a number of indoles could be sulfenylated with Bunte salts, thiols, or disulfides to generate 3-sulfenylindoles in good yields. This protocol provided an efficient and environmentally benign strategy for the synthesis of 3-sulfenylindoles.

2021 ◽  
Vol 903 ◽  
pp. 143-148
Author(s):  
Svetlana Cornaja ◽  
Svetlana Zhizhkuna ◽  
Jevgenija Vladiko

Supported 3wt%Pd/α-Al₂O₃ catalyst was tested in selective oxidation of 1,2-propanediol by molecular oxygen. It was found that the catalyst is active in an alkaline water solution. Lactic acid was obtained as the main product of the reaction. Influence of different reaction conditions on 1,2-PDO conversion and oxidation process selectivity was studied. Partial kinetic orders of the reaction with respect to 1,2-propanediol, c0(NaOH), p(O2), n(1,2-PDO)/n(Pd)) were determined and an experimental kinetic model of the catalytic oxidation reaction was obtained. Activation energy of the process was calculated and was found to be about 53 ± 5 kJ/mol.


2017 ◽  
Vol 41 (2) ◽  
pp. 88-92
Author(s):  
Shenggui Liu ◽  
Rongkai Pan ◽  
Wenyi Su ◽  
Guobi Li ◽  
Chunlin Ni

2,6-Bis[1-(pyridin-2-yl)-1H-benzo[d]-imidazol-2-yl]pyridine (bpbp), which has been synthesised by intramolecular thermocyclisation of N2,N6-bis[2-(pyridin-2-ylamino)phenyl]pyridine-2,6-dicarboxamide, reacts with sodium pyridine-2,6-dicarboxylate (pydic) and RuCl3 to give [Ru(bpbp)(pydic)] which can catalyse the oxidation of (1H-benzo[d]imidazol-2-yl)methanol to 1H-benzo[d]imidazole-2-carbaldehyde by H2O2. The optimal reaction conditions were: molar ratios of catalyst to substrate to H2O2 set at 1: 1000: 3000; reaction temperature 50 °C; reaction time 5 h. The yield of (1H-benzo[d]imidazol-2-yl) methanol was 70%.


Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1281 ◽  
Author(s):  
Yongwei Ju ◽  
Zhongtian Du ◽  
Chuhong Xiao ◽  
Xingfei Li ◽  
Shuang Li

Selective oxidation of α-hydroxy esters is one of the most important methods to prepare high value-added α-keto esters. An efficient catalytic system consisting of Zn(NO3)2/VOC2O4 is reported for catalytic oxidation of α-hydroxy esters with molecular oxygen. Up to 99% conversion of methyl DL-mandelate or methyl lactate could be facilely obtained with high selectivity for its corresponding α-keto ester under mild reaction conditions. Zn(NO3)2 exhibited higher catalytic activity in combination with VOC2O4 compared with Fe(NO3)3 and different nitric oxidative gases were detected by situ attenuated total reflection infrared (ATR-IR) spectroscopy. UV-vis and ATR-IR results indicated that coordination complex formed in Zn(NO3)2 in CH3CN solution was quite different from Fe(NO3)3; it is proposed that the charge-transfer from Zn2+ to coordinated nitrate groups might account for the generation of different nitric oxidative gases. The XPS result indicate that nitric oxidative gas derived from the interaction of Zn(NO3)2 with VOC2O4 could be in favor of oxidizing VOC2O4 to generate active vanadium (V) species. It might account for different catalytic activity of Zn(NO3)2 or Fe(NO3)3 combined with VOC2O4. This work contributes to further development of efficient aerobic oxidation under mild reaction conditions.


2015 ◽  
Vol 13 (28) ◽  
pp. 7599-7613 ◽  
Author(s):  
H. Iida ◽  
Y. Imada ◽  
S.-I. Murahashi

Using simple riboflavin related compounds as biomimetic catalysts, catalytic oxidation of various substrates with hydrogen peroxide or molecular oxygen can be performed selectively under mild conditions. The principle of these reactions is fundamental and will provide a wide scope for environmentally benign future practical methods.


2014 ◽  
Vol 997 ◽  
pp. 51-56
Author(s):  
Feng Xu ◽  
Chuang Li ◽  
Shao Yang Jia

A set of experimental system was self-designed and made for liquid phase catalytic oxidation of gas to methanol. It was used to investigate the impacts of catalyst and reaction conditions on catalytic oxidation of gas to methanol in acetic acid solution, and to analyze its reaction mechanism. It has been showed that the yield of the methanol is 1840 μmol under the catalysis of 0.5 g of 0.5% Pd-CuPc/Y and the following conditions: CH3COOH:H2O = 4:1 (v/v), 1000 μmol of p-benzoquinone; reaction time, 3 h; reaction temperature, 150°C; gas composition, 2.5MPa CH4+0.4MPaO2 +0.4MPa N2; in acetic acid solution, catalytic oxidation of mine gas to methanol follows mechanisms of electrophilic substitution and oxidation of reactive oxygen species (ROS).


2013 ◽  
Vol 781-784 ◽  
pp. 182-185 ◽  
Author(s):  
Sheng Chun Yang ◽  
Jia Qiang Wang

A novel method for the catalytic oxidation of o-chlorotoluene (OCT) to o-chlorobenzaldehyde (CBD) was proposed using vanadium doped anatase mesoporous TiO2 (V/MTiO2), the catalytic reaction conditions were investigated. Under the optimum catalytic reaction conditions: 10 mL of acetic acid 100 °C of reaction temperature, 10 h of reaction time and 100 mg of catalyst, the conversion rate of OCT could reach to 95.3%, with a selectivity of 63.5%.


2020 ◽  
Vol 98 (11) ◽  
pp. 667-669
Author(s):  
Xiao-Yu Zhou ◽  
Xia Chen

Herein, we described a ruthenium catalyzed oxidation and C–C bond formation reaction of 2-alkyl or 2-aryl substituted indoles using tert-butyl hydroperoxide (TBHP) as oxidant. Coupled with cascade transformation, it provided a mild catalytic oxidation system for the synthesis of 2-indolylindolin-3-ones. The reaction could readily occur using RuCl3·3H2O as catalyst, and the target product was obtained with medium to high yield.


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