1629-75-0Relevant academic research and scientific papers
Mechanism of the CuII-catalyzed benzylic oxygenation of (aryl)(heteroaryl)methanes with oxygen
Sterckx, Hans,De Houwer, Johan,Mensch, Carl,Caretti, Ignacio,Tehrani, Kourosch Abbaspour,Herrebout, Wouter A.,Van Doorslaer, Sabine,Maes, Bert U. W.
, p. 346 - 357 (2016)
A mechanistic study of the copper-catalyzed oxidation of the methylene group of aryl(di)azinylmethanes was performed. Initial reaction rates were measured making use of in situ IR reaction monitoring and a kinetic analysis of the reaction was executed. The reaction proved to be first order in oxygen concentration. For substrate and acid concentration, saturation kinetics due to O2 mass transfer limitation were observed. The occurrence of mass transfer limitation was further confirmed by examining the effect of the stirring rate on the initial reaction rate. Interestingly, the effect of the concentration of the catalyst on the rate shows that higher loadings result in a maximal initial rate, followed initially by a steady decrease and subsequently a rate plateau when the concentration is increased further. Mass transfer limitation and increased concentration of dinuclear catalytically active species rationalizes this hitherto unprecedented rate behavior. Continuous-wave and pulsed electron paramagnetic resonance methods were used to characterize the catalytic species present in the solution during the reaction and confirmed the presence of both mono- and dinuclear copper species. Analysis of a diverse substrate scope points towards imine-enamine tautomerization as a crucial process in the oxidation reaction. DFT calculations of these equilibrium constants (pKeq) provided us with a qualitative tool to predict whether or not a substrate is viable for oxidation under the reaction conditions developed.
Silver-Assisted Oxidative Isocyanide Insertion of Ethers: A Direct Approach to β-Carbonyl α-Iminonitriles
Zhao, Leiyang,Liu, Bingxin,Tan, Qitao,Ding, Chang-Hua,Xu, Bin
, p. 9223 - 9227 (2019)
An efficient silver-assisted oxidative coupling of simple ethers with tert-butyl isocyanide was realized in the presence of DDQ. The direct synthesis of high density functional β-carbonyl α-iminonitriles was achieved in a single step with high yields through the synergetic cascade isocyanide insertion into C(sp3)-H bond, where the isocyanide was used as crucial "CN" and "C=N" sources and the tert-butoxyl group acted as the carbonyl source. Diverse reactivity of β-carbonyl α-iminonitriles has been demonstrated.
S 8-Mediated Cyclization of Bis(2-aminophenyl) Disulfide/Diselenide with Arylacetylenes/Styrenes: Access to 2-(Arylmethyl)-1,3-benzothiazoles/benzoselenazoles
Gan, Haifeng,Feng, Caojian,Zhao, Lihuan,Cao, Mengru,Wu, Hongli
, p. 70 - 75 (2021/11/17)
A novel S8-mediated approach to benzothiazoles/benzoselenazoles from bis(2-aminophenyl) disulfides/diselenides and phenylacetylenes or styrenes has been developed. 2-(Arylmethyl)-1,3-benzoselenazoles were comprehensively synthesized for the first time. The reactions proceeded in moderate to excellent yields, and with a gramscale application.
A Novel PIFA/KOH Promoted Approach to Synthesize C2-arylacylated Benzothiazoles as Potential Drug Scaffolds
Hu, Zhi-Gang,Huang, Zhen,Sun, Xiao-Tong,Weng, Jian-Quan,Zhou, Ling-Li
, (2022/01/31)
To discover an efficient and convenient method to synthesize C2-arylacylated benzothiazoles as potential drug scaffolds, a novel [bis(trifluoroacetoxy)iodo]benzene(PIFA)/KOH synergistically promoted direct ring-opening C2-arylacylation reaction of 2H-benz
Microwave-assisted controllable synthesis of 2-acylbenzothiazoles and bibenzo[b][1,4]thiazines from aryl methyl ketones and disulfanediyldianilines
Qi, Yuquan,Gu, Xiaoyu,Huang, Xianqiang,Shen, Guodong,Yang, Bingchuan,He, Qingpeng,Xue, Zechun,Du, Mengcheng,Shi, Lilong,Yu, Bing
supporting information, p. 3544 - 3547 (2021/07/02)
A condition-controlled strategy for selectively synthesis of 2-acylbenzothiazoles and bibenzo[b][1,4]thiazines from aryl methyl ketones and disulfanediyldianilines was realized using I2/DMSO or I2/MeCN systems, respectively. The desired products were synthesized in only 15 min with moderate to excellent yields (50%-90%) under microwave-assisted, metal-free conditions. The strategy provides a great advantage for selective synthetic applications in the efficient synthesis of benzothiazoles and bibenzothiazines heterocycle compounds.
Visible-light-promoted photocatalyst-free alkylation and acylation of benzothiazoles
Jiang, Pengxing,Liu, Li,Tan, Jiajing,Du, Hongguang
supporting information, p. 4487 - 4491 (2021/05/31)
Herein we report a protocol for the visible-light-mediated alkylation/acylation reaction of benzothiazoles. Alkyl/acyl substituted Hantzsch esters are easily prepared and rationally used as radical precursors. In the presence of BF3·Et2O and Na2S2O8, various benzothiazole derivatives were readily obtained in good yields. Our user-friendly protocol can proceed by simple irradiation with blue LEDs (λ = 465 nm) and without the assistance of external photocatalysts. The reaction is also characterized by mild conditions and scalability, thus offering an alternative and efficient tool for the synthesis of 2-functionalized benzothiazoles.
Oxidant/Solvent-Controlled I2-Catalyzed Domino Annulation for Selective Synthesis of 2-Aroylbenzothiazoles and 2-Arylbenzothiazoles under Metal-Free Conditions
Ma, Renchao,Ding, Yuxin,Chen, Rener,Wang, Zhiming,Wang, Lei,Ma, Yongmin
, p. 310 - 321 (2021/01/09)
A simple and practical domino protocol for the selective synthesis of 2-aroylbenzothiazoles and 2-aryl benzothiazoles catalyzed by I2 is developed under metal-free conditions. The reaction outcomes are exclusively controlled by the reaction oxidant/medium. With DMSO employed as both the solvent and the oxidant, an oxidation of aromatic methyl ketones takes precedence over the condensation with 2-aminobenzenethiols. On the other hand, when the reaction was carried out in PhNO2 or in 1,4-dioxane containing PhNO2, the condensation of aromatic methyl ketones with 2-aminobenzenethiols has priority to form imines which is followed by an oxidation of the methyl group from ketones to afford 2-arylbenzothiazoles as a sole product. The PhNO2/I2 co-catalytic system is proposed first time.
C2 substituted 2H-benzothiazole aryl acylated derivative, and synthesis method and application thereof
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Paragraph 0020-0022, (2021/07/08)
The invention discloses a C2 substituted 2H-benzothiazole aryl acylated derivative, and a synthesis method and application thereof. The preparation method of the derivative comprises the following steps: mixing substituted 2H-benzothiazole and substituted methyl benzene, adding into a solvent, in the presence of an oxidizing agent Selectfluor and an additive trifluoroacetic acid, carrying out a heating and stirring reaction in the air atmosphere, performing TLC monitoring is conducted till the reaction is finished, and separating and purifying the obtained reaction liquid to obtain the target product C2 substituted 2H-benzothiazole aryl acylated derivative. The substituted methyl benzene used in the invention is low in price, easy to obtain and good in chemical stability, the method has the advantages of being high in atom economy, simple in catalytic system, free of transition metal catalysts, good in product yield, wide in substrate range and the like, and the prepared compound structure can be further optimized as an anti-tumor drug lead.
C2-arylacylation of 2H-benzothiazoles with methyl arenes via Selectfluor oxidation
Chen, Bo,Kong, Yao-Lei,Liu, Jin-Chuan,Lu, Qi,Sun, Xiao-Tong,Weng, Jian-Quan
supporting information, (2021/06/03)
An efficient Selectfluor-oxidative protocol was developed for the direct C2-arylacylation of 2H-benzothiazoles via the radical reaction of 2H-benzothiazoles with methyl arenes. Selectfluor can effectively promote the oxidative cross-coupling without an ex
Electrochemical Oxidative Functionalization of Arylalkynes: Access to α,α-Dibromo Aryl Ketones
Wang, Dan,Wan, Zhaohua,Zhang, Heng,Lei, Aiwen
supporting information, p. 1022 - 1027 (2020/12/31)
A general and effective protocol to synthesize α,α-dibromo aryl ketones has been developed via an electrochemical oxidative method. The reaction proceeds smoothly at room temperature in an undivided cell without the addition of external oxidants. In the reaction process, LiBr acts as both bromine source and supporting electrolyte. This electrooxidation strategy has good substrate applicability and functional group compatibility. Moreover, the reaction could be scaled up efficiently in a continuous flow cell. The target product could undergo further functionalization for the synthesis of some useful heterocyclic compounds. (Figure presented.).
