1629-92-1Relevant academic research and scientific papers
Method for preparing benzothiazole compound from visible light promoted N-(2-bromophenyl) thioamide
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Paragraph 0052-0054, (2021/06/22)
The invention discloses a method for preparing a benzothiazole compound from N-(2-bromophenyl) thioamide under the promotion of visible light. Specifically, under the protection of inert gas, according to the molar ratio of N-(2-bromophenyl) thioamide to inorganic base being 1: 0.5, reactants are added into a reaction container provided with a stirring device, then dimethyl sulfoxide is added, and stirring reaction is carried out for 2-24 hours at room temperature under the irradiation of visible light to obtain the benzothiazole compound. Under the condition of not adding any photosensitizer or transition metal catalyst, sodium phosphate is used as alkali, and under the irradiation of a 45W household compact fluorescent lamp, a series of intramolecular cross-coupling reactions of N-(2-bromophenyl) thioamide are realized. In addition, the benzothiazole compound can be obtained with high yield. The whole process is green, efficient and easy to operate, and the method is a good method for synthesizing the benzothiazole compound.
Photocatalyst- And Transition-Metal-Free Visible-Light-Promoted Intramolecular C(sp2)-S Formation
Wang, Hao,Wu, Qi,Zhang, Jian-Dong,Li, Hai-Yan,Li, Hong-Xi
, p. 2078 - 2083 (2021/04/05)
A photocatalyst- and transition-metal-free visible-light-induced cyclization of ortho-halothiobenzanilides has been developed. Upon irradiation with visible light, substrates undergo dehalogenative cyclization to 2-aryl benzothiazoles with high efficiency and selectivity. This photocyclization exhibits a high tolerance to various functional groups, is applicable for the synthesis of 2-alkyl benzothiazoles, and is easy to set up for gram-scale reaction.
Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C-H Thiolation via Reverse Hydrogen Atom Transfer
Xu, Ze-Ming,Li, Hong-Xi,Young, David James,Zhu, Da-Liang,Li, Hai-Yan,Lang, Jian-Ping
, p. 237 - 241 (2019/01/10)
Visible-light-driven, intramolecular C(sp2)-H thiolation has been achieved without addition of a photosensitizer, metal catalyst, or base. This reaction induces the cyclization of thiobenzanilides to benzothiazoles. The substrate absorbs visible light, and its excited state undergoes a reverse hydrogen-atom transfer (RHAT) with 2,2,6,6-tetramethylpiperidine N-oxyl to form a sulfur radical. The addition of the sulfur radical to the benzene ring gives an aryl radical, which then rearomatizes to benzothiazole via RHAT.
Palladium-catalyzed C-H cyclization in water: A milder route to 2-arylbenzothiazoles
Inamoto, Kiyofumi,Nozawa, Kanako,Kondo, Yoshinori
, p. 1678 - 1682 (2012/07/17)
Water was successfully employed as a reaction medium in palladium-catalyzed C-H cyclization of thiobenzanilides. Reactions efficiently proceeded under considerably mild conditions such as 40 °C in water, providing a more practical, greener method for the synthesis of 2-arylbenzothiazoles. For some substrates, the addition of an amphiphilic surfactant greatly enhanced the process. The method represents a rare example of palladium-catalyzed C-H functionalization processes performed in water. Georg Thieme Verlag Stuttgart · New York.
Aerobic visible-light photoredox radical C-H functionalization: Catalytic synthesis of 2-substituted benzothiazoles
Cheng, Yannan,Yang, Jun,Qu, Yue,Li, Pixu
supporting information; experimental part, p. 98 - 101 (2012/02/04)
An aerobic visible-light driven photoredox catalytic formation of 2-substituted benzothiazoles through radical cyclization of thioanilides has been accomplished. The reaction features C-H functionalization and C-S bond formation with no direct metal involvement except the sensitizer. The reaction highlights the following: (1) visible-light is the reaction driving force; (2) molecular oxygen is the terminal oxidant, and (3) water is the only byproduct.
Use of molecular oxygen as a reoxidant in the synthesis of 2-substituted benzothiazoles via palladium-catalyzed C-H functionalization/intramolecular C-S bond formation
Inamoto, Kiyofumi,Hasegawa, Chisa,Kawasaki, Junpei,Hiroya, Kou,Doi, Takayuki
experimental part, p. 2643 - 2655 (2010/12/25)
Molecular oxygen (O2) was successfully employed as a reoxidant in cyclizations of thiobenzanilides 1a-s through a palladium-catalyzed C-H functionalization/intramolecular C-S bond formation process, leading to an efficient, green method for the synthesis of 2-arylbenzothiazoles 2a-s. Addition of cesium fluoride (CsF) greatly enhanced the reactions, which produced variously substituted 2-arylbenzothiazoles with good functional group tolerance. Thioureas 4a-j were also found to be suitable substrates for the cyclization process using a palladium/O2 catalyst system, thus generating 2-aminobenzothiazoles 5a-j. One-pot syntheses of 2-aminobenzothiazoles 5a-j from aryl isothiocyanates 6 and amines 7 were also successful.
Palladium-catalyzed synthesis of 2-substituted benzothiazoles via a C-H functionalization/intramolecular C-S bond formation process
Inamoto, Kiyofumi,Hasegawa, Chisa,Hiroya, Kou,Doi, Takayuki
supporting information; experimental part, p. 5147 - 5150 (2009/05/30)
(Chemical Equation Presented) Catalytic synthesis of 2-substituted benzothiazoles from thiobenzanilides was achieved in the presence of a palladium catalyst through C-H functionalization/C-S bond formation. This method features the use of a novel catalytic system consisting of 10 mol % of Pd(II), 50 mol % of Cu(I), and 2 equiv of Bu4NBr that produced variously substituted benzothiazoles in high yields with good functional group tolerance.
