19654-14-9Relevant academic research and scientific papers
α-Keto Acids as Triggers and Partners for the Synthesis of Quinazolinones, Quinoxalinones, Benzooxazinones, and Benzothiazoles in Water
Huang, Jian,Chen, Wei,Liang, Jiazhi,Yang, Qin,Fan, Yan,Chen, Mu-Wang,Peng, Yiyuan
, p. 14866 - 14882 (2021/10/25)
A general and efficient method for the synthesis of quinazolinones, quinoxalinones, benzooxazinones, and benzothiazoles from the reactions of α-keto acids with 2-aminobenzamides, benzene-1,2-diamines, 2-aminophenols, and 2-aminobenzenethiols, respectively, is described. The reactions were conducted under catalyst-free conditions, using water as the sole solvent with no additive required, and successfully applied to the synthesis of sildenafil. More importantly, these reactions can be conducted on a mass scale, and the products can be easily purified through filtration and washing with ethanol (or crystallized).
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.
Method for preparing benzothiazole compound from visible light promoted N-(2-bromophenyl) thioamide
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Paragraph 0091-0093, (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.
NCS/TBHP promoted C2 arylation of benzothiazoles with aldehydes in DMSO
Xu, Wen-Xiu,Ye, Fei-Xia,Liu, Xing-Hai,Weng, Jian-Quan
, (2020/03/19)
A N-chlorosuccinimide catalyzed oxidative synthesis of 2-aryl benzothiazole from benzothiazoles and aryl aldehydes using tert-butyl peroxybenzoate as an oxidant in dimethyl sulfoxide (DMSO) has been developed in moderate to good yields. Solvent DMSO as a strong Lewis base plays an efficient role in the reaction. Various substrates were tolerated under optimized conditions affording the arylated products in 12–94% yields for 28 examples. Additionally, acylated benzothiazoles were produced with 4 examples.
Preparation method of substituted benzothiazole C2 arylated derivative
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Paragraph 0043-0044, (2020/05/02)
The invention discloses a substituted benzothiazole C2 arylated derivative and a preparation method thereof. The preparation method comprises the following steps: mixing substituted benzothiazole represented by a formula (II) and substituted benzaldehyde represented by a formula (III); adding a free radical initiator N-chlorosuccinimide (NCS) and an oxidant tert-butyl hydroperoxide (TBHP), carrying out a stirring reaction for about 12 h at 120 DEG C in a nitrogen atmosphere by using DMSO as a solvent, and after the reaction is finished, separating and purifying the reaction liquid to prepare the substituted benzothiazole C2 arylated derivative represented by a formula (I). The invention provides a new method for synthesizing a benzothiazole C2 arylated derivative by taking an NCS/TBHP double component as an oxidation system through a stirring and reaction for about 12 hours at 120 DEG C in a nitrogen atmosphere under the assistance of a strong Lewis base DMSO; and according to the method, an NCS/TBHP double-component oxidation system and an aprotic solvent are selected, and the method has the advantages of being simple in catalytic system, good in product yield and wide in substrate range.
Photoinduced Heterogeneous C?H Arylation by a Reusable Hybrid Copper Catalyst
Choi, Isaac,Müller, Valentin,Lole, Gaurav,K?hler, Robert,Karius, Volker,Vi?l, Wolfgang,Jooss, Christian,Ackermann, Lutz
supporting information, p. 3509 - 3514 (2020/03/03)
Heterogeneous copper catalysis enabled photoinduced C?H arylations under exceedingly mild conditions at room temperature. The versatile hybrid copper catalyst provided step-economical access to arylated heteroarenes, terpenes and alkaloid natural products with various aryl halides. The hybrid copper catalyst could be reused without significant loss of catalytic efficacy. Detailed studies in terms of TEM, HRTEM and XPS analysis of the hybrid copper catalyst, among others, supported its outstanding stability and reusability.
Synthesis of 2-substituted benzothiazoles via the Br?nsted acid catalyzed cyclization of 2-amino thiophenols with nitriles
Yu, Xiaoqiang,Yin, Qing,Zhang, Zhiheng,Huang, Tianyu,Pu, Zichao,Bao, Ming
supporting information, p. 1964 - 1966 (2019/06/27)
A convenient and efficient method for the synthesis of 2-substituted benzothiazoles from simple and readily available 2-amino thiophenols and nitriles is described. The Br?nsted acid-catalyzed cyclization reaction was performed under metal and solvent-free conditions.
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.
Synthesis and characterization of a new poly(N–heterocyclic carbene Cu complex) immobilized on nano–silica, (CuII–NHCs)n@nSiO2, and its application as an efficient and reusable catalyst in the synthesis of benzimidazoles,
Khajehzadeh, Mostafa,Moghadam, Majid,Jamehbozorgi, Saeed
, p. 173 - 189 (2018/10/21)
The present study describes the synthesis and characterization of a new poly(N–heterocyclic carbene Cu complex) immobilized on nano silica, (CuII–NHCs)n@nSiO2. The (CuII–NHCs)n@nSiO2 dendri
Method for synthesizing benzothiazole by microwave radiation of benzothioamide compound in aqueous phase
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Paragraph 0013; 0058, (2019/02/13)
The invention discloses a method for synthesizing benzothiazole by microwave radiation of a benzothioamide compound in an aqueous phase. The method includes the steps: adding the benzothioamide compound into the aqueous phase under microwave conditions; performing cyclization under alkaline conditions to generate the benzothiazole. The method for preparing the benzothiazole is environmentally friendly, simple and convenient in operation, safe, cheap and efficient. Compared with the prior art, the method is applicable to a lot of functional groups, high in yield, few in by-products, simple in operation, safe, low in cost and environmentally friendly.
