24622-31-9Relevant academic research and scientific papers
Ionic Reactivity of 2-Isocyanoaryl Thioethers: Access to 2-Halo and 2-Aminobenzothia/Selenazoles
Dong, Jinhuan,Hu, Junlin,Liu, Xiaoli,Sun, Shaoguang,Bao, Lan,Jia, Mengying,Xu, Xianxiu
, p. 2845 - 2852 (2022/02/23)
An ionic cascade insertion/cyclization reaction of thia-/selena-functionalized arylisocyanides has been successfully developed for the efficient and practical synthesis of 2-halobenzothiazole/benzoselenazole derivatives. This synthetic protocol, incorporating a halogen atom when forming the five-membered ring of benzothia/selenazoles, is different from the existing ones, where halogenation of the preformed benzothia/selenazole precursors happens. Additionally, a facile access to 2-aminobenzothiazoles is also achieved by the one-pot cascade reaction of 2-isocyanoaryl thioethers, iodine, and amines.
Room-Temperature Amination of Chloroheteroarenes in Water by a Recyclable Copper(II)-Phosphaadamantanium Sulfonate System
Dandela, Rambabu,Desai, Aman A.,Kapdi, Anant R.,Kori, Santosh,Maity, Dilip K.,Parmar, Udaysinh,Somvanshi, Dipesh
, p. 8900 - 8925 (2021/07/20)
Buchwald-Hartwig amination of chloroheteroarenes has been a challenging synthetic process, with very few protocols promoting this important transformation at ambient temperature. The current report discusses about an efficient copper-based catalytic system (Cu/PTABS) for the amination of chloroheteroarenes at ambient temperature in water as the sole reaction solvent, a combination that is first to be reported. A wide variety of chloroheteroarenes could be coupled efficiently with primary and secondary amines as well as selected amino acid esters under mild reaction conditions. Catalytic efficiency of the developed protocol also promotes late-stage functionalization of active pharmaceutical ingredients (APIs) such as antibiotics (floxacins) and anticancer drugs. The catalytic system also performs efficiently at a very low concentration of 0.0001 mol % (TON = 980,000) and can be recycled 12 times without any appreciable loss in activity. Theoretical calculations reveal that the π-acceptor ability of the ligand PTABS is the main reason for the appreciably high reactivity of the catalytic system. Preliminary characterization of the catalytic species in the reaction was carried out using UV-VIS and ESR spectroscopy, providing evidence for the Cu(II) oxidation state.
Method for synthesizing benzothiazole by microwave radiation of benzothioamide compound in aqueous phase
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Paragraph 0013; 0022, (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.
Copper-catalyzed one-pot coupling reactions of aldehydes (ketones), tosylhydrazide and 2-amino(benzo)thiazoles: An efficient strategy for the synthesis of N-alkylated (benzo)thiazoles
Xie, Zengyang,Chen, Ruijiao,Ma, Mingfang,Kong, Lingdong,Liu, Jun,Wang, Cunde
, (2019/08/16)
An efficient and practical C–N bond formation methodology for the synthesis of N-alkylated (benzo)thiazoles was developed, via the copper-catalyzed one-pot two-step reactions of 2-amino(benzo)thiazoles and aldehydes (ketones) with tosylhydrazide. This cross-coupling reaction proceeded smoothly and tolerated a broad range of functional groups (46 examples). A variety of functionalized N-alkylated (benzo)thiazoles were obtained in moderate to high yields. Notably, gram-scale synthesis of fanetizole (anti-inflammatory drug) was also realized through this protocol.
Synthesis method of 2-aminobenzothiazole compounds
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Paragraph 0067; 0068; 0069, (2017/11/16)
The invention discloses a preparation method of 2-aminobenzothiazole compounds. The 2-aminobenzothiazole compounds is prepared from the following steps of dissolving phenyl/naphthalene isothiocyanateand primary amine into a solvent, adding a catalyst iodine and an oxidant, carrying out one-pot multi-step tandem reaction to prepare the 2-aminobenzothiazole compounds under the temperature of 80 to 150 DEG C. The synthesis method has the advantages that raw materials are cheap and easily available, the reaction condition is mild, the substrate application range is broad, atom economy is high, requirements of green chemical are met, and a novel method which is economical and practical and green and environmentally friendly is provided for synthesis of the 2-aminobenzothiazole compounds.
An aerobic oxidative coupling approach for the synthesis of N-substituted 2-aminobenzothiazole derivatives using iron catalyst
Kumar, N. V. Anil,Kamath, Shailesha,Gaonkar, Santosh L.,Shetty, Nitinkumar S.
, p. 1697 - 1702 (2016/08/06)
A facile and convenient method was developed for the formation of novel N substituted 2-aminobenzothiazoles via an iron-catalysed condensation of 2-aminobenzothizole with different amines. This method is applicable for a wide range of aliphatic, aromatic and heterocyclic amines furnishing moderate yields of the corresponding products and thus rendering the methodology as a highly eco-friendly, inexpensive alternative to the existing methods.
Iodine-catalyzed formation of substituted 2-aminobenzothiazole derivatives in PEG400
Dumonteil,Hiebel,Scherrmann,Berteina-Raboin
, p. 73517 - 73521 (2016/08/19)
An iodine-catalyzed formation of substituted 2-aminobenzothiazole derivatives is herein described using hydrogen peroxide as an oxidant in PEG400. The method enabled an efficient environmentally sound access to this valuable scaffold in moderate to excellent yields under metal-free conditions.
Convenient and reliable routes towards 2-aminothiazoles: Palladium-catalyzed versus copper-catalyzed aminations of halothiazoles
Toulot, Stephanie,Heinrich, Timo,Leroux, Frederic R.
supporting information, p. 3263 - 3272 (2013/12/04)
Two efficient methods for the amination of 2-halothiazoles are presented here. A first protocol requires a Pd/L system. Several 2-aminothiazoles were synthesized under optimized conditions and isolated in good yields. The first palladium-catalyzed C-N coupling reactions between 2-halothiazoles and primary alkylamines are presented. In a second part, ligand-free copper-catalyzed aminations of 2-halothiazoles by alkylamines and aniline in a green solvent have been developed. The protocol is very effective for primary and secondary amines and perfectly tolerates the presence of another halide moiety on the 2-halothiazole. The reaction occurs under the assistance of microwave irradiation, which drastically decreases the reaction time. The reaction leads to the formation of 2-aminothiazoles, key molecules in pharmaceutical research. Copyright
Laccase-catalysed homocoupling of primary aromatic amines towards the biosynthesis of dyes
Sousa, Ana Catarina,Martins, Lígia O.,Robalo, M. Paula
supporting information, p. 2908 - 2917 (2014/03/21)
Coloured disubstituted benzoquinonimine trimeric structures are obtained as main reaction products of the oxidation of p-electron donor pri-mary aromatic amines using two different laccases, CotA-laccase from Baccilus subtilus and TvL from Trametes versicolor. These orange-red to purple products, presenting high molar extinction coeffi-cients, presumably result from oxidative homocou-pling reactions, through the formation of N-C bonds at positions 2 and 5, of the laccase oxidised inter-mediate as showed in the proposed oxidative path-way. The product of 1,4-phenylenediamine is shown to be the trimer known as Bandrowski's base which has an established role in hair and fur dyeing. Our results also show that the occurrence and/or rates of oxidation of aromatic amines are strongly dependent on the presence of p-electron releasing substituents in the aromatic ring and are independent on the properties of the enzyme used. Overall our data con-tribute for (i) understanding key features of laccase reactivity with p-substituted aromatic amines and (ii) establishing enzymatic processes that lead to the syn-thesis of coloured bio-products under mild condi-tions with potential impact in the cosmetic and dye industries.
Cobalt-catalyzed oxidative isocyanide insertion to amine-based bisnucleophiles: Diverse synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzothiazoles, and 2-aminobenzoxazoles
Zhu, Tong-Hao,Wang, Shun-Yi,Wang, Gao-Nan,Ji, Shun-Jun
supporting information, p. 5850 - 5853 (2013/06/26)
Cobalt catalysis: Synthesis of substituted 2-aminobenzimidazoles, 2-aminobenzothiazoles, and 2-aminobenzoxazoles was achieved by using cobalt(II) acetate catalyzed isocyanide insertion to o-diaminobenzene, 2-aminobenzenethiol, and 2-aminophenol derivatives in 1,4-dioxane (see scheme). It was found that the reaction proceeded efficiently to give the desired products in up to 95 % isolated yields by C-N and C-S (O, N) formation in a single step. Copyright
