- Intramolecular oxidative cyclizations in heteroarylthioureas: A versatile pathway to bridgehead heterocyclic systems
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Intramolecular oxidations in N-alkyl-N'-heteroarylthioureas represent a facile and versatile synthetic pathway to fused heterocyclic systems including the bridgehead ones. This kind of heterocycles are the main feature in commom biologically active compou
- Castro, Ana,Martinez, Ana
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- Direct N-Alkylation/Fluoroalkylation of Amines Using Carboxylic Acids via Transition-Metal-Free Catalysis
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A scalable protocol of direct N-mono/di-alkyl/fluoroalkylation of primary/secondary amines has been constructed with various carboxylic acids as coupling agents under the catalysis of a simple air-tolerant inorganic salt, K3PO4. Advantageous features include 100 examples, 10 drugs and drug-like amines, fluorinated complex tertiary amines, gram-scale synthesis and isotope-labelling amine, thus demonstrating the potential applicability in industry of this methodology. The involvement of relatively less reactive silicon-hydride compared with the traditional reactive metal-hydride or boron-hydride species required to reduce the amide intermediates presumably contributes to the remarkable functional group compatibility. (Figure presented.).
- Lu, Chunlei,Qiu, Zetian,Xuan, Maojie,Huang, Yan,Lou, Yongjia,Zhu, Yiling,Shen, Hao,Lin, Bo-Lin
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supporting information
p. 4151 - 4158
(2020/08/21)
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- Microwave assisted one pot synthesis of 2-ethylamino benzimidazole, benzoxazole and benzothiazole derivatives
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A rapid and efficient one-pot method for the synthesis of 2-ethylamino benzimidazole, benzoxazole, and benzothiazole derivatives has been described. The reaction of o-phenylenediamines or o-aminophenols or 2-mercaptoanilines with EDC.HCl under microwave irradiation afforded the corresponding 2-ethylamino benzimidazole, benzoxazole and benzothiazole derivatives in excellent yields.
- Rapolu, Thirupathi,K. V. P, Pavan Kumar,Babu, Korupolu Raghu,Dende, Satheesh Kumar,Nimmareddy, Rajashekar Reddy,Reddy, Leleti Krishnakanth
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supporting information
p. 1308 - 1315
(2019/04/30)
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- Method for synthesizing benzothiazole by microwave radiation of benzothioamide compound in aqueous phase
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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.
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Paragraph 0013; 0020
(2019/02/13)
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- Copper-catalyzed synthesis of 2-aminobenzothiazoles from carbodiimide and sodium hydrosulfide
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An efficient copper-catalyzed method for the synthesis of a variety of 2-aminobenzothiazoles has been developed. The reaction proceeded from carbodiimide and sodium hydrosulfide via a tandem reaction in the presence of copper(ii) trifluoromethanesulfonate to afford the corresponding 2-aminobenzothiazole derivatives in good to perfect yields. This journal is the Partner Organisations 2014.
- Zeng, Weilan,Dang, Pan,Zhang, Xiaoyun,Liang, Yun,Peng, Caiyun
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p. 31003 - 31006
(2014/08/05)
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- Convenient and reliable routes towards 2-aminothiazoles: Palladium-catalyzed versus copper-catalyzed aminations of halothiazoles
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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
- Toulot, Stephanie,Heinrich, Timo,Leroux, Frederic R.
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supporting information
p. 3263 - 3272
(2013/12/04)
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- Laccase-catalysed homocoupling of primary aromatic amines towards the biosynthesis of dyes
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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.
- Sousa, Ana Catarina,Martins, Lígia O.,Robalo, M. Paula
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supporting information
p. 2908 - 2917
(2014/03/21)
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- Iron-catalyzed tandem reactions of ortho-aminobenzenethiols with isothiocyanates leading to 2-aminobenzoazoles under ligand-and solvent-free conditions
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An efficient route to synthesize a variety of 2-aminobenzoazoles has been discovered. It involves the reaction of ortho-aminobenzenethiols with isothiocyanates via iron-catalyzed tandem addition-annulations process under ligand and solvent free conditions on silica gel surface. Copyright Taylor &Francis Group, LLC.
- Ding, Qiuping,Cao, Banpeng,Yang, Qin,Liu, Xianjin,Peng, Yiyuan
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experimental part
p. 1782 - 1789
(2011/10/02)
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- Synthesis of 2-aminobenzothiazole via FeCl3-catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in water
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An FeCl3-catalyzed tandem reaction of 2-iodoaniline with isothiocyanate in water is described, which provides an environmentally benign, efficient, and practical route for the generation of 2-aminobenzothiazole. This present tandem process shows broad substrate scope in the presence of octadecyltrimethylammonium chloride as a phase-transfer catalyst. In addition, the reaction media can be recovered and recycled without loss of efficiency.
- Ding, Qiuping,Cao, Banpeng,Liu, Xianjin,Zong, Zhenzhen,Peng, Yi-Yuan
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supporting information; experimental part
p. 1607 - 1610
(2010/12/19)
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- Substituted 2-aminobenzothiazoles and derivatives useful as cerebrovascular agents
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A series of substituted 2-aminobenzothiazoles and derivatives useful for treating cerebrovascular disorders are disclosed. Also disclosed is a new method for treating such disorders.
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- Process for the manufacture of 2-amino-aryleno-thiazole compounds and of derivatives thereof N-substituted in the ring
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2-Amino-aryleno-thiazoles in which the amino group in 2-position can be substituted by aryl, alkyl and/or cycloalkyl, and 2-imino-aryleno-thiazolines substituted at the ring nitrogen by aryl, alkyl or cycloalkyl are produced by cyclization of arylthioureas carrying corresponding substituents at the respective nitrogen atom, using thionyl chloride as cyclization agent. The advantage of the improved process resides in that the amount of sulfur formed is very low and that the other by-products are easy to separate and can be used further. The thiazoles and thiazolines are obtained in a high yield and purity. They are valuable starting compounds, especially for the manufacture of dyestuffs.
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