- Synthesis of benzothiazoles from 2-aminobenzenethiols in the presence of a reusable polythiazolium precatalyst under atmospheric pressure of carbon dioxide
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Synthesis of benzothiazoles from 2-aminobenzenethiols and carbon dioxide was carried out using poly(3,4-dimethyl-5-vinylthiazolium) iodide as a precatalyst to in situ generation of NHCs by deprotonation. The reaction was successfully carried out under mild conditions (1 atm of CO2 and 60–70 °C) with a broad substrate scope and functional group tolerance. The precatalyst salt was recovered and reused for several times without any loss of activity.
- Chun, Supill,Yang, Sabyuk,Chung, Young Keun
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- Atmospheric CO2 promoted synthesis of N-containing heterocycles over B(C6F5)3 catalyst
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B(C6F5)3 combined with atmospheric CO2 was found to be highly effective for the cyclization of ortho-substituted aniline derivatives with N,N-dimethylformamide (DMF), and a series of N-containing heterocycles including benzothiazoles, benzimidazoles, quinazolinone and benzoxazole were obtained in good to excellent yields.
- Gao, Xiang,Yu, Bo,Mei, Qingqing,Yang, Zhenzhen,Zhao, Yanfei,Zhang, Hongye,Hao, Leiduan,Liu, Zhimin
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- Ionic Liquid-Catalyzed C-S Bond Construction using CO2 as a C1 Building Block under Mild Conditions: A Metal-Free Route to Synthesis of Benzothiazoles
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The construction of the C-S bond using CO2 as a C1 feedstock can be considered as a green route for the synthesis of S-containing compounds and is of great significance. Herein, we report the acetate-based ionic liquids (ILs)-catalyzed synthesis of benzothiazoles via cyclization of 2-aminothiophenols with CO2 and hydrosilane under mild conditions (e.g., 60 °C, 0.5 MPa). It was found that the IL (e.g., 1-butyl-3-methylimidazolium acetate, [Bmim][OAc]) served as a multifunctional catalyst with activating CO2 and hydrosilane to form a formoxysilane intermediate, as well as simultaneously activating 2-aminothiophenols through a hydrogen bond, finally resulting in the production of benzothiazoles. [Bmim][OAc] showed the best performance, and a series of benzothiazoles were obtained in high yields. To the best of our knowledge, this is the first protocol for the synthesis of benzothiazoles using CO2 as a C1 building block under metal-free and mild conditions.
- Gao, Xiang,Yu, Bo,Yang, Zhenzhen,Zhao, Yanfei,Zhang, Hongye,Hao, Leiduan,Han, Buxing,Liu, Zhimin
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- N-Iodosuccinimide involved one-pot metal-free synthesis of 2-heteroaromatic benzothiazole compounds
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A one-pot protocol for the synthesis of structurally diverse 2-hetarylbenzothiazoles via oxidative condensation of the sp3 C-H bond with benzothiazoles has been described. This process is metal free and operationally simple. A series of 2-hetarylbenzothiazoles were prepared in moderate to good yield under mild conditions.
- Chu, Xianglong,Duan, Tiantian,Liu, Xuan,Feng, Lei,Jia, Jiong,Ma, Chen
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- Photoelectrochemical cross-dehydrogenative coupling of benzothiazoles with strong aliphatic C-H bonds
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A photoelectrochemical strategy for the cross-dehydrogenative coupling of unactivated aliphatic hydrogen donors (e.g.alkanes) with benzothiazoles is reported. We used tetrabutylammonium decatungstate as the photocatalyst to activate strong C(sp3)-H bonds in the chosen substrates, while electrochemistry scavenged the extra electrons.
- Capaldo, Luca,Quadri, Lorenzo L.,Merli, Daniele,Ravelli, Davide
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supporting information
p. 4424 - 4427
(2021/05/10)
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- Iron-catalyzed tandem oxidative coupling and acetal hydrolysis reaction to prepare formylated benzothiazoles and isoquinolines
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The aldehyde group is one of the most versatile intermediates in synthetic chemistry, and the introduction of an aldehyde group into heteroarenes is important for the transformation of molecular structure. Herein, we achieved the direct formylation of benzothiazo/les and isoquinolines. The reaction features a novel iron-catalyzed Minisci-type oxidative coupling process using commercially available 1,3-dioxolane as a formylated reagent followed by acetal hydrolysis without a separation process. The reaction can be performed under exceedingly mild reaction conditions and exhibits broad functional group tolerance.
- Wu, Yue,Guo, Peng,Chen, Long,Duan, Weijie,Yang, Zengzhuan,Wang, Tao,Chen, Ting,Xiong, Fei
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supporting information
p. 3271 - 3274
(2021/04/07)
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- K2S as Sulfur Source and DMSO as Carbon Source for the Synthesis of 2-Unsubstituted Benzothiazoles
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We describe a three-component reaction of o-iodoanilines with K2S and DMSO that provides 2-unsubstituted benzothiazoles in moderate to good isolated yields with good functional group tolerance. Electron-rich aromatic amines and o-phenylenediamines instead of o-iodoanilines provided 2-unsubstituted benzothiazoles and 2-unsubstituted benzimidazoles with and without K2S under similar conditions. Notably, DMSO plays three vital roles: carbon source, solvent, and oxidant.
- Deng, Guobo,Kuang, Daizhi,Liang, Yun,Yang, Yuan,Yu, Jiangxi,Zhang, Fuxing,Zhu, Xiaoming
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supporting information
p. 3789 - 3793
(2020/06/04)
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- Synthetic method of ammonium acetate-mediated benzothiazole compound
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The invention discloses a synthetic method of an ammonium acetate-mediated benzothiazole compound . The synthetic method comprises the steps: adding an o-haloaniline derivative, potassium sulfide, dimethyl sulfoxide, a catalyst, an additive 1 and an additive 2 into a reaction tube, carrying out a stirring reaction at the temperature of 130-150 DEG C, cooling to room temperature after the reactionis finished, and separating and purifying the product to obtain the benzothiazole compound. The invention provides the synthetic method of the benzothiazole compound by taking K2S as a sulfur source,DMSO as a carbon source and an oxidizing agent, an o-haloaniline derivative as a substrate and an ammonium acetate mediated three-component one-pot method. The method has the advantages of fewer reaction steps, mild reaction conditions, good functional group tolerance and the like.
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Paragraph 0051-0053
(2020/11/23)
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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; 0068
(2019/02/13)
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- Derisking the Cu-Mediated 18F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands
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Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18F-fluorination of aryl boron reagents with 18F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
- Taylor, Nicholas J.,Emer, Enrico,Preshlock, Sean,Schedler, Michael,Tredwell, Matthew,Verhoog, Stefan,Mercier, Joel,Genicot, Christophe,Gouverneur, Véronique
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supporting information
p. 8267 - 8276
(2017/06/27)
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- Deaminizing method for amidogen-containing aromatic compounds
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The invention relates to the technical field of organic synthesis, and provides a deaminizing method for amidogen-containing aromatic compounds. The deaminizing method aims at solving the problems that as for a deaminizing method commonly used at present, as strong acid is used, the environment is polluted, the reaction temperature needs to be accurately controlled and production is not facilitated. The deaminizing method for the amidogen-containing aromatic compounds includes the steps that the amidogen-containing aromatic compounds, nitrite and solvents are mixed to be put into a pressure-proof tube, a stirring reaction is carried out for 12 hours to 72 hours at the temperature of 80 DEG C to 130 DEG C, and the deaminized-amidogen aromatic compounds are separated and obtained. The deaminizing method is efficient, easy and convenient to operate and free of waste acid pollution.
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Paragraph 0022
(2016/10/09)
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- Dual C-H activations of electron-deficient heteroarenes: Palladium-catalyzed oxidative cross coupling of thiazoles with azine N-oxides
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The palladium-catalyzed, copper-promoted cross-dehydrogenative-coupling (CDC) of electron-deficient thiazoles with azine N-oxides through dual C-H activations was developed. It was found that copper(II) pivalate was an efficient dual-function reagent for the oxidative cross-coupling reactions, playing the roles of both an oxidant and a C-H bond activation promoter. This methodology provides a simple way to construct 2-thiazolyl pyridine moiety.
- Fu, Xiao-Pu,Xuan, Qing-Qing,Liu, Li,Wang, Dong,Chen, Yong-Jun,Li, Chao-Jun
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p. 4436 - 4444
(2013/06/26)
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- Cu-catalyzed cross-dehydrogenative coupling reactions of (benzo)thiazoles with cyclic ethers
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Copper-catalyzed cross-dehydrogenative coupling (CDC) reactions of (benzo)thiazoles with cyclic ethers were developed under mild conditions. In particular, the formation of C-C bonds via the CDC reactions between non-benzo-fused azoles and ethers are reported for the first time. In addition, the acetals, known as the masked 2-thiazolecarboxaldehydes, could be successfully obtained by this CDC reaction. The preliminary mechanism and supportive DFT calculations are discussed as well.
- Xie, Zengyang,Cai, Yuping,Hu, Hongwen,Lin, Chen,Jiang, Juli,Chen, Zhaoxu,Wang, Leyong,Pan, Yi
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supporting information
p. 4600 - 4603
(2013/09/24)
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- TBHP-mediated oxidative thiolation of an sp3 C-H bond adjacent to a nitrogen atom in an amide
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The first example of molecular sieve-promoted TBHP-mediated direct oxidative thiolation of an sp3 C-H bond adjacent to a nitrogen atom with disulfides under metal-free conditions, which allows for preparation of numerous S,N-containing compounds, is presented. Moreover, diverse benzothiazoles and a fipronil analog can be synthesized through this strategy.
- Tang, Ri-Yuan,Xie, Ye-Xiang,Xie, Yi-Li,Xiang, Jian-Nan,Li, Jin-Heng
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supporting information; experimental part
p. 12867 - 12869
(2012/02/03)
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- In-depth study of tripeptide-based α-ketoheterocycles as inhibitors of thrombin. Effective utilization of the S1′ subsite and its implications to structure-based drug design
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Thrombin inhibitors are potentially useful in medicine for their anticoagulant and antithrombotic effects. We synthesized and evaluated diverse heterocycle-activated ketones based on the D-Phe-Pro-Arg, and related thrombin active-site recognition motifs, as candidate inhibitors. The peptide-based α-ketoheterocycles were typically prepared by either an imidate or a Weinreb amide route (Schemes 1 and 2), the latter of which proved to be more general. Test compounds were generally assayed for inhibition of human α-thrombin and bovine trypsin. From a structure-based design standpoint, the heterocycle allows one to explore and adjust interactions within the S1′ subsite of thrombin. The preferred α-ketoheterocycle is a π-rich 2-substituted azole with at least two heteroatoms proximal to the carbon bearing the keto group, and a preferred thrombin inhibitor is 2-ketobenzothiazole 3, with a potent Ki value of 0.2 nM and ca. 15-fold selectivity over trypsin. 2-Ketobenzothiazole 13 exhibited exceedingly potent thrombin inhibition (Ki = 0.000 65 nM; slow tight binding). Several α-ketoheterocycles had thrombin Ki values in the range 0.1-400 nM. The "Arg" unit in the α-ketoheterocycles can be sensitive to stereomutation under mildy basic conditions. For example, 2-ketothiazoles 4 and 59 readily epimerize at pH 7.4, although they are fairly stable stereochemically at pH 3-4; thus, suitable conditions had to be selected for the enzymatic assays. Lead D-Phe-Pro-Arg 2-benzothiazoles 3, 4, and 68 displayed good selectivity for thrombin over other key coagulation enzymes (e.g., factor Xa, plasmin, protein Ca, uPA, tPA, and streptokinase); however, their selectivity for thrombin over trypsin was modest (50 = 30-40 nM). They also proved to be potent anticoagulant/ antithrombotic agents in vivo on intravenous administration, as determined in the canine arteriovenous shunt (ED50 = 0.45-0.65 mg/kg) and the rabbit deep vein thrombosis (ED50 = 0.1-0.4 mg/kg) models. Intravenous administration of 3, and several analogues, to guinea pigs caused hypotension and electrocardiogram abnormalities. Such cardiovascular side effects were also observed with some nonguanidine inhibitors and inhibitors having recognition motifs other than D-Phe-Pro-Arg. 2-Benzothiazolecarboxylates 4 and 68 exhibited significantly diminished cardiovascular side effects, and benzothiazolecarboxylic acid 4 had the best profile with respect to therapeutic index. The X-ray crystal structures of the ternary complexes 3-thrombin-hirugen and 4-thrombin-hirugen depict novel interactions in the S1′ region, with the benzothiazole ring forming a hydrogen bond with His-57 and an aromatic stacking interaction with Trp-60D of thrombin's insertion loop. The benzothiazole ring of 3 displaces the Lys-60F side chain into a U-shaped gauche conformation, whereas the benzothiazole carboxylate of 4 forms a salt bridge with the side chain of Lys-60F such that it adopts an extended anti conformation. Since 3 has a 10-fold greater affinity for thrombin than does 4, any increase in binding energy resulting from this salt bridge is apparently offset by perturbations across the enzyme (viz. Figure 4). The increased affinity and selectivity of 2-ketobenzothiazole inhibitors, such as 3, may be primarily due to the aromatic stacking interaction with Trp-60D. However, energy contour calculations with the computer program GRID also indicate a favorable interaction between the benzothiazole sulfur atom and a hydrophobic patch on the surface of thrombin.
- Costanzo, Michael J.,Almond Jr., Harold R.,Hecker, Leonard R.,Schott, Mary R.,Yabut, Stephen C.,Zhang, Han-Cheng,Andrade-Gordon, Patricia,Corcoran, Thomas W.,Giardino, Edward C.,Kauffman, Jack A.,Lewis, Joan M.,De Garavilla, Lawrence,Haertlein, Barbara J.,Maryanoff, Bruce E.
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p. 1984 - 2008
(2007/10/03)
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- PEPTIDYL HETEROCYCLES USEFUL IN THE TREATMENT OF THROMBIN RELATED DISORDERS
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Compounds of the Formula I: STR1 useful in the treatment of thrombin and trypsin related disorders.
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- Synthesis and antifungal activity of novel thiazole-containing triazole antifungals. II. Optically active ER-30346 and its derivatives
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A series of novel thiazole-containing triazole antifungals was synthesized and evaluated for antifungal activity against a variety of clinically isolated pathogenic fungi in vitro and against systemic candidosis in vivo. These compounds showed potent antifungal activities in vitro and in vivo. In particular, (2R,3R)-3-[4-(4-cyanophenyl)thiazol-2-yl]-2-(2,4- difluorophenyl)-1-(1H-1,2,4-triazol-l-yl)-2-butanol (12g; ER-30346) showed potent and well-balanced in vitro activities and potent in vivo efficacy, and had a good safety profile.
- Tsuruoka, Akihiko,Kaku, Yumiko,Kakinuma, Hiroyuki,Tsukada, Itaru,Yanagisawa, Manabu,Nara, Kazumasa,Naito, Toshihiko
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p. 623 - 630
(2007/10/03)
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- Highly selective aldose reductase inhibitors. II. Optimization of the aryl part of 3-(arylmethyl)-2,4,5-trioxoimidazolidine-1-acetic acids
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Accumulation of intracellular sorbitol, the product of glucose reduction catalyzed by aldose reductase (AR) [EC 1.1.1.21], is thought to be the main culprit in the development of diabetic complications. A series of 3- arylalkyl-2,4,5-trioxoimidazolidine-1-acetic acids was prepared and tested for inhibitory activities towards AR and aldehyde reductase (ALR) [EC 1.1.1.2]. These derivatives showed strong inhibitory activity against AR without markedly inhibiting ALR. In particular, the compounds with 3- nitrophenyl, 4-chloro-3-nitrophenyl, and chloro-substituted benzothiazolyl groups as the aryl part showed powerful AR-inhibitory activity. The chloro- substituted benzothiazolyl compound showed an AR selectivity of more than 5000 fold.
- Kotani, Takayuki,Ishii, Akira,Nagaki, Yasuhiro,Toyomaki, Yoshio,Yago, Hisashi,Suehiro, Seishi,Okukado, Nobuhisa,Okamoto, Kaoru
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p. 297 - 304
(2007/10/03)
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- PEPTIDYL HETEROCYCLES USEFUL IN THE TREATMENT OF THROMBIN RELATED DISORDERS
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Compounds of the Formula I: STR1 useful in the treatment of thrombin and trypsin related disorders.
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