- Recyclable copper-catalyzed cyclization of o-haloanilides and metal sulfides: An efficient and practical access to substituted benzothiazoles
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An efficient heterogeneous copper-catalyzed cyclization of o-haloanilides and metal sulfides has been achieved via the C–S coupling in DMF at 80 or 140 °C in the existence of an MCM-41-bound NHC-Cu(I) catalyst and then intramolecular condensation, delivering a wide range of substituted benzothiazoles in mostly good to high yields. This new MCM-41-NHC-CuI complex can facilely be obtained by a two-step procedure starting from easily accessible and inexpensive reagents and reused more than seven times without any significant loss of its catalytic efficiency. The present protocol has been successfully applied to the gram-scale synthesis of two antitumor agents 5F203 and PMX 610.
- Cai, Mingzhong,Hao, Wenyan,Huang, Wencheng,Ye, Qian
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- Synthesis and antileishmanial activity of fluorinated rhodacyanine analogues: The ‘fluorine-walk’ analysis
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In a search for potent antileishmanial drug candidates, eighteen rhodacyanine analogues bearing fluorine or perfluoroalkyl substituents at various positions were synthesized. These compounds were tested for their inhibitory activities against Leishmania martiniquensis and L. orientalis. This ‘fluorine-walk’ analysis revealed that the introduction of fluorine atom at C-5, 6, 5′, or 6′ on the benzothiazole units led to significant enhancement of the activity, correlating with the less negative reduction potentials of the fluorinated analogues confirmed by the electrochemical study. On the other hand, [sbnd]CF3 and [sbnd]OCF3 groups were found to have detrimental effects, which agreed with the poor aqueous solubility predicted by the in silico ADMET analysis. In addition, some of the analogues including the difluorinated species showed exceptional potency against the promastigote and axenic amastigote stages (IC50 = 40–85 nM), with the activities surpassing both amphotericin B and miltefosine.
- Lasing, Thitiya,Phumee, Atchara,Siriyasatien, Padet,Chitchak, Kantima,Vanalabhpatana, Parichatr,Mak, Kit-Kay,Hee Ng, Chew,Vilaivan, Tirayut,Khotavivattana, Tanatorn
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- Di- tert-butyl Peroxide-Mediated Radical C(sp2/sp3)-S Bond Cleavage and Group-Transfer Cyclization
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A novel strategy of cascade radical C(sp2/sp3)-S bond cleavage and group-transfer cyclization is disclosed. Triggered by alkyl radicals, varieties of 2-isocyanoaryl thioethers containing aliphatic, aryl, and heteroaromatic groups can be cleaved and precisely reinstalled to give benzothiazole derivatives. Mechanistic studies reveal that the cascade reaction undertakes an intermolecular pathway, and the inner radical sources (R radicals) exhibit high priority over those of methyl radical origin from di-tert-butyl peroxide.
- Luo, Kai,Yang, Wen-Chao,Wei, Kai,Liu, Yue,Wang, Jun-Ke,Wu, Lei
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supporting information
p. 7851 - 7856
(2019/10/11)
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- Rational design and synthesis of 2-anilinopyridinyl-benzothiazole Schiff bases as antimitotic agents
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Based on our previous results and literature precedence, a series of 2-anilinopyridinyl-benzothiazole Schiff bases were rationally designed by performing molecular modeling experiments on some selected molecules. The binding energies of the docked molecules were better than the E7010, and the Schiff base with trimethoxy group on benzothiazole moiety, 4y was the best. This was followed by the synthesis of a series of the designed molecules by a convenient synthetic route and evaluation of their anticancer potential. Most of the compounds have shown significant growth inhibition against the tested cell lines and the compound 4y exhibited good antiproliferative activity with a GI50 value of 3.8?μM specifically against the cell line DU145. In agreement with the docking results, 4y exerted cytotoxicity by the disruption of the microtubule dynamics by inhibiting tubulin polymerization via effective binding into colchicine domain, comparable to E7010. Detailed binding modes of 4y with colchicine binding site of tubulin were studied by molecular docking. Furthermore, 4y induced apoptosis as evidenced by biological studies like mitochondrial membrane potential, caspase-3, and Annexin V-FITC assays.
- Shaik, Thokhir B.,Hussaini, S.M. Ali,Nayak, V. Lakshma,Sucharitha, M. Lakshmi,Malik, M. Shaheer,Kamal, Ahmed
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p. 2549 - 2558
(2017/05/09)
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- Discovery of 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]indole-N-acetic acid (lidorestat) and congeners as highly potent and selective inhibitors of aldose reductase for treatment of chronic diabetic complications
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Recent efforts to identify treatments for chronic diabetic complications have resulted in the discovery of a novel series of highly potent and selective 3-[(benzothiazol-2-yl)methyl]indole-N-alkanoic acid aldose reductase inhibitors. The lead candidate, 3-[(4,5,7-trifluorobenzothiazol-2-yl)methyl]indole-N-acetic acid (lidorestat, 9) inhibits aldose reductase with an IC50 of 5 nM, while being 5400 times less active against aldehyde reductase, a related enzyme involved in the detoxification of reactive aldehydes. It lowers nerve and lens sorbitol levels with ED50's of 1.9 and 4.5 mg/kg/d po, respectively, in the 5-day STZ-induced diabetic rat model. In a 3-month diabetic intervention model (1 month of diabetes followed by 2 months of drug treatment at 5 mg/kg/d po), it normalizes polyols and reduces the motor nerve conduction velocity deficit by 59% relative to diabetic controls. It has a favorable pharmacokinetic profile (F, 82%; t1/2, 5.6 h; Vd, 0.694 L/kg) with good drug penetration in target tissues (Cmax in sciatic nerve and eye are 2.36 and 1.45 μg equiv/g, respectively, when dosed with [14C] lidorestat at 10 mg/kg po).
- Van Zandt, Michael C.,Jones, Michael L.,Gunn, David E.,Geraci, Leo S.,Jones, J. Howard,Sawicki, Diane R.,Sredy, Janet,Jacot, Jorge L.,DiCioccio, A. Thomas,Petrova, Tatiana,Mitschler, Andre,Podjarny, Alberto D.
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p. 3141 - 3152
(2007/10/03)
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- Solid phase synthesis of benzothiazole and thiophene derivatives based on resin-bound cyclic malonic acid ester
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A new method for the solid phase synthesis of benzothiazoles and 2-arylamino-3-carboxyl-4-hydroxy-5-arylthiophenes is described. Resin bound cyclic malonic acid ester was reacted with aryl isothiocyanates and then with bromine or α-bromoketones, followed by treatment with perchloric acid or sodium methoxide to afford substituted 2-methylbenzothiazoles or 2-arylamino-3-carboxyl-4-hydroxy-5-arylthiophenes, respectively, in high yields and purities.
- Huang, Xian,Tang, Jing
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p. 4851 - 4856
(2007/10/03)
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