排序方式: 共有45条查询结果,搜索用时 593 毫秒
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Biswanath Das Katta Venkateswarlu Maddeboina Krishnaiah Harish Holla 《Tetrahedron letters》2006,47(49):8693-8697
A simple, efficient and rapid method has been developed for high-yielding regioselective nuclear monobromination of aromatic and heteroaromatic compounds using NBS in the presence of sulfonic-acid-functionalized silica at room temperature. The catalyst works under heterogeneous conditions and can be recycled. 相似文献
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Harish Holla Ian D. Jenkins Juliette E. Neve Rebecca H. Pouwer Ngoc Pham Simon J. Teague Ronald J. Quinn 《Tetrahedron letters》2012,53(52):7101-7103
A synthesis of the unusual cyclobutane-quinolinone alkaloids melicodenines C, D and E by intermolecular [2+2] cycloaddition is described. 相似文献
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K. Subrahmanya Bhat B. Shivarama Holla 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):1019-1026
1,2,4-Triazolo[3,4-b]thiazole derivatives 5a–j have been synthesized by novel multi-component reaction of 2,4-dichloro-5-fluorophenacyl bromide (1), thiosemicarbazide (2), and aromatic carboxylic acids (4) using phosphorous oxychloride as the cyclizing agent. This reaction protocol is simple, efficient, and requires shorter reaction times in comparison to the conventional multi-step synthesis. The products were identified to be same by an alternate synthesis. All the compounds were screened for their antimicrobial activity against some of bacterial and fungal strains. 相似文献
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E. Wolfgang Holla Manfred Schudok Angelika Weber Matthias Zulauf 《Journal of carbohydrate chemistry》2013,32(5):659-663
Abstract In 1988, MOSBACH et aL1 reported the synthesis of a-D-mannopyranosy1-L-serine and Q -D-N-acetylgalactosamino-L-serine by reversing the hydrolytic activity of a -mannosidase from jack beans and a -N-acetylgalactosaminidase from beef liver, respectively. The yields in these equilibrium-controlled syntheses2 using high concentrations of monosaccharide and serine were highly dependent on the enzyme concentration and ranged from 5 to 10 percent in both cases. 相似文献
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Mari S. Karthikeyan Bantwal S. Holla Shalini Shenoy 《Monatshefte für Chemie / Chemical Monthly》2008,139(6):707-716
2,4-Dichloro-5-fluorophenyl containing 7-arylidenetriazolothiadiazines were obtained by the reaction of 4-amino-3-(2,4-dichloro-5-fluorophenyl)-5-mercapto-1,2,4-triazole
with 2,3-dibromo-1,3-diarylpropan-1-ones, and also by the reaction of 4-amino-3-(2,4-dichloro-5-fluorophenyl)-5-mercapto-1,2,4-triazole
with α-bromopropenones in the presence of a base. The structure of the 7-arylidenetriazolothiadiazines was confirmed by an
alternative synthesis. A plausible mechanism for the formation of 7-arylidenetriazolothiadiazines is proposed. All newly synthesized
compounds were screened for their analgesic and antimicrobial activities. Compounds bearing 4-chlorophenyl or 3,4-methylenedioxyphenyl
moieties at position 7 of the arylidenetriazolothiadiazines showed excellent analgesic activity. Arylidenetriazolothiadiazines
carrying a phenyl, 4-chlorophenyl, 4-methylphenyl, 3,4-dimethoxyphenyl, and 2,4-dichlorophenyl moieties at position 7 showed
excellent antibacterial and antifungal activities.
Correspondence: Mari Sithambaram Karthikeyan, Department of Chemistry, Mangalore University, Mangalagangothri 574199, Karnataka,
India. 相似文献
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Neubert L Michalik D Bähn S Imm S Neumann H Atzrodt J Derdau V Holla W Beller M 《Journal of the American Chemical Society》2012,134(29):12239-12244
A novel and convenient protocol for the catalytic hydrogen-deuterium exchange of biologically active tertiary amines utilizing the borrowing hydrogen methodology has been developed. In the presence of the readily available Shvo catalyst, excellent chemoselectivity toward α- and β-protons with respect to the nitrogen atom as well as high degree of deuterium incorporation and functional group tolerance is achieved. This allowed for the deuteration of complex pharmaceutically interesting substrates, including examples for actual marketed drug compounds. Notably, this method constitutes a powerful tool for the generation of valuable internal standard materials for LC-MS/MS analyses highly demanded for various life-science applications. 相似文献
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