- Supramolecular Catalysis of Acyl Transfer within Zinc Porphyrin-Based Metal-Organic Cages
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To illustrate the supramolecular catalysis process in molecular containers, two porphyrinatozinc(II)-faced cubic cages with different sizes were synthesized and used to catalyze acyl-transfer reactions between N-acetylimidazole (NAI) and various pyridylcarbinol (PC) regioisomers (2-PC, 3-PC, and 4-PC). A systemic investigation of the supramolecular catalysis occurring within these two hosts was performed, in combination with a host-guest binding study and density functional theory calculations. Compared to the reaction in a bulk solvent, the results that the reaction of 2-PC was found to be highly efficient with high rate enhancements (kcat/kuncat = 283 for Zn-1 and 442 for Zn-2), as well as the different efficiencies of the reactions with various ortho-substituted 2-PC substrates and NAI derivates should be attributed to the cages having preconcentrated and preoriented substrates. The same cage displayed different catalytic activities toward different PC regioisomers, which should be mainly attributed to different binding affinities between the respective reactant and product with the cages. Furthermore, control experiments were carried out to learn the effect of varying reactant concentrations and product inhibition. The results all suggested that, besides the confinement effect caused by the inner microenvironment, substrate transfer, including the encapsulation of the reactant and the release of products, should be considered to be a quite important factor in supramolecular catalysis within a molecular container.
- Li, Lili,Yang, Linlin,Li, Xuezhao,Wang, Jing,Liu, Xin,He, Cheng
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supporting information
p. 8802 - 8810
(2021/06/28)
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- A 6 - methyl - 2 - pyridyl methanol preparation method
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The invention discloses a preparation method of 6-methyl-2-pyridyl methanol and belongs to the field of organic chemical synthesis, solving the problems of poor selectivity, abundant byproducts, low yield and environment pollution in the prior art. The preparation method of 6-methyl-2-pyridyl methanol comprises the following steps: carrying out high-selectivity oxidization on 2,6-dimethyl pyridine based on 2,6-dimethyl pyridine and glacial acetic acid which serve as raw materials in the presence of tungsten oxide and hydrogen peroxide which serve as catalysts, introducing an acetyl group into an alpha position of a pyridine ring, then carrying out alpha-carbon electronic transfer rearrangement to generate 6-methyl-2-pyridyl ethyl formate, subsequently carrying out hydrolysis to generate 6-methyl-2-pyridyl methanol, then carrying out extraction and distillation to obtain high-purity 6-methyl-2-pyridyl methanol. The preparation method of 6-methyl-2-pyridyl methanol can fully accord with the synthesis requirements of medical manufacturing enterprises, has the advantages of high selectivity, few byproducts, high product yield and low production cost, is mild in reaction conditions and is suitable for industrial production.
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- Substituted triazolo-pyridazine derivatives as ligands for GABA receptors
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Substituted triazolo-pyridazine derivative compounds represented by wherein the variables are disclosed herein are selective ligands for GABA-A receptors, particularly for the α2 and/or α3 subunits.
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- 2--1H-thienoimidazoles. A Novel Class of Gastric H+/K+-ATPase Inhibitors
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2-thienoimidazoles were synthesized and investigated as potential inhibitors of gastric H+/K+-ATPase.The isomers of the two possible thienoimidazole series were found to be potent inhibitors of gastric acid secretion in vitro and in vivo.Structure-activity relationships indicate that especially lipophilic alkoxy, benzyloxy, and phenoxy substituents with additional electron-demanding properties in the 4-position of the pyridine moiety combined with an unsubstituted thienoimidazole lead to highly active compounds with a favorable chemical stability.Various substitution patterns in the thienoimidazole moiety result in lower biological activity.The heptafluorobutyloxy derivative saviprazole (HOE 731, 5d) was selected for further development and is currently undergoing clinical evaluation.Comprehensive pharmacological studies indicate a pharmacodynamic profile different to omeprazole, the first H+/K+-ATPase blocker introduced on the market.
- Weidmann, Klaus,Herling, Andreas W.,Lang, Hans-Jochen,Scheunemann, Karl-Heinz,Rippel, Robert,et al.
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p. 438 - 450
(2007/10/02)
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- Triazolopyridines. Part 6. Ring Opening Reactions of Triazolopyridines
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The triazole ring in 1,2,3-triazolo-pyridines and -quinolines, and in 1,2,3-triazoloisoquinolines can be opened with loss of nitrogen.The reagents described are bromine, aqueous sulphuric acid, glacial acetic acid, and selenium dioxide; the products from the triazolopyridines are dibromomethyl, hydroxymethyl, acetoxymethyl, and acyl derivatives of pyridine.The generality of the reactions is discussed.The first reported reaction in which the six-membered ring of a 1,2,3-triazolopyridine is opened, by hydride reduction, gives a triazolylbutadiene.
- Jones, Gurnos,Mouat, Deborah J.,Tonkinson, Daryl J.
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p. 2719 - 2724
(2007/10/02)
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