The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Thaddeus A. Tomaszek - One of the best experts on this subject based on the ideXlab platform.
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Cyclic Ketone inhibitors of the cysteine protease cathepsin K.
Journal of Medicinal Chemistry, 2001Co-Authors: Robert W. Marquis, Stephen M Locastro, Robert E. Lee Trout, Ashley E. Fenwick, Benedicte Garnier, Andrew Derrick Gribble, Yu Ru, Jason Witherington, Jin Zeng, Thaddeus A. TomaszekAbstract:Cathepsin K (EC 3.4.22.38), a cysteine protease of the papain superfamily, is predominantly expressed in osteoclasts and has been postulated as a target for the treatment of osteoporosis. Crystallographic and structure−activity studies on a series of aCyclic Ketone-based inhibitors of cathepsin K have led to the design and identification of two series of Cyclic Ketone inhibitors. The mode of binding for four of these Cyclic and aCyclic inhibitors to cathepsin K is discussed and compared. All of the structures are consistent with addition of the active site thiol to the Ketone of the inhibitors with the formation of a hemithioketal. Cocrystallization of the C-3 diastereomeric 3-amidotetrahydrofuran-4-one analogue 16 with cathepsin K showed the inhibitor to occupy the unprimed side of the active site with the 3S diastereomer preferred. This C-3 stereochemical preference is in contrast to the X-ray cocrystal structures of the 3-amidopyrrolidin-4-one inhibitors 29 and 33 which show these inhibitors to prefer ...
Chen-chao Wang - One of the best experts on this subject based on the ideXlab platform.
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catalyst free synthesis of spiropyrazolines from chalcones and Cyclic Ketone n tosylhydrazones
ChemInform, 2015Co-Authors: Hongshuang Wang, Zhenguo Zhang, Chen-chao WangAbstract:The title compounds are efficiently obtained with high selectivity and functional-group tolerance from readily available and stable starting materials.
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Catalyst-free synthesis of spiropyrazolines from chalcones and Cyclic-Ketone N-tosylhydrazones
Synlett, 2014Co-Authors: Wang Hongshuang, Zhang Zhenguo, Chen-chao WangAbstract:Treatment of Cyclic Ketone N-tosylhydrazones with chalcones in the presence of cesium carbonate at 110 °C affords spiropyrazolines with high selectivity and excellent yields. This protocol possesses many advantages such as readily available and stable starting materials, high selectivity, operational simplicity, and catalyst-free conditions.
Steven P Crossley - One of the best experts on this subject based on the ideXlab platform.
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stabilization of furanics to Cyclic Ketone building blocks in the vapor phase
Applied Catalysis B-environmental, 2019Co-Authors: Taiwo Omotoso, Leidy V Herrera, Tyler Vann, Nicholas M Briggs, Laura A Gomez, Lawrence Barrett, Don J Jones, Tram Ngoc Pham, Bin Wang, Steven P CrossleyAbstract:Abstract Furanics are produced in high abundance from the decomposition of biomass. The thermal and chemical instability of these species leads to the formation of humins upon condensation. The ring rearrangement of furfural to form 2-cyclopentenone and cyclopentanone is known to occur in the condensed aqueous phase, but this requires operation in condensed acidic media where humin formation readily occurs. High hydrogen pressures are typically used to offset rapid polymerization reactions, limiting the yields of stable unsaturated products that result. Here we report that furfural can be selectively converted to 2-cyclopentenone and cyclopentanone in a single step over supported TiO2 catalysts with both model compounds and real biomass-derived streams in the vapor phase. Selectivity for ring rearrangement vs. C O cleavage over TiO2 supported Ru and Pd catalysts can be tuned by manipulating the water partial pressure. The formation of these products in the absence of a condensed acidic stream also enables the tuning of reaction environments to favor the selective formation of unsaturated Ketones, which could be valuable diolefin precursors. The incorporation of a TiO2 support in the catalysts tested leads to the suppression of C C hydrogenolysis/decarbonylation and enhancement of ring rearrangement reactions. The nature of the active sites for selective C O cleavage as well as vapor phase ring rearrangement are discussed.
Tapas Chakraborty - One of the best experts on this subject based on the ideXlab platform.
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photoisomerization of a small Cyclic Ketone in the vapor phase
Chemical Physics Letters, 2017Co-Authors: Aparajeo Chattopadhyay, Koushik Mondal, Monoj Samanta, Tapas ChakrabortyAbstract:Abstract Photoisomerization channels in the vapor phase photochemistry of cyclohexanone (CH) are studied by performing photolysis with 311 nm UV light, and analyzing the photoproducts by means of FTIR spectroscopy. In addition to 5-hexenal, identified previously as a photoisomerization product, we observe an efficient parallel isomerization channel producing butylketene as a primary photoproduct, but it remained unidentified in earlier studies. Calculation at DFT/B3LYP/6-311++G ∗∗ level predicts formation of this ketene to be favorable both with respect to thermodynamic and kinetic factors.
Robert W. Marquis - One of the best experts on this subject based on the ideXlab platform.
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Cyclic Ketone inhibitors of the cysteine protease cathepsin K.
Journal of Medicinal Chemistry, 2001Co-Authors: Robert W. Marquis, Stephen M Locastro, Robert E. Lee Trout, Ashley E. Fenwick, Benedicte Garnier, Andrew Derrick Gribble, Yu Ru, Jason Witherington, Jin Zeng, Thaddeus A. TomaszekAbstract:Cathepsin K (EC 3.4.22.38), a cysteine protease of the papain superfamily, is predominantly expressed in osteoclasts and has been postulated as a target for the treatment of osteoporosis. Crystallographic and structure−activity studies on a series of aCyclic Ketone-based inhibitors of cathepsin K have led to the design and identification of two series of Cyclic Ketone inhibitors. The mode of binding for four of these Cyclic and aCyclic inhibitors to cathepsin K is discussed and compared. All of the structures are consistent with addition of the active site thiol to the Ketone of the inhibitors with the formation of a hemithioketal. Cocrystallization of the C-3 diastereomeric 3-amidotetrahydrofuran-4-one analogue 16 with cathepsin K showed the inhibitor to occupy the unprimed side of the active site with the 3S diastereomer preferred. This C-3 stereochemical preference is in contrast to the X-ray cocrystal structures of the 3-amidopyrrolidin-4-one inhibitors 29 and 33 which show these inhibitors to prefer ...
