- Ultrathin Amorphous/Crystalline Heterophase Rh and Rh Alloy Nanosheets as Tandem Catalysts for Direct Indole Synthesis
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Heterogeneous noble-metal-based catalysis plays an essential role in the production of fine chemicals. Rh-based catalysts are one of the most active candidates for indole synthesis. However, it is still highly desired to develop heterogeneous Rh-based catalysts with high activity and selectivity. In this work, a general, facile wet-chemical method is reported to synthesize ultrathin amorphous/crystalline heterophase Rh and Rh-based bimetallic alloy nanosheets (NSs), including RhCu, RhZn, and RhRu. Impressively, the amorphous/crystalline heterophase Rh NSs exhibit enhanced catalytic activity toward the direct synthesis of indole compared to the crystalline counterpart. Importantly, the obtained amorphous/crystalline heterophase RhCu alloy NSs can further enhance the selectivity to indole of >99.9% and the conversion is 100%. This work demonstrates the importance of phase engineering and metal alloying in the rational design and synthesis of tandem heterogeneous catalysts toward fine chemical synthesis.
- Ge, Jingjie,Yin, Peiqun,Chen, Ye,Cheng, Hongfei,Liu, Jiawei,Chen, Bo,Tan, Chaoliang,Yin, Peng-Fei,Zheng, Hong-Xing,Li, Qiang-Qiang,Chen, Shuangming,Xu, Wenjie,Wang, Xiaoqian,Wu, Geng,Sun, Rongbo,Shan, Xiang-Huan,Hong, Xun,Zhang, Hua
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- Guanine-rich RNAs and DNAs that bind heme robustly catalyze oxygen transfer reactions
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Diverse guanine-rich RNAs and DNAs that fold to form guanine quadruplexes are known to form tight complexes with Fe(III) heme. We show here that a wide variety of such complexes robustly catalyze two-electron oxidations, transferring oxygen from hydrogen peroxide to thioanisole, indole, and styrene substrates. Use of 18O-labeled hydrogen peroxide reveals the source of the oxygen transferred to form thioanisole sulfoxide and styrene oxide to be the activated ferryl moiety within these systems. Hammett analysis of the kinetics of thioanisole sulfoxide formation is unable to distinguish between a one-step, direct oxygen transfer and a two-step, oxygen rebound mechanism for this catalysis. Oxygen transfer to indole produces a range of products, including indigo and related dyes. Docking of heme onto a high-resolution structure of the G-quadruplex fold of Bcl-2 promoter DNA, which both binds heme and transfers oxygen, suggests a relatively open active site for this class of ribozymes and deoxyribozymes. That heme-dependent catalysis of oxygen transfer is a property of many RNAs and DNAs has ramifications for primordial evolution, enzyme design, cellular oxidative disease, and anticancer therapeutics.
- Poon, Lester C.-H.,Methot, Stephen P.,Morabi-Pazooki, William,Pio, Frederic,Bennet, Andrew J.,Sen, Dipankar
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supporting information; experimental part
p. 1877 - 1884
(2011/04/22)
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- Functionalized heterocycles as modulators of chemokine receptor function and methods of use therefor
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Disclosed are novel compounds having the formula or a physiologically acceptable salt, amide, ester or prodrug thereof. The compounds can be used to modulate (antagonize, agonize) chemokine receptor function. Also disclosed is a method for treating a patient having an inflammatory disease and/or viral infection comprising administering an effective amount of a compound of Formula I. In particular embodiments, the invention is a method for treating a patient infected with HIV.
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- Hypoglycemic imidazoline compounds
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This invention relates to certain novel imidazoline compounds and analogues thereof, to their use for the treatment of diabetes, diabetic complications, metabolic disorders, or related diseases where impaired glucose disposal is present, to pharmaceutical compositions comprising them, and to processes for their preparation.
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