1504-55-8Relevant articles and documents
A Highly Active and Easily Accessible Cobalt Catalyst for Selective Hydrogenation of C=O Bonds
R?sler, Sina,Obenauf, Johannes,Kempe, Rhett
, p. 7998 - 8001 (2015)
The substitution of high-price noble metals such as Ir, Ru, Rh, Pd, and Pt by earth-abundant, inexpensive metals like Co is an attractive goal in (homogeneous) catalysis. Only two examples of Co catalysts, showing efficient C=O bond hydrogenation rates, are described. Here, we report on a novel, easy-to-synthesize Co catalyst family. Catalyst activation takes place via addition of 2 equiv of a metal base to the cobalt dichlorido precatalysts. Aldehydes and ketones of different types (dialkyl, aryl-alkyl, diaryl) are hydrogenated quantitatively under mild conditions partially with catalyst loadings as low as 0.25 mol%. A comparison of the most active Co catalyst with an Ir catalyst stabilized by the same ligand indicates the superiority of Co. Unique selectivity toward C=O bonds in the presence of C=C bonds has been observed. This selectivity is opposite to that of existing Co catalysts and surprising because of the directing influence of a hydroxyl group in C=C bond hydrogenation.
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Braude,Evans
, p. 3333,3336 (1956)
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CoOx@Co Nanoparticle-based Catalyst for Efficient Selective Transfer Hydrogenation of α,β-Unsaturated Aldehydes
Gong, Wanbing,Han, Miaomiao,Chen, Chun,Lin, Yue,Wang, Guozhong,Zhang, Haimin,Zhao, Huijun
, p. 1019 - 1024 (2020)
Currently, developing simple and effective catalysts for selective hydrogenation of α,β-unsaturated aldehydes to unsaturated alcohols is challenging. Herein, an efficient CoOx-shell/Co-core structured nanoparticle catalyst is synthesized by a facile ultrasonic-assisted carbothermal reduction method. The resultant catalyst exhibits outstanding catalytic performance toward the selective transfer hydrogenation of a wide spectrum of α,β-unsaturated aldehydes into corresponding unsaturated alcohols with over 90 % selectivity. This is the simplest nonprecious metal catalyst to be reported for the selective hydrogenation of unsaturated aldehydes.
Photoenzymatic Synthesis of α-Tertiary Amines by Engineered Flavin-Dependent "ene"-Reductases
Gao, Xin,Turek-Herman, Joshua R.,Choi, Young Joo,Cohen, Ryan D.,Hyster, Todd K.
supporting information, p. 19643 - 19647 (2021/12/01)
α-Tertiary amines are a common motif in pharmaceutically important molecules but are challenging to prepare using asymmetric catalysis. Here, we demonstrate engineered flavin-dependent ‘ene'-reductases (EREDs) can catalyze radical additions into oximes to prepare this motif. Two different EREDs were evolved into competent catalysts for this transformation with high levels of stereoselectivity. Mechanistic studies indicate that the oxime contributes to the enzyme templated charge-transfer complex formed between the substrate and cofactor. These products can be further derivatized to prepare a variety of motifs, highlighting the versatility of ERED photoenzymatic catalysis for organic synthesis.
Discovery of a novel inhibitor of nitric oxide production with potential therapeutic effect on acute inflammation
Zhu, Long-Qing,Fan, Xiao-Hong,Li, Jun-Fang,Chen, Jin-Hong,Liang, Yan,Hu, Xiao-Ling,Ma, Shu-Meng,Hao, Xiang-Yong,Shi, Tao,Wang, Zhen
supporting information, (2021/05/26)
Inflammation as a host's excessive immune response to stimulation, is involved in the development of numerous diseases. To discover novel anti-inflammatory agents and based on our previous synthetic work on marine natural product Chrysamide B, it and a series of derivatives were synthesized and evaluated for their anti-inflammatory activity on inhibition of LPS-induced NO production. Then the preliminary structure–activity relationships were conducted. Among them, Chrysamide B is the most potent anti-inflammatory agent with low cytotoxicity and strong inhibition on the production of NO (IC50 = 0.010 μM) and the activity of iNOS (IC50 = 0.082 μM) in LPS-stimulated RAW 264.7 cells. Primary studies suggested that the mechanism of action may be that it interfered the formation of active dimeric iNOS but not affected transcription and translation. Furthermore, its good performance of anti-inflammatory effect on LPS-induced multiple inflammatory cytokines production, carrageenan-induced paw edema, and endotoxin-induced septic mice, was observed. We believe that these findings would provide an idea for the further modification and research of these analogs in the future.
