PHYTOCHEMISTRY
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2024
·
IF 3.2
Hao-Dong Yang,Yuan-Gui Yang,Zhi-Shu Tang,Kang Ma,Hong-Bo Xu
Acanthopanacis cortex (the dried root bark of Acanthopanax gracilistylus W. W. Smith) has been used for the treatment of rheumatic diseases in China for over 2000 years. Four previously undescribed lignans ( 1 – 4 ) and 12 known lignans ( 5 – 16 ) were isolated from Acanthopanacis cortex. In this study, the inhibitory activities of compounds 1 – 16 against neutrophil elastase (NE), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) are reported. The results show that compounds 1 – 16 exhibit weak inhibitory activities against NE and COX-1. However, compounds 2 , 6 – 8 and 13 – 16 demonstrate better COX-2 inhibitory effects with IC 50 values from 0.75 to 8.17 μ Μ. These findings provide useful information for the search for natural selective COX-2 inhibitors.
研究领域:
药理学
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中药学
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天然产物化学
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DOI
PubMed
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-10
·
IF 15.7
Dong Hao,Luo Ran,Zhang Gong,Li Lulu,Wang Chaoxi,Sun Guodong,Wang Hongyi,Liu Jiachang,Wang Tuo,Zhao Zhi-Jian,Zhang Peng,Gong Jinlong
Direct electrochemical ethylene (C 2 H 4 ) epoxidation with water (H 2 O) represents a promising approach for the production of value-added ethylene oxide (EO) in a sustainable way. However, the activity remains limited due to the sluggish activation of C 2 H 4 and the stiff formation of *OH intermediate. This paper describes the design of a Ag/SnO 2 electrocatalyst to achieve efficient electrochemical C 2 H 4 epoxidation with a high faradaic efficiency of 39.4% for EO and a high selectivity of 91.5% at 25 mA/cm 2 in a membrane electrode assembly. Results of in situ attenuated total reflection infrared spectra characterizations and computational calculations reveal that the Ag/SnO 2 interface promotes C 2 H 4 adsorption and activation to obtain *C 2 H 4 . Moreover, electrophilic *OH is generated on the catalyst surface through H 2 O dissociation, which further reacts with *C 2 H 4 to facilitate the formation of *C 2 H 4 OH, contributing to the enhanced electrochemical epoxidation activity. This work would provide general guidance for designing catalysts for electrochemical olefin epoxidation through interface engineering.
研究领域:
材料科学
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电化学
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催化化学
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DOI
PubMed
高影响因子
POLYMER
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2023
·
IF 4.6
Shilin Liu,Ling Liu,Qifei Wu,Liqun Zhang
Solution-polymerized styrene butadiene rubber (SSBR) and high cis -polybutadiene rubber (BR) are usually used as matrix and silane coupling agent (SCA) modified silica as the filler in the conventional green tire tread. However, the SCA cannot achieve uniform distribution of silica, moreover the modification process generates volatile organic compounds. In this work, a novel silica reinforced epoxidized SSBR(ESSBR)/epoxidized BR (EBR) nanocomposite (S-ESSBR/EBR) without SCA is prepared. The ESSBR and EBR with different epoxidation degree are synthesized by an oxidant H 2 O 2 and reaction-controlled phase-transfer catalyst CPC-PW 4 O 16 . The microstructure and performance of S-ESSBR/EBR nanocomposites are investigated and compared with the silica reinforced SSBR/BR nanocomposite (S-SSBR/BR-Si75) using Si75 as SCA. Silica nanoparticles transfer from ESSBR phase to EBR phase with increasing epoxidation degree of EBR, so the distribution of silica in two phases becomes homogeneous. The S-ESSBR/EBR nanocomposite exhibits high wet skid resistance , low rolling resistance and excellent abrasion resistance as green tire tread.
研究领域:
材料科学
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橡胶化学
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DOI
高影响因子
MOLECULES
·
2025
·Vol. 30
·期 5
·1042
·
IF 4.6
Min Zhang,Gaolei Qin,Pengfei Li,Xiangjie Zhang,Hongying Chang,Ziyu Zhou,Wei Zhao,Xumeng Huang,Kui Tang,Yonghe Ning,Chang Song,Peng He
Epoxidation of long-chain α-olefins (LAOs) is a process of paramount importance, particularly in the preparation of epoxides. Traditional epoxidation methods, such as the chlorohydrin method and peracid method, suffer from issues such as poor selectivity, by-product formation, and environmental pollution. Mukaiyama epoxidation, with its mild reaction conditions and exceptional selectivity, has attracted widespread attention and considerable research. Transition metal oxide catalysts show potential in the reaction; however, the catalytic efficiency still require substantial improvement due to dilemma of substance activation. In this study, a synergistic enhancement method was employed, achieved through the creation of oxygen vacancies and the electron-rich nature of Cu. The substitution of Cu with Sn in CuO facilitates the creation of oxygen vacancy (Vo), thereby enhancing absorption and activation of O2. The conversion for O2activation paves the way for the formation of benzoyl peroxy radicals. Moreover, the interaction between Sn and Cu promotes charge transfer from Sn to Cu, resulting in an electron-rich Cu surface that significantly accelerates the dehydrogenation of benzaldehyde. The synergistic enhancement protocol exhibits near-quantitative performance, delivering an oxide yield of 92.9%. This study introduces an innovative dual-promotion catalytic strategy for Mukaiyama epoxidation utilizing readily available O2, providing profound insights into the optimization design of transition metal oxide catalysts and beyond.
研究领域:
催化化学
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材料科学
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环境化学
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DOI
PubMed
高影响因子
Russian Journal of Physical Chemistry A
·
2022
·Vol. 96
·期 9
·1925-1934
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IF 0.791
Zhang Haifu,Lu Xinhuan,Li Xixi,Wang Beibei,Dong Yanhong,Zhou Dan,Xia Qinghua
Abstract The epoxy compounds are useful intermediates and precursors in the production of fine chemicals and drugs. In the epoxidation reaction system, Co-MOF, a kind of cobalt-based heterogeneous catalytic material, has been widely studied for its simple synthesis, stable structure and excellent ability of molecular oxygen activation. For the first time, we used potassium persulfate as the initiator for the efficient air epoxidation reaction catalyzed by Co-MOF materials, which had better catalytic effects than aldehydes or peroxy compounds. As a new initiator, potassium persulfate reduces the reaction temperature and increased the amount of substrate olefins. In addition, potassium persulfate reduced the activation energy of the reaction, so that the ratio of olefin to initiator was further reduced, showing a better efficiency than initiators of aldehydes or peroxy compounds. Moreover, the application of potassium persulfate to the epoxidation reaction of other catalysts has also achieved good results.
研究领域:
化学工程
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催化
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有机化学
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DOI
高影响因子
RUSSIAN JOURNAL OF GENERAL CHEMISTRY
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2017
·Vol. 87
·期 11
·2643-2647
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IF 0.553
Liang G.-P.,Guo J.-H.,Jiang R.-W.
Istaroxime 1 , a novel cardiotonic agent with high efficiency and low toxicity was synthesized from dehydroepiandrosterone 2 using a novel approach that included epoxidation, ring-opening, substitution, and oximation. The new protocol without gas protection was milder than the reported approaches. The overall yield of the method was 24.1%.
研究领域:
药物化学
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有机合成
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DOI
高影响因子
CHEMICAL PAPERS
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2022
·Vol. 76
·期 4
·2145-2152
·
IF 2.146
Zhu Xingji,Kou Xinhui
We disclose a metal-free catalyst system of organic bases/protic acids for effective fully alternating copolymerization of cyclohexene oxide and phthalic anhydride. A series of commercial organic bases and protic acids were employed as binary catalysts, and the effects of different kinds and ratios of organic bases and protic acids were performed to find optimal conditions for achieving the highest catalytic performance. And our results indicated that DMAP/DPP showed higher activity (TOF = 574 h −1 at 140 °C) and perfectly alternating selectivity (ester > 99%), producing polymers with narrow polydispersity (Ð = 1.08 ~ 1.22). Moreover, analysis of the resultant polymers was confirmed by GPC, NMR spectra and MALDI-TOF MS techniques which revealed that P(PA- alt -CHO) polyester with well-defined alternating structure without formation of polyether and DMAP can act as an initiator in DMAP/DPP catalyst system, resulting more effective ring-opening alternating copolymerization. However, trace amount of phthalic acid as an impurity in the system also acted as a bifunctional initiator influencing the molecular weight of the polymer. In addition, the DMAP/DPP catalytic system remained stable at high temperature and the development of this simple catalytic process provided a new chance to exploit in organocatalyzed polymerization.
研究领域:
高分子化学
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有机催化
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DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xin Huang,Zhongqing Yang,Jiaqi Qiu,Bo Tang,Changlei Qin,Yunfei Yan,Jingyu Ran
Ethylene is a valuable and widely used platform in industrial chemical. Herein, we report a potential route for selective and efficient ethylene production via chemical looping oxidative dehydrogenation of ethane using alkaline, rare earth and transition metals modified BaCoO 3 perovskite as the circulative redox catalyst. The catalysts were characterized by XRD, XPS, SEM, TEM, N 2 adsorption-desorption, H 2 -TPR, and O 2 -TPD analyses. Results showed that ethane conversion and ethylene selectivity were mainly regulated by lattice oxygen and Co valence of the catalysts, respectively. Doping of La to A-site of BaCoO 3 promoted ethane conversion while doping of Cu to B-site contributed to ethylene selectivity. Both ethane conversion and ethylene selectivity were enhanced by the co-doping of La and Cu to A/B-site of BaCoO 3 , obtaining the highest selectivity of 81.2% at ethane conversion of 67.6%. The ethylene yield over Ba 0.7 La 0.3 Co 0.8 Cu 0.2 O 3 was 7.9% higher than that over patent BaCoO 3 (53.7% versus 45.8%). In addition, the Ba 0.7 La 0.3 Co 0.8 Cu 0.2 O 3 catalyst also exhibited a stable catalytic performance during 12 redox recycles.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
CHEMISTRY & BIODIVERSITY
·
2021
·Vol. 18
·期 4
·e2000910
·
IF 2.408
Bingbing Ma,Qianwen Wang,Bing-Nan Han,Haruo Ikeda,Chunfang Zhang,Lian-Hua Xu
Cytochrome P450 enzymes (P450s) are versatile biocatalysts, which insert a molecular oxygen into inactivated C−H bonds under mild conditions. CYP105D7 from Streptomyces avermitilis has been reported as a bacterial substrate-promiscuous P450 which catalyzes the hydroxylation of 1-deoxypentalenic acid, diclofenac, naringenin, compactin and steroids. In this study, CYP105D7 catalyzes hydroxylation, epoxidation and dehydrogenation of capsaicin, a pharmaceutical agent, revealing its functional diversity. The kinetic parameters of the CYP105D7 oxidation of capsaicin were determined as K m =311.60±87.30 μM and k cat =2.01±0.33 min −1 . In addition, we conducted molecular docking, mutagenesis and substrate binding analysis, indicating that Arg81 plays crucial role in the capsaicin binding and catalysis. To our best knowledge, this study presents the first report to illustrate that capsaicin can be catalyzed by prokaryotic P450s.
研究领域:
生物化学
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药物代谢
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DOI
PubMed
高影响因子
Journal of the American Chemical Society
·
2019
·
IF 14.695
Cheng-Jian Zhang,Tian-Cheng Zhu,Xiao-Han Cao,Xin Hong,Xing-Hong Zhang
The synthesis of poly(thioether), a highly desired sulfur-containing polymer, is still a key challenge. Herein, we report a simple and facile approach to poly(thioether)s by closed-system one-pot reaction of carbonyl sulfide (COS) and epoxides. This route underwent the coupling reaction of COS with epoxides, followed by decarboxylative ring-opening polymerization (ROP) of the generated mixed cyclic thiocarbonates with releasing of CO2 and a little bit of COS. Organic base was used as catalyst and initiator in the two steps, respectively. The oxygen/sulfur exchange reaction was driven by successive regioselective elementary reactions and spontaneous releasing of CO2 (COS), leading to the sulfur atom of COS transferring to poly(thioether)s, which was well demonstrated by DFT studies. This work provides an easy-to-handle, metal-free route to poly(thioether)s bearing diverse structures by using readily available chemicals.
研究领域:
高分子化学
·
材料科学
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DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2025
·
IF 9.5
Chang'an Wang,Zuoshuai Xi,Tao Ban,Zhiyuan Liu,Yibin Luo,Hongyi Gao,Ge Wang,Xingtian Shu
The fine design and regulation of the microenvironment surrounding active sites in metal–organic frameworks (MOFs) are crucial for optimizing electron distribution and enhancing oxygen activation, thereby achieving superior catalytic performance in epoxidation reactions. In this study, we focus on the synergistic modulation of the cobalt (Co) microenvironment in MOF-74 through the introduction of lanthanum (La) sites and defect engineering. The incorporation of rare-earth La species effectively redirects the electron density of Co sites, enhancing their oxygen activation capabilities. Additionally, the presence of coordination-unsaturated Co sites facilitates rapid electron transfer from active sites to substrates, promoting the generation of superoxide radicals. Notably, the Co0.50La0.50-MOF-74-4eq sample demonstrates exceptional molecular oxygen utilization and epoxidation performance, achieving a cyclohexene conversion of 92.2% with a selectivity of 93.9% for 1,2-epoxycyclohexane at 40 °C within 1 hour. Furthermore, this catalyst exhibits broad applicability across different substrates. Density functional theory calculations, complemented by in situ analysis, confirm that molecular oxygen activation occurs at Co sites while suppressing the allylic oxidation pathway, thus favoring the conversion of cyclohexene to epoxides. This work elucidates how strategically tailoring the electronic properties around catalytic sites can dramatically influence catalytic behavior in heterogeneous catalysis, providing new insights for the rational design of advanced catalysts.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
CATALYSIS LETTERS
·
2021
·Vol. 152
·期 1
·162-171
·
IF 3.186
Yang Xingyu,Li Xu,Dong Jinxiang
The epoxidation of terminal olefins (e.g., 1-octene) presents an enormous challenge owing to their electron-deficient nature, whereas the vicinal diols that are derived from epoxides are highly desirable as fine chemicals. We report the facile preparation of magnesium pyrophosphate via the thermal decomposition of commercially available newberyite and the first use of magnesium pyrophosphate as a solid catalyst for terminal olefin epoxidation. The as-synthesized magnesium pyrophosphate was characterized by XRD, FTIR, SEM–EDS, and CO 2 -TPD techniques. The CO 2 -TPD results proved that the medium base was dominant in magnesium pyrophosphate. Magnesium pyrophosphate exhibited an effective catalytic activity in the liquid-phase epoxidation of 1-octene with a 94.2% selectivity of epoxide using aqueous hydrogen peroxide as oxidant in the presence of acetonitrile solvent. The influences of various reaction parameters, including solvent, temperature, H 2 O 2 to 1-octene molar ratio, amount of magnesium pyrophosphate, reaction time, and solvent amount were investigated. According to the reaction mechanism, the perhydroxyl ion that originated from H 2 O 2 heterocracking formed in the presence of magnesium pyrophosphate and reacted with acetonitrile to generate active intermediate peroxycarboximidic acid. The epoxide and amide formed when active oxygen was transferred from peroxycarboximidic acid to the olefin. Therefore, magnesium pyrophosphate was an appropriate catalyst for 1-octene epoxidation. Graphic Abstract
研究领域:
化学
·
催化化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）