Promotion Effect of Pd in the Ru/C-Catalyzed Hydrogenation of Benzofurans

The selective hydrogenation of benzofurans (BFs) over supported metal catalysts is of fundamental interest for producing biologically active and pharmacologically relevant chemicals. However, most supported metal catalysts are confronted with the dilemmas of activity and selectivity. Herein, we report that the deposition of a small amount of Pd on commercial Ru/C makes inactive Ru/C active in BF hydrogenation at low temperatures (e.g., 4 °C), and the selectivity to 2,3-dihydrobenzofuran as high as 92% was obtained. Systematic investigations show that the catalytic performance of Pd^Ru/C is attributed to the synergy of Pd and Ru, respectively, for the activation of H2 and BF and a significantly reduced energy barrier for the C1 (O–C1C2) addition step due to the interaction between BF and oxyphilic Ru. Besides, a series of bioactive compounds could be successfully produced by the hydrogenation of BF derivatives with Pd^Ru/C as a catalyst. This study provides insights into the activation of O-containing heteroaromatics by the incorporation of oxyphilic sites in supported metal catalysts

Methanol Steam Reforming for Hydrogen Production over CuZnZrOx: Promotion Effect of Cu

Mixed metal oxides catalyze steam reforming of methanol (SRM) usually at reaction temperatures of >400 °C, leading to high energy consumption. Herein, we report that a small amount of Cu doping can greatly promote the activity of ZnZrOx in the SRM at low temperatures. The 2%CuZnZrOx can efficiently catalyze the SRM at temperatures as low as 300 °C to give 95.3% methanol conversion, but ZnZrOx only shows low methanol conversion (23.6%) under similar reaction conditions. Structural characterizations show that CuZnZrOx catalysts are ternary solid solutions rich in Ov, which is favorable for water activation. CuZnZrOx with low-valence Cuδ+ shows faster kinetics for the generation and decomposition of HCOOH intermediate than ZnZrOx. The co-presence of Cuδ+ and Ov contributes to the excellent performance of CuZnZrOx. These findings provide an efficient strategy for promoting the catalytic performance of metal oxides toward SRM

Cationic Zn–Porphyrin Polymer Coated onto CNTs as a Cooperative Catalyst for the Synthesis of Cyclic Carbonates

The development of solid catalysts containing multiple active sites that work cooperatively is very attractive for biomimetic catalysis. Herein, we report the synthesis of bifunctional catalysts by supporting cationic porphyrin-based polymers on carbon nanotubes (CNTs) using the direct reaction of 5,10,15,20-tetrakis­(4-pyridyl)­porphyrin zinc­(II), di­(1<i>H</i>-imidazol-1-yl)­methane, and 1,4-bis­(bromomethyl)­benzene in the presence of CNTs. The bifunctional catalysts could efficiently catalyze the cycloaddition reaction of epoxides and CO₂ under solvent-free conditions with porphyrin zinc­(II) as the Lewis acid site and a bromine anion as a nucleophilic agent working in a cooperative way. Furthermore, a relative amount of porphyrin zinc­(II) and quaternary ammonium bromide could be facilely adjusted for facilitating cooperative behavior. The bifunctional catalyst with a TOF up to 2602 h^–1 is much more active than the corresponding homogeneous counterpart and is one of the most active heterogeneous catalysts ever reported under cocatalyst-free conditions. The high activity is mainly attributed to the enhanced cooperation effect of the bifunctional catalyst. With a wide substrate scope, the bifunctional catalyst could be stably recycled. This work demonstrates a new approach for the generation of a cooperative activation effect for solid catalysts

The summary of OR in cancer vs. control.

<p>The summary of OR in cancer vs. control.</p

Forest plot of the correlation between <i>MGMT</i> methylation and gender.

<p>Forest plot of the correlation between <i>MGMT</i> methylation and gender.</p

The Correlation of <i>MGMT</i> Promoter Methylation and Clinicopathological Features in Gastric Cancer: A Systematic Review and Meta-Analysis

<div><p>The silencing of the tumor suppressor gene O-6-methylguanine-DNA methyltransferase (<i>MGMT</i>) by promoter methylation commonly occurs in human cancers. The relationship between <i>MGMT</i> promoter methylation and gastric cancer (GC) remains inconsistent. This study aimed to evaluate the potential value of <i>MGMT</i> promoter methylation in GC patients. Electronic databases were searched to identify eligible studies. The pooled odds ratio (OR) and the corresponding 95% confidence interval (95% CI) were used to evaluate the effects of <i>MGMT</i> methylation on GC risk and clinicopathological characteristics. In total, 31 eligible studies including 2988 GC patients and 2189 nonmalignant controls were involved in meta-analysis. In the pooled analysis, <i>MGMT</i> promoter methylation was significantly associated with GC risk (OR = 3.34, P < 0.001) and substantial heterogeneity (P < 0.001). Meta-regression and subgroup analyses based on the testing method, sample material and ethnicity failed to explain the sources of heterogeneity. Interestingly, <i>MGMT</i> methylation showed a trend associated with gender, and methylation is lower in males compared with females (OR = 0.76, 95% CI = 0.56–1.03). We did not find a significant association in relation to tumor types, clinical stage, age status or <i>H</i>. <i>pylori</i> status in cancer (all P > 0.1). <i>MGMT</i> promoter methylation may be correlated with the prognosis of GCs in disease free survival (DFS) or overall survival (OS) for univariate analysis. <i>MGMT</i> promoter methylation may play a crucial role in the carcinogenesis and prognosis of GC. <i>MGMT</i> methylation was not correlated with tumor types, clinical stage, age status, <i>H</i>. <i>pylori</i> status. However, the result of the association of <i>MGMT</i> methylation and gender should be considered with caution.</p></div

Meta-regression analysis in cancer vs. control.

<p>Meta-regression analysis in cancer vs. control.</p

Flow chart of the literature search strategy.

<p>Flow chart of the literature search strategy.</p

The correlation of <i>MGMT</i> promoter methylation and clinicopathological features.

<p>The correlation of <i>MGMT</i> promoter methylation and clinicopathological features.</p

Forest plot of the correlation between <i>MGMT</i> methylation and GC.

<p>Forest plot of the correlation between <i>MGMT</i> methylation and GC.</p