Triazole–Au(I) complex as chemoselective catalyst in promoting propargyl ester rearrangements

Triazole–Au (TA–Au) catalysts were employed in several transformations involving propargyl ester rearrangement. Good chemoselectivity was observed, which allowed the effective activation of the alkyne without affecting the reactivity of the allene ester intermediates. These results led to the investigation of the preparation of allene ester intermediates with TA–Au catalysts under anhydrous conditions. As expected, the desired 3,3-rearrangement products were obtained in excellent yields (generally \u3e90% yields with 1% loading). Besides the typical ester migrating groups, carbonates and carbamates were also found to be suitable for this transformation, which provided a highly efficient, practical method for the preparation of substituted allenes

Dynamic Optimal Pricing Strategies for Knowledge-Sharing Platforms

The sharing economy is a fast-growing business model, and the sharing resources have crept from physical assets (e.g., vehicles and houses) to intangible assets (e.g., skills and knowledge). Online knowledge-sharing platforms allow sharers to offer knowledge products in various forms and can generate revenue through charging users subscription and/or transaction fees. How to charge bilateral users is an essential and complex decision-making problem that puzzles knowledge-sharing platforms. This study proposes a dynamic optimal pricing model that involves multiple development stages based on the optimal control theory. In addition, the inherent features of knowledge products and sharers’ social capitals are considered. The applicability and utility of the proposed model is verified through numerical experiments on an empirical dataset from the China’s largest knowledge-sharing platform named Zhihu. The results reveal that the platform can adjust its pricing strategies to achieve different optimization goals and this is conducive to its sustainable development

Antitumor Efficacy and Mechanism in Hepatoma H22-Bearing Mice of Brucea javanica

Brucea javanica is a traditional herbal medicine in China, and its antitumor activities are of research interest. Brucea javanica oil, extracted with ether and refined with 10% ethyl alcohol from Brucea javanica seed, was used to treat hepatoma H22-bearing mice in this study. The antitumor effect and probable mechanisms of the extracted Brucea javanica oil were studied in H22-bearing mice by WBC count, GOT, GPT levels, and western blotting. The H22 tumor inhibition ratio of 0.5, 1, and 1.5 g/kg bw Brucea javanica oil were 15.64%, 23.87%, and 38.27%. Brucea javanica oil could inhibit the involution of thymus induced by H22 tumor-bearing, but it could not inhibit the augmentation of spleen and liver. Brucea javanica oil could decrease the levels of WBC count and GOT and GPT in H22-bearing mice. The protein levels of GAPDH, Akt, TGF-β1, and α-SMA in tumor tissues decreased after being treated with Brucea javanica oil. Disturbing energy metabolism and neoplastic hyperplasia controlled by Akt and immunoregulation activity were its probable antitumor mechanisms in hepatoma H22-bearing mice

Nucleophile Promoted Gold Redox Catalysis with diazonium: CBr, C-S and C-P Bond Formation through Catalytic Sandmeyer Coupling

Gold-catalyzed C-heteroatom (C-X) coupling reactions are evaluated without using sacrificial oxidants. Vital to the success of this methodology is the nucleophile-assisted activation of aryldiazonium salts, which could be an effective oxidant to convert Au(I) to Au(III) even without the addition of assisting ligand or photocatalyst. By accelerating reaction kinetics to outcompete C-C homo-coupling or diazonium dediazoniation, gold-catalyzed Sandmeyer reactions were achieved with different nucleophiles, forming C-Br, C-S and C-P bonds in high yields and selectivity

Nucleophile Promoted Gold Redox Catalysis With Diazonium: C-Br, C-S And C-P Bond Formation Through Catalytic Sandmeyer Coupling

Gold-catalyzed C-heteroatom (C–X) coupling reactions are evaluated without using sacrificial oxidants. Vital to the success of this methodology is the nucleophile-assisted activation of aryldiazonium salts, which could be an effective oxidant for converting Au(I) to Au(III) even without the addition of an assisting ligand or photocatalyst. By accelerating the reaction kinetics to outcompete C–C homo-coupling or diazonium dediazoniation, gold-catalyzed Sandmeyer reactions were achieved with different nucleophiles, forming C–Br, C–S and C–P bonds in high yields and selectivities