In order to understand the hot and forward trend of the research about the blockchain in the Chinese e-commerce field, it takes the literature in e-commerce field with the blockchain of the CNKI database as the sample, and it also uses CiteSpace V, SPSS21.0, Excel2010 and CNKI platform to carry out bibliometrics and visualization analysis. The energy distribution in the area of China's block chain research in e-commerce field is analyzed from the aspects of subject distribution, research level, source journals, author distribution, research institutions, fund projects and so on. And from the high frequency key words, key words social network and other dimensions depth analysis of the research hot spots and frontiers in the e-commerce field of block chain in Chinese academic circles. The study found: The research of China's block chain in the field of publishing has not yet started completely. It needs to be paid attention to by the academic circle, and its research field, scale of cooperation，scale and depth of research need to be strengthened. The research focuses mainly on the application of the agricultural products, the payment of e-commerce, the traceability of the electric business field and the regulatory aspects of the e-commerce. E-commerce segments, e-commerce related areas, e-commerce payment refinement, e-business logistics refinement, e-commerce finance, new technology or ideas related aspects are relatively cutting-edge potential research trends.
Abstract Echinoside A, a sulfonylated holostane tetrasaccharide with potent anticancer and antifungal activity, was synthesized in a longest linear sequence of 35 steps and 0.6 % overall yield. The synthetic approach is adaptable to the synthesis of congeners and analogues, as exemplified by the ready synthesis of ds‐echinoside A and echinoside B, and thus will facilitate in‐depth studies on the promising biological effects of echinoside A. Moreover, the present synthesis demonstrates the feasibility of synthetic access to the characteristic complex triterpene glycosides that occur ubiquitously in sea cucumbers.
A mechanism that enables direct aldehyde C-H functionalization has been achieved via the synergistic merger of photoredox, nickel, and hydrogen atom transfer catalysis. This mild, operationally simple protocol transforms a wide variety of commercially available aldehydes, along with aryl or alkyl bromides, into the corresponding ketones in excellent yield. This C-H abstraction coupling technology has been successfully applied to the expedient synthesis of the medicinal agent haloperidol.
Container multimodal transport is the main transport mode and development trend of international logistics.Information system plays an important role in the development of multimodal transport and is an important part of regional multimodal transport network layout.Due to the influence of global economic integration and borderless logistics, the improvement of logistics efficiency depends more on information management technology.Based on the research results at home and abroad, this paper introduces the image processing system, and establishes the research model of container multimodal transport logistics security emergency decision support system based on image processor by using mathematical modeling optimization method, summary and induction method, and the combination of qualitative analysis and quantitative analysis method Based on the theory, early warning management method and emergency decision system, an emergency decision support system for container multimodal transportation logistics safety based on image processor is established.This study is prospective.The results show that the overall efficiency is improved by 20% and the overall efficiency is higher after using the method in this paper, which has certain practical value.
The incorporation of aromatic difluoromethyl motifs has proven to be a fruitful strategy for enhancing the therapeutic profiles of modern pharmaceutical candidates. While the defluorofunctionalization of trifluoromethylarenes offers a promising pathway toward diverse aromatic difluoromethyl compounds, current methods are predominantly limited to two-component reactions. Multicomponent cascade reactions (MCRs) involving a transient aromatic difluoromethyl radical are still uncommon and highly sought after, owing to their capacity to rapidly generate challenging molecular structures. In this study, we present a photocatalytic manifold that combines commercially available trifluoromethylarenes, feedstock dienes, and various nucleophiles to achieve a modular defluorinative MCR. This method features mild reaction conditions and a broad substrate scope with excellent functional group compatibility. Furthermore, this protocol enables a previously unreported process of defluorinative editing for the resulting MCR aromatic difluoromethyl adducts. Preliminary mechanistic studies support the proposed photoexcited palladium catalytic cycle.
The incorporation of aromatic difluoromethyl motifs has proven to be a fruitful strategy for enhancing the therapeutic profiles of modern pharmaceutical candidates. While the defluorofunctionalization of trifluoromethylarenes offers a promising pathway towards diverse aromatic difluoromethyl compounds, current methods are predominantly limited to two-component reactions. Multicomponent cascade reactions (MCRs) involving a transient aromatic difluoromethyl radical are still uncommon and highly sought after owing to their capacity to rapidly generate challenging molecular structures. In this study, we present a photocatalytic manifold that combines commercially available trifluoromethylarenes, feedstock dienes and various nucleophiles to achieve a modular defluorinative MCR. This method features mild reaction conditions and a broad substrate scope with excellent functional group compatibility. Furthermore, this protocol enables a previously unreported process of formal defluorinative editing for the resulting MCR aromatic difluoromethyl adducts. Preliminary mechanistic studies support the proposed photoinduced palladium catalytic cycle.
By selecting the representative e-commerce enterprises as samples, combined with the domestic and foreign agricultural e-commerce quality research results, the paper constructs consumer satisfaction evaluation index of agricultural products e-commerce. AHP method and entropy weight method are utilized to calculate the combination weight of each index. Together with the TOPSIS method, the evaluation model of agricultural products e-commerce is designed. Through the empirical analysis, it finds that JD fresh platform satisfaction evaluation is the highest, and Womai.com satisfaction evaluation is the lowest.
Alkyl oxalates, prepared from their corresponding alcohols, are engaged for the first time as carbon radical fragments in metallaphotoredox catalysis. In this report, we demonstrate that alcohols, native organic functional groups, can be readily activated with simple oxalyl chloride to become radical precursors in a net redox-neutral Csp3–Csp2 cross-coupling with a broad range of aryl halides. This alcohol-activation coupling is successfully applied to the functionalization of a naturally occurring steroid and the expedient synthesis of a medicinally relevant drug lead.
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