Probing the Binding of 4β-(Benzoyl-thioureido)-4-deoxypodophyllotoxin to Human Serum Albumin by Molecular Spectroscopy

Journal of Solution Chemistry - The binding interaction of 4β-(benzoyl-thioureido)-4-deoxypodophyllotoxin (HY-1) with human serum albumin (HSA) was investigated by fluorescence,...     

Iron‐Catalyzed Highly Enantioselective cis‐Dihydroxylation of Trisubstituted Alkenes with Aqueous H2O2

Reliable methods for enantioselective cis‐dihydroxylation of trisubstituted alkenes are scarce. The iron(II) complex cis‐α‐[Fe^II(2‐Me₂‐BQPN)(OTf)₂], which bears a tetradentate N₄ ligand (Me₂‐BQPN=(R,R)‐N,N′‐dimethyl‐N,N′‐bis(2‐methylquinolin‐8‐yl)‐1,2‐diphenylethane‐1,2‐diamine), was prepared and characterized. With this complex as the catalyst, a broad range of trisubstituted electron‐deficient alkenes were efficiently oxidized to chiral cis‐diols in yields of up to 98 % and up to 99.9 % ee when using hydrogen peroxide (H₂O₂) as oxidant under mild conditions. Experimental studies (including ¹⁸O‐labeling, ESI‐MS, NMR, EPR, and UV/Vis analyses) and DFT calculations were performed to gain mechanistic insight, which suggested possible involvement of a chiral cis‐Fe^V(O)₂ reaction intermediate as an active oxidant. This cis‐[Fe^II(chiral N₄ ligand)]²⁺/H₂O₂ method could be a viable green alternative/complement to the existing OsO₄‐based methods for asymmetric alkene dihydroxylation reactions.     

A PRIORI ESTIMATE FOR LOWER SOLUTIONS OF ACLASS QUASILINEAR ELLIPTIC EQUATIONS

LetGbeaboundeddomaininthen-dimensionEuclideanspaceE",I相似文献   

双退缩抛物型方程解的一个性质

在Ｑ＝Ｇ×（０，Ｔ）考虑一类双退缩抛物型方程，在满足较一般的结构条件下，证明了如果它的解在抛物边界等于零，那么必是平凡解．     

各向异性Sobolev空间中拟线性椭圆型方程解的局部有界性

本文在很一般的结构条件下，证明了各向异性Ｓｏｂｏｌｅｖ空间中的拟线性椭圆方程解的局部有界性。     

Platinum(II)-catalyzed cyclization sequence of aryl alkynes via C(sp3)-H activation: a DFT study

The mechanism and intermediates of hydroalkylation of aryl alkynes via C(sp(3))-H activation through a platinum(II)-centered catalyst are investigated with density functional theory at the B3LYP/[6-31G(d) for H, O, C; 6-31+G(d,p) for F, Cl; SDD for Pt] level of theory. Solvent effects on reactions were explored using calculations that included a polarizable continuum model for the solvent (THF). Free energy diagrams for three suggested mechanisms were computed: (a) one that leads to formation of a Pt(II) vinyl carbenoid (Mechanism A), (b) another where the transition state implies a directed 1,4-hydrogen shift (Mechanism B), and (c) one with a Pt-aided 1,4-hydrogen migration (Mechanism C). Results suggest that the insertion reaction pathway of Mechanism A is reasonable. Through 4,5-hydrogen transfer, the Pt(II) vinyl carbenoid is formed. Thus, the stepwise insertion mechanism is favored while the electrocyclization mechanism is implausible. Electron-withdrawing/electron-donating groups substituted at the phenyl and benzyl sp(3) C atoms slightly change the thermodynamic properties of the first half of Mechanism A, but electronic effects cause a substantial shift in relative energies for the second half of Mechanism A. The rate-limiting step can be varied between the 4,5-hydrogen shift process and the 1,5-hydrogen shift step by altering electron-withdrawing/electron-donating groups on the benzyl C atom. Additionally, NBO and AIM analyses are applied to further investigate electronic structure changes during the mechanism.     

Optimal pricing and inventory policies with reliable and random-yield suppliers: characterization and comparison

In this paper, we study the joint pricing and inventory replenishment problem for a periodic-review inventory system with random demand and dual suppliers, one of the suppliers is reliable but more expensive, the other supplier is less expensive but is unreliable with random yield. We characterize the firm’s optimal policies that simultaneously determine the optimal ordering and pricing decisions in each period over a finite planning horizon, and investigate the impacts of supply source diversification and supplier reliability on the firm and on its customers. We show that having source diversification or higher reliability of suppliers not only increases the firm’s expected profit, but also results in a lower optimal selling price, thus they benefit both the firm and its customers.