Glucose-conjugated malonato-platinum(II) complexes are designed and synthesized to target tumor-specific active transporters, namely, glucose transporters (GLUTs); the complexes exhibit much higher aqueous solubility by 150 times, improved potency in cytotoxicities by 10 times, and increased therapeutic index by over 30 fold compared to the newest generation of clinical drugs oxaliplatin.
The reaction of phenyliodine bis(trifluoroacetate) (PIFA) with a series of anilides 1 (E = CO(2)Et) in CF(3)CH(2)OH was found to give 3-hydroxy-2-oxindole derivatives 2, while that with various anilides 1' (E = CON(R(4))Ar) afforded the C(2)-symmetric or unsymmetric spirooxindoles 3. These processes feature a metal-free oxidative C(sp(2))-C(sp(3)) bond formation, followed by oxidative hydroxylation or spirocyclization.
A group of functionalized oxazoles were synthesized in moderate to good yields from enamides via phenyliodine diacetate (PIDA)-mediated intramolecular cyclization. The main advantageous features of the present method include its broad substrate scope and the heavy-metal-free characteristic of the oxidative carbon-oxygen bond formation process.
The glucose transporter 1 (GLUT1) belongs to the major facilitator superfamily (MFS) and is responsible for the constant uptake of glucose. However, the molecular mechanism of sugar transport remains obscure. In this study, homology modeling and molecular dynamics (MD) simulations in lipid bilayers were performed to investigate the combination of the alternate and multisite transport mechanism of glucose with GLUT1 in atomic detail. To explore the substrate recognition mechanism, the outward-open state human GLUT1 homology model was generated based on the template of xylose transporter XylE (PDB ID: 4GBZ), which shares up to 29% sequence identity and 49% similarity with GLUT1. Through the MD simulation study of glucose across lipid bilayer with both the outward-open GLUT1 and the GLUT1 inward-open crystal structure, we investigated six different conformational states and identified four key binding sites in both exofacial and endofacial loops that are essential for glucose recognition and transport. The study further revealed that four flexible gates consisting of W65/Y292/Y293-M420/TM10b-W388 might play important roles in the transport cycle. The study showed that some side chains close to the central ligand binding site underwent larger position changes. These conformational interchanges formed gated networks within an S-shaped central channel that permitted staged ligand diffusion across the transporter. This study provides new inroads for the understanding of GLUT1 ligand recognition paradigm and configurational features which are important for molecular, structural, and physiological research of the MFS members, especially for GLUT1-targeted drug design and discovery.
A variety of enaminones and enamine carboxylic esters were converted to trifluoroethoxylated 2H-azirines through reactions with PhIO in trifluoroethanol (TFE). The cascade reaction is postulated to proceed via a PhIO-mediated oxidative trifluoroethoxylation and a subsequent azirination of the α-trifluoroethoxylated enamine intermediates.
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