Investigation on the Ring-Opening Reactions of 3-(1H-1,2,4-Triazol-1-yl)1,5-benzothiazepines with Arylonitrile Oxides

Abstract

Novel ring opening compounds, (Z)-2-((Z)-((E)-1,3-diaryl-2-(1H-1,2,4-triazol-1-yl)allylidene)amino)aryl N-hydroxybenzimidothioates 4a–r, were obtained from the reaction of 2,4-diaryl-3-(1H-1,2,4-triazol-1-yl)-2,5-dihydro-1,5-benzothiazepines 3a–f and arylonitrile oxides. The structure of these products has been elucidated by spectroscopic analysis and, in one case, X-ray crystallographic analysis. According to the result, it was presumed that this reaction did not proceeded through 1,3-dipolar cycloaddition reaction.

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GRAPHICAL ABSTRACT      

Diffusion Mechanism of As‐spun Polyacrylonitrile Fiber in a Dimethyl Sulfoxide‐Water Coagulation Bath

In this paper, the diffusion mechanism of as‐spun PAN fiber was investigated in dimethyl sulfoxide‐water by determining the dynamic compositions of the fibers and the diffusion coefficients of solvent and nonsolvent during coagulation. The diffusion process could be divided into two stages. Results showed that the first stage of the diffusion process was the most important during the whole process, which was fundamental to further study on the formation mechanism. Also, compared with wet spinning, the dry‐jet wet spinning method had the advantage of mild coagulating at a high jet‐stretch. At high concentrations, the diffusion coefficients increased and the ratio of solvent diffusion coefficient to nonsolvent diffusion coefficient decreased; an increasing temperature resulted in the increase of both diffusion coefficients with a decrease in their ratios. To some extent, for the PAN‐DMSO‐water system, the more the ratios D_s*/D_n* tended to 1, the more the cross‐section shapes of as‐spun PAN fiber tended to be circular.     

A Facile Synthesis of Fused Phosphorus-Heterocycle with Bioactivity via Lawesson's Reagent

A convenient one-pot synthesis of fused phosphorus-heterocycles with biological activity via the cyclization reactions of Lawesson's reagent with bifunctional substrates is reported.     

A Novel Fission Process in Mini-emulsion RAFT Polymerization: Shell Crosslinked Nanoparticles as a Model

Shell crosslinked nanoparticles, prepared from copolymerization of styrene and disulfide crosslinker, using poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) as stabilizer and macroinitiator, exhibited a special fission behavior during the mini-emulsion RAFT polymerization process.     

Arylidene Copolyether Sulfones. I. Synthesis and Characterization of Some New Copolyether Sulfones Containing Dibenzylidene Cyclopentanone Moieties

Abstract

New copolyether sulfones containing 2,5-bis(4-oxo-benzylidene)-cyclopentanone moieties were prepared in the conventional literature manner by condensing the dipotassium salts of 2,5-bis(4-hydroxyphenzyl- idene)cyclopentanone (I) and 2, 2-bis(4-hydroxyphenyl)propane (Bisphenol A, III) with 4,4′-dichlorodiphenyl sulfone (II), or by condensing the dipotassium salts of I with chlorine-terminated Bisphenol A-4,4′-di-chlorodiphenylsulfone copolymers (V). The resulting copolyether sulfones were confirmed by IR, viscometry, DSC measurements, thermooptical (TOA), and thermogravimetric analysis (TGA).     

Physalinol A,a 1,10-seco-physalin with an epidioxy from Physalis alkekengi L. var. franchetii (Mast.) Makino

Physalinol A (1), a novel 1, 10-seco-physalin with a peroxy bridge, was isolated from the organic extracts of Physalis alkekengi L. var. franchetii (Mast.) Makino. The structure was determined on the basis of 1D and 2D NMR spectra and HR-ESI-MS data. The absolute configuration of 1 was evidenced by X-ray diffraction data and further confirmed by ECD calculations. The isolated compound 1 has no cytotoxicity against HCT-116 and PC-3 cancer cell lines and a weak antimicrobial activity against Escherichia coil. In addition, compound 1 also exhibited a weak anti-inflammatory action in lipopolysacaride (LPS)-induced RAW 264.7 macrophages with an IC₅₀ value of 57.3?±?1.03?μM.     

A novel azide-free asymmetric synthesis of oseltamivir phosphate (Tamiflu) starting from Roche’s epoxide

A novel azide-free asymmetric synthesis of oseltamivir phosphate 1 (Tamiflu®) starting from Roche’s epoxide is described. Roche epoxide 2 was converted into N-acetyl aminoalcohol 3 in 95% yield via a BF₃·OEt₂-catalyzed epoxide-opening with acetonitrile as a nucleophile. Compound 3 was then transformed into a methanesulfonate 4 in 98% yield. Compound 4 was converted into aziridine 5 in 91% yield. Aziridine 5 was subsequently converted into oseltamivir phosphate 1 via two paths (a and b). In the path a, compound 5 underwent aziridine-opening with diallylamine as a nucleophile to afford compound 7 in 93% yield; compound 7 could then be converted into oseltamivir phosphate 1 in 88% yield. In path b, compound 5 underwent aziridine-opening with isopropyl 2,2,2-trichloroacetimidate as a nucleophile to afford compound 8 in 94% yield, which was then converted into oseltamivir phosphate 1 in 82% yield.     

Enhancing the electrochemical performance of Li1.2Ni0.2Mn0.6O2 by surface modification with nickel–manganese composite oxide

Li-rich layered Li_1.2Ni_0.2Mn_0.6O₂ has been surface modified by nickel–manganese composite oxide (Ni_0.5Mn_1.5O _x ) to serve as a novel cathode material with novel layered spinel structure for lithium-ion battery. The as-prepared Li_1.2Ni_0.2Mn_0.6O₂ before and after surface modification by Ni_0.5Mn_1.5O _x as well as simply blended Li_1.2Ni_0.2Mn_0.6O₂ with spinel LiNi_0.5Mn_1.5O₄, have been characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electronic microscopy, and differential scanning calorimetry. Electrochemical studies indicate that the Ni_0.5Mn_1.5O _x surface modified Li_1.2Ni_0.2Mn_0.6O₂ with peculiar layered spinel character dramatically represented increased discharge capacity, improved cycling stability as well as excellent rate capability at high-voltage even up to 5.0 V.