The first fluorescent chemical traps for (1)O(2) have been developed. DPAXs react specifically with (1)O(2) to yield the corresponding endoperoxides, DPAX-EPs (see scheme; X = H, Cl, F). DPAXs scarcely fluoresce, while DPAX-EPs are strongly fluorescent. Since the fluorescence of these probes is unaffected by H(2)O(2), superoxide, and nitric oxide, they are useful for the selective detection of (1)O(2) in biological systems.
A new approach is demonstrated for the synthesis of macrotetralides through an olefin metathesis reaction using Grubbs' second-generation catalyst with titaniumisopropoxide as a cocatalyst. This study demonstrates a tandemself-cross and ring-closingmetathesisapproach to form macrocyclic ring systems with excellent (E) selectivity. The reaction was optimized with regard to functional group, catalyst
Water-Soluble and Water-Insoluble, Ring Opening Metathesis Polymerization Products, Monomers and Related Methods
申请人:Tew Gregory N.
公开号:US20090082524A1
公开(公告)日:2009-03-26
The invention provides certain novel water-soluble and water-insoluble monomers for ring opening metathesis polymerization and novel polymers, compositions and products, and related methods thereof.
Diels-Alder reaction of furan with some dienophiles
作者:T.A. Eggelte、H. de Koning、H.O. Huisman
DOI:10.1016/s0040-4020(01)93382-4
日期:1973.1
The reaction of furan and maleic acid was carried out in several solvents. The endo-adduct was isolated and the structure established by its spectral properties and conversion into known compounds. The adducts of furan with fumaric acid, diethyl fumarate and diethyl maleate are reported.
reduction of abundant carboxylic acids with molecular hydrogen has been of both practical and theoretical value. We herein report the homogeneous hydrogenation of dicarboxylicacids with the strategy of desymmetrization. Using a rhodium/bisphosphine catalyst, one carboxyl group of meso-diacids was selectively reduced to yield chiral lactones with satisfactory enantioselectivity. This method provides a straightforward
Ion Conducting ROMP Monomers Based on (Oxa)norbornenes with Pendant Imidazolium Salts Connected via Oligo(oxyethylene) Units and with Oligo(ethyleneoxy) Terminal Moieties
作者:Terry L. Price、U Hyeok Choi、Daniel V. Schoonover、Murugan Arunachalam、Renxuan Xie、Steven Lyle、Ralph H. Colby、Harry W. Gibson
DOI:10.1021/acs.macromol.8b02295
日期:2019.2.26
A matrix of 22 two-armed norbornene-based imidazolium TFSI monomers (8) was synthesized to determine the optimal structure in terms of single ion conductivity. For the chain tethering the imidazolium ring to the norbornene ring three or four oxyethylene units are optimal. A terminal group of two ethyleneoxy units was optimal. NMR studies indicated that both the tether oxyethylene units and the terminal ethyleneoxy units interact with the imidazolium cation via hydrogen bonding. 8r (X = 4, Y = 2) exhibited a conductivity of 9.57 x 10(-5) S/cm at 25 degrees C and a T-g of -46 degrees C. Low T-g values do not correlate with higher conductivity as a result of the H-bonding interactions. Stability toward autopolymerization and reasonable conductivities provide an acceptable platform for ion conducting ROMP polymers. Four one-armed norbornene-based imidazolium TFSI monomers (15) were prepared with tetra(ethyleneoxy) linkers/spacers and variable terminal groups. All of these exhibited low T(g)s (<-55 degrees C) and room temperature conductivities >10(-4) S/cm, the highest being 4.39 X 10(-4) S/cm for 15c (T-g = -69 degrees C), the analogue of 8r, providing hope for outstanding polymers. Three oxanorbornene-based two-armed imidazolium TFSI monomers (18) were prepared with varied linkers and terminal groups. 18b possesses a room temperature conductivity of 1.2 X 10(-4) S/cm, again augering well for polymers derived therefrom by ROMP.