116404-47-8Relevant academic research and scientific papers
Design, Synthesis, and Self-Assembly of Polymers with Tailored Graft Distributions
Chang, Alice B.,Lin, Tzu-Pin,Thompson, Niklas B.,Luo, Shao-Xiong,Liberman-Martin, Allegra L.,Chen, Hsiang-Yun,Lee, Byeongdu,Grubbs, Robert H.
, p. 17683 - 17693 (2017)
Grafting density and graft distribution impact the chain dimensions and physical properties of polymers. However, achieving precise control over these structural parameters presents long-standing synthetic challenges. In this report, we introduce a versatile strategy to synthesize polymers with tailored architectures via grafting-through ring-opening metathesis polymerization (ROMP). One-pot copolymerization of an ω-norbornenyl macromonomer and a discrete norbornenyl comonomer (diluent) provides opportunities to control the backbone sequence and therefore the side chain distribution. Toward sequence control, the homopolymerization kinetics of 23 diluents were studied, representing diverse variations in the stereochemistry, anchor groups, and substituents. These modifications tuned the homopolymerization rate constants over 2 orders of magnitude (0.36 M-1 s-1 homo -1 s-1). Rate trends were identified and elucidated by complementary mechanistic and density functional theory (DFT) studies. Building on this foundation, complex architectures were achieved through copolymerizations of selected diluents with a poly(d,l-lactide) (PLA), polydimethylsiloxane (PDMS), or polystyrene (PS) macromonomer. The cross-propagation rate constants were obtained by nonlinear least-squares fitting of the instantaneous comonomer concentrations according to the Mayo-Lewis terminal model. In-depth kinetic analyses indicate a wide range of accessible macromonomer/diluent reactivity ratios (0.08 1/r2 20), corresponding to blocky, gradient, or random backbone sequences. We further demonstrated the versatility of this copolymerization approach by synthesizing AB graft diblock polymers with tapered, uniform, and inverse-tapered molecular "shapes." Small-angle X-ray scattering analysis of the self-assembled structures illustrates effects of the graft distribution on the domain spacing and backbone conformation. Collectively, the insights provided herein into the ROMP mechanism, monomer design, and homo- and copolymerization rate trends offer a general strategy for the design and synthesis of graft polymers with arbitrary architectures. Controlled copolymerization therefore expands the parameter space for molecular and materials design.
STEREOSELECTIVE PIG LIVER ESTERASE-CATALYZED HYDROLYSIS OF RIGID BICYCLIC MESO-DIESTERS : PREPARATION OF OPTICALLY PURE 4,7-EPOXYTETRA- AND HEXA-HYDROPHTHALIDES.
Bloch, R.,Guibe-Jampel, E.,Girard, C.
, p. 4087 - 4090 (1985)
The bicyclic and rather rigid meso-diesters 1 - 3 have been found to be good substrates for pig liver esterase.The half-esters obtained have been converted to either one of the enantiomers of tricyclic lactones, of potential value for natural product synthesis.
Serendipitous and acid catalyzed synthesis of spirolactones
Kotha, Sambasivarao,Dipak, Mirtunjay Kumar,Mobin, Shaikh M.
, p. 4616 - 4619 (2011)
Formation of three diasteroisomeric spirodilactones 14a-c and 11 has been reported from diester 13 and 9, respectively, under the influence of mineral acid.
Stabilization and controlled release of reactive molecules by solid-state van der waals capsules
Wei, Wei,Li, Wanlong,Li, Zhongfeng,Su, Weiping,Hong, Maochun
, p. 469 - 473 (2013)
Control by encapsulation: A dimeric capsule assembled from a tripodal host by van der Waals forces can stabilize a series of reactive molecules, such as cyclopentadiene and trichlorosilane, in the crystalline state even under relatively harsh conditions. Moreover, these reactive molecules can be controllably released into liquid media for further chemical reaction by thermal programming, leaving the insoluble host molecules behind for easy separation and reuse (see scheme). Copyright
Diels-Alder reactions in chloroaluminate ionic liquids: Acceleration and selectivity enhancement
Lee, Carlos W.
, p. 2461 - 2464 (1999)
The utility of room temperature chloroaluminate ionic liquids as solvent and catalyst for the synthetically important Diels-Alder reaction was studied. The AlCl3-1-ethyl-3-methyl-1H-imidazolium chloride medium proved to be ideally suited for Diels-Alder reactions. Endo selectivity and rate enhancement were observed for the cyclopentadiene/methyl acrylate Diels- Alder reaction.
Synthesis and evaluation of cationic norbornanes as peptidomimetic antibacterial agents
Hickey, Shane M.,Ashton, Trent D.,Khosa, Simren K.,Robson, Ryan N.,White, Jonathan M.,Li, Jian,Nation, Roger L.,Yu, Heidi Y.,Elliott, Alysha G.,Butler, Mark S.,Huang, Johnny X.,Cooper, Matthew A.,Pfeffer, Frederick M.
, p. 6225 - 6241 (2015)
A series of structurally amphiphilic biscationic norbornanes have been synthesised as rigidified, low molecular weight peptidomimetics of cationic antimicrobial peptides. A variety of charged hydrophilic functionalities were attached to the norbornane scaffold including aminium, guanidinium, imidazolium and pyridinium moieties. Additionally, a range of hydrophobic groups of differing sizes were incorporated through an acetal linkage. The compounds were evaluated for antibacterial activity against both Gram-negative and Gram-positive bacteria. Activity was observed across the series; the most potent of which exhibited an MIC's ≤ 1 μg mL-1 against Streptococcus pneumoniae, Enterococcus faecalis and several strains of Staphylococcus aureus, including multi-resistant methicillin resistant (mMRSA), glycopeptide-intermediate (GISA) and vancomycin-intermediate (VISA) S. aureus.
The mechanism of on-water catalysis
Beattie, James K.,McErlean, Christopher S. P.,Phippen, Christopher B. W.
, p. 8972 - 8974 (2010)
Acid catalysis by interfacial water: A new mechanism is proposed for onwater catalysis, the acceleration of organic reactions when conducted in aqueous emulsions. It involves the protonation of a substrate by water, driven by the strong adsorption of hydroxide ions at aqueous interfaces with oils. This accounts for the specific role of water, and a deuterium isotope effect, at the interface, on reactions known to be acid-catalysed.
EIN BEITRAG ZUR STEREOSPEZIFITAET VON (4+2)-CYCLOADDITIONEN
Prantl, B.,Eibler, E.,Sauer, J.
, p. 1139 - 1142 (1982)
Addition of maleo-, fumaronitrile and maleic-, fumaric ester (with and without AlCl3) to cyclopentadiene are stereospecfic to a degree of higher than 99.8-99.98 percent.
Diels-Alder reaction in protic ionic liquids
Janus, Ewa,Goc-Maciejewska, Izabela,?ozyński, Marek,Pernak, Juliusz
, p. 4079 - 4083 (2006)
Protic imidazolium ionic liquids have been tested as reaction media in the Diels-Alder reaction between cyclopentadiene and two dienophiles (dimethyl maleate and methyl acrylate). Good conversions and endo/exo selectivities were achieved. The activation of the dienophile by hydrogen bonding with protic imidazolium ILs was demonstrated.
Cycloaddition reactions of dimethyl maleate and fumarate with cyclopentadiene on γ-alumina. Competing mechanisms for epimerization of the Diels-Alder adducts
Bains,Pagni,Kabalka
, p. 5663 - 5666 (1991)
The Diels-Alder adducts, formed in the reaction of cyclopentadiene and dimethyl maleate and fumarate, epimerize on γ-alumina by competing mechanisms involving the retro-Diels-Alder reaction and enolates.
