81660-73-3Relevant academic research and scientific papers
Very Facile Polarity Umpolung and Noncovalent Functionalization of Inorganic Nanoparticles: A Tool Kit for Supramolecular Materials Chemistry
Zeininger, Lukas,Petzi, Stefanie,Sch?namsgruber, J?rg,Portilla, Luis,Halik, Marcus,Hirsch, Andreas
, p. 14030 - 14035 (2015)
The facile assembly of shell-by-shell (SbS)-coated nanoparticles [TiO2-PAC16]@shell1-7 (PAC16=hexadecylphosphonic acid), which are soluble in water and can be isolated as stable solids, is reported. In these functional architectures, an umpolung of dispersibility (organic apolar versus water) was accomplished by the noncovalent binding of ligands 1-7 to titania nanoparticles [TiO2-PAC16] containing a first covalent coating with PAC16. Ligands 1-7 are amphiphilic and form the outer second shell of [TiO2-PAC16]@shell1-7. The tailor-designed dendritic building blocks 3-5 contain negative and positive charges in the same molecule, and ligands 6 and 7 contain a perylenetetracarboxylic acid dimide (PDI) core (6/7) as a photoactive reporter component. In the redox and photoactive system [TiO2-PAC16]@shell7, electronic communication between the inorganic core to the PDI ligands was observed. Nanochameleons with switchable dispersion behavior: In these new shell-by-shell architectures, ionic and redox-active amphiphiles make the difference because they form an outer ligand shell that provides polarity umpolung, water solubility, and facile nanoparticle functionalization (see figure).
A mesoporous organosilica grafted Pd catalyst (MOG-Pd) for efficient base free and phosphine free synthesis of tertiary butyl esters via tertiary-butoxycarbonylation of boronic acid derivatives without using carbon monoxide
Ghosh, Kajari,Molla, Rostam Ali,Iqubal, Md. Asif,Islam
, p. 3540 - 3551 (2015/06/25)
A mesoporous organosilica grafted palladium(ii) catalyst was synthesized and characterized using various spectroscopic techniques. Its catalytic activity was evaluated for the synthesis of tertiary butyl esters via tert-butoxycarbonylation of boronic acid
Evolutionary Design of Low Molecular Weight Organic Anolyte Materials for Applications in Nonaqueous Redox Flow Batteries
Sevov, Christo S.,Brooner, Rachel E. M.,Chénard, Etienne,Assary, Rajeev S.,Moore, Jeffrey S.,Rodríguez-López, Joaquín,Sanford, Melanie S.
supporting information, p. 14465 - 14472 (2015/11/27)
The integration of renewable energy sources into the electric grid requires low-cost energy storage systems that mediate the variable and intermittent flux of energy associated with most renewables. Nonaqueous redox-flow batteries have emerged as a promising technology for grid-scale energy storage applications. Because the cost of the system scales with mass, the electroactive materials must have a low equivalent weight (ideally 150 g/(mol·e-) or less), and must function with low molecular weight supporting electrolytes such as LiBF4. However, soluble anolyte materials that undergo reversible redox processes in the presence of Li-ion supports are rare. We report the evolutionary design of a series of pyridine-based anolyte materials that exhibit up to two reversible redox couples at low potentials in the presence of Li-ion supporting electrolytes. A combination of cyclic voltammetry of anolyte candidates and independent synthesis of their corresponding charged-states was performed to rapidly screen for the most promising candidates. Results of this workflow provided evidence for possible decomposition pathways of first-generation materials and guided synthetic modifications to improve the stability of anolyte materials under the targeted conditions. This iterative process led to the identification of a promising anolyte material, N-methyl 4-acetylpyridinium tetrafluoroborate. This compound is soluble in nonaqueous solvents, is prepared in a single synthetic step, has a low equivalent weight of 111 g/(mol·e-), and undergoes two reversible 1e- reductions in the presence of LiBF4 to form reduced products that are stable over days in solution.
Preparation of tert-butyl esters via Pd-catalyzed tert-butoxycarbonylation of (hetero)aryl boronic acid derivatives
Wu, Yusheng,Li, Xinjian,Zou, Dapeng,Zhu, Helong,Wang, Yaping,Li, Jingya,Wu, Yangjie
supporting information, p. 1836 - 1839 (2014/05/06)
A novel protocol to synthesize tert-butyl esters from boronic acids or boronic acid pinacol esters and di-t-butyl dicarbonate has been successfully achieved. The cross-coupling reactions can produce up to 94% yields by using palladium acetate and triphenylphosphine as catalyst system, dioxane as a solvent. Moreover, a wide range of substrates including benzenes, pyridines, and quinolines boronic acids or boronic acid pinacol esters can fit with this system as well.
Transition-metal catalyzed oxidations. 7. Zirconium-catalyzed oxidation of primary and secondary alcohols with hydroperoxides
Krohn, Karsten,Vinke, Ingeborg,Adam, Horst
, p. 1467 - 1472 (2007/10/03)
A new procedure for the oxidation (dehydrogenation) of primary and secondary alcohols employing Zr(O-t-Bu)4 or Zr(O-n-Pr)4/tert-butyl hydroperoxide/3 A molecular sieves is presented. Secondary alcohols - if not severely sterically hindered - are usually converted quantitatively to the corresponding ketones. Esters or acids can be by products in the reaction of primary alcohols. However, the aldehydes are obtained in good yield by lowering the reaction temperature, decreasing the amount of TBHP or replacing TBHP by cumene hydroperoxide (CHP), and/or exchanging the catalyst Zr(O-t-Bu)4 by Zr(O-n-Pr)4 or silica gel-supported Zr(OR)(x). A remarkable selectivity of equatorial alcohol groups (e.g., 11 and 13) is observed in contrast to chromium(VI)-based oxidations. Strongly chelating substrates such as furfuryl alcohol (18) or 1,2-diol 25 that prevent hydride transfer in the six-membered transition state A are not converted.
GAS-PHASE PYROLYTIC REACTIONS. PART 3. HAMMETT ρ CONSTANTS OF GAS-PHASE ELIMINATIONS OF ALKYLARYLCARBOXYLATE AND ETHANOATE ESTERS AND THEIR CORRELATION WITH SUBSTRATE MOLECULAR FRAMEWORK
Al-Awadi, Nouria A.,Al-Bashir, Rasha F.,ElDusouqui, Osman M. E.
, p. 2903 - 2910 (2007/10/02)
The kinetics of the gas-phase thermal elimination of seven tert-butyl (hetero)arylcarboxylate esters (GCO2But) were measured over a temperature range 50 K; the groups were the phenyl, 3- and 4-pyridyl, 2- and 3-furyl, and 2- and 3-thienyl moieties.The reactions were homogeneous and unimolecular with log A/s-1 scaling 12.45 +/- 0.44, and with an entropy of activation uniformly negative and small.The kinetics obeyed a first-order rate equation, and at 600 K the rate coefficients (103k/s-1) of the esters, in the order given above, were: 54.1, 85.3, 120.5, 76.9, 43.2, 86.3 and 46.1, respectively.Hammett correlation of the present kinetic data with the literature ρ0 - values of the given substituents gave a reaction ρ constant compatible with the ethanoate molecular frame rather than with the carboxylate structure.The physical constants of five new t-butyl heteroarylcarboxylate esters are also described.
Bridged-ring Nitrogen Compounds. Part 8. The Chemistry of the 2,6-Methano-3-benzazonine Ring System.
McKnight, William E.,Proctor, George R.,Sneddon, Andrew H.,Scopes, David I. C.
, p. 642 - 679 (2007/10/02)
The previously described route to 1,2,3,4,5,6-hexahydro-3-methyl-2,6-methano-3-benzazonin-7-one (1a) has been fully investigated with particular reference to the Stevens rearrangement of N-benzyl-4-ethoxycarbonyl-1,2,3,6-tetrahydro-1-methylpyridinium bromide which leads to two basic products.The major product on reduction gives cis-2-benzyl-4-ethoxycarbonyl-1-methylpiperidine.Alternative routes to the latter were unsuccessful.The ketone (1a) was converted to several other 2,6-methano-1H-3-benzazonine derivatives of interest as potential analgesics. 2-Benzyl-4-ethoxycarbonyl-1-methylpiperidines give with methyllithium tertiary alcohols which cyclise (PPA) yielding 6,7-benzomorphans.
