Search results for "Benzil"
showing 10 items of 16 documents
9-benzil-9-azabiciklo[3.3.1]nonan-3-ona sintēze
2016
9-benzil-9-azabiciklo[3.3.1]nonān-3-ona sintēze. Mertsa K., zinātniskais vadītājs Dr.Chem. Kļimenkovs I. Bakalaura darbs, 37 lappuses, 5 attēli, 1 tabula, 22 literatūras avoti, 8 pielikumi. Latviešu valodā. Darbā tika izpētītas un salīdzinātas dažādas 9-benzil-9-azabiciklo[3.3.1]nonān-3-ona sintēzes metodes, no kurām tika izvēlētas dažas, kas teorētiski ir izdevīgākas. Eksperimentālajā daļā tika atkārtotas sintēzes pēc publikāciju aprakstiem, kā arī daļēji mainīti reakciju apstākļi. Pēc iegūtajiem rezultātiem tika analizēta dažādu reakcijas apstākļu ietekme uz reakcijas gaitu, izvirzot pieņēmumus, kuri no tiem ir labāk piemēroti. Rezultātu izvērtējumā tika izvirzīti priekšlikumi, kā uzlabot…
Investigation of molecular dimers by ensemble and single molecule spectroscopy
2002
International audience; We have investigated molecular dimers with different electronic coupling strengths by bulk and single molecule spectroscopy. In one of the dimers the two monomers (perylene-monoimide) are directly connected via a single bond while in the other one they are separated by the benzil motif. The close proximity of the monomers in the first case gives rise to excitonic band splitting which is clearly observable in the bulk absorption spectra. For the benzil structure the electronic interactions are governed by Förster-type energy hopping between the monomers. Fluorescence intensity trajectories at the single molecule level show one-step and two-step bleaching behaviour whi…
Efficient ultraviolet-light energy dissipation by an aromatic ketone.
2010
Experimental evidence on the efficiency of 2,2'4,4'-tetramethoxybenzil for UV-light energy dissipation is provided. This non-phenolic aromatic ketone has a low energy triplet which quickly decays to the ketone ground state, thus avoiding the generation of undesirable reactive species. El Moncef, Abdelkarim, elmonab@alumni.uv.es ; Cuquerella Alabort, Maria Consuelo, Chelo.Cuquerella@uv.es ; Zaballos Garcia, Elena, Elena.Zaballos@uv.es ; Ramirez de Arellano Sanchez, Maria del Carmen, Carmen.Ramirezdearellano@uv.es ; Stiriba, Salah Eddine, Salah.Stiriba@uv.es ; Perez Prieto, Julia, Julia.Perez@uv.es
Dalton communication. Crystal structure and oxo-transfer properties of [NH4]2[WVIO2{O2CC(S)Ph2}2]
1994
The complex [NH4]2[WVIO2{O2CC(S)Ph2}2] is the first example of a non-dithiolene tungsten complex capable of oxidising benzoin to benzil in methanol; the reduced complex product formed, presumably a monomeric WVIO species, was reoxidised with nitrate ions, regenerating the starting WVIO2 complex which then acts as a true homogeneous catalyst.
The reduction mechanism of the CO group.
2001
A detailed study of the electrochemical reduction of benzil in aqueous medium between H0=−5 and pH 11 is presented. A global 2e−, 3H+ or 2e−, 2H+ surface reaction leads to cis and trans endiols. Analysis, using the theory of the square schemes with protonations at equilibrium, shows that in all the pH range the reaction is controlled by the second electron uptake, the paths being successively H+, e− and e−, H+. The electrochemical reaction is followed by surface isomerizations whose rate constants vary from 7 to 200 s−1 for the trans/cis and from 1 to 2000 s−1 for the cis/trans transformations.
DDQ mediēta elektroķīmiska para-metoksibenzil aizsarggrupas šķelšana
2019
DDQ mediēta elektroķīmiska para-metoksibenzil aizsarggrupas šķelšana. Baunis, H., zinātniskā darba vadītājs Dr. chem. prof. Sūna. E. Bakalaura darbs, 50 lappuses, 27 attēli, 9 tabulas, 55 literatūras avoti, 2 pielikumi. Latviešu valodā. Bakalaura darbā izstrādāta jauna elektroķīmiska para-metoksibenzil aizsarggrupas šķelšanas metode, izmantojot 2,3-dihlor-5,6-diciāno-1,4-benzohinonu kā elektronu pārneses mediatoru. Metode piemērota para-metoksibenzil aizsargātiem funkcionalizētiem fenoliem. Sintezēti fenolu para-metoksibenzilēteri, veikta sintezēto savienojumu pierādīšana ar spektroskopijas metodēm.
Bio-predictive tablet disintegration: Effect of water diffusivity, fluid flow, food composition and test conditions
2013
Abstract Food intake may delay tablet disintegration. Current in vitro methods have little predictive potential to account for such effects. The effect of a variety of factors on the disintegration of immediate release tablets in the gastrointestinal tract has been identified. They include viscosity of the media, precipitation of food constituents on the surface of the tablet and reduction of water diffusivity in the media as well as changes in the hydrodynamics in the surrounding media of the solid dosage form. In order to improve the predictability of food affecting the disintegration of a dosage form, tablet disintegration in various types of a liquefied meal has been studied under stati…
Oxygen atom transfer reaction involving oxomolybdenum complexes with sterically bulky thiocarboxylate ligands and biochemical interesting substrates …
1999
Abstract Oxidation–reduction reactions of substrates in systems containing the complex [Mo VI O 2 (O 2 CC(S)CH 3 Ph) 2 ] 2− in methanol have been investigated as models of oxo-transfer reactions. At neutral pH, the [Mo VI O 2 (O 2 CC(S)CH 3 Ph) 2 ] 2− reacts with Me 2 PhP or n -butanethiol to yield a [Mo IV O(O 2 CC(S)CH 3 Ph) 2 ] 2− species and Me 2 PhPO or disulfide, respectively. The Mo IV O complex reduces a variety of substrates XO = Me 2 SO and pyridine N-oxide conducing formation of X = Me 2 S and pyridine. The occurrence of these reactions produces a catalytic system Me 2 PhP + XO → Me 2 PhPO + X and 2BuSH + XO → [BuS] 2 + X + H 2 O. In this work we have also included the study of …
Mechanistic basis for unexpected bioavailability enhancement of polyelectrolyte complexes incorporating BCS class III drugs and carrageenans
2013
The objective of this study was to investigate the potential of λ-carrageenan to work as an absorption modifying excipient in combination with formulations of BCS class 3 substances. Trospium chloride was used as a model BCS class 3 substance. Polyelectrolyte complexes of trospium and λ-carrageenan were produced by layer-by-layer complexation. A λ-carrageenan-containing formulation was administered either in capsules size 9 to rats by gavage or directly into ligated intestinal loops of rats. Exceptionally strong variations were observed in the plasma concentrations of the rats that received λ-carrageenan compared to the control group, but enhanced plasma concentrations were observed only in…
Ion Pairing with Bile Salts Modulates Intestinal Permeability and Contributes to Food–Drug Interaction of BCS Class III Compound Trospium Chloride
2013
In the current study the involvement of ion pair formation between bile salts and trospium chloride (TC), a positively charged Biopharmaceutical Classification System (BCS) class III substance, showing a decrease in bioavailability upon coadministration with food (negative food effect) was investigated. Isothermal titration calorimetry provided evidence of a reaction between TC and bile acids. An effect of ion pair formation on the apparent partition coefficient (APC) was examined using (3)H-trospium. The addition of bovine bile and bile extract porcine led to a significant increase of the APC. In vitro permeability studies of trospium were performed across Caco-2-monolayers and excised seg…