Search results for "Benzophenone"
showing 10 items of 52 documents
CO2 as a C1-organic building block: Electrocarboxylation of aromatic ketones. A quantitative study of the effect of the concentration of substrate an…
2006
The purpose of this work is to establish and discuss quantitative relationships between the selectivity in preparative scale electrolysis and intrinsic and operational parameters for the electrocarboxylation of aromatic ketones. For the investigated ketones, under appopriate experimental conditions the selectivity of the process is mainly determined by the competition between carboxylation and protonation, de-halogenation reactions (when an halogenated ketone is involved), and possibly dimerizations involving the electrogenerated radical anion. A simple model was proposed to account for these unwanted side paths which allows to predict the dependence of the selectivity as a function of the …
Influence of the nature of the substrate and of operative parameters in the electrocarboxylation of halogenated acetophenones and benzophenones
2005
Abstract The electrocarboxylation of halogenated acetophenones and benzophenones to the corresponding hydroxycarboxylic acids has been carried out in undivided cell equipped with aluminium sacrificial anode and using 1-methyl-2-pyrrolidinone (NMP) as the solvent. The radical anion generated by the electro-reduction of the aromatic ketone is involved in several competitive reactions which lead to the formation of the target hydroxycarboxylic acid, the corresponding alcohol and pinacol and the de-halogenated parent ketone. If sufficiently negative working potentials are imposed, the latter is reduced to the corresponding carboxylate, pinacol and alcohol. Very different results in terms of sel…
Synthèse de chalcones à base de tétrathiafulvalène: RC(O)CHC(CH3)TTF, TTFC(O)CHC(CH3)R (R TTF: C6H3S4; Bct: C6H5Cr(CO)3; Fc: C5H4FeC5H5). Propr…
1992
Abstract Novel chalcones that contain tetrathiafulvalene (TTF) and/or metallocene (ferrocenyl or benchrotrenyl) moieties: RC(O)CHC(CH 3 )R′ (R and/or R′ TTF: C 6 H 3 S 4 ; Fc: C 5 H 4 FeC 5 H 5 ; Bct: C 6 H 5 Cr(CO) 3 ) were prepared using TiCl 3 /Et 3 N as the condensation reagent. The 1-1 charge transfer complex with TCNQ (tetracyanoquinodimethane was obtained for the ditetrathiafulvalenic derivative (R R′ TTF). This complex exhibits the semiconducting behaviour.
Durability of a strach-based biodegradable polymer
2007
Abstract The photo-oxidation and the photo-stabilization of a commercial biodegradable polymer have been investigated in order to establish the possibility of using this polymer as raw material for films for agriculture. The degradation has been followed by measuring the mechanical properties as a function of photo-oxidation time and in particular by following the elongation at break. The virgin polymer, made from maize starch and a synthetic biodegradable polyester, shows poor resistance to the UV irradiation as observed by the fast decay of the elongation at break, but the presence of small amounts of conventional UV stabilizers strongly improves the durability of this polymer. The UV sta…
Photocatalysis within Hyperbranched Polyethers with a Benzophenone Core
2008
Quenching and product studies have been performed to demonstrate the suitability of hyperbranched polyethers with a tetrafunctionalized benzophenone core as photocatalysts. The triplet photosensitized transformation of an unsaturated diazo compound has been used as the model reaction. The polymer with highest molecular weight led to a similar product distribution even after several catalytic cycles, which evidences its excellent photostability under prolonged irradiation time. We attribute this to the stabilizing effect of the hyperbranched polymer shell.
Über umsetzungen an poly-p-lithiumstyrol. 4. Mitt. Darstellung carbonylgruppenhaltiger derivate des polystyrols
1961
In Fortsetzung fruherer Arbeiten wird die Reaktivitat von Poly-p-lithiumstyrol gegenuber solchen Agenzien gepruft, die zur Bildung von carbonylgruppenhaltigen Verbindungen fuhren. Wahrend bei der Umsetzung mit Orthoameisensaureester nur vernetzte Polymere entstechen, last sich mit Dimethylformamid ein losliches Derivat des Polystyrols herstellen das p-standige Formylgruppen tragt. Die Reaktion mit Nitrilen liefert polymere Ketone; mit Acetophenon entsteht Poly-p-vinylacetophenon, das mit dem aus dem Monomeren durch Polymerisation erhaltenen Produkt verglichen wird. Mit Benzonitril erhalt man Poly-p-vinylbenzophenon. Die polymeren Ketone konnen in die Oxime ubergefuhrt werden, deren Sticksto…
Photocrosslinkable dextran hydrogel films as substrates for osteoblast and endothelial cell growth
2012
Functional hydrogel films on solid supports are versatile materials with large potential for cell growth and tissue engineering. Here, we report on a modular approach to generate functional hydrogel composite films for endothelial and osteoblast cell co-culture. The polymer network of the parent hydrogel was formed by a dextran derivative (BP-CMD), which contained carboxymethyl (CM) groups for further chemical functionalization and benzophenone (BP) moieties as a photocrosslinkable unit. BP-CMD could be synthesized by three different routes, first with the benzophenone unit attached via an amide bond, or second by an ether bond, or third as an ion pair between the benzophenone ammonium salt…
ChemInform Abstract: Light Induced C-C Coupling of 2-Chlorobenzazoles with Carbamates, Alcohols, and Ethers.
2016
A light induced, transition-metal-free C-C coupling reaction of 2-chlorobenzazoles with aliphatic carbamates, alcohols, and ethers is presented. Inexpensive reagents, namely sodium acetate, benzophenone, water, and acetonitrile, are employed in a simple reaction protocol using a cheap and widely available 25 W energy saving UV-A lamp at ambient temperature.
A resorcinol derived calix[5]arene with C5-symmetry
1994
Abstract Condensation of 2,4-dihydroxy-3-hydroxymethyl benzophenone (4) in dioxane/H2SO4 gave the cyclic pentamer 5, a calix[5]arene with regular incorporation of the resorcinol units via their 2- and 6-positions. The structure follows from the 1H NMR and mass spectra and was further confirmed by single crystal X-ray analysis. Dynamic NMR in C2D2Cl4 gave a surprisingly high barrier of ΔG‡ = 17.3 kcal/mol for the cone-to-cone ring inversion.
Darstellung von phenolischen verbindungen und phenol/formaldehyd-polykondensaten mit ketoxim-, aldoxim- oder 1-methyl-4-hydroxyiminomethylpyridinium-…
1979
Thirteen low molecular weight oximes were prepared: one derivative of acetophenone (1), two derivatives of benzophenone (2 and 3), two derivatives of salicylaldehyde containing two phenolic nuclei (4c and 5c), and eight compounds in which a phenol unit is substituted by a 4-hydroxyiminomethylpyridiniummethyl group (8a–f, 10c, and 11c). Besides these compounds polymeric phenol formaldehyde condensates were synthesized which contain units deriving from benzophenoneoxime (15b) or from salicylaldehyde (22b) and condensates containing 4-hydroxyiminomethylpyridiniummethyl groups (23c). A series of low molecular weight and water soluble compounds (8a–f) were proved as antidotes on mice which were …