Search results for "Carbonyl group"
showing 10 items of 13 documents
Design of new sensitive α,β-unsaturated carbonyl 1,8-naphtalimide fluorescent probes for thiol bioimaging
2017
International audience; We report herein an efficient synthesis of news naphtalimide-based fluorescent derivatives functionalized with an a,(3-unsaturated carbonyl group. Probes were synthesized from reaction of an amino-naphtalimide precursor with maleic anhydride. Photophysical study of fluorescent probes and cells labelling were performed, and showed that the reactive derivatives exhibit rich turn on fluorescence properties in presence of different biological thiol (Glutathione and Cysteine) making these systems a very promising way for thiol bioimaging.
Protein carbonyl groups in trained subjects.
2012
The purpose of this research was to evaluate the plasma protein carbonyl groups (PC) in 81 trained subjects (TS) who practiced regular, non professional physical activity. They were divided into three groups according to the type of sport they practiced (endurance, mixed or power). On fasting venous blood we examined the PC groups employing an enzyme-linked immunosorbent assay (ELISA) kit, in which 2,4-dinitrophenyl-hydrazine reacts with the PC forming a stable hydrazone product. In the whole group of TS a significant decrease in PC was present, in comparison with sedentary controls (SC). Dividing TS into groups, we observed a decreased PC concentration in those practicing endurance and mix…
Highly diastereoselective additions of organometallic reagents to 1-O-silylated 3,4-Di-O-benzyl-L-erythrulose derivatives
1993
Abstract The diastereoselectivity of the addition of several organometallic reagents to the carbonyl group of the title compounds has been investigated. Some organomagnesium reagents display high diastereoselectivities (90–99%) and the major products are those predicted by the α-chelation model.
Enantioselective addition of nitromethane to α-keto esters catalyzed by copper(ii)–iminopyridine complexes
2008
The copper complex of a chiral iminopyridine easily prepared from (R)-(-)-fenchone and picolylamine catalyzes the enantioselective Henry (nitroaldol) reaction between nitromethane and alpha-keto esters. Good yields and modest to good enantioselectivities are obtained for a wide range of alpha-keto esters, bearing aromatic, alkyl or alkenyl groups attached to the ketone carbonyl group.
ChemInform Abstract: Enantioselective Addition of Nitromethane to α-Keto Esters Catalyzed by Copper(II)-Iminopyridine Complexes.
2008
The copper complex of a chiral iminopyridine easily prepared from (R)-(−)-fenchone and picolylamine catalyzes the enantioselective Henry (nitroaldol) reaction between nitromethane and α-keto esters. Good yields and modest to good enantioselectivities are obtained for a wide range of α-keto esters, bearing aromatic, alkyl or alkenyl groups attached to the ketone carbonyl group.
ChemInform Abstract: Toward an Understanding of the Mechanisms of the Intramolecular [5 + 2] Cycloaddition Reaction of γ-Pyrones Bearing Tethered Alk…
2000
The molecular mechanism for the intramolecular [5 + 2] cycloaddition reaction of β-silyloxy-γ-pyrones bearing tethered alkenes has been characterized using ab initio methods. A comparative study for this sort of cycloaddition carried out at different computational levels points out that the B3LYP/6-31G* calculations give similar barriers to those obtained with the MP3/6-31G* level. Analysis of the energetic results shows that the reaction takes place along a stepwise process: first, the migration of the neighboring silyl group to the carbonyl group of the γ-pyrone takes place to give a weak oxidopyrylium ylide intermediate, which by a subsequent concerted intramolecular [5 + 2] cycloadditi…
Time–carbonyl groups equivalence in photo-oxidative aging of virgin/recycled polymer blends
2004
AbstractThe photo-oxidation behaviour of polymers is strongly dependent on the initial amount of carbonyl groups along the chains. The growing use of recycled post-consumer polymers coming from products used outdoors and then photo-oxidised, both pure and blended with the same virgin polymer, gives rise to an unpredictable behaviour of weathering resistance of products made with these materials. The present work shows that the carbonyl group–exposure time curves can be shifted along the time axis to give a single generalised master plot. It is then possible to predict the formation of the new carbonyl groups by knowing only the initial amount of the same carbonyl groups. The same shift fact…
Über Segmentlängenverteilung und Lichtabsorption bei Copolymeren aus Methacrylnitril und Acrolein oder Methacrolein. Polymere Acroleine. 31. Mitt.
1964
Copolymere aus Methacrylnitril und Acrolein oder Methacrolein werden hinsichtlich der Absorption der Carbonylgruppe im Ultravioletten und Infraroten untersucht. Zur Beschreibung des Absorptionsverhaltens wird die statistische Theorie von ALFREY und GOLDFINGER uber die Segmentlangenverteilung in copolymeren benutzt. Es ergibt sich, das im wesentlichen die isoliert stehenden Aldehydgrundbausteine einen Beitrag zur Carbonyl-absorption liefern. Bei Sequenzen aus zwei und drei Aldehydgrundbausteinen reagieren die Carbonylgruppen zu cyclischen Aldehydhydratathern, wahrend bei langeren Sequenzen ungefahr 20% der Carbonylgruppen nicht cyclisieren. Copolymers from methacrylnitrile and acrolein or me…
Toward an Understanding of the Mechanisms of the Intramolecular [5 + 2] Cycloaddition Reaction of γ-Pyrones Bearing Tethered Alkenes. A Theoretical S…
2000
The molecular mechanism for the intramolecular [5 + 2] cycloaddition reaction of β-silyloxy-γ-pyrones bearing tethered alkenes has been characterized using ab initio methods. A comparative study for this sort of cycloaddition carried out at different computational levels points out that the B3LYP/6-31G* calculations give similar barriers to those obtained with the MP3/6-31G* level. Analysis of the energetic results shows that the reaction takes place along a stepwise process: first, the migration of the neighboring silyl group to the carbonyl group of the γ-pyrone takes place to give a weak oxidopyrylium ylide intermediate, which by a subsequent concerted intramolecular [5 + 2] cycloadditi…
Darstellung und spektroskopische Analyse von Oligo{[4-(1,1,3,3-tetramethylbutyl) (bzw. 4-octyl)2-hydroxy-1,3-phenylen]methylen}en und ihrer Ausgangsv…
1978
4-(1,1,3,3-Tetramethylbutyl)phenol und 4-Octylphenol, erhalten durch Friessche Verschiebung der entsprechenden Phenylester und anschliesende Reduktion der Carbonylgruppe, wurden in ortho-Stellung monobromiert und mit Formaldehyd hydroxymethyliert. Aus diesen Verbindungen konnten sechs 2,2′-Methylendiphenole (2a–f) sowie sieben 2,6-Bis(2-hydroxybenzyl)phenole (3a–g) dargestellt werden, die in 4-Stellung zu den phenolischen Hydroxygruppen Methyl-, 1,1,3,3-Tetramethylbutyl- und Octyl-Substituenten in verschiedenen Verhaltnissen enthalten. Die IR- und 1H-NMR-spektroskpischen Analysen bestatigten die angegebenen Strukturen der dargestellten phenolischen Mehrkernverbindungen. 4-(1,1,3,3-Tetrameth…