Search results for "Ketone"

Synthesis, spectroscopic and conformational analysis of 1,4-dihydroisonicotinic acid derivatives

2014

Abstract Structural and conformational properties of 1,4-dihydroisonicotinic acid derivatives, characterized by ester, ketone or cyano functions at positions 3 and 5 in solid and liquid states have been investigated by X-ray analysis and nuclear magnetic resonance and supported by quantum chemical calculations. The dihydropyridine ring in each of the compounds exists in flattened boat-type conformation. The observed ring distortions around the C(4) and N(1) atoms are interrelated. The substituent at N(1) has great influence on nitrogen atom pyramidality. The 1H, 13C and 15N NMR chemical shifts and coupling constants are discussed in terms of their relationship to structural features such as…

Alkane oxidation by a carboxylate-bridged dimanganese(III) complex

2001

[EN] A new manganese( III) oxamato dimer possesing an unprecedented Mn-2(mu -O2CR)(mu -OH2. . .O2CR) core has been synthesised, structurally and magnetically characterised, and used as a catalyst for the oxidation of alkanes to alcohols and ketones by (BuO2H)-O-t and O-2 in CH2Cl2 at rt.

Lack of nucleophilic addition in the isoxazole and pyrazole diketone modified analogs of curcumin; implications for their antitumor and chemosensitiz…

2009

Curcumin (CUR) can be considered as a good lead compound for the design of new anticancer drugs. Further, structure-activity relationship studies may clarify the importance of the redox activities in the antitumor effects of the drug. We have elaborated the alpha,beta-unsaturated 1,3-diketone moiety of CUR into the isoxazole (ISO) and pyrazole (PYR) derivatives. These derivatives should be much less prone to nucleophilic addition than CUR and benzyl mercaptan addition analyses showed that indeed they do not form isolable conjugated products. When compared with CUR, ISO and PYR exhibited increased cell growth inhibitory and pro-apoptotic effects in liver cancer HA22T/VGH cells as well as in …

Organotitanium reagents in organic synthesis a simple means to adjust reactivity and selectivity of carbanions

1982

The synthesis of fluorinated heteroaromatic compounds. Part 2. Five-membered rings with two heteroatoms. A review

2007

Manipulating mtDNA in vivo reprograms metabolism via novel response mechanisms.

2019

Mitochondria have been increasingly recognized as a central regulatory nexus for multiple metabolic pathways, in addition to ATP production via oxidative phosphorylation (OXPHOS). Here we show that inducing mitochondrial DNA (mtDNA) stress in Drosophila using a mitochondrially-targeted Type I restriction endonuclease (mtEcoBI) results in unexpected metabolic reprogramming in adult flies, distinct from effects on OXPHOS. Carbohydrate utilization was repressed, with catabolism shifted towards lipid oxidation, accompanied by elevated serine synthesis. Cleavage and translocation, the two modes of mtEcoBI action, repressed carbohydrate rmetabolism via two different mechanisms. DNA cleavage activ…

Cr(III)/Cr(VI) speciation in aerosol particles by extractive separation and thermal ionization isotope dilution mass spectrometry

1997

An isotope dilution mass spectrometric (IDMS) method, using the formation of positive thermal ions, was developed for Cr(III) and Cr(VI) speciation in aerosol particles. Cr(III) and Cr(VI) spike species, enriched in 53Cr, were applied for the isotope dilution step. After leaching of filter collected aerosol samples by an alkaline solution at pH 13, species separation was carried out by extraction with a liquid anion exchanger in methyl isobutyl ketone. Cr(VI) in the organic phase was re-extracted into an ammoniacal solution and chromium was then isolated from both fractions of species by electrodeposition. Detection limits of 30 pg/m3 for Cr(III) and of 8 pg/m3 for Cr(VI) were achieved in a…

Determination of carbonyl compounds in particulate matter PM2.5 by in-tube solid-phase microextraction coupled to capillary liquid chromatography/mas…

2013

Abstract In this paper, a new procedure based on in-tube solid phase microextraction (IT-SPME)-capillary liquid chromatography hyphenated to mass spectrometry detection by using microelectrospray ionisation (CapLC–MS), has been reported. The device was proposed to quantify 12 carbonyl compounds (10 aliphatic aldehydes, an unsaturated aldehyde and a ketone) derivatized with 2,4-dinitrophenylhidrazine (DNPH) reagent in aqueous extracts of PM 2.5 . This methodology involves the on-line preconcentration of DNPH-carbonyl compounds derivatives coupled to the CapLC–MS system, efficiently providing appropriate sensitivity for the determination of the target analytes. Detection limits for the analyt…

[The ketogenic diet: an underappreciated therapeutic option?].

2011

Obesity is reaching epidemic proportions in Western countries and is a strong risk factor for cardiovascular disease. Despite the constant recommendations of health care organizations regarding the importance of weight control, this goal often fails. Although there is a common agreement about the concept that exercise and diet are two key factors for the control of body weight, the ideal amount and type of exercise and also the ideal diet for weight control are still under debate. A widely accepted nutritional regime is the Mediterranean diet that has evident health benefits although less attention has been paid to see if the effects are due to other lifestyle factors which may contribute t…

Herbizide, 3. Mitt. Synthese von 4,6-Dialkyl-2-cyanaminopyrimidinen und Untersuchungen ihrer Struktur durch13C-NMR-Spektroskopie

1985

Die Kondensation von Dicyandiamid (1) mit den β-Diketonen 2a–c fuhrt zu den 2,4-unsymmetrisch substituierten 2-Cyanaminopyrimidinen 3a–c, fur deren Struktur sich aus den13C-NMR-spektroskopischen Untersuchungen das Vorliegen eines Gleichgewichts mit den tautomeren Formen 7 und 8 der 2-Cyaniminopyrimidine ableitet. Das 2-Cyanamino-4,6-diethylpyrimidin hat sich als herbizid wirksam erwiesen. Herbicides, III: Synthesis of 4,6-Dialkyl-2-(cyanoamino)pyrimidines and Investigations of Their Structures by 13C-NMR Spectroscopy Condensation of dicyandiamide (1) with the β-diketones 2a–c leads to the 2,4-unsymmetrically substituted 2-(cyanoamino)pyrimidines 3a–c. According to investigations by 13C-NMR …