Search results for "Alcohol"

ChemInform Abstract: Enantioselective Synthesis of Tertiary Alcohols Through a Zirconium-Catalyzed Friedel-Crafts Alkylation of Pyrroles with α-Ketoe…

2011

Chiral complexes of 1,1′-bi-2-naphthol-based ligands with zirconium tert-butoxide catalyze the Friedel–Crafts alkylation of pyrroles with α-ketoesters to afford tertiary alcohols in good yields and ee up to 98%. The reaction is also of application to 4,7-dihydroindole to give C2-alkylated indoles after oxidation with p-benzoquinone.

Enantioselective Synthesis of Tertiary Alcohols through a Zirconium-Catalized Friedel-Crafts Alkylation of Pyrroles with alpha-Ketoesters

2011

Chiral complexes of 1,10-bi-2-naphthol-based ligands with zirconium tert-butoxide catalyze the Friedel Crafts alkylation of pyrroles with R-ketoesters to afford tertiary alcohols in good yields and ee up to 98%. The reaction is also of application to 4,7-dihydroindole to give C2-alkylated indoles after oxidation with p-benzoquinone.

The paradoxical cyanide-stimulated respiration of Zymomonas mobilis: cyanide sensitivity of alcohol dehydrogenase (ADH II)

2003

The respiratory inhibitor cyanide stimulates growth of the ethanologenic bacteriumZymomonas mobilis, perhaps by diverting reducing equivalents from respiration to ethanol synthesis, thereby minimizing accumulation of toxic acetaldehyde. This study sought to identify cyanide-sensitive components of respiration. In aerobically grown, permeabilizedZ. mobiliscells, addition of 200 μM cyanide caused gradual inhibition of ADH II, the iron-containing alcohol dehydrogenase isoenzyme, which, in aerobic cultures, might be oxidizing ethanol and supplying NADH to the respiratory chain. In membrane preparations, NADH oxidase was inhibited more rapidly, but to a lesser extent, than ADH II. The time-cours…

Kinetic modelling of the Zymomonas mobilis Entner-Doudoroff pathway: insights into control and functionality.

2013

Zymomonas mobilis, an ethanol-producing bacterium, possesses the Entner-Doudoroff (E-D) pathway, pyruvate decarboxylase and two alcohol dehydrogenase isoenzymes for the fermentative production of ethanol and carbon dioxide from glucose. Using available kinetic parameters, we have developed a kinetic model that incorporates the enzymic reactions of the E-D pathway, both alcohol dehydrogenases, transport reactions and reactions related to ATP metabolism. After optimizing the reaction parameters within likely physiological limits, the resulting kinetic model was capable of simulating glycolysis in vivo and in cell-free extracts with good agreement with the fluxes and steady-state intermediate …

Identification of bound alcohols in soil humic acids by gas chromatography-mass spectrometry

2000

International audience; Humic acids are complex, partly macromolecular, yellow-brownish substances occurring in soils, waters and sediments. In order to shed some light on their molecular structure, crop humic acids were cleaved by alkaline hydrolysis (KOH). The products were fractionated by thin layer chromatography to give mono-alcohols which were analysed as acetate derivatives by gas chromatography coupled to mass spectrometry. Linear alcohols, sterols, stanols and plant-derived triterpenoid alcohols were identified by co-injection of pure standards and by comparison with literature data. These findings imply that alcohols could have been incorporated into the humic matrix by esterifica…

Contribution of the Temporal Dominance of Sensations (TDS) method to the sensory description of subtle differences in partially dealcoholized red win…

2007

ln this study, effect of partial alcohol reductio.n on the sensory modification of red wines was investigated. Preliminary triangle tests indicated the existencèof very slight differences between the dealcoholized wines of the study. Therefore, adapted descriptive methodologies had ta be used. ln addition to a comparative sensory profile, the Temporal Dominance of Sensations (TDS) method was chosen. Both types of profiles will be linked ta consumer preferences. A Merlat and a Syrah wine were partially dealcoholized using reverse osmosis technique to span a range of four different alcohol contents (14 % to 10 %) by grape variety. ln a first step, the four wines of each variety were compared …

Alcoholic beverages, obesity, physical activity and other nutritional factors, and cancer risk: A review of the evidence

2016

International audience; Purpose: Prevention is a priority in the fight against cancers, especially nutritional prevention. To update the levels of evidence of relationships between 10 nutritional factors and cancer risk, the scientific literature published from 2006 to 2014 was reviewed by an expert group.Methods: Data from 133 meta-analyses, pooled analyses or intervention trials were examined. Nearly 150 relationships between nutritional factors and cancer at various sites were evaluated.Results: According to the evidence graded as convincing or probable, these factors were divided in two groups. Factors which increase the risk of cancer are alcoholic beverages, overweight and obesity, re…

Population Structure and Comparative Genome Hybridization of European Flor Yeast Reveal a Unique Group of Saccharomyces cerevisiae Strains with Few G…

2014

Wine biological aging is a wine making process used to produce specific beverages in several countries in Europe, including Spain, Italy, France, and Hungary. This process involves the formation of a velum at the surface of the wine. Here, we present the first large scale comparison of all European flor strains involved in this process. We inferred the population structure of these European flor strains from their microsatellite genotype diversity and analyzed their ploidy. We show that almost all of these flor strains belong to the same cluster and are diploid, except for a few Spanish strains. Comparison of the array hybridization profile of six flor strains originating from these four co…

Duplex PCR method for rapid detection of Zymomonas mobilis in cider

2005

L'arôme du gin : identification des composés clés et rôle des matières premières

2012

Le texte intégral de cette thèse est confidentiel à durée indéfinie.; Afin d’identifier les composés responsables de l’arôme du gin, une procédure GC-O-MS se basant sur la fréquence de détection a été développée. Elle a permis de déterminer l’intensité odorante des composés volatils. Leur qualité d’odeur a pu être définie par le développement d’une roue des odeurs utilisée pour catégoriser les descripteurs obtenus. Cette approche nous a dans un premier temps permis d’identifier les composés potentiellement importants pour l’arôme du gin. L’origine de ces composés a ensuite été déterminée par l’étude de la fraction volatile de différents « botanicals » appartenant à la recette du gin. Cette …