Showing papers on "Alcohol published in 1996"

On the use of stable organic nitroxyl radicals for the oxidation of primary and secondary alcohols

Abstract: This article reviews the oxidation of primary and secondary alcohols using nitroxyl radicals from the first publication in which this reaction was described in 1965. A variety of stoichiometric and catalytic methods is discussed, with reactions in organic solvents, under biphasic conditions as well as in water. Mechanistic studies and general experimental procedures are included. The high regioselectivity for the oxidation of primary alcohols that can be achieved in the presence of secondary alcohols is emphasised.

Effects of moderate consumption of red wine on platelet aggregation and haemostatic variables in healthy volunteers.

Abstract: Objective To evaluate the effect of moderate consumption of red wine on platelet aggregation and haemostatic variables, discriminating the effect of alcohol from that of non-alcoholic components. Design A randomised crossover study. Setting The Department of Food Science and Technology, University of Milan. Subjects Eleven healthy male volunteers who were moderate drinkers. Interventions For three periods of four weeks, subjects drank three different beverages [320 ml of red wine (providing 30 g/day of alcohol), 30 g/day of alcohol diluted in 320 ml of clear fruit juice or 320 ml of dealcoholised red wine] during the two main meals. Each treatment was preceded by a period of four weeks of complete withdrawal from any alcoholic beverage. At the end of each period platelet aggregation after collagen and ADP stimulus, and levels of fibrinogen, plasminogen, tissue-type plasminogen activator (t-PA) antigen and von Willebrand factor (vWF) were determined. Results Consumption for a period of four weeks of 30 g/day of alcohol either from red wine or alcohol resulted in similar decreases of collagen-induced platelet aggregation and fibrinogen levels. ADP-induced platelet aggregation, t-PA antigen, vWF and plasminogen levels were not affected by any treatment. No differences were detected when we compared platelet function and the other haemostatic variables at the end of red wine and dealcoholised treatments with findings at the end of alcohol treatment and abstinence. Conclusions The well known positive effect of moderate consumption of red wine on haemostasis seems due to alcohol and not to the non-alcoholic fraction present in red wine.

Hypervalent Iodine Oxidants: Structure and Kinetics of the Reactive Intermediates in the Oxidation of Alcohols and 1,2-Diols by o-Iodoxybenzoic Acid (IBX) and Dess−Martin Periodinane. A Comparative 1H-NMR Study

Abstract: Alcohols and 1,2-diols oxidation by o-iodoxybenzoic acid (IBX) has been examined by 1H-NMR spectroscopy. Reversible formation of reactive intermediates, iodic esters 5, has been observed, and their structures in DMSO-d6 solution have been defined as 10-I-4 axial alkoxyiodinane oxides by comparison of the chemical shift difference data with those obtained for Dess−Martin periodinane (DMP)−alcoholate and −diolate adducts. The dichotomous behavior exhibited by IBX and DMP with 1,2-diols can be explained in terms of the different architecture of the reactive intermediates involved in the oxidation. With aliphatic alcohols, kinetic evidences support a two-step reaction mechanism involving a fast pre-equilibrium step leading to 5, followed by a rate-determining disproportionation step. With electronically activated benzyl alcohol, the attainment of pre-equilibrium is largely dependent on initial water concentration as a consequence of a particularly high k2 value. The influence of the alcohol structure on measu...

Solvent-Controlled Excited State Behavior: 2-(2‘-Pyridyl)indoles in Alcohols

Abstract: Efficient fluorescence quenching caused by rapid internal conversion from the first excited singlet state is observed in alcohol solutions of 2-(2‘-pyridyl)indoles, molecules which may simultaneously act as hydrogen bonding donors and acceptors. Electronic and infrared absorption studies show that upon adding alcohols to nonpolar solutions of pyridylindoles, 1:1 complexes are formed in the ground state, with hydrogen bonding occurring to the indole NH group. At higher alcohol concentrations 1:n (n ≥ 2) solvates dominate. Investigations of the fluorescence intensity as a function of temperature and deuterium substitution in the hydroxylic group of the alcohol, and the results obtained for the N-methylated derivatives and 2-phenylindole show that the quenching may be described by a stepwise mechanism. First, a 1:1 cyclic, doubly hydrogen-bonded complex between alcohol and pyridylindole is formed after photoexcitation. This process is controlled by solvent reorientation. Excited state double proton transfer ...

Ready Access to Fluorinated Phosphonate Mimics of Secondary Phosphates. Synthesis of the (α,α-Difluoroalkyl)phosphonate Analogues of l-Phosphoserine, l-Phosphoallothreonine, and l-Phosphothreonine

Abstract: In addition to the previously recorded reactions of diethyl lithio(difluoromethyl)phosphonate (8) with primary triflates and aldehydes, we report here that 8 reacts with functionalized, but unactivated, methyl esters to give efficient acyl substitution. Thus, 8 reacts cleanly (−78 °C, THF) with the following methyl esters (product, yield): methyl (S)-isopropylideneglycerate (14, 99%), methyl (S)-3-O-(tert-butyldimethylsilyl)-2 -O-tetrahydropyranylglycerate (16, 85%), and the Garner ester derived from d-serine (15, 77%). Expeditious treatment of the resultant α,α-difluoro-β-keto phosphonates with hydride or Grignard reagents followed by alcohol deoxygenation provides a general method for the synthesis of (α,α-difluoroalkyl)phosphonate analogues of secondary phosphates. For tertiary alcohols, Dolan−MacMillan deoxygenation conditions are employed. The requisite methyl oxalate esters are obtained by an improved procedure wherein the lithium alkoxide of the hindered tertiary alcohol is irreversibly generated ...

Chemical surface modification of poly(ethylene terephthalate).

Abstract: Reactions of semicrystalline poly(ethylene terephthalate) (PET) film with ester-selective reagents at the film−solution interface can be controlled to produce modified film samples containing a thin (less than ∼ 40 A) surface layer of the reagent-induced functionality. Hydrolysis of PET yields a surface mixture of alcohol and carboxylic acid groups. Reduction with lithium aluminum hydride and transesterification with ethylene glycol (glycolysis) both produce surfaces with alcohol functionality (PET−OHR and PET−OHG, respectively). Each of these modification reactions involves chain cleavage and can lead to significant sample degradation (reactive dissolution); for each modification reaction, conditions were optimized to maximize conversion and minimize degradation. The reactivity of surface alcohols (PET−OH) was assessed for samples prepared by both reduction and glycolysis, and a comparative analysis was made: the presence of benzylic alcohols in reduced samples and their absence in glycolyzed samples as...

Additives and fuel oil compositions

Abstract: An additive composition comprising: (a) an ashless dispersant comprising an acylated nitrogen compound; and (b) a carboxylic acid, or an ester of the carboxylic acid and an alcohol wherein the acid has from 2 to 50 carbon atoms and the alcohol has one or more carbon atoms provides an improvement in the lubricity of fuel oils and exhibits improved solubility in the fuel oil.

Toward an Alcohol Treatment Model: A Comparison of Treated and Untreated Respondents with DSM‐IV Alcohol Use Disorders in the General Population

Abstract: The purpose of this study was to compare characteristics of person with alcohol use disorders who sought alcohol treatment with those who did not using data from a nationally representative sample of the United States. Applying an organizing framework from the larger literature on service utilization, a logistic regression analysis was conducted to examine the interaction among factors influencing treatment. The results identified unemployment status and lower educational level as barriers to alcohol treatment, but the impact of these factors differed depending on whether the respondent had previous experience with alcohol treatment. The major findings of this study are discussed in terms of consumer satisfaction, minimizing barriers to alcohol treatment services, and the need to examine individual determinants of alcohol treatment within the larger context of organizational and sociopolitical factors.

Ethnic differences in gastric sigma-alcohol dehydrogenase activity and ethanol first-pass metabolism

Abstract: We assessed whether the low sigma-alcohol dehydrogenase (ADH) activity in Japanese (compared with Caucasians) affects the first-pass metabolism of ethanol. ADH isozyme activities were determined in endoscopic biopsies of the gastric corpus from 24 Japanese and 41 Caucasian men by starch gel electrophoresis and by comparing the reduction of m-nitrobenzaldehyde (a preferred substrate of sigma-ADH) with that of acetaldehyde (a preferred substrate of gamma-ADH) and the glutathione-dependent formaldehyde oxidation (a specific reaction of chi-ADH). Alcohol pharmacokinetics was compared in 10 Japanese and 10 Caucasians after administration of ethanol (300 mg/kg of body weight) intravenously or orally, using 5 and 40% oral solutions. Japanese exhibited lower sigma-ADH activity than Caucasians, with no difference in the other gastric isozymes. With 5% ethanol, first-pass metabolism was strikingly lower in Japanese than in Caucasians. Blood alcohol levels were similar because of the high elimination rate in Japanese due to the hepatic beta 2-ADH variant. With 40% ethanol, the first-pass metabolism increased in both groups to comparable levels, suggesting an additional contribution by chi-ADH at high ethanol concentrations. These results indicate that sigma-ADH activity contributes significantly to gastric ethanol oxidation and its lower activity in Japanese is associated with lesser first-pass metabolism.

Laboratory testing for recent alcohol consumption: comparison of ethanol, methanol, and 5-hydroxytryptophol.

Abstract: The ratio of 5-hydroxytryptophol to 5-hydroxyindole-3-acetic acid (5HTOL/5HIAA) in urine was compared with concentrations of ethanol and methanol as a way to monitor recent alcohol consumption. During detoxification of alcohol-dependent subjects, ethanol persisted longer in urine than in breath or plasma. Blood and urinary methanol remained increased for 2-6 h after blood ethanol had returned to background concentrations, whereas 5HTOL/5HIAA remained increased for 6-15 h. In healthy volunteers who had ingested alcohol (range 3-98 g) the previous afternoon or evening, 87% (for men) and 59% (for women) of all drinking occasions exceeding 7 g of alcohol were identified by an increased 5HTOL/5HIAA in the first morning urine void. This compared with 32% and 12%, respectively, identified by analysis of ethanol (>200 micromol/L). No gender difference in the excretion pattern of 5HTOL/5HIAA was seen. The results demonstrate that 5HTOL/5HIAA provides a specific and more sensitive method to detect recent alcohol consumption than does ethanol or methanol.

Losses of arachidonic acid in rat liver after alcohol inhalation

Abstract: This paper presents an animal model of alcoholism in which rats were exposed to alcohol by inhalation and were fed a diet that simulated the poor diet of some alcoholics. It is hypothesized that some of the pathophysiological effects of alcohol are related to its effects on essential fatty acid metabolism and composition of vital organs. A diet that contains no 20- and 22-carbon essential fatty acids and has low levels of 18-carbon essential fatty acids was used as a dietary challenge. Addition of a second metabolic challenge, i.e., alcohol, led to loss of tissue polyunsaturates, particularly liver arachidonate. A method of cycling alcohol inhalation for 12 h/d was also presented, which was also shown to lower liver arachidonic acid content.

A Convenient One-Pot Preparative Method for 4,5-Diarylisoxazoles Involving Amine Exchange Reactions

Abstract: 4,5-Diarylisoxazoles 1 are efficiently prepared by submitting enaminones 2, readily obtained from deoxybenzoins 3, to oximation conditions. This conversion implies an uncommon amine group exchange reaction. Preparation of 4-isoxazolines 5 and ring-opening transformations to β-keto nitriles 4 and 1,3-amino alcohol derivatives 7 are also described.

The Effect of Acid Strength on the Mitsunobu Esterification Reaction: Carboxyl vs Hydroxyl Reactivity.

Abstract: In the presence of carboxylic acids, the adduct formed between triphenylphosphine and diisopropyl azodicarboxylate reacts to form mono- and bis-acylated hydrazides and the carboxylic acid anhydrides. These products are formed via attack of the carboxylate on the triphenylphosphonium group of the adduct, with weaker acids reacting much faster than stronger acids. This provides an explanation for the observation in the literature that acids stronger than acetic acid, such as 4-nitrobenzoic acid and chloroacetic acid, provide better yields in esterification reactions, since reaction of the alcohol with the phosphonium group of the adduct is more rapid than the competing reaction of the carboxylate for the phosphonium group.

Alcohol mediates increases in hepatic and serum nonheme iron stores in a rat model for alcohol-induced liver injury.

Abstract: The notion that prolonged ethanol consumption promotes hepatocellular damage through interactions with iron was evaluated in rats fed ethanol with or without supplemental dietary carbonyl iron. The individual and combined pro-oxidant potential of these agents was evaluated in terms of their ability to perturb iron homeostasis and initiate hepatocellular injury. Sprague-Dawely rats received a high fat liquid diet for 8 weeks supplemented with : 35% ethanol-derived calories (Alcohol group), 0.02 to 0.04% (w/v) carbonyl iron (Iron group), ethanol plus carbonyl iron (Alcohol + Iron group), or a diet containing carbohydrate-derived isocaloric calories (Control group). Hepatic and serum nonheme iron stores were significantly elevated (p < 0.05) in all treatment groups, compared with the Controls. Catalytically active low-molecular weight iron was detected in rats consuming alcohol and was markedly elevated (p < 0.05) in rats ingesting iron alone or iron in combination with alcohol. Elevations in serum ALT indicated significant hepatocellular injury in rats ingesting only alcohol, but was most prominent in the rats consuming ethanol in combination with iron (p < 0.05). Significant hepatic fatty infiltration, increased hydroxyproline content, and perturbations in reduced glutathione were also observed in the Alcohol and Iron treatment groups. Histochemical assessment of hepatic iron sequestration revealed that alcohol feeding resulted in deposition of ferric iron in the centrilobular area of the liver lobule. This unique alcohol-mediated iron deposition was histologically graded above Control group and was observed in both hepatocytes and Kupffer cells. Data presented herein suggest that alcohol alone or in combination with iron results in rather specific lobular patterns of hepatic iron deposition relevant to iron overload observed in human alcoholics. Furthermore, data suggest that alcohol- and iron-initiated prefibrotic events occur before extensive hepatocellular necrosis.

Toluene and ethylbenzene oxidation by purified naphthalene dioxygenase from Pseudomonas sp. strain NCIB 9816-4.

Abstract: Purified naphthalene dioxygenase (NDO) from Pseudomonas sp. strain NCIB 9816-4 oxidized toluene to benzyl alcohol and benzaldehyde by reactions involving benzylic monooxygenation and dioxygen-dependent alcohol oxidation, respectively. Xylene and nitrotoluene isomers were also oxidized to substituted benzyl alcohol and benzaldehyde derivatives. NDO oxidized ethylbenzene sequentially through (S)-1-phenethyl alcohol (77% enantiomeric excess) and acetophenone to 2-hydroxyacetophenone. In addition, NDO also oxidized ethylbenzene through styrene to (R)-1-phenyl-1,2-ethanediol (74% enantiomeric excess) by reactions involving desaturation and dihydroxylation, respectively. Isotope experiments with 18O2, H2 18O, and D2O suggest that 1-phenethyl alcohol is oxidized to acetophenone by a minor reaction involving desaturation followed by tautomerization. The major reaction in the conversion of 1-phenethyl alcohol and benzyl alcohol to acetophenone and benzaldehyde, respectively, probably involves monohydroxylation to form a gem-diol intermediate which stereospecifically loses the incoming hydroxyl group to leave the carbonyl product. These results are compared with similar reactions catalyzed by cytochrome P-450.

Process for the carbonylation of alkyl alcohols and/or reactive derivatives thereof

Abstract: In a process for the liquid phase carbonylation of an alkyl alcohol such as methanol, and/or a reactive derivative thereof to produce the corresponding carboxylic acid and/or ester, in the presence of an iridium catalyst, an alkyl halide and water, the reaction is promoted by the presence of at least one promoter selected from cadmium, mercury, zinc, gallium, indium and tungsten, optionally with a co-promoter selected from ruthenium, osmium and rhenium

Total Synthesis of the Pseudopterane (−)-Kallolide B, the Enantiomer of Natural (+)-Kallolide B

Abstract: A total synthesis of the enantiomer 35 of kallolide B was achieved starting from (S)-(−)-perillyl alcohol (8). Oxidative cleavage to the ester aldehyde 11 was effected by treatment of the epoxide 9 with H5IO6 followed by CH2N2. The allenyl ketone 13, obtained by SnCl2-promoted addition of 1-bromo-2-butyne to aldehyde 11 and subsequent Swern oxidation, cyclized to the furan 14 in the presence of catalytic AgNO3. Homologation of the derived aldehyde 15 with CBr4−Ph3P followed by n-BuLi and CH2O led to the propargylic alcohol 17. Formylation of the furan 17 (s-BuLi, DMF) and then Still−Horner−Emmons homologation yielded the (Z)-conjugated ester 22. Conversion of the propargylic alcohol function to the chloride 23 and ester reduction (DIBAL-H) furnished the chloro alcohol 24, which formed the cyclic ether 25 upon treatment with NaH. Ether 25 underwent a highly diastereoselective [2,3]Wittig ring contraction to the propargylic alcohol 26. The derived mesylate 36 was converted to the allenic ester 37 with CO an...

Direct formation of alcohols by hydrocarbonylation of alkenes under mild conditions using rhodium trialkylphosphine catalysts

Abstract: The complex[RhH(PEt3)3] catalysed the hydroformylation of hex-1-ene to heptanal and 2-methylhexanal in toluene, but heptanol and 2-methylhexanol were significant products in tetrahydrofuran especially over long reaction times(16h). In protic solvents only alcohols were produced even after short reaction times. The reactions are very rapid and also occur readily with alkenes such as hex-2-ene, propene, ethene, styrene and 3,3-dimethylbutene. The highest rates observed are for ethene (54 000 turnovers h–1) and the products in all cases are alcohols. Other phosphines containing primary alkyl groups also produced alcohols, but in contrast reactions in ethanol using rhodium complexes containing PPh3, PPh2Et, PPhEt2 or PPri3 produced significant amounts of aldehydes and/or acetals whilst Me2PCH2CH2PMe2 inhibited the reaction. The NMR studies showed that species present in equilibrium in ethanol solution are [RhH(CO)(PEt3)3], [RhH(CO)2(PEt3)2], [Rh2(CO)4(PEt3)4], [Rh2(CO)2(PEt3)6] and PEt3 but that [RhH(CO)(PEt3)3] predominates under the catalytic conditions. Reactions carried out under D2–CO in EtOH produced, 90% BuCHDCH2CD2OH/D and 10% BuCHDCH2CHDOH/D but hydrogenation of heptanal under the same conditions gave a mixture of C6H13CHDOH/D (39%) and C6H13CH2OH/D (61%). These results are interpreted to indicate that the alcohols produced from hex-1-ene are primary reaction products and not produced via intermediate aldehydes. A new mechanism for this direct hydrocarbonylation is proposed in which the key acyl intermediate becomes protonated by the alcoholic solvent because of the high electron density it bears as a result of the presence of the electron-donating trialkylphosphines. Oxidative addition of H2 followed by two H-atom transfers leads directly to the alcohol. High pressure NMR studies showed that [Rh{C(O ⋯ HOEt)Et}(CO)2(PEt3)2] is present during catalytic hydrocarbonylation of ethene in ethanol. Two different cycles are proposed to explain the products obtained from the catalytic reaction of heptanal with D2–CO. Again, protonation, this time of the metal, appears to be important.

Transition-Metal Catalyzed Oxidations. 7. Zirconium-Catalyzed Oxidation of Primary and Secondary Alcohols with Hydroperoxides

Abstract: A new procedure for the oxidation (dehydrogenation) of primary and secondary alcohols employing Zr(O-t-Bu)4 or Zr(O-n-Pr)4/tert-butyl hydroperoxide/3 A molecular sieves is presented. Secondary alcoholsif not severely sterically hinderedare usually converted quantitatively to the corresponding ketones. Esters or acids can be byproducts in the reaction of primary alcohols. However, the aldehydes are obtained in good yield by lowering the reaction temperature, decreasing the amount of TBHP or replacing TBHP by cumene hydroperoxide (CHP), and/or exchanging the catalyst Zr(O-t-Bu)4 by Zr(O-n-Pr)4 or silica gel-supported Zr(OR)x. A remarkable selectivity of equatorial alcohol groups (e.g., 11 and 13) is observed in contrast to chromium(VI)-based oxidations. Strongly chelating substrates such as furfuryl alcohol (18) or 1,2-diol 25 that prevent hydride transfer in the six-membered transition state A are not converted.

Total Synthesis of the Pentacyclopropane Antifungal Agent FR-900848

Abstract: Quatercyclopropane 31 was oxidized, homologated, reduced, and monocyclopropanated to provide the pentacyclopropane alcohol 35. Subsequent deoxygenation of alcohol 35 was effected using N-(phenylthio)succinimide (24) and tributylphosphine followed by Raney nickel desulfurization and deprotection to produce the alcohol 3. This was oxidized, homologated, and hydrolyzed to provide the fatty acid 2. BOP-Cl-mediated coupling of acid 2 and the nucleoside amine 40 gave amide 1, which was spectroscopically identical with an authentic sample of FR-900848 (1).

Preparation of an acylated protein powder

Abstract: A method for recovering an acylated protein as a powder, especially in cases where the acylated protein is one that resists isolation by isoelectric precipitation from aqueous solutions of the protein, the method comprising in combination adjusting the aqueous solution to near the isoelectric pH of the protein and providing a suitable alcohol concentration to cause precipitation of the protein in the form of filterable particles at the adjusted pH.

Combined nonenzymatic-enzymatic method for the synthesis of simple alkyl fatty acid esters from soapstock

Abstract: Soapstock (SS) is a by-product of the extraction of oilseeds to produce edible oils. Annual U.S. production exceeds one-half million tons. A representative sample of SS consists of 45.1% water, 10.0% free fatty acids, 10.1% triglycerides, 1.8% diglycerides, 3.6% phosphatidylethanolamine, 2.2% phosphatidylinositol, 2.7% phosphatidylcholine, 14.0% solvent-insolubles and 10.5% other material, which was not characterized. A process has been developed that sequentially employs a nonenzymatic and an enzymatic step to convert the lipid-linked and the free fatty acids of SS to the esters of monohydric alcohols. The first step of the process employed alcohol and potassium hydroxide to transesterify the glyceride-and phosphoglyceride-linked fatty acids of the substrate. Because water inhibited the reaction, it was necessary that the SS be dried before use. Nonetheless, even with some batches of SS with water contents below 1% (weight basis), ester hydrolysis accompanied esterification. Each of five examined simple primary alcohols participated effectively in the transesterification reaction, which proceeded rapidly at room temperature and was essentially complete within 1 h. The average ratio of transesterification to hydrolysis in four examined small primary alcohols was 4:1. However, in methanol this value was 99:1 due to the virtual absence of hydrolysis. Significant transesterification by a secondary alcohol (isopropanol) did not occur at room temperature. The minimum effective molar ratio of alcohol to lipid-linked fatty acids was 20:1. The minimum effective concentration of KOH was between 0.10 and 0.15N. The efficiency of the transesterification reaction exceeded 90% of theoretical maximum. The second step of the process involves lipase-mediated esterification of the free fatty acids in the preparation that are not esterified by the alkaline transesterfication. Of four lipase preparations examined (Novo Lipozyme IM 20 and SP435, and Amano PS30 and CE), only SP-435 catalyzed significant esterification of the free fatty acids. The reaction was not catalyzed by heat-denatured enzyme. In the pH range between 6 and 13.5, the enzyme reaction proceeded best at pH 6, although also well at pH 7. The optimal water concentration was 0.70% (vol/vol). At an enzyme dosage of 1.1% (weight basis, relative to the dry weight of SS present) under optimal conditions and at 42°C, 63% of the free fatty acids in a post-alcoholysis mixture were enzymatically esterified. The addition of molecular sieves did not increase esterification, which was probably retarded by the high viscosities of the reactions. Under the optimal conditions identified here, the degree of conversion of the fatty acids in SS to simple alkyl esters by the combined reaction scheme was 81%. Opportunities exist for further optimization of these reactions.

Oxidative susceptibility of low-density lipoproteins--influence of regular alcohol use.

Abstract: In population studies, a low-to-moderate intake of alcohol has been consistently linked to a lower risk of coronary artery disease. The recent suggestion that alcoholic beverages may be confemng this decrease in risk because they contain antioxidant phenolic compounds that reduce the oxidizability of low-density lipoprotein (LDL) has to be reconciled with the possible counteracting influence of a pro-oxidant effect of alcohol. In a controlled crossover study, we have now measured the oxidizability of LDL in 27 regular beer drinkers during consecutive 4-week periods, wherein they consumed a high versus low alcohol beer (4.9 vs. 0.9% alcohol v/v, respectively), with the two beers being similar in phenolic content. This resulted in a decrease in alcohol consumption by -80% (408 f 25 muweek vs. 75 f 11 muweek). During the low alcohol period, there was no change in LDL vitamin E or its cholesterol or protein content. Analysis of LDL oxidation kinetics revealed an increase in oxidizabilii during the high alcohol phase. This was despite a decrease in arachidonic acid content of LDL and a corresponding increase in palmitic acid during high alcohol intak- change in fatty acid composition that has the potential to favor a decrease in oxidizabilii. Our results suggest that alcohol ingestion increases LDL oxidation, despite reducing the polyunsaturated fatty acid composition. The overall effect of alcoholic beverages on LDL oxidation may be a balance between the pro-oxidant and antioxidant activity of its various constituents. The predominant pro-oxidant effect demonstrated in these beer drinkers, although not relevant to any potential decrease in coronary artery disease, may be important in the pathogenesis of alcohol-related disease in other organ systems.

Cytochrome P450-dependent transformations of 15R- and 15S-hydroperoxyeicosatetraenoic acids: stereoselective formation of epoxy alcohol products.

Abstract: Although there are many reports of epoxy alcohol synthesis from lipoxygenase products (fatty acid hydroperoxides) in mammalian tissues, there are no well-defined examples of the stereoselective synthesis of individual epoxy alcohol diastereomers. An earlier report on the metabolism of 15S-hydroperoxyeicosatetraenoic acid (15S-HPETE) in rat liver microsomes suggested such a specific reaction [Weiss, R. H., et al. (1987) Arch. Biochem. Biophys. 252, 334−338]. To characterize this reaction further, we set out to determine the precise structures and mechanism of biosynthesis of the epoxy alcohol products. We compared the products formed from 15R- and 15S-HPETE by hematin (a nonenzymatic reaction), by liver microsomes isolated from control and phenobarbital-treated rats, and by purified cytochrome P450 2B1. Eight epoxy alcohol isomers were identified by mass spectrometry and 1H NMR. In the hematin reaction, the major products are four epoxy alcohols with the epoxide in the trans configuration, diastereomers ar...

Alcohol and the regulation of energy balance: overnight effects on diet-induced thermogenesis and fuel storage.

Abstract: The effect of alcohol on overnight energy expenditure and substrate disposal was studied in eleven subjects (five men, six women) using whole-body indirect calorimetry for 15.5 h after test meals. Three test meals were studied in random order with at least 48 h between treatments: control, 50% of maintenance energy needs provided as 14, 40 and 46% energy from protein, fat and carbohydrate respectively; alcohol addition, control plus 23% energy as alcohol; alcohol substitution, control with alcohol replacing 23% of carbohydrate energy. ANOVA revealed no significant sex effects. Alcohol-induced thermogenesis dissipated only 15 (SD 14)% of the alcohol energy. Alcohol addition had no significant effect on protein or carbohydrate oxidation but fat oxidation was suppressed (P < 0.0005) to an extent equivalent to storing 74 (SD 51)% of the alcohol energy as fat. Alcohol substitution reduced carbohydrate oxidation (P < 0.009) to an equivalent of 42 (SD 41)% and also spared fat (P < 0.005) to an equivalent of 59 (SD 37)% of the alcohol energy. It is concluded that alcohol has no special thermogenic capacity, and that its energy can be accounted for in a similar way to carbohydrate.

Kinetics of esterification of acetic acid with propyl alcohol by heterogeneous catalysis

Abstract: Kinetic data on the esterification of acetic acid with propyl alcohol catalyzed by the ion exchange resin DOWEX MONOSPHERE 650 C have been obtained using a stirred batch reactor. It was checked if there is an influence of pore diffusion and film resistance on the reaction rate when varying reaction temperature, initial molar ratios, and amount of resin. The possible mechanisms of reaction were mathematically treated using the theories of Langmuir-Hinshelwood and Rideal-Eley. Taking the nonideal behavior of the system acetic acid, propyl alcohol, propyl acetate, and water into account, all calculations were realized with activities using the UNIQUAC-equation. By using the experimental results in a process of model discrimination the best kinetic parameter set was found out by the aid of the commercial software package SIMUSOLV. The resulting data of rate constants and the experimental determined equilibrium constants served as a basis for the calculation of the thermodynamic parameters of esterification, as reaction enthalpy, reaction entropy, and activation enthalpies. © 1996 John Wiley & Sons, Inc.