Showing papers on "Alcohol published in 2014"
TL;DR: In this paper, a PNP pincer ligand was used for acceptingless dehydrogenation of alcohols, an important organic transformation, supported by inexpensive iron-based catalysts supported by a cooperating PNP ligand.
Abstract: Acceptorless dehydrogenation of alcohols, an important organic transformation, was accomplished with well- defined and inexpensive iron-based catalysts supported by a cooperating PNP pincer ligand. Benzylic and aliphatic secondary alcohols were dehydrogenated to the corresponding ketones in good isolated yields upon release of dihydrogen. Primary alcohols were dehydrogenated to esters and lactones, respectively. Mixed primary/secondary diols were oxidized at the secondary alcohol moiety with good chemoselectivity. The mechanism of the reaction was investigated using both experiment and DFT calculations, and the crucial role of metal−ligand cooperativity in the reaction was elucidated. The iron complexes are also excellent catalysts for the hydrogenation of challenging ketone substrates at ambient temperature under mild H2 pressure, the reverse of secondary alcohol dehydrogenation.
313 citations
TL;DR: A broad, new family of enantioselective C-C coupling reactions that are catalyzed by iridium or ruthenium complexes have been developed, which are summarized in this Minireview.
Abstract: As organic molecules are defined as compounds composed of carbon and hydrogen, stereoselective, atom-efficient methods for skeletal assembly involving the addition, removal or redistribution of hydrogen in the absence of discrete oxidation level adjustment, or non-constructive functional group interconversions represent a natural endpoint in the evolution of synthetic methods.[1] This view of synthetic efficiency tacitly recognizes the value of merged redox-construction events (“redox-economy”),[2] chemo- (site-), regio- and stereoselectivity,[3] protecting group-free chemical synthesis,[4] as well as the minimization of preactivation, defined as the degree of separation between reagent and feedstock.[5] Transformations and strategies that adhere to these ideals are inherently process-relevant.[6]
Application of these concepts to the chemistry of carbonyl addition reveals a significant opportunity for invention. In classical carbonyl additions, premetallated C-nucleophiles and carbonyl compounds are typically generated through separate streams of redox reactions: discrete alcohol-to-aldehyde oxidation is frequently used to generate carbonyl electrophiles, and discrete reduction is often used to generate organometallic nucleophiles. By exploiting the native reducing capability of alcohols, redox-triggered carbonyl additions may be developed wherein hydrogen exchange between alcohols and unsaturated reactants generates transient electrophile- nucleophile pairs en route to products of formal alcohol C-H functionalization via carbonyl addition.[7] To date, three major mechanistic pathways for C-C coupling have been identified wherein alcohol oxidation is balanced by (A) C=C π-bond hydrometallation, (B) C-X reductive cleavage, and (C) transfer hydrogenolysis of oxametallacycles (Figure 1).
Figure 1
Redox-economy in carbonyl addition: three general mechanistic pathways identified for redox-triggered alcohol C-H functionalization.
In this review, catalytic enantioselective methods for C-C bond formation via alcohol CH functionalization are surveyed on the basis of the aforementioned mechanistic pathways. Related redox-triggered alcohol C-H functionalizations that have not been rendered asymmetric are covered elsewhere,[7] For most alcohol C-C couplings described in this account, corresponding aldehyde reductive couplings are reported,[7] but for the sake of brevity are not covered. Dehydrogenative C-C bond formations that result in formal alcohol substitution, that is, so-called “borrowing hydrogen” or “hydrogen auto-transfer” processes, radical mediated alcohol C-C couplings and processes involving stoichiometric oxidants are not discussed.[8,9]
255 citations
TL;DR: A method for cobalt-catalyzed, aminoquinoline-directed ortho-functionalization of sp2 C–H bonds with alkenes has been developed and excellent functional group tolerance is observed.
208 citations
TL;DR: In this article, the effect of alcohol hydrogen donor on methyl furan production through catalytic transfer hydrogenation of furfural in the liquid phase has been investigated over a mildly calcined Ru/C catalyst in the temperature range of 110-200°C.
Abstract: The effect of alcohol hydrogen donor on methyl furan production through catalytic transfer hydrogenation of furfural in the liquid phase has been investigated over a mildly calcined Ru/C catalyst in the temperature range of 110–200 °C. It has been found that several parameters contribute to furfural hydrogenolysis, including alcohol dehydrogenation activity, solvent properties, as well as side reactions such as etherification between the intermediate, furfuryl alcohol, and the hydrogen donor. Methyl furan yield increases from 0 to 68% at 180 °C following the order of 2-methyl-2-butanol
181 citations
TL;DR: The important role of hydroxyl for these two oxidation reactions catalyzed by gold, in terms of its influence on the turnover frequency is discussed, and the use of water as a "green" solvent becomes an attractive choice.
Abstract: Although gold is generally considered to be a relatively inert metal, supported gold nanoparticles have demonstrated exceptionally high catalytic activity for the oxidation of carbon monoxide and alcohols at modest temperatures. In both cases, the presence of hydroxyl groups substantially promotes the reaction rate, presumably by participating in the reaction. Direct comparisons of CO oxidation to alcohol oxidation over gold catalysts have been difficult for scientists to explain. The former reaction is usually performed with gas phase reagents, whereas the latter reaction is often performed in the condensed phase. In this Account, we discuss the important role of hydroxyl for these two oxidation reactions catalyzed by gold, in terms of its influence on the turnover frequency. During CO oxidation over gold, a hydroxyl can directly react with CO to form COOH, which eventually decomposes to CO2. The gas phase CO oxidation reaction likely occurs at the gold-support interface, where adsorbed hydroxyl groups can be found after the addition of water to the feed. When we perform CO oxidation in liquid water, increasing the pH substantially promotes the reaction rate by providing an external source of hydroxyl. Likewise, we can also promote alcohol oxidations over gold catalysts in aqueous media by increasing the pH of the system. Since the hydroxyl groups are supplied through the reaction medium instead of on the support surface, the gold-support interface is much less important in the aqueous phase reactions. Even bulk gold powder becomes an active oxidation catalyst in alkaline water. The role of O2 in both CO and alcohol oxidation in aqueous media is to remove electrons from the gold surface that are deposited during oxidation, maintaining electroneutrality. Thus, the oxidation of CO and alcohols in water at high pH is analogous to the electrochemical oxidation reactions performed on gold electrodes. As the field of chemistry continues to encourage the development of sustainable chemical processes utilizing environmentally benign reaction conditions, the use of water as a "green" solvent becomes an attractive choice. In general, however, heterogeneous catalysts that scientists have developed over the last century for the petrochemical industry have not been optimized for use in aqueous media. Given the active role of water in oxidation reactions catalyzed by gold, additional research is needed to understand how water affects other catalytic transformations on traditional transition metal catalysts.
170 citations
TL;DR: Persistence of adolescent-typical phenotypes is not always evident, and may be related to regionally specific ethanol influences on the interplay between CNS excitation and inhibition critical for the timing of neuroplasticity.
162 citations
TL;DR: Several bisbenzoxazolyl iridium(III) complexes have been synthesized and characterized through X-ray crystallography as discussed by the authors, and these complexes exhibit excellent catalytic activity in C-C and C-N bond formation reactions.
Abstract: Several new bisbenzoxazolyl iridium(III) complexes have been synthesized and characterized through X-ray crystallography. These complexes exhibit excellent catalytic activity in C–C and C–N bond formation reactions from the alkylation of amine with amine, amine with alcohol, ketone with alcohol, and alcohol with alcohol through a borrowing hydrogen reaction. Moreover, these iridium(III) complexes are effective catalysts for the alkylation of amine with alcohol and ketone with alcohol under solvent-free conditions. The catalytic activity of these complexes is greatly enhanced by noncoordinating, while the experiments have excluded the possibility of a “silver effect” (bimetallic catalysis or silver-assisted metal catalysis) from the experiments.
153 citations
TL;DR: Findings from numerous rodent studies of stress and alcohol interactions are synthesized to identify several attractive targets for novel treatments of alcohol abuse and addiction.
144 citations
TL;DR: This work has helped lay the groundwork for several ongoing clinical trials for alcohol dependence and has been repeatedly demonstrated that this model reliably produces physical and motivational symptoms of alcohol dependence.
142 citations
TL;DR: It is suggested that the compounds usually found in spruce hydrolysates have different cellular targets and inhibitory mechanisms in the cells, and that other structural properties such as additional functional groups attached to the compound may determine its toxicity.
Abstract: We investigated the severity of the inhibitory effects of 13 phenolic compounds usually found in spruce hydrolysates (4-hydroxy-3-methoxycinnamaldehyde, homovanilyl alcohol, vanillin, syringic acid, vanillic acid, gallic acid, dihydroferulic acid, p-coumaric acid, hydroquinone, ferulic acid, homovanillic acid, 4-hydroxybenzoic acid and vanillylidenacetone). The effects of the selected compounds on cell growth, biomass yield and ethanol yield were studied and the toxic concentration threshold was defined for each compound. Using Ethanol Red, the popular industrial strain of Saccharomyces cerevisiae, we found the most toxic compound to be 4-hydroxy-3-methoxycinnamaldehyde which inhibited growth at a concentration of 1.8 mM. We also observed that toxicity did not generally follow a trend based on the aldehyde, acid, ketone or alcohol classification of phenolic compounds, but rather that other structural properties such as additional functional groups attached to the compound may determine its toxicity. Three distinctive growth patterns that effectively clustered all the compounds involved in the screening into three categories. We suggest that the compounds have different cellular targets, and that. We suggest that the compounds have different cellular targets and inhibitory mechanisms in the cells, also compounds who share similar pattern on cell growth may have similar inhibitory effect and mechanisms of inhibition.
137 citations
TL;DR: This work reports that simple vanadyl (VO(2+)) cations catalyze the conversions of cellulose and its monomer, glucose, into lactic acid and formic acid in water and demonstrates that the addition of an alcohol suppresses the formation of CO2 and enhances the formic Acid yield significantly to 70-75 %.
Abstract: The transformation of cellulose or cellulose-derived carbohydrates into platform chemicals is the key to establish biomass-based sustainable chemical processes. The systems able to catalyze the conversion of cellulose into key chemicals in water without the consumption of hydrogen are limited. We report that simple vanadyl (VO2+) cations catalyze the conversions of cellulose and its monomer, glucose, into lactic acid and formic acid in water. We have discovered an interesting shift of the major product from formic acid to lactic acid on switching the reaction atmosphere from oxygen to nitrogen. Our studies suggest that VO2+ catalyzes the isomerization of glucose to fructose, the retro-aldol fragmentation of fructose to two trioses, and the isomerization of trioses, which leads to the formation of lactic acid under anaerobic conditions. The oxidative cleavage of CC bonds in the intermediates caused by the redox conversion of VO2+/VO2+ under aerobic conditions results in formic acid and CO2. We demonstrate that the addition of an alcohol suppresses the formation of CO2 and enhances the formic acid yield significantly to 70–75 %.
TL;DR: The UV/S2O8(2-) (UV/ peroxydisulfate) was more efficient than UV/HSO5(-) ( UV/peroxysulfrate) and UV/H2O2 (UV /hydrogen peroxide) processes when natural water samples were used as reaction matrices and UV fluence based pseudo-first-order rate constants followed the expected order of radical quantum yields.
TL;DR: In this article, a combination system of 2-cyanopyridine hydration and carboxylation was proposed for the direct synthesis of organic carbonates from CO2 and alcohols.
TL;DR: In this paper, the production of alkyl levulinates from furfuryl alcohol (FAL) in alcohol media was investigated at moderate temperature in the presence of Bronsted acidic ionic liquids.
TL;DR: It is reported that the electrophilic main-group cations thallium(III) and lead(IV) stoichiometrically oxidize methane, ethane, and propane, separately or as a one-pot mixture, to corresponding alcohol esters in trifluoroacetic acid solvent, and posit that the comparatively high reactivity of these d10 main- group cations stems from facile alkane coordination at vacant sites.
Abstract: Much of the recent research on homogeneous alkane oxidation has focused on the use of transition metal catalysts. Here, we report that the electrophilic main-group cations thallium(III) and lead(IV) stoichiometrically oxidize methane, ethane, and propane, separately or as a one-pot mixture, to corresponding alcohol esters in trifluoroacetic acid solvent. Esters of methanol, ethanol, ethylene glycol, isopropanol, and propylene glycol are obtained with greater than 95% selectivity in concentrations up to 1.48 molar within 3 hours at 180°C. Experiment and theory support a mechanism involving electrophilic carbon-hydrogen bond activation to generate metal alkyl intermediates. We posit that the comparatively high reactivity of these d 10 main-group cations relative to transition metals stems from facile alkane coordination at vacant sites, enabled by the overall lability of the ligand sphere and the absence of ligand field stabilization energies in systems with filled d-orbitals.
TL;DR: The thermodynamically leveraged conversion of ethers and alcohols to saturated hydrocarbons is achieved efficiently with low loadings of homogeneous M(OTf)n + heterogeneous Pd tandem catalysts, and the reaction scope extends to efficient conversion of biomass-derived ethers to the corresponding alkanes.
Abstract: The thermodynamically leveraged conversion of ethers and alcohols to saturated hydrocarbons is achieved efficiently with low loadings of homogeneous M(OTf)n + heterogeneous Pd tandem catalysts (M = transition metal; OTf = triflate; n = 4). For example, Hf(OTf)4 mediates rapid endothermic ether ⇌ alcohol and alcohol ⇌ alkene equilibria, while Pd/C catalyzes the subsequent, exothermic alkene hydrogenation. The relative C–O cleavage rates scale as 3° > 2° > 1°. The reaction scope extends to efficient conversion of biomass-derived ethers, such as THF derivatives, to the corresponding alkanes.
TL;DR: The results of this study revealed the unique potential of Cp*Ir complexes bearing a functional bipyridonate ligand for the development of C-C bond-forming reactions with the activation of primary alcohols as electrophiles.
Abstract: A Cp*Ir complex bearing a functional bipyridonate ligand was found to be a highly effective and versatile catalyst for the α-alkylation of ketones with primary alcohols under extremely environmentally benign and mild conditions (0.1 equiv of Cs2CO3 per substrate, reflux in tert-amyl alcohol under an air atmosphere for 6 h). Furthermore, this complex also exhibited a high level of catalytic activity for the α-methylation of ketones with methanol. The mechanistic investigation revealed that the carbonyl group on the ligand is of critical importance for catalytic hydrogen transfer. Notably, the results of this study revealed the unique potential of Cp*Ir complexes bearing a functional bipyridonate ligand for the development of C–C bond-forming reactions with the activation of primary alcohols as electrophiles.
TL;DR: Using a simple amino amide ligand, ruthenium-catalyzed one-pot alkylation of primary and secondary amines with simple alcohols was carried out under a wide range of conditions, with high conversion and selectivity.
Abstract: Using a simple amino amide ligand, ruthenium-catalyzed one-pot alkylation of primary and secondary amines with simple alcohols was carried out under a wide range of conditions. Using the alcohol as solvent, alkylation was achieved under mild conditions, even as low as room temperature. Reactions occurred with high conversion and selectivity in many cases. Reactions can also be carried out at high temperatures in organic solvent with high selectivity using stoichiometric amounts of the alcohol.
TL;DR: In this paper, the condensation of ethanol to butanol was investigated over a commercial hydroxyapatite catalyst in the 350-410°C temperature range, and it was shown that the pathway involving self-aldol condensation is irrelevant at such high temperatures for the present catalyst.
TL;DR: The terahertz data show the maximum absorption relative to that predicted for an ideal mixture at that composition, while the PFG-NMR data exhibit a minimum in the alkyl chain self-diffusivity at x2, showing that the alcohol has reached a Minimum in diffusion when this extended alcohol-water network has reached the highest degree of structuring.
Abstract: Terahertz and PFG-NMR techniques are used to explore transitions in the structuring of binary alcohol/water mixtures. Three critical alcohol mole fractions (x1, x2, x3) are identified: methanol (10, 30, 70 mol %), ethanol (7, 15, 60 mol %), 1-propanol (2, 10, 50 mol %), and 2-propanol (2, 10, 50 mol %). Above compositions of x1 no isolated alcohol molecules exist, and below x1 the formation of large hydration shells around the hydrophobic moieties of the alcohol is favored. The maximum number of water molecules, N0, in the hydration shell surrounding a single alcohol molecule increases with the length of the carbon chain of the alcohol. At x2 the greatest nonideality of the liquid structure exists with the formation of extended hydrogen bonded networks between alcohol and water molecules. The terahertz data show the maximum absorption relative to that predicted for an ideal mixture at that composition, while the PFG-NMR data exhibit a minimum in the alkyl chain self-diffusivity at x2, showing that the alcohol has reached a minimum in diffusion when this extended alcohol-water network has reached the highest degree of structuring. At x3 an equivalence of the alkyl and alcohol hydroxyl diffusion coefficients is determined by PFG-NMR, suggesting that the molecular mobility of the alcohol molecules becomes independent of that of the water molecules.
01 May 2014
TL;DR: Overall, the P and HAD1,2 rats have characteristics attributed to an early onset alcoholic, and can be used to study various aspects of alcohol use disorders.
Abstract: The objective of this article is to review the literature on the utility of using the selectively bred alcohol-preferring (P) and high-alcohol-drinking (HAD) lines of rats in studies examining high alcohol drinking in adults and adolescents, craving-like behavior, and the co-abuse of alcohol with other drugs. The P line of rats meets all of the originally proposed criteria for a suitable animal model of alcoholism. In addition, the P rat exhibits high alcohol-seeking behavior, demonstrates an alcohol deprivation effect (ADE) under relapse drinking conditions, consumes amounts of ethanol during adolescence equivalent to those consumed in adulthood, and co-abuses ethanol and nicotine. The P line also exhibits excessive binge-like alcohol drinking, attaining blood alcohol concentrations (BACs) of 200 mg% on a daily basis. The HAD replicate lines of rats have not been as extensively studied as the P rats. The HAD1,2 rats satisfy several of the criteria for an animal model of alcoholism, e.g., these rats will voluntarily consume ethanol in a free-choice situation to produce BACs between 50 and 200 mg%. The HAD1,2 rats also exhibit an ADE under repeated relapse conditions, and will demonstrate similar levels of ethanol intake during adolescence as seen in adults. Overall, the P and HAD1,2 rats have characteristics attributed to an early onset alcoholic, and can be used to study various aspects of alcohol use disorders.
TL;DR: In this article, it was shown that the Bronsted acidic resin catalyst, Amberlyst-15, is highly active and selective for the etherification of furanyl alcohols by both ethanol and butanol.
TL;DR: Alcohol consumption exhibits a dose-dependent inverse association with MS and is associated with attenuation of the effect of smoking, and may have relevance for clinical practice because they give no support for advising patients with MS to completely refrain from alcohol.
Abstract: Importance Alcohol consumption may be a modifiable lifestyle factor that affects the risk of developing multiple sclerosis (MS). Results of previous studies have been inconsistent. Objective To investigate the possible association of alcohol consumption with the risk of developing MS and to relate the influence of alcohol to the effect of smoking. Design, Setting, and Participants This report is based on 2 case-control studies: Epidemiological Investigation of Multiple Sclerosis (EIMS) included 745 cases and 1761 controls recruited from April 2005 to June 2011, and Genes and Environment in Multiple Sclerosis (GEMS) recruited 5874 cases and 5246 controls between November 2009 and November 2011. All cases fulfilled the McDonald criteria. Both EIMS and GEMS are population-based studies of the Swedish population aged 16 to 70 years. In EIMS, incident cases of MS were recruited via 40 study centers, including all university hospitals in Sweden. In GEMS, prevalent cases were identified from the Swedish national MS registry. In both studies, controls were randomly selected from the national population register, matched by age, sex, and residential area at the time of disease onset. Main Outcome and Measure Multiple sclerosis status. Results There was a dose-dependent inverse association between alcohol consumption and risk of developing MS that was statistically significant in both sexes. In EIMS, women who reported high alcohol consumption had an odds ratio (OR) of 0.6 (95% CI, 0.4-1.0) of developing MS compared with nondrinking women, whereas men with high alcohol consumption had an OR of 0.5 (95% CI, 0.2-1.0) compared with nondrinking men. The OR for the comparison in GEMS was 0.7 (95% CI, 0.6-0.9) for women and 0.7 (95% CI, 0.2-0.9) for men. In both studies, the detrimental effect of smoking was more pronounced among nondrinkers. Conclusions and Relevance Alcohol consumption exhibits a dose-dependent inverse association with MS. Furthermore, alcohol consumption is associated with attenuation of the effect of smoking. Our findings may have relevance for clinical practice because they give no support for advising patients with MS to completely refrain from alcohol.
TL;DR: In this paper, the authors demonstrate the selective removal of water from a bio-oil containing 73% of water by using X-ray diffraction analysis and find that the selectivity of the water and alcohols is closely related to the molecular sizes of the solvents and their polarity.
TL;DR: A review of the literature on the utility of using the selectively bred alcohol-preferring (P) and high-alcohol-drinking (HAD) lines of rats in studies examining high alcohol drinking in adults and adolescents, craving-like behavior, and the co-abuse of alcohol with other drugs is presented in this article.
TL;DR: In this article, a Lewis-acid catalyzed dehydration of simple alcohols on TiO2, ZrO2 and γ-Al2O3 oxide-catalysts was investigated by combining ab initio theoretical calculations with temperature programmed desorption (TPD) experiments.
TL;DR: The catalytic mechanism for oxidizing alcohols to carboxylate in basic aqueous solution by the bipyridine-based ruthenium complex 2 (BIPY-PNN)Ru(H)(Cl)(CO) is investigated by density functional theory (DFT) with the ωB97X-D functional to derive chemoselectivity for the formation of carboxylic acid rather than ester.
Abstract: The catalytic mechanism for oxidizing alcohols to carboxylate in basic aqueous solution by the bipyridine-based ruthenium complex 2 (BIPY-PNN)Ru(H)(Cl)(CO) (Nat. Chem. 2013, 5, 122) is investigated by density functional theory (DFT) with the ωB97X-D functional. Using water as the oxygen donor with liberation of dihydrogen represents a safe and clean process for such oxidations. Under NaOH, the active catalyst is 3 (BIPY-PNN)Ru(H)(CO). Four steps are involved: dehydrogenation of alcohol to aldehyde (Step 1); coupling of aldehyde and water to form the gem-diol (Step 2); dehydrogenation of gem-diol to carboxylic acid (Step 3); and deprotonation of carboxylic acid to carboxylate anion under base (Step 4). The dehydrogenations of alcohol (Step 1) and gem-diol (Step 3) prefer the double hydrogen transfer mechanism to the β-H elimination mechanism. The coupling of aldehyde and water (Step 2) proceeds through cleavage of water by catalyst 3 followed by concerted hydroxyl and hydrogen transfer to the aldehyde. The formation of the carboxylate anion occurs via direct deprotonation of the carboxylic acid under base (Step 4), while in the absence of base a stable carboxylic acid-addition complex 6 was formed. Added base was found to play important roles in the generation of catalyst 3 from both the stable carboxylic acid-addition complex 6 and its chloride precursor complex 2. The chemoselectivity for the formation of carboxylic acid rather than ester is ascribed to the favorable cleavage of water and the subsequent generation of the stable carboxylate anion that leads to carboxylic acid upon acidification.
TL;DR: Data indicate that alcohol cues elicit an approach bias among LS individuals, translating into greater difficulty inhibiting behavioral responses in the presence of such cues, a pattern generally supportive of dual process models of substance use.
Abstract: Low sensitivity to the acute effects of alcohol is a risk factor for heavy drinking and related problems. However, little research has tested process explanations for such effects. The current study tested the hypothesis that low sensitivity is associated with automatic approach biases for alcohol cues, coupled with deficits inhibiting responses in the presence of such cues. Eighty-five participants varying in alcohol sensitivity completed an Alcohol-Approach Avoidance Task and a Cued Go/No-Go Task while event-related potentials were recorded. Low sensitivity (LS) individuals showed evidence of automatic approach tendencies toward alcohol cues in both tasks, and experienced deficits inhibiting prepotent responses cued by alcohol images. Additionally, the event-related potential data indicated that LS individuals experienced more conflict when attempting to inhibit alcohol-cued responses, but not nonalcohol-cued responses, compared with their high-sensitivity counterparts. Together, these data indicate that alcohol cues elicit an approach bias among LS individuals, translating into greater difficulty inhibiting behavioral responses in the presence of such cues, a pattern generally supportive of dual process models of substance use.
TL;DR: Poor HIV treatment outcomes and nonadherence were prevalent among adults treated for HIV infection who drink alcohol; drinking in relation to missed medications and drinking in social settings are targets for interventions among alcohol drinkers at greatest risk for poor treatment outcomes.
Abstract: Substance use is a known predictor of poor adherence to antiretroviral therapies (ART) in people living with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome. Less studied is the association between substance use and treatment outcomes, namely, suppression of HIV replication. Adults living with HIV (N = 183) who reported alcohol use in the previous week and receiving ART were observed over a 12-month period. Participants completed computer interviews, monthly unannounced pill counts to monitor ART adherence, and daily cell-phone delivered interactive-text assessments for alcohol use. HIV viral load was collected at baseline and 12-month follow-up from medical records. Analyses compared participants who had undetectable HIV viral loads at baseline and follow-up (sustained viral suppression) to those with unsustained viral suppression. Analyses also compared participants who were adherent to their medications (>85 % pills taken) over the year of observation to those who were nonadherent. Fifty-two percent of participants had unsustained viral suppression; 47 % were ART nonadherent. Overall results failed to demonstrate alcohol use as a correlate of sustained viral suppression or treatment adherence. However, alcohol use was associated with nonadherence among participants who did not have sustained viral suppression; nonadherence in unsustained viral suppression patients was related to drinking on fewer days of assessment, missing medications when drinking, and drinking socially. Poor HIV treatment outcomes and nonadherence were prevalent among adults treated for HIV infection who drink alcohol. Drinking in relation to missed medications and drinking in social settings are targets for interventions among alcohol drinkers at greatest risk for poor treatment outcomes.
TL;DR: In this paper, the authors demonstrate that the process is general and can be used to convert model lignin compounds to both aryl silyl ethers and alkanes.
Abstract: The exploitation of lignin, the second most abundant naturally occurring polymer on earth, has been hampered by its network structure, which makes it difficult to process. Hydrosilanes have previously been shown to convert aryl ethers to hydrolyzable silyl ethers in the presence of B(C6F5)3. We demonstrate that the process is general and can be used to convert model lignin compounds to both aryl silyl ethers and alkanes. The relative reactivity of functional groups on model lignin compounds was found to be phenol > primary alcohol > methoxybenzene > alkyl silyl ethers. The process thus leads to cleavage of β-O-4, α-O-4, and methoxybenzene groups with concomitant silylation of phenolic and secondary alcohol groups. At longer time points provided sufficient silane was present, the full reduction of primary and secondary alcohols to alkyl groups was observed. Softwood lignin itself could only be partially solubilized (∼30%) even using excess hydrosilane and high catalyst loadings; the products were not chara...