Alcoholic OH Groups Research Articles

Using gas-phase chloride attachment for selective detection of morphine in a morphine/codeine mixture by ion mobility spectrometry.

Morphine and codeine are two important compounds of the opiate family that have vast applications in medicine. Several techniques have been reported for the determination of these opiates. Although ion mobility spectrometry (IMS) in positive ion mode can be applied for detection of both morphine and codeine, this technique on its own cannot detect a mixture of these two compounds because of the overlapping of their peaks. An IMS instrument equipped with a corona discharge ion source operating in negative ion mode was used for the detection of anionic clusters of morphine and codeine. In normal negative ion mode, NOx - , CO3 - , and On - act as the main reactant ions (RIs) which can deprotonate the analytes. We also used chloroform as a dopant to produce Cl- as an alternative RI. Morphine has a phenolic and an alcoholic OH group, while codeine bears only an alcoholic OH group. Because the phenolic OH group is more acidic, only morphine is deprotonated in negative ion mode in a morphine/codeine mixture. Furthermore, since morphine has two OH groups that can act as hydrogen-bond donors, it acts as an anion receptor. Hence, in the presence of chloroform where Cl- acts as the RI, morphine traps the Cl- anion to form a morphine-Cl- (Mor.Cl- ) adduct ion, while because of its structure codeine does not have this capability. Using the difference in the structures of morphine and codeine, two ionization methods were proposed for selective detection of morphine. Morphine is more acidic than codeine and has greater anion-receiving capability than codeine. Hence, it can both be deprotonated and form a adduct anion with Cl- . The Cl- attachment method is recommended for measurements at ambient temperature.

The mechanism studies of catalytic chemoselective conjugate addition of amino alcohols to α,β-unsaturated ester

The competing mechanisms of silver-/aminolithium-catalyzed hydrofunctionalization of α,β-unsaturated ester with an amino alcohol have been systematically studied with the DFT methods. Here, the acidity of a weaker nucleophile OH group of an amino alcohol is significantly higher than that of NH2 group, so it is easy to deprotonate by Ag(HMDS)/dppe. However, the generated Ag–O bond is more stable than the corresponding Ag–N bond. Therefore, the OH group shows higher reactivity than the NH2 group in the presence of a Lewis acid/Bronsted base pair catalyst. Then, α,β-unsaturated esters can be inserted into corresponding Ag–O bonds to obtain alkyl silver species. Alkyl silver can be protonated by bis(trimethylsilyl)amines to obtain hydrogen functionalized products and regenerate silver amino active compounds Ag(HMDS)/dppe.

Modification of the aspen lignin structure during integrated fractionation process of autohydrolysis and formic acid delignification

Integrated fractionation process based on autohydrolysis (H) and subsequent formic acid delignification (FAD) has been considered as an effective strategy to separate the main lignocellulosic components in view of the biorefinery. For the better understanding of the structural changes of the lignin during the integrated process, the fractionated aspen lignins were thoroughly characterized by Fourier transform infrared (FT IR), 13C, two-dimensional heteronuclear single quantum coherence (2D-HSQC) and 31P nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC), and thermogravimetric analysis (TGA). Compared to the milled wood lignin (MWL), the fractionated lignins had higher amounts of phenolic OH groups as due to the cleavage of β-O-4 linkages and less alcoholic OH groups mainly due to the esterification of the aliphatic OH groups by formic acid. Demethylation action of the lignin was not significant during the FAD process. More syringyl-propane (S) units were extracted during the H-FAD process than guaiacyl-propane (G) units resulting in a higher S/G ratio and more OCH3 in the fractionated lignins. Furthermore, autohydrolysis of aspen at higher temperature led to more condensation of the fractionated lignins which exhibited higher molecular weight and more β-5 and β-β linkages. The fractionated lignins exhibited high purities due to the breakage of the lignin-carbohydrate bonds.

Preparation and properties of silver nanopowders and composites based on a radiation-chemical method

Silver nanopowders with specific surface area up to 39.1 cm2/g, as well as alumina powders coated with silver consisting of nanoparticles with sizes of 50 and 80 nm, were produced by a radiation-chemical method. The influence of the number of OH groups of polyhydric alcohols on the specific surface area of obtained silver nanopowders is shown in the first time. The coating area of the oxide base can be varied from 2-3%–40%. Antibacterial properties of the composite have been studied on wine yeast, as well as E. coli and S. aureus bacteria. The results of the study of photocatalytic properties of the composite showed its potential.

Polyoxometalate catalyzed imine synthesis: Investigation of mechanistic pathways

The syntheses of imines by oxidative coupling of primary alcohols and amines were achieved by using 2 mol% polyoxometalate (POM) Na12[WZn3(H2O)2(ZnW9O34)2] (Zn–WZn3) catalyst in the presence of t-BuOK and di-oxygen with excellent conversion (up to 100%) and selectivity (up to 100%). Non-noble metal-based POM catalyst in the presence of base represents a new reaction protocol for the selective synthesis of imine from both aromatic and aliphatic primary amines with functional group tolerance. Control experiment shows the formation of di-oxygen bind Zn–WZn3 activated species. The electron-density of POM is mostly situated on the surface oxygen atoms of W–O–W bonds which can engage the alcoholic OH group and helps for the imine selectivity in the second step of imine synthesis.

Kinetic Study of Lornoxicam Hydrolysis

Gastrointestinal tract (GIT) side effects due to the local action of lornoxicam considered the most common problem that associated with using of this analgesic drug. Masking of the enolic alcohol OH group of lornoxicam to overcoming this problem was the aim, however, applying Williamson ether synthesis led to amide hydrolysis. Therefore, the objective of this study was shifted to study the hydrolytic kinetics and the influence of different bases as a function of time and temperature in the reaction media. The effects of all bases used in the study on the hydrolysis process of lornoxicam have been studied; NaOH was found to be the strongest followed by Na2CO3 and K2CO3. All three temperatures (25°C, 50°C and 80°C) have approximately similar effect  except  reflux condition that accelerates the hydrolysis process compare with the others. The hydrolysis process is proportional with time. Williamson ether synthetic procedure that followed to synthesize lornoxicam prodrugs was failed despite attempting different conditions. Using bases were induced the hydrolysis process of lornoxicam. The hydrolysis rate accelerated under reflux more than other conditions. In addition, reaction time gives more hydrolysis process.

Importance of the electrolyte cation on the non-covalent interactions in the electrooxidation of 1-heptanol on gold in 0.1 M alkali metal hydroxides

In order to determine the possible non-covalent influence of the alkali metal cation on the electrooxidation of 1-heptanol on gold in alkali metal hydroxides, 0.1 M MOH solutions, where M = Li, Na, K, Rb, and Cs, have been used. The charge-transfer resistance, determined by Electrochemical Impedance Spectroscopy, of heptanol oxidation at a fixed potential increased monotonically by a factor of 4 from LiOH to RbOH, that is, the heptanol oxidation current decreased. Since the degree of hydration of the OH group of the alcohol, as estimated by Molecular Dynamics Simulation, increased by a factor of 5 from LiOH to RbOH, it can be concluded that the decrease of the heptanol oxidation current from LiOH to RbOH is due to an increasing hydration of the heptanol OH group, which would hinder its access to the electrode surface. This result is in line with the previous finding [M.S. Ureta-Zañartu, C. Mascayano, C. Gutiérrez, doi:10.1016/j.electacta.2015.02.230] that the increase of the alcohol oxidation current at a fixed potential of linear saturated aliphatic alcohols from C1 to C7 on gold, both in a pH 11 buffer and in 0.1 M NaOH, increased with increasing chain length, that is, with decreasing hydration (because of the increasing hydrophobicity) of the alcoholic OH group.

Optimization of the process of abies ethanol lignin sulfation by sulfamic acid–urea mixture in 1,4-dioxane medium

The new process of abies ethanol lignin sulfation by a low-toxic mixture of sulfamic acid and urea in 1,4-dioxane medium was optimized, and the structure of sulfated ethanol lignin was studied. The process of lignin sulfation is described by a first-order equation in the temperature range 70–100 °C. The value of the rate constants is weakly dependent on the ratios of lignin and sulfating complex (sulfamic acid–urea mixture). The activation energy of the sulfation process decreases from 11.5 to 7.5 kJ/mol with an increase in the content of the sulfating complex (SC). The optimal conditions for sulfation of abies ethanol lignin with a high yield of water-soluble sulfated lignin [(100% of mass) with sulfur content of 7.9%] were found: temperature 95–100 °C, L/SC ratio 1:2.3–1:2.9, time 2 h. The composition and structure of water-soluble sulfated ethanol lignin were determined by elemental analysis, FTIR spectroscopy, two-dimensional NMR spectroscopy and gel permeation chromatography. It was shown that only alcoholic OH groups of ethanol lignin react with sulfamic acid. Sulfated ethanol lignin has a higher molecular weight and a lower degree of polydispersity compared to the initial ethanol lignin.

Intramolecular substitutions of secondary and tertiary alcohols with chirality transfer by an iron(III) catalyst

Optically pure alcohols are abundant in nature and attractive as feedstock for organic synthesis but challenging for further transformation using atom efficient and sustainable methodologies, particularly when there is a desire to conserve the chirality. Usually, substitution of the OH group of stereogenic alcohols with conservation of chirality requires derivatization as part of a complex, stoichiometric procedure. We herein demonstrate that a simple, inexpensive, and environmentally benign iron(III) catalyst promotes the direct intramolecular substitution of enantiomerically enriched secondary and tertiary alcohols with O-, N-, and S-centered nucleophiles to generate valuable 5-membered, 6-membered and aryl-fused 6-membered heterocyclic compounds with chirality transfer and water as the only byproduct. The power of the methodology is demonstrated in the total synthesis of (+)-lentiginosine from D-glucose where iron-catalysis is used in a key step. Adoption of this methodology will contribute towards the transition to sustainable and bio-based processes in the pharmaceutical and agrochemical industries.

DETERMINATION OF COMPOSITION AND CONSTRUCTION OF COMPLEX COMPOUNDS OF TRANSITION METALS WITH DERIVATIVES OF AMINES BY METHOD OF IR-SPECTROSCOPIES

Complex compounds of chloride and copper nitrate (II) with aliphatic amines R – NH 2 , R 2 – NH, R 3 – N, where R is C 2 H 5 ; C 3 H 5 ; C 4 H 9 ; CH 3 (CH 2 ) 9 ; C 5 H 11 ; and its substitutes from ethyl alcohol by merging solutions of copper (II) salts and amines in molecular ratios of 1:2, as well as complex compounds of copper (II) with N - derivatives of diethanolamine and benzyldiethylamine (RDEA), where R is C 3 H 5 ; C 3 H 7 ; C 4 H 7 or C 6 thH 5 CH 2 , diethanolamine – NH (C 2 H 4 OH) 2 , are synthesized. The absorption bands in the 440-420 cm -1 region, are identified which are related to ν (Cu – N) vibrations, that indicates about coordination through the nitrogen atom grounds. In the IR spectra of all complexes, an absorption band is observed in ligands in the region of 220-210 cm -1 , which disappears in the complex. In the complexes there are bands of absorption in the region 460-430 cm -1 , which are typical for copper (II) complexes with all amines and are practically independent of the amine radical. The absorption frequencies of copper (II) complexes with benzyl, alliamines can be explained by the dual nature of σ- and π-dative interactions. In the low-frequency region of complexes of copper (II) halides with pyridine and its substituted an increase in the oscillation frequencies in the region 270-240 cm -1 is observed. In the IR spectra of copper complexes with benzyldiethanolamines [Cu (BZDEA) 2 ] X 2 at interval 3500-3100 cm -1 two absorption bands appear. A band with a maximum at 3150 cm -1 probably refers to the absorption of coordinated OH groups. The coordination of the OH groups is confirmed by data in the absorption region v (C – 0), and also the appearance of the bands ν (Cu – O). The band of deformation vibrations of alcohol OH-groups at ~ 1650 cm -1 is shifted to the low-frequency region by 15 to 30 cm -1 . It can be determined only by the interaction of hydroxy groups with cis. Ligand is also coordinated through the nitrogen atom. This is confirmed by the pre-sence of absorption bands ν (Cu – N) in the region of 480-400 and 280-230 cm -1 . Therefore, the ligand is tridentate. Thus, according to the data of IR spectroscopy, molecules of N-derivatives diethanolamine form the bonds with c.y. through oxygen atoms of oxy groups. The fourth coordination site may be occupied by acid residues or the deprotonated oxygen atom of the hydroxy group performs a bridging function. Then the complex must have a dimeric or, in general, a polymeric structure.

Different morphologies of strontium carbonate in water/ethylene glycol and their photocatalytic activity

Three-dimensional SrCO3 flower-like nanostructures self-assembly from nanocrystals have been successfully synthesized by solvothermal method at the temperature of 120 °C. In the presence of anionic surfactant sodium dodecyl sulfate, SrCO3 is crystallized in different alcohols and aqueous solutions. X-ray diffraction (XRD) pattern reveals that needles and flakes flower-like SrCO3 are orthorhombic phases. The product also has a high specific surface area of about 60.52 m2 g−1. Based on the nucleation and self-assembly process, a possible formation mechanism is proposed. The effects of SDS and alcohol on the product are also studied. Results suggest that –OH groups of alcohol play a key role in morphological controlling of SrCO3. Moreover, the FCNS exhibits excellent photocatalytic activity for the photodegradation of RhB under visible light irradiation and the degradation rate approached to 90.32%.

Mechanistic Elucidation of Gold(I)-Catalyzed Oxidation of a Propargylic Alcohol by a N-Oxide in the Presence of an Imine Using DFT Calculations

Density functional theory (DFT) calculations were utilized to investigate the mechanism of the oxidation of an indolyl propargylic alcohol by a N-oxide in the presence of an imine and a gold(I) catalyst. The catalytic reaction is proposed to start from regioselective oxidation of the gold(I)-activated alkyne dictated by a hydrogen bond interaction between the OH group of the propargylic alcohol and the N-oxide. This oxidation was expected to give an α-carbonyl gold carbene complex. In contrast to this expectation, our calculations showed that the corresponding carbene is not a local minimum and the complex undergoes a very fast 1,2 aryl shift to form an alkene complex. Subsequently, an imine is added to the ensuing alkene complex to give an iminium cation from which a cycloaddition process occurs and an indolium is formed. Finally, an N-oxide deprotonates the indolium complex and affords an intermediate which is significantly reactive toward water elimination. Our calculations indicate that the 1,2-aryl s...

The first example of bis(indolyl)methane based hyperbranched polyurethanes: Synthesis, solar cell application and anti-bacterial and anti-oxidant properties

Two new AB2-type blocked-isocyanate monomers containing bis(indolyl)methane moiety were synthesized via a scalable synthetic routes. Except the “A” functional groups, both of the monomers are structurally identical; one was designed with phenolic OH group (Monomer-1) and the other one was designed with alcoholic OH group (Monomer-2). The first examples of indole based hyperbranched polyurethanes were derived from these monomers in DMF and THF solvents. Blocked-isocyanate end-groups of these polymers were modified with PEG-mono methyl ether. The structures of the AB2-type monomers and their intermediates were confirmed using FT-IR, 1H NMR, and 13C NMR spectroscopy. The formation of hyperbranched polyurethanes and their end-group modifications were confirmed using 1H NMR spectra. The absolute molecular weights of the polymers were determined using SEC-MALLS technique and the values were found to be varied from 6.8×103g/mole to 1.1×105g/mole. The diverse functions of all the synthesised polymers were studied. Dye-sensitized solar cells (DSSC) fabricated with a polymer derived from Monomer-2 (InHBPU-5) yielded an overall energy conversion efficiency of η=6.59% upon 1 sun illumination with visible light. Also, this polymer showed activity almost equal to tetracycline (control) toward both gram-positive and gram-negative bacterial strains. In addition, this polymer and its monomer, both exhibited good capacity for scavenging DPPH free radical.

A new, simplified model for the estimation of polyphenol oxidation potentials based on the number of OH groups.

We present a new and simpler regression model for the estimation of the first oxidation potentials (Ep1) of flavonoids based on the number of phenolic, alcoholic, and carboxylic OH groups. In the regression we included the Ep1 of 12 polyphenols (mostly flavonols and catechins) that were measured in our laboratory at pH 3. The model yielded r=0.986 and SE=0.040. Later successive inclusions of previously reported Ep values into the regression model, 7 at pH 3, the model (N=19) yielded r=0.980, SE=0.046 and 19 at pH 7 the model (N=38), yielded r=0.985, SE=0.044.

Photochemical Formation of Anthracene Quinone Methide Derivatives.

Anthrols 2-7 were synthesized and their photochemical reactivity investigated by irradiations in aq CH3OH. Upon excitation with visible light (λ > 400 nm) in methanolic solutions, they undergo photodehydration or photodeamination and deliver methyl ethers, most probably via quinone methides (QMs), with methanolysis quantum efficiencies ΦR = 0.02-0.3. Photophysical properties of 2-7 were determined by steady-state fluorescence and time-correlated single photon counting. Generally, anthrols 2-7 are highly fluorescent in aprotic solvents (ΦF = 0.5-0.9), whereas in aqueous solutions the fluorescence is quenched due to excited-state proton transfer (ESPT) to solvent. The exception is amine 4 that undergoes excited-state intramolecular proton transfer (ESIPT) in neat CH3CN where photodeamination is probably coupled to ESIPT. Photodehydration may take place via ESIPT (or ESPT) that is coupled to dehydration or via a hitherto undisclosed pathway that involves photoionization and deprotonation of radical cation, followed by homolytic cleavage of the alcohol OH group from the phenoxyl radical. QMs were detected by laser flash photolysis and their reactivity with nucleophiles investigated. Biological investigation of 2-5 on human cancer cell lines showed enhancement of antiproliferative effect upon exposure of cells to irradiation by visible light, probably due to formation of electrophilic species such as QMs.

Bio-inspired crosslinking and matrix-drug interactions for advanced wound dressings with long-term antimicrobial activity.

There is a growing demand for durable advanced wound dressings for the management of persistent infections after deep burn injuries. Herein, we demonstrated the preparation of durable antimicrobial nanofiber mats, by taking advantage of strong interfacial interactions between polyhydroxy antibiotics (with varying number of OH groups) and gelatin and their in-situ crosslinking with polydopamine (pDA) using ammonium carbonate diffusion method. Polydopamine crosslinking did not interfere with the antimicrobial efficacy of the loaded antibiotics. Interestingly, incorporation of antibiotics containing more number of alcoholic OH groups (NOH≥5) delayed the release kinetics with complete retention of antimicrobial activity for an extended period of time (20 days). The antimicrobials-loaded mats displayed superior mechanical and thermal properties than gelatin or pDA-crosslinked gelatin mats. Mats containing polyhydroxy antifungals showed enhanced aqueous stability and retained nanofibrous morphology under aqueous environment for more than 4 weeks. This approach can be expanded to produce mats with broad spectrum antimicrobial properties by incorporating the combination of antibacterial and antifungal drugs. Direct electrospinning of vancomycin-loaded electrospun nanofibers onto a bandage gauze and subsequent crosslinking produced non-adherent durable advanced wound dressings that could be easily applied to the injured sites and readily detached after treatment. In a partial thickness burn injury model in piglets, the drug-loaded mats displayed comparable wound closure to commercially available silver-based dressings. This prototype wound dressing designed for easy handling and with long-lasting antimicrobial properties represents an effective option for treating life-threatening microbial infections due to thermal injuries.

A solid acetylene reagent with enhanced reactivity: fluoride-mediated functionalization of alcohols and phenols

The direct vinylation of an OH group in alcohols and phenols was carried out utilizing an easy-to-use CaC2/KF solid acetylene reagent.

ChemInform Abstract: Nucleophilic Substitution of the Hydroxyl Group in Stereogenic Alcohols with Chirality Transfer.

AbstractAn intramolecular substitution of the OH group in enantioenriched alcohols is achieved by acid/base bifunctional catalysis.

Direct Olefination of Alcohols with Sulfones by Using Heterogeneous Platinum Catalysts.

Carbon-supported Pt nanoparticles (Pt/C) were found to be effective heterogeneous catalysts for the direct Julia olefination of alcohols in the presence of sulfones and KOtBu under oxidant-free conditions. Primary alcohols, including aryl, aliphatic, allyl, and heterocyclic alcohols, underwent olefination with dimethyl sulfone and aryl alkyl sulfones to give terminal and internal olefins, respectively. Secondary alcohols underwent methylenation with dimethyl sulfone. Under 2.5 bar H2, the same reaction system was effective for the transformation of alcohol OH groups to alkyl groups. Structural and mechanistic studies of the terminal olefination system suggested that Pt(0) sites on the Pt metal particles are responsible for the rate-limiting dehydrogenation of alcohols and that KOtBu may deprotonate the sulfone reagent. The Pt/C catalyst was reusable after the olefination, and this method showed a higher turnover number (TON) and a wider substrate scope than previously reported methods, which demonstrates the high catalytic efficiency of the present method.

Calcium l-tartrate complex formation in neutral and in hyperalkaline aqueous solutions.

The complex formation reaction between the l-tartrate (Tar2-) and calcium ions taking place in neutral and in hyperalkaline (pH > 13) aqueous solutions has been investigated. It was demonstrated that upon NaOH addition the solubility of the CaTar(s) precipitate significantly increases. Conductometric and freezing point depression measurements further confirmed that in this process water soluble species are formed as a result of a reaction between the CaTar(s) and the hydroxide ion (or, conversely, between Ca(OH)2(s) and the Tar2- ion). 13C NMR spectroscopic measurements yielded the value of pK3 = 15.4 ± 0.2 for the proton dissociation of one of the alcoholic OH groups of Tar2- (at 25.0 °C and 4 M Na(Cl) ionic strength). Upon addition of calcium ions to an alkaline Tar2- solution, the 1H NMR signal gradually broadened and the 13C-satellite peaks split to two components, which also indicate complexation. From H2/Pt potentiometric titrations performed with solutions in the 13.6 ≤ pH ≤ 14.4 range, it was observed, that this complex formation is accompanied by a hydroxide ion consuming process. The titration curves can be best described via assuming the formation of the CaTarH-1-(aq) (lg β11-1 = -11.2 ± 0.1) and CaTarH-22-(aq) (lg β11-2 = -25.3 ± 0.1) complexes. In hyperalkaline solutions, these two species account for more than 90-99% of the calcium ions present and the contribution of the other reasonable and well-established calcium-containing solution species is rather small. The possible structures of the above complexes have been modeled via ab initio calculations. The stoichiometries are consistent both with species containing coordinated alcoholate group(s) and with mixed Ca(ii)-hydroxo-tartrato complexes. From the data available at present, both types of structures can be considered as chemically reasonable.