Butyl Ester Research Articles

Dwarf Interstocks Improve Aroma Quality of ‘Huahong’ Apple (Malus × domestica)

‘Huahong’ is a popular apple cultivar because of its anti-browning properties and appealing aroma and flavor. It is mainly planted by grafting on dwarf interstocks in Northeast China. We investigated the different aroma profiles of apple fruits grown from six dwarf interstocks (‘CG24’, ‘SH38’, ‘SH3’, ‘MD001’, ‘Mac9’, and ‘CX5’) and from no interstocks (CK). A total of 55 VOCs were detected, including esters (25), aldehydes (14), alcohols (8), ketones (3), alkane hydroxyls (3), and acids (2). Among the VOCs, 48 were detected in the skin and 21 in the pulp. The skin of ‘Huahong’ apples had a strong sweet aroma, and the pulp was green with a subtle aroma. The dominant compounds (>5% of total content) in the skin were 2-methyl butyl acetate, hexyl 2-methyl butyrate, caproic acid butyl ester, hexanal, (Z)-2-heptene aldehyde, and 6-methyl-5-heptene-2-ketone, while in the pulp, they were 2-methyl butyl acetate, methanol, 2-methyl-1-butanol, hexanol, and hexane. Compared with CK, ‘SH38’, ‘MD001’, and ‘SH3’ interstocks had increased total aroma content, and ‘CX5’ and ‘CG24’ had suppressed aroma. The effects of interstocks on aroma were mainly reflected in skin. The VOC content ranged from 3297.52 to 9895.75 µg·kg−1 in skin, and from 748.62 to 1369.21 µg·kg−1 in pulp. PCA revealed that use of interstock ‘SH38’ mainly affected esters. ‘MD001’ affected hexane and 4-pentene-1-acetate; ‘Mac9’ and ‘SH3’ affected octanoic acid-2-methyl butyl ester, hexyl butyrate, and 2-methyl-1-butanol; and ‘CX5’ and ‘CG24’ had a greater impact on isoamyl propionate and 1-pentene-3-ol. Finally, ‘SH38’ had the highest principal comprehensive score. ‘SH38’ and ‘SH3’ interstocks resulted in significantly increased apple VOC content.

The inhibitory effects of Ulva prolifera extracts on early growth of Spartina alterniflora and the underlying mechanisms

Spartina alterniflora, a highly invasive plant, has caused a serious threat to ecosystem biodiversity and economic development in coastal areas of many countries. In this study, the allelopathic effect of Ulva prolifera extracts on seed germination and seedling growth of S. alterniflora was studied. The results showed that three different treatments (water, methanol and ethyl acetate extract) could inhibit the seed germination and seedling growth of S. alterniflora by reducing the germination proportion and germination index of seeds, decreasing the seedling length and root length of seedlings, and affecting the lipid peroxidation and enzyme activity. The higher the concentration of the extracts, the higher the inhibition effect. When the aqueous extract concentration reached 0.20g/mL, the germination proportion of S. alterniflora decreased to 49.53% of the control. RNA-seq analysis showed that the expression of genes related to amino acid metabolism and photosynthesis were both upregulated, and genes related to energy generation and metabolism were both downregulated after adding the extracts. GC-MS analysis indicated that the U. prolifera extract was rich in organic acids, alcohols and esters, among which butanoic acid, butyl ester, Valine and Hexanedioic acid, bis (2-ethylhexyl) ester might be the dominant allelochemicals. In order to facilitate field dosing, prolong action time and control release effect, PVA/SA hydrogel embedded U. prolifera extract was used to obtain a sustained-release agent. In addition, the survival rate of S. alterniflora was significantly reduced, which was only 21.67% at the salinity of 30ppt. The results of this study provide a feasible method for controlling the invasion of S. alterniflora and achieving the waste utilization of U. prolifera.

Study of tyramine-binding mechanism and insecticidal activity of oil extracted from Eucalyptus against Sitophilus oryzae.

The rice weevil, Sitophilus oryzae (L.), is a major pest of stored grains throughout the world, which causes quantitative and qualitative losses of food commodities. Eucalyptus essential oils (EOs) possess insecticidal and repellent properties, which make them a potential option for insect control in stored grains with environmentally friendly properties. In the current study, the binding mechanism of tyramine (TA) as a control compound has been investigated by funnel metadynamics (FM) simulation toward the homology model of tyramine1 receptor (TyrR) to explore its binding mode and key residues involved in the binding mechanism. EO compounds have been extracted from the leaf and flower part of Eucalyptus camaldulensis and characterized by GC/MS, and their effectiveness has been evaluated by molecular docking and conventional molecular dynamic (CMD) simulation toward the TyrR model. The FM results suggested that Asp114 followed by Asp80, Asn91, and Asn427 are crucial residues in the binding and the functioning of TA toward TyrR in Sitophilus Oryzae. The GC/MS analysis confirmed a total of 54 and 31 constituents in leaf and flower, respectively, where most of the components (29) are common in both groups. This analysis also revealed the significant concentration of Eucalyptus and α-pinene in leaves and flower EOs. The docking followed by CMD was performed to find the most effective compound in Eucalyptus EOs. In this regard, butanoic acid, 3-methyl-, 3-methyl butyl ester (B12) and 2-Octen-1-ol, 3,7-dimethyl- (B23) from leaf and trans- β-Ocimene (G04) from flower showed the maximum dock score and binding free energy, making them the leading candidates to replace tyramine in TyrR. The MM-PB/GBSA and MD analysis proved that the B12 structure is the most effective compound in inhibition of TyrR.

Comparison of the Combustion Process Parameters in a Diesel Engine Powered by Second-Generation Biodiesel Compared to the First-Generation Biodiesel

The use of biofuels to power compression–ignition engines makes it possible to reduce emissions of certain harmful components of exhaust gases. The purpose of this study was to determine the influence of second-generation biofuels on the course of indicator graphs and heat release characteristics of the Perkins 1104D-44TA compression–ignition engine. For comparative purposes, the same tests were carried out by feeding the engine with first-generation biofuel and diesel fuel. Babassu butyl esters (BBuE) were used as the second-generation biofuel. The second fuel was a first-generation biofuel—rapeseed oil methyl esters (RME). Analysis of the results made it possible to draw conclusions about the effect of using 2nd and 1st generation biofuels on the parameters of the combustion process. When the DF engine was powered, the lowest fuel dose per work cycle was obtained. In the case of RME and BBuE fuels, it depends on the engine load. For low loads, higher consumption is for RME, and for higher loads, fuel consumption for BBuE in-creases most often. This is due to the lower calorific value of the esters. The results of these tests indicate that feeding the engine with BBuE and RME fuel in most loads resulted in higher maximum combustion pressures compared to feeding the engine with DF which may be directly related to the higher cetane number of these fuels compared to DF and the oxygen content of these fuels. Feeding the engine with BBuE and RME esters compared to DF did not result in large differences in the maximum heat release rates HRmax. However, the values of the first and second maximum heat release rates x1max and x2max, in addition to the type of fuel, are strongly influenced by the operating conditions, especially the engine load. Analyzing the combustion angles of 5, 10, 50, and 90% of the fuel dose, it can be seen that feeding the engine with BBuE and RME esters for most measurement points results in faster combustion of the fuel dose compared to DF.

The Content Variation of Four Active Components in Amygdalus persica L. during Different Harvesting Periods

In this study, a quantitative method for the content determination of rutin, 5-O-coumaroylquinic acid methyl ester, chlorogenic acid butyl ester, and kaempferol in Amygdalus persica L. flowers during different harvest periods was established to investigate its various rules and determine the optimal harvesting period. The determination was performed on the XTERRA MS C18 column with a mobile phase consisting of 0.1% formic acid aqueous solution and acetonitrile (gradient elution) at a flow rate of 1.0 mL/min. In combination with other validation data, including precision, stability, and recovery tests, this method demonstrated good reliability and sensitivity. The results showed that the contents of rutin, 5-O-coumaroylquinic acid methyl ester, chlorogenic acid butyl ester, and kaempferol in A. persica flowers during different harvest periods were quite different, and the content in samples at the early blooming stage was the highest. The method is simple, accurate, and rapid for determining the contents of four active ingredients in A. persica flowers.

Two Novel Flavonoids with Lipid-Lowering Activity from Yi Medicine Shekaqi.

Yi medicine Shekaqi is the most attractive traditional ethnic medicine due to its significant and diverse pharmacological activities. Two novel flavonoids, including 5,2'-dihydroxy-6-methoxy-7-decyloxyflavone and tenaxin II-7-O-β-D-glucuronopyranosyl acid butyl ester, along with six known flavonoids, were isolated from Yi medicine Shekaqi. Their structures were elucidated based on the analysis of their comprehensive spectral data. The in vitro lipid-lowering activities of the eight compounds showed that all the compounds significantly inhibited the lipopolysaccharide (LPS)-induced increase in the total cholesterol (TC) level, while compounds 1, 4, 6, 7, and 8 significantly inhibited the LPS-induced increase in the triglyceride (TG) level.

Lipase-Catalyzed Synthesis, Antioxidant Activity, Antimicrobial Properties and Molecular Docking Studies of Butyl Dihydrocaffeate.

Green chemistry approaches, such as lipase-catalyzed esterification, are promising methods for obtaining valuable chemical compounds. In the case of the use of lipases, unlike in aqueous environments, the processes of the ester bond formations are encountered in organic solvents. The aim of the current research was to carry out the lipase-catalyzed synthesis of an ester of dihydrocaffeic acid. The synthesized compound was then evaluated for antioxidant and antimicrobial activities. However, the vast majority of its antioxidant activity was retained, which was demonstrated by means of DPPH· (2,2-diphenyl-1-picrylhydrazyl) and CUPRAC (cupric ion reducing antioxidant capacity) methods. Regarding its antimicrobial properties, the antifungal activity against Rhizopus oryzae is worth mentioning. The minimum inhibitory and fungicidal concentrations were 1 and 2 mM, respectively. The high antifungal activity prompted the use of molecular docking studies to verify potential protein targets for butyl ester of dihydrocaffeic ester. In the case of one fungal protein, namely 14-α sterol demethylase B, it was observed that the ester had comparable binding energy to the triazole medication, isavuconazole, but the interacted amino acid residues were different.

Glycerol Utilization as a Sole Carbon Source Disrupts the Membrane Architecture and Solventogenesis in Clostridium beijerinckii NCIMB 8052

Efficient bioconversion of abundant waste glycerol to value-added chemicals calls for a wider range of fermentative workhorses that can catabolize glycerol. In this study, we used quantitative gene expression and solvent profiling, qualitative metabolite analysis, and enzyme activity assays to investigate the factors that limit glycerol utilization as a sole carbon source by Clostridium beijerinckii NCIMB 8052. C. beijerinckii NCIMB 8052 did not produce acetate, acetone and butanol on glycerol. Congruently, the genes encoding the coenzyme A transferase subunits (ctfAB) and bifunctional acetaldehyde-CoA/alcohol dehydrogenase (adhE) were down-regulated up to 135- and 21-fold, respectively, at 12 h in glycerol-grown cells compared to glucose-grown cells. Conversely, NADH-dependent butanol dehydrogenase A (bdhA) was upregulated 2-fold. Glycerol dehydrogenase (gldA) and dihydroxyacetone kinase (subunit dhaK) were upregulated up to 5- and 881-fold, respectively. Glyceraldehyde-3-phosphate dehydrogenase (gapdh) showed mostly similar expression profiles at 12 h on glucose and glycerol. At 24 h, gapdh was downregulated 1.5-fold, while NADP+-dependent gapdh was upregulated up to 1.9-fold. Glycerol-grown cells showed higher or similar activity profiles for all solventogenic enzymes studied, compared to glucose-grown cells. Butyraldehyde (3 g/L) supplementation led to the production of ~0.1 g/L butanol, whilst butyrate (3.5 g/L) supplementation produced 0.7 and 0.5 g/L acetone and butanol, respectively, with glycerol. Further, the long chain saturated fatty acids cyclopentaneundecanoic acid, methyl ester and hexadecanoic acid, butyl ester were detected in glucose- but not in glycerol-grown cells. Collectively, growth on glycerol appears to disrupt synthesis of saturated long chain fatty acids, as well as solventogenesis in C. beijerinckii NCIMB 8052.

Chemical constituents and antimicrobial ability of essential oil from the fruits of Lonicera maackii (Rupr.) Maxim.

Essential oils are the natural products that can pave the way for the creation of effective drugs with various beneficial properties. Plants of Lonicera maackii are well known in the natural growth regions of temperate Asia due to therapeutic effects and a high content of the bioactive compounds. Species diversity of steppe vegetation is enriched by the introduction of plants, but the assessment of this process effectiveness should also take into account the realization of plant genetic potential for the accumulation of secondary metabolites in the new growth conditions. The aim of the work was to establish whether the plants of L. maackii introduced in the steppe zone could reproduce the health promoting properties. The essential oil from the fruits of L. maackii was obtained by hydro distillation method. Chloroform and ethyl acetate fractions isolated from the aqueous distillate of L. maackii fruits were analyzed by gas chromatography combined with mass spectrometry (GC-MS analysis). Chemical constituents identified in ethyl acetate and chloroform fraction represented 98.6% and 94.2 % of the total compounds content, respectively. Among the most abundant components were hexadecane, acetic acid, butyl ester, hexadecanoic acid, methyl ester, linoleic acid, and linoleic acid methyl ester in the and the alkanes heptacosane, hexadecane, and tetradecane in chloroform fraction. Linoleic acid and some minor constituents of L. maackii fruit essential oil, such as ethyl-isoallocholate, arachidic acid, linalool and d-mannitol-1-decylsulfonyl are well known because of their reported bioactivities. The antimicrobial activity of essential oil was assessed against several clinical and collection bacterial and fungal strains. The results of disc-diffusion assays showed low to moderate activity of L. maackii fruit essential oil against Gram-positive and Gram-negative bacterial strains, as well as against fungal itraconazole-resistant clinical strain of Candida albicans. Thus, the essential oil derived from Lonicera maackii fruits may serve as potential resource of bioactive compounds having beneficial properties, in particular, the ability to overcome the resistance of pathogenic microorganisms to drugs. Further research is needed to identify the full range of bioactivities of the essential oil obtained from honeysuckle fruits.

Gas chromatography-mass spectrometric determination of organic acids by ion pair liquid extraction followed by in-situ butylation from aqua feed samples.

A rapid and sensitive analytical method was developed to quantitatively determine organic acids (OAs) from fish feed samples extracted by ion-pair (IP) solvent extraction, followed by in-situ butylation and gas chromatography-mass spectrometric (GC-MS) analysis. The extraction of OAs was carried out with acetonitrile containing 10 mM tetrabutylammonium hydroxide (TBAH), and the analytes were derivatized to their butyl esters in the injection port of the GC-MS system. The developed method was validated in the range of 1-5000 ng/g, with recoveries ranging from 93-117%. The limit of detection (LOD) and limit of quantification (LOQ) of the method was 1-5 ng/g and 2-10 ng/g, respectively, yielding good linearity (R2 > 0.9990) and precision with a relative standard deviation less than 10%. The proposed method was successfully applied to analyze OAs in sinking and floating fish feed samples. The analyzed samples showed the presence of benzoic, succinic, fumaric, glutaric, adipic, and phthalic acids in sinking feed samples; and benzoic, succinic, adipic, phthalic acids in floating feed samples, respectively.

Two new iridoid glycosides from Hedyotis diffusa

Two new iridoid glycosides, named productasperulosidic acid butyl ester (1) and E-6-O-3-hydroxy-p-methoxycinnamoyl scandoside methyl ester (2), along with nine known ones (3–11), were isolated from Hedyotis diffusa Willd. The structures of them were elucidated by extensive 1D, 2D NMR and HR-ESI-MS spectral data. Compounds 1–11 showed no significant cytotoxic activity against HeLa cells.

Ionic-liquid-modified magnetite nanoparticles for MSPE-GC-MS determination of 2,4-D butyl ester and its metabolites in water, soil, and bottom sediments

Efficient sorbents based on magnetite nanoparticles and ionic liquids are proposed for solid-phase extraction of the pesticide, butyl 2,4-dichlorophenoxyacetate (2,4-DB), and its metabolites, 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4-dichlorophenol (2,4-DCP), and 4-chlorophenol (4-CP). Fe3O4 nanoparticles were modified with 1-carboxymethyl-3-methylimidazolium chloride, 1,3-dimethylimidazolium-2-carboxylate, and 1,3-dimethylimidazolium-2-carboxylate. The obtained sorbents possess a saturation magnetization of 29–37 emu/g and a specific surface area of 89.7–119.5 m2g−1. The highest extraction efficiency was achieved for the sorbent modified with 1,3-dimethylimidazolium-2-carboxylate. Upon single extraction (the sorbent weight was 0.02 g, pH 4–5, t = 20 min), 98–99% of 2,4-D and 2,4-DB, 92% of 2,4-DCP, and 94% of 4-CP were extracted. The enrichment factor after desorption reached 1602–1710. The limit equilibrium sorption was 303.1–520.8 mg g−1.The combination of MSPE with GC-MS was used to monitor the pollution of soils, ground and river waters, and bottom sediments by 2,4-DB and its metabolites. Also, the distribution of the pesticide and its metabolites over the profile of typical and residual-calcareous chernozems up to a depth of 110 cm was studied. The limits of detection of 2,4-D and 2,4-DB were 0.1 ngL−1 upon determination in distilled water, 0.5–0.6 ngL−1 in river and ground waters, 10 ng kg−1 in soil, and 25–30 ng kg−1 in bottom sediments. The limits of detection of 4-CP and 2,4-DCP were slightly lower to be 5 ngL−1 in distilled water and 8–10 ngL−1 in river and ground waters. Upon determination in complex matrices, such as soils, the limits of detection of 4-CP and 2,4-DCP were 10–15 ng kg−1.

Field investigation of pollutant characteristics and targeted ventilation control strategies in high-ceiling aircraft spraying workshop

To achieve efficient ventilation and purification in the high-ceiling painting workshop is faced with the contradiction between effect and energy consumption. Understanding the characteristics of gaseous pollutants is of paramount importance for ventilation and purification system design. The composition and concentration of volatile organic compounds (VOCs) emitted from aircraft painting workshop were sampled by Tenax-TA tubes and analyzed with gas chromatography-mass spectrometry (GC-MS). Approximately 50 types of VOCs (detection rate>50%) were detected in the aircraft spraying workshop, with percentages of 36.3% for esters, 31.9% for aldehyde ketones, 28.5% for biphenylenes, 1.9% for alcohols and 1.4% for alkanes. The TVOC concentrations in the workshop were 48.6 mg/m3 and 132.4 mg/m3, during the varnish painting and the finish painting processes, respectively, and these are several times higher than those observed in other industries (automobile painting and wooden furniture painting). The field test data of spraying workshops from 197 spraying factories in five industry sectors were collected from field measurement and existing literature. Some VOCs components are the general pollutants in the painting workshops, such as Acetic acid, butyl ester, Toluene, and 2-Butanone. A novel ventilation model using multiple target purification units is proposed to eliminate the pollutants in an aircraft spraying workshop. Compared with the original trench exhaust system, the air volume of the proposed targeted ventilation system is reduced by 75%, and the energy consumption is reduced by 45,000 kW·h per aircraft.

Quercetin -3-O-β-D-glucouronide butyl ester from Vitis vinifera leaves of potent anti-helicobacter pylori activity and impact of its combination with clarithromycin

Quercetin -3-O-β-D-glucouronide butyl ester from Vitis vinifera leaves of potent anti-helicobacter pylori activity and impact of its combination with clarithromycin

Synthesis and computational study of 4-hydroxylbenzamide analogous as potential anti-breast cancer agent

Due to their role in cell growth and survival, HDAC (II), JAK 2 and EGFR receptors are important targets in many chemotherapies that aim to produce their biological response in malignancy solid tumors. In this work, several 4-hydroxybenzamide analogues coupled with 1,3-benzodioxole, a,ß-unsaturated carbonyl, and tert -butyl ester bases small molecules were synthesized via imidation, EDC coupling, and etherification reactions , then bio-active 4-hydroxybenzamide analogues were studied using quantum calculations and molecular docking. The Frontier molecular orbitals and energy gap values were calculated using Time-Dependent Density Functional Theory (TD-DFT). Docking results showed A and E as potent JAK2 inhibitors. B, C, and F may be good HDAC II inhibitors. D may act as a potent EGFR inhibitor. These were followed by cytotoxic evaluation of 4-hydroxybenzamide analogues on human estrogen receptor breast cancer cells (MCF-7), metastatic breast adenocarcinome cancer cells (MDA-MB-231), and fibroblast cells (NIH/3T3) respectively. Molecule E was found to have insignificant apoptosis against MCF 7 cell line and MDM-MD-231 cell lines with IC50 value 5.0 µg⁄mL and 5.0 µg⁄mL respectively.

Analysis of Biological Degradation and Life Cycle Indicators of Mineral Diesel Fuel Mixtures, Containing 10% Biodiesel, Obtained by Simultaneous Oil Extraction and Transesterification

This article provides data on the environmental properties of biofuels obtained by the simultaneous extraction of oil from spoiled rapeseed and transesterification, with the addition of mineral diesel to the reaction mixture. The resulting reaction product contained 10% biodiesel: fatty acid methyl, ethyl, or butyl esters in mixtures with mineral diesel. The addition of biodiesel has been found to increase the rate of biodegradation of fuels. Such fuels are classified as partially biodegradable, according to the OECD classification. Life cycle analysis showed that the mixtures of biodiesel and mineral diesel have lower negative environmental impacts, compared to pure mineral diesel. The values of indicators such as abiotic depletion, acidification, global warming, ozone depletion, and human toxicity for these mixtures were 40–58% lower compared to the corresponding values for mineral diesel.

A density functional theory calculations of infrared spectra of galactomannan butyl ether

Alkylated derivatives of polysaccharides are widely used in many fields such as construction, medicine and pharmaceuticals. Galactomannan is a common polysaccharide obtained from plants and microorganisms. In this work, the theoretical FTIR spectra of galactomannan butyl ether are calculated using method (DFT+PBE0 density functional) was implemented with Def2-SVP basis set. It is shown the largest total relative error (36.5%) is observed in the theoretical spectrum of galactomannan butyl ether in the position of the butyl group at O14 of the oxygen atom. The smallest relative error (both average (1.1%) and total (14.7%) is observed in the theoretical spectrum of galactomannan butyl ether in the position of the butyl group at O4 of the oxygen atom. The attachment of the butyl group to galactomannan primarily occurs at the O4 oxygen atom of the galactomannan. The synthesized butyl esters of galactomannan were also characterized by optical microscopy and gel permeation chromatography.

Sn‐Pb Mixed Perovskites with Fullerene‐Derivative Interlayers for Efficient Four‐Terminal All‐Perovskite Tandem Solar Cells

AbstractInterfacial engineering is the key to high‐performance perovskite solar cells (PSCs). While a wide range of fullerene interlayers are investigated for Pb‐based counterparts with a bandgap of >1.5 eV, the role of fullerene interlayers is barely investigated in Sn‐Pb mixed narrow‐bandgap (NBG) PSCs. In this work, two novel solution‐processed fullerene derivatives are investigated, namely indene‐C60‐propionic acid butyl ester and indene‐C60‐propionic acid hexyl ester (IPH), as the interlayers in NBG PSCs. It is found that the devices with IPH‐interlayer show the highest performance with a remarkable short‐circuit current density of 30.7 mA cm−2 and a low deficit in open‐circuit voltage. The reduction in voltage deficit down to 0.43 V is attributed to reduced non‐radiative recombination that the authors attribute to two aspects: 1) a higher conduction band offset of ≈0.2 eV (>0 eV) that hampers charge‐carrier‐back‐transfer recombination; 2) a decrease in trap density at the perovskite/interlayer/C60 interfaces that results in reduced trap‐assisted recombination. In addition, incorporating the IPH interlayer enhances charge extraction within the devices that results in considerable enhancement in short‐circuit current density. Using a NBG device with an IPH interlayer, a respectable power conversion efficiency of 24.8% is demonstrated in a four‐terminal all‐perovskite tandem solar cell.

Assessment of the Effect of Structural Modification of Ibuprofen on the Penetration of Ibuprofen from Pentravan® (Semisolid) Formulation Using Human Skin and a Transdermal Diffusion Test Model.

The effect of transdermal vehicle (Pentravan®) on skin permeability was examined for unmodified ibuprofen (IBU) and ion pairs of ibuprofen with new L-valine alkyl esters [ValOR][IBU]. The percutaneous permeation across the human skin and transdermal diffusion test model (Strat-M® membranes) of ibuprofen and its structural modification were measured and compared using Franz diffusion cells. For comparison, the penetration of ibuprofen from a commercial product was also investigated. The cumulative amount of drug permeated through human skin at the end of the 24 h study was highest for ibuprofen derivatives containing propyl (C3), isopropyl (C3), ethyl (C2), and butyl (C4) esters. For Strat-M®, the best results were obtained with the alkyl chain length of the ester from C2 to C5. The permeation profiles and parameters were appointed, such as steady-state flux, lag time, and permeability coefficient. It has been shown that L-valine alkyl ester ibuprofenates, with the propyl, butyl, and amyl chain, exhibit a higher permeation rate than ibuprofen. The diffusion parameters of analyzed drugs through human skin and Strat-M® were similar and with good correlation. The resulting Pentravan-based creams with ibuprofen in the form of an ionic pair represent a potential alternative to other forms of the drug-containing analgesics administered transdermally. Furthermore, the Strat-M® membranes can be used to assess the permeation of transdermal preparations containing anti-inflammatory drugs.

Homo‐ and Copolymerization of Norbornene with Allyl Palladium and Nickel Complexes Bearing Imidazo[1,5‐a]pyridine Sulfonate Ligands

AbstractA series of allyl palladium and nickel complexes based on imidazo[1,5‐a]pyridine sulfonate ligands were synthesized. All these complexes were fully characterized by 1H and 13C NMR, elemental analysis, and high‐resolution mass spectrometry (HRMS). By treatment with Me2AlCl, palladium complexes showed high activities (up to 4.5×107 g of PNB (mol of Pd)−1 h−1) in norbornene polymerization, and the steric hindrance of the catalysts had little effect on the catalytic activities. They could also catalyze the copolymerization of norbornene with butyl vinyl ether (BVE) and ester monomers, but could not catalyze the copolymerization of norbornene with allyl butyl ether (ABE). In addition, the catalytic activities of nickel complexes for norbornene polymerization were similar to that of palladium complexes upon activation with MAO. They could catalyze copolymerization of norbornene with BVE and ABE, but not with ester monomers. In nickel system, the lower steric hindrance of the substituent led to higher activity.