Pentyl Ester Research Articles

Каталитическое гидрирование пентановой кислоты на металлах VIII группы

Liquid phase pentanoic acid hydrogenation in nonpolar hydrocarbon solutions (180 o C, hydrogen pressure 25 bar) was studied over rhenium on titanium oxide catalysts modified also with group VIII metals - platinum, palladium, ruthenium and rhodium. It was shown that during hydrogenation pentanoic acid was converted into pentanol followed by esterification with unreacted pentanoic acid into its pentyl ester, resulting in an equilibrium mixture of pentanoic acid - pentanol – pentyl pentanoate. Conversion of pentanoic acid increased in the row PdRe/TiO 2 2 2 2 2 . Selectivity to pentanol was elevated over bimetallic catalysts in the sequence RhRe/TiO 2 ~ PtRe/TiO 2 2 ~ RuRe/TiO 2 and was significantly different from ReOx/TiO 2 . The highest selectivity to pentanol was observed over ReOx, supported on the thermally modified titanium oxide while Re over unmodified titania was completely inactive under the same reaction conditions.

GC–MS analysis of bioactive constituents of Peristrophe bicalyculata (Retz.) Nees. (Acanthaceae)

ObjectiveTo characterize the chemical constituents of Peristrophe bicalyculata (P. bicalyculata) Received 9 January 2012 (Retz.) Nees. using GC-MS. MethodsTen grams of powdered sample was extracted with Received in revised form 7 February 2012 30 mL ethanol overnight and filtered through ash less filter paper with sodium sulphate (2 g) and the extract was concentrated to 1 mL by bubbling nitrogen into the solution. The Clarus 500 GC used in the analysis employed a column packed with Elite–1 (100% dimethyl poly siloxane, 30 nm × 0.25 nm ID. × 1 μm df) and the components were separated using Helium (1 mL/min) as the carrier gas. The 2 μL sample extract injected into the instrument was detected by the Turbo gold mass detector (Perkin Elmer) with the aid of the Turbo mass 5.1 software. ResultsThe GC-MS analysis provided different peaks determining the presence of seven different phytochemical Phytochemistrycompounds namely propane,1,1-diethoxy (68.89%), (6Z)-nonen-1-ol (24.00%), 4-methyl-2,4Chemical profilebis(4'-trimethylsilyloxyphenyl)pentene-1 (3.56%), cyclooctyl alcohol (1.78%), oxirane, butyl-(0.89%), Medicinal plants (2H)pyrrole-2-carbonitrile,5-amino-3,4-dihydro-(0.44%) and ethaneperoxoic acid,1-cyano 1-[2-(2-phenyl-1,3-dioxolan-2-yl)ethyl] pentyl ester (0.44%). ConclusionsThe presence of various bioactive compounds confirms the application of P. bicalyculata for various ailments by traditional practitioners. However, isolation of individual phytochemical constituents may proceed to find a novel drug.

Control of Postharvest Botrytis Fruit Rot of Strawberry by Volatile Organic Compounds of Candida intermedia

A study was conducted to identify volatile organic compounds or volatiles produced by Candida intermedia strain C410 using gas chromatography-mass spectrometry, and to determine efficacy of the volatiles of C. intermedia in suppression of conidial germination and mycelial growth of Botrytis cinerea and control of Botrytis fruit rot of strawberry. Results showed that, among 49 volatiles (esters, alcohols, alkenes, alkanes, alkynes, organic acids, ketones, and aldehydes) identified from C. intermedia cultures on yeast extract peptone dextrose agar, two compounds, 1,3,5,7-cyclooctatetraene and 3-methyl-1-butanol, were the most abundant. Synthetic chemicals of 1,3,5,7-cyclooctatetraene; 3-methyl-1-butanol; 2-nonanone; pentanoic acid, 4-methyl-, ethyl ester; 3-methyl-1-butanol, acetate; acetic acid, pentyl ester; and hexanoic acid, ethyl ester were highly inhibitory to conidial germination and mycelial growth of B. cinerea. Inhibition of conidial germination and mycelial growth of B. cinerea by volatiles of C. intermedia was also observed. Meanwhile, results showed that incidence and severity of Botrytis fruit rot of strawberry was significantly (P < 0.01) reduced by exposure of the strawberry fruit to the volatiles from C. intermedia cultures or C. intermedia-infested strawberry fruit. These results suggest that the volatiles of C. intermedia C410 are promising biofumigants for control of Botrytis fruit rot of strawberry.

Dynamics of functionalized single wall carbon nanotubes in solution studied by incoherentneutron scattering experiments

We have studied, by incoherent neutron scattering experiments, the dynamics of acolloidal suspension of functionalized single wall carbon nanotubes (SWNTs).The nanotubes have been functionalized with pentyl ester groups attached atthe ends and suspended in deuterated toluene with a concentration of 2.6 mgSWNT/1 ml of deuterated toluene. The experimental techniques were incoherent elastic neutron scattering(IENS) and incoherent quasielastic neutron scattering (IQNS). In the temperature rangebetween 4 K and 300 K, three phases were observed by IENS measurements: a solid phase forT<Tg, an undercooledliquid phase for Tg<T<Tm anda liquid phase for T>Tm. Furthermore, in the high temperature range of the undercooled liquidphase, hysteresis loops in the heating and cooling scans were observed. Thelower limit of the hysteresis loop defines the critical crossover temperatureTc. IQNS measurements in the liquid phase and a cooling scan of the undercooledliquid phase were performed. Three different quasielastic peaks were identified,two in the liquid phase and another one in the undercooled liquid phase. Thewidths of the quasielastic peaks are discussed as a generalized diffusion functionwhich can be factorized as a temperature dependent diffusion function and aQ dependent structure function. From the comparison of the diffusion function with theviscosity of toluene, we conclude that two components are in the long-time rangeBrownian motion and the other one in the short-time range Brownian motion.

Novel Depots of Ketorolac Esters Have Long-Acting Antinociceptive and Antiinflammatory Effects

No long-acting nonsteroidal antiinflammatory drug is clinically available for the treatment of pain. In this study, we evaluated the antinociceptive and antiinflammatory effects and duration of action of several novel depots of ketorolac esters, such as ketorolac propyl ester, pentyl ester, heptyl ester, and decyl ester, and observed whether they had a long-acting effect. Four studies in Sprague-Dawley rats were performed. In Studies 1-3, the antinociceptive and antiinflammatory effects of IM ketorolac tromethamine and its base and propyl ester were evaluated. In Study 4, the antinociceptive and antiinflammatory effects of several other ketorolac esters were evaluated. We found that ketorolac tromethamine 24, 80, and 240 micromol/kg (in saline) produced significant antinociceptive and antiinflammatory effects with duration of action of approximately 6-8 h. The four ketorolac esters at a dose of 240 micromol/kg (in oil) produced significant long-acting antinociceptive and antiinflammatory effects, with duration of action of approximately 52-76 h. We concluded that IM injection of novel depots of ketorolac esters in rats produce long-acting antinociceptive and antiinflammatory effects that are 6.5- to 9.5-fold longer than the traditional dosage form of ketorolac tromethamine.

Pharmacokinetics of Ketorolac Pentyl Ester, a Novel Ester Derivative of Ketorolac, in Rabbits

Ketorolac is a potent nonsteroidal anti-inflammatory drug. Recently, a novel ester of ketorolac, ketorolac pentyl ester, was synthesized. When prepared in injectable oil, the new agent demonstrated a long duration of action. Ketorolac pentyl ester was synthesized using a prodrug design by esterification of ketorolac, and appeared to be a prodrug of ketorolac in vivo, which needed to be confirmed. The aim of the present study was to establish the prodrug's pharmacokinetics in vivo, and to confirm whether or not ketorolac pentyl ester was a prodrug of ketorolac. Pharmacokinetic profiles of intravenous ketorolac and its pentyl ester on an equal-molar basis in six rabbits were evaluated. A high-performance liquid chromatographic method was used to determine the plasma concentrations of ketorolac and its pentyl ester. We found that the plasma concentrations of ketorolac pentyl ester declined rapidly after injection and so did the conversion of ketorolac pentyl ester to ketorolac. Also, the conversion of ketorolac was proved complete when compared with intravenous ketorolac under an equi-molar basis. In conclusion, this in vivo pharmacokinetic study confirmed that keterolac pentyl ester was a prodrug of keterolac.

The Relationship Between the Production of Volatile Aromas and the Induction of Ethylene in Apple Fruits

The volatile aromas from the fruits of `Naganofuji No.2' apple (Malus domestica Mill.) were determined by gas chromatography (GC) and combined GC-mass spectrometry (GC-MS) after different temperature conditions. The fruits from CA storage were sealed in glass and the volatiles in the headspace were determined. Eleven compounds of four chemical classes from active carbon absorbed samples were measured and three of them—tormic acid pentyl ester, butanoic acid-1-methyl ethylester and 4-hydroxy-3-methyl-2-butanone, were identified at 20 °C, but not at °C. Under 20 °C condition, the contents of three volatiles increased from 1 hour and reached to their peaks at the 4th to 7th hour. The content of ethylene reached its peak at 4 hours and changed synchronically with the other volatiles during the experiment. The content of ethylene was significantly positively correlated with the contents of volatile aromas (r = 0.96-0.98, P ≤ 0.01). Under °C condition, the content of ethylene was significant lower than that of at 20°C and there was no ethylene peak produced during experiment. When the fruits were treated with ethephon (0.1 mg·L-1) at 5°C, the content of ethylene increased greatly. The highest level of ethylene was found at 4 to 7 hours and the peaks of volatiles also appeared at 7 hours or 10 hours after the treatment. It was suggested that the production of ethylene in fruits could be thought as an indicator of some volatile aromas.

Synthesis of a conformationally rigid scyllo-inositol polymer as a novel chelating ligandElectronic supplementary information (ESI) available: experimental procedures for preparation of compounds 3, 5, 6 and 20. See http://www.rsc.org/suppdata/p1/b1/b105105a/

A poly(pentyl methacrylate) carrying a conformationally rigid scyllo-inositol substituent (with all axial hydroxy groups) in the 5-position of the pentyl ester chain has been synthesised.

In vitro and in vivo expression of protoporphyrin IX induced by lipophilic 5-aminolevulinic acid derivatives

We estimated the expression level of protoporphyrin IX (PpIX) induced by lipophilic 5-aminolevulinic acid (ALA) derivatives and observed its histological distribution by fluorescence microscopy. In vitro PpIX expression in Hepe2 cells was the highest when induced by ALA pentyl ester. This level was 2.8-fold higher than that induced by ALA after 4 h incubation and 2.5-fold higher than that after 24 h incubation. The differences between ALA pentyl ester and ALA were significant at both time points ( P<0.01). In HeLa cells, ALA butyl ester showed the highest induction of PpIX, which was 2.6-fold higher than ALA after 4 h incubation and 3.5-fold higher after 24 h incubation. The differences were significant at both time points ( P<0.01). In mice with squamous cell carcinoma, the in vivo expression of PpIX in the tumors was highest with ALA methyl ester, which was 1.3-fold higher than ALA. The difference was significant ( P<0.01). The expression of PpIX by means of fluorescence microscopy was highest by ALA methyl ester. Under in vitro conditions, PpIX expression was efficiently induced by long chain ALA esters, while better in vivo PpIX induction was obtained with short chain ALA esters. In this study, ALA methyl ester was found to be the best among the ALA derivatives in inducing PpIX expression in vivo, and would be more effective in treatment of skin cancers than ALA.

Thermodynamic properties of (a pentyl ester + an-alkane). XIV. The HmEand VmEfor (an ester + an-alkane)

This paper presents experimental data for the excess molar enthalpies HmEand excess molar volumes VmEat T= 298.15 K and atmospheric pressure for 21 binary mixtures consisting of one of three pentyl esters (ethanoate, propanoate, and pentanoate) and one of seven odd n -alkanes (from pentane to heptadecane). The results have shown the mixing of these mixtures to be endothermic, with HmEvarying uniformly with the n -alkane chain length. The variation of VmEwas also found to be uniform, with contraction effects observed for the mixtures that contained low molecular-weight hydrocarbons, and increasing with the pentyl ester chain length. Different group-contribution theories were used to calculate the excess properties for (an ester + an n -alkane). Comparison of the calculated and experimental results revealed that, in most cases, the differences increased with the molecular weight of the components. However, the differences for the calculated values of the excess volumes using the model of Nitta et al. decreased with n -alkane chain length but increased with ester chain length, the mean differences for the excess volumes being larger than 20 per cent.

Compaction and Sintering Behavior of Silica Particles Surface-Modified by Al Chelate Compounds.

Al chelate compounds with different carbon chain lengths were synthesized through reactions of aluminum sec-butoxide with acetoacetic acid ethyl ester (n=2), acetoacetic acid pentyl ester (n=5), acetoacetic acid octyl ester (n=8) and acetoacetic acid oleyl ester (n=18). Silica powder was modified with aluminum sec-butoxide (ALK) and its Al chelate compounds abbreviated as C2, C5, C8 and C18 according to chain length. The effects of carbon chain length on the tap density, specific surface area, compaction and sintering behavior of modified silica were investigated. The tap density of modified silica decreased with an increase in the length of the carbon chain. In ALK, porous Al2O3 was formed by hydrolysis of aluminum sec-butoxide upon drying at 100°C. In contrast, in C2, C5, C8 and C18, porous Al2O3 was formed by thermal decomposition of Al chelate compounds above 200°C. The green density of the pressed bodies increased with an increase in the length of the carbon chain, resulting in the decrease in the porosity of sintered bodies fired at 1400-1500°C.

Topical Application of 5-Aminolevulinic Acid Hexyl Ester and 5-Aminolevulinic Acid to Normal Nude Mouse Skin: Differences in Protoporphyrin IX Fluorescence Kinetics and the Role of the Stratum Corneum¶

An important limitation of topical 5-aminolevulinic acid (ALA)-based photodetection and photodynamic therapy is that the amount of the fluorescing and photosensitizing product protoporphyrin IX (PpIX) formed is limited. The reason for this is probably the limited diffusion of ALA through the stratum corneum. A solution to this problem might be found in the use of ALA derivatives, as these compounds are more lipophilic and therefore might have better penetration properties than ALA itself. Previous studies have shown that ALA hexyl ester (ALAHE) is more successful than ALA for photodetection of early (pre)malignant lesions in the bladder. However, ALA pentyl ester slightly increased the in vivo PpIX fluorescence in early (pre)malignant lesions in hairless mouse skin compared to ALA. The increased PpIX fluorescence is located in the stratum corneum and not in the dysplastic epidermal layer. In the present study, ALA- and ALAHE-induced PpIX fluorescence kinetics are compared in the normal nude mouse skin, of which the permeability properties differ from the bladder. Application times and ALA(HE) concentrations were varied, the effect of a penetration enhancer and the effect of tape stripping the skin before or after application were investigated. Only during application for 24 h, did ALAHE induce slightly more PpIX fluorescence than ALA. After application times ranging from 1 to 60 min, ALA-induced PpIX fluorescence was higher than ALAHE-induced PpIX fluorescence. ALA also induced higher PpIX production than ALAHE after 10 min of application with concentrations ranging from 0.5 to 40%. The results of experiments with the penetration enhancer and tape stripping indicated that the stratum corneum acts a barrier against ALA and ALAHE. Use of penetration enhancer or tape stripping enhanced the PpIX production more in the case of ALAHE application than in the case of ALA application. This, together with the results from the different application times and concentrations indicates that ALAHE diffuses more slowly across the stratum corneum than ALA.

Protoporphyrin IX fluorescence kinetics and localization after topical application of ALA pentyl ester and ALA on hairless mouse skin with UVB-induced early skin cancer.

In order to improve the efficacy of 5-aminolevulinic acid-based (ALA) photodynamic therapy (PDT), different ALA derivatives are presently being investigated. ALA esters are more lipophilic and therefore may have better skin penetration properties than ALA, possibly resulting in enhanced protoporphyrin IX (PpIX) production. In previous studies it was shown that ALA pentyl ester (ALAPE) does considerably enhance the PpIX production in cells in vitro compared with ALA. We investigated the in vivo PpIX fluorescence kinetics after application of ALA and ALAPE to hairless mice with and without UVB-induced early skin cancer. ALA and ALAPE (20% wt/wt) were applied topically to the mouse skin and after 30 min, the solvent was wiped off and PpIX fluorescence was followed in time with in vivo fluorescence spectroscopy and imaging. At 6 and 12 h after the 30 min application, skin samples of visible lesions and adjacent altered skin (UVB-exposed mouse skin) and normal mouse skin were collected for fluorescence microscopy. From each sample, frozen sections were made and phase contrast images and fluorescence images were recorded. The in vivo fluorescence kinetics showed that ALAPE induced more PpIX in visible lesions and altered skin of the UVB-exposed mouse skin, but not in the normal mouse skin. In the microscopic fluorescence images, higher ALAPE-induced PpIX levels were measured in the stratum corneum, but not in the dysplastic layer of the epidermis. In deeper layers of the skin, PpIX levels were the same after ALA and ALAPE application. In conclusion, ALAPE does induce higher PpIX fluorescence levels in vivo in our early skin cancer model, but these higher PpIX levels are not located in the dysplastic layer of the epidermis.

Preparation of Al Chelate Compounds with Different Carbon Chain Length and Its Application for Surface Modifier of Silica.

Al chelate compounds with different carbon chain length were synthesized by reactions of aluminum sec-butoxide with β-ketoesters having different carbon chain length, such as acetoacetic acid ethyl ester (n=2), acetoacetic acid pentyl ester (n=5), acetoacetic acid octyl ester (n=8) and acetoacetic acid oleyl ester (n=18). Silica was modified by aluminum sec-butoxide and these Al chelate compounds (ALK, C2, C5, C8 and C18 respectively). Then the modified silica was dried at 100°C and heated up to 400°C. We studied the influence of carbon chain length on the hydrophilic-hydrophobic property of dried silica by measurement of adsorption amount of water vapor. In addition the surface property of heated silica was studied by measurement of specific surface area and pore size distribution. It was found that the adsorption amount of water vapor on dried silica decreased with increasing the length of carbon chain such as ALK, C2 and C5. Adsorption amount of water vapor was the same on C5, C8 and C18. Porous Al2O3 was prepared from ALK and C2 by drying at 100°C by hydrolysis of aluminum sec-butoxide and Al chelate compounds. Porous Al2O3 was also prepared by thermal decomposition of Al chelate compounds from C5, C8 and C18 by heating at 200°C. The mechanism of pore formation changed according to the carbon chain length of Al chelate compounds. The porous Al2O3 prepared from Al chelate compounds had smaller and more uniform pore size than that prepared from aluminum sec-butoxie.

Evaluation and Improvement of Transesterification Methods of Triglycerides

The causes responsible for the low reproducibility of the gas chromatographic method used to analyze fatty acid methyl esters, derived from the transesterification of triglycerides in n-hexane by means of methanol potassium hydroxide, were identified and eliminated. Partition coefficients (Kd) of short-chain fatty acid methyl esters between n-hexane and methanol were determined. These results indicate that even under the best experimental conditions, a substantial portion of these compounds are transferred in the methanol phase and therefore are not analyzed. Accurate results, to within 2%, were obtained by rigorously controlling the volume of the reagents and introducing appropriate correction factors. The accuracy of the results, reported as a percentage by weight, did not depend on the completeness of the transesterification reaction. In the analysis of fatty acids as butyl esters, a measurable quantity of butyric ester was lost during the washing phase with water. By contract, butyric acid pentyl ester is insoluble in water. Therefore we propose an accurate method to analyze fatty acids as pentyl esters. Oleic and elaidinic acids derived from triglyceride transesterification are easier to separate as methyl esters than as longer butyl or pentyl esters.

Synthesis and some properties of a homologous series of beta-carboline-3-carboxylic esters.

A homologous series of esters of beta-carboline-3-carboxylic acid was prepared by a new synthetic procedure. The first members of the series are convulsant or pro-convulsant agents while those with acyl residues longer than C4 show anticonvulsant activity. The affinity of the members of the series for the benzodiazepine receptor from rat brain decreases with the increasing chain length of the esters. The pentyl ester was studied in particular for its anti-convulsant effect on rats and mice treated with cardiazol. The compound also acts as a membrane stabilizer by inhibiting red cell hypotonic hemolysis and rat brain Na/K ATPase; its LD50 value is 12.5 mg/Kg and of particular interest is its lack of inhibitory effect on memory retention in mice at doses at which diazepam has inhibitory effects.

The antifungal activity of alkyl benzimidazol‐2‐ylcarbamates and related compounds

AbstractThe fungistatic activity against Penicillium digitatum and Diplodia natalensis decreased slightly in ascending a homologous series of alkyl esters of benzimidazol‐2‐ylcarbamic acid from the methyl ester (carbendazim) to the pentyl ester; the hexyl and octyl esters were inactive. 2‐(Acylamino)benzimidazoles were slightly less active than the analogous alkyl benzimidazol‐2‐ylcarbamates. Introduction of a methylene bridge between the benzimidazole ring and the 2‐methoxycarbonylamino group abolished antifungal activity. Methylation of either the carbamate nitrogen or an imidazole nitrogen of carbendazim produced inactive compounds. Replacement of the benzimidazole ring of carbendazim with various other ring systems was accompanied by marked reduction in antifungal activity.