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Acid Hydrolysis (acid + hydrolysis)
Kinds of Acid Hydrolysis Selected AbstractsUnprecedented Stability of Vinyloxy Group under Conditions of Acid Hydrolysis: Synthesis of 1-[(2-Vinyloxy)ethyl]-1,5-dihydro-2H-pyrrol-2-ones.CHEMINFORM, Issue 50 2002N. A. Nedolya Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Acid Hydrolysis of 3-Aryl-5-trinitromethyl-1,2,4-oxadiazoles.CHEMINFORM, Issue 23 2002A. G. Tyrkov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] In search of stable soil organic carbon fractions: a comparison of methods applied to soils labelled with 14C for 40 days or 40 yearsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2008S. Bruun Summary A reliable method for the isolation of a stable fraction of soil organic carbon (SOC) would be very helpful for improving our understanding of the mechanisms responsible for stabilization of SOC and the dynamics of SOC turnover. We tested acid hydrolysis, physical fractionation (particle density/size), photo-oxidation, treatment with chemical oxidants (NaOCl and NaS2O8) and thermal treatment on two soils incubated with 14C-labelled barley straw for either 40 days or 40 years. Different intensities of the treatments were included. Acid hydrolysis, photo-oxidation and treatment with a chemical oxidant consistently removed more 40-year-old C than 40-day-old C, which suggests that the isolated fractions contained a large proportion of material with a relatively rapid turnover. The clay + silt associated SOC fraction contained a small proportion of 40-day-old C and a large proportion of 40-year-old C. This is consistent with a SOC fraction with medium turnover. The thermal treatment removed more 40-year-old C than 40-day-old C. At 400°C there was still a small proportion of the 40-year-old C remaining, whereas almost all the 40-day-old C was removed. This is consistent with a stable SOC fraction. However, because only 2,3% of the C remained after this treatment, the isolated SOC fraction may be of little quantitative importance. Furthermore, the thermally resistant fraction is likely to be heavily altered by the treatment, and therefore unsuitable for further studies of the chemical nature of stable SOC. [source] Carbon and nitrogen isotope composition of bulk soils, particle-size fractions and organic material after treatment with hydrofluoric acidEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2005M. W. I. Schmidt Summary Soils and sediments contain only small amounts of organic matter, and large concentrations of paramagnetic metals can give poor solid-state nuclear magnetic resonance (NMR) spectra of organic matter. Pretreatment of samples with hydrofluoric acid (HF) dissolves significant proportions of the mineral matrix and extracts paramagnetic elements. We investigated the effects of 10% HF treatment on the stable isotope content of carbon (C) and nitrogen (N) of organic matter from soils, composts and shales. Additionally we inferred molecular and isotopic characteristics of lost materials from calculations of isotope mass balances. Treatment with HF enriched C and N in mineral samples substantially (factors 2.5,42.4), except for Podzol B horizons (1.1,1.7) and organic material (1.0,1.3). After treatment most of the C (59.7,91.7%) and N (53.7,86.6%) was recovered, although changing C/N ratios often indicated a preferential loss of N-rich material. Isotope ratios of C and N in the remaining material became more negative when net alterations exceeded 0.3,. The isotope ratios of the lost material contained more 13C (1,2,) and 15N (1,4,) than the initial organic matter. Acid hydrolysis typically removes proteins, amino acids and polysaccharides, all of which are enriched in 13C, and in the case of proteins and amino acids, enriched in 15N as well. We conclude that HF treatment released fresh, soluble, probably microbial, biomass in addition to carbohydrates. Net changes of the bulk chemical composition of organic matter were small for most soils, size fractions and plant material, but not for samples containing little organic matter, or those rich in easily soluble organic matter associated with iron oxides, such as Podzol B horizons. [source] Biomarker Assays in Nipple Aspirate FluidTHE BREAST JOURNAL, Issue 6 2001Pamela Klein MD The noninvasive technique of nipple aspiration as a potential source of biomarkers of breast cancer risk was evaluated. The feasibility of performing mutagenesis assays, amplifying DNA, and performing protein electrophoresis on nipple aspirate fluid was explored. A tool was developed to measure the level of discomfort, if any, from this procedure. Twenty-five healthy women (20 premenopausal and 5 postmenopausal) were enrolled. Fluid was obtained using a modified breast pump. Premenopausal women were scheduled for four to six weekly aspirations, and postmenopausal women were scheduled for one to two weekly aspirations. Mutagenesis assays were performed using the Salmonella (Ames) assay. DNA amplification of several microsatellite regions was carried out using polymerase chain reaction. Protein was quantified, and two-dimensional protein electrophoresis was performed. Overall, fluid was obtained from 80% of the women, and the level of discomfort was minimal. Acid hydrolysis of one sample resulted in mutagenicity; all six nonhydrolyzed samples were not mutagenic. The ability to amplify DNA ranged from 34% to 96%, depending on length of the microsatellite region examined. The average protein concentration was 71 ,g/mL. Two-dimensional protein electrophoresis was successfully performed on samples from two subjects. Nipple aspiration is a simple technique and is easily learned and well tolerated, which yields a reagent useful for a variety of investigations. This technique may facilitate the identification and application of biomarkers for future breast cancer risk assessment and chemopreventive protocols. [source] Functional Characterization of the Recombinant N -Methyltransferase Domain from the Multienzyme Enniatin SynthetaseCHEMBIOCHEM, Issue 9 2007Till Hornbogen Dr. Abstract A 51 kDa fusion protein incorporating the N -methyltransferase domain of the multienzyme enniatin synthetase from Fusarium scirpi was expressed in Saccharomyces cerevisiae. The protein was purified and found to bind S -adenosyl methionine (AdoMet) as demonstrated by cross-linking experiments with 14C-methyl-AdoMet under UV irradiation. Cofactor binding at equilibrium conditions was followed by saturation transfer difference (STD) NMR spectroscopy, and the native conformation of the methyltransferase was assigned. STD NMR spectroscopy yielded significant signals for H2 and H8 of the adenine moiety, H1' of D -ribose, and SCH3 group of AdoMet. Methyl group transfer catalyzed by the enzyme was demonstrated by using aminoacyl- N -acetylcysteamine thioesters (aminoacyl-SNACs) of L -Val, L -Ile, and L -Leu, which mimic the natural substrate amino acids of enniatin synthetase presented by the enzyme bound 4,-phosphopantetheine arm. In these experiments the enzyme was incubated in the presence of the corresponding aminoacyl-SNAC and 14C-methyl-AdoMet for various lengths of time, for up to 30 min. N -[14C-Methyl]-aminoacyl-SNAC products were extracted with EtOAc and separated by TLC. Acid hydrolysis of the isolated labeled compounds yielded the corresponding N -[14C-methyl] amino acids. Further proof for the formation of N - 14C-methyl-aminoacyl-SNACs came from MALDI-TOF mass spectrometry which yielded 23,212 Da for N -methyl-valyl-SNAC, accompanied by the expected postsource decay (PSD) pattern. Interestingly, L -Phe, which is not a substrate amino acid of enniatin synthetase, also proved to be a methyl group acceptor. D -Val was not accepted as a substrate; this indicates selectivity for the L isomer. [source] Separation of Escherichia coli 055:B5 lipopolysaccharide and detoxified lipopolysaccharide by high-performance capillary electrophoresisELECTROPHORESIS, Issue 17 2003Nicola Volpi Abstract A rapid, highly sensitive and reproducible high-performance capillary electrophoresis (HPCE) method (electrokinetic chromatography with sodium dodecyl sulfate) is described for the determination of the lipopolysaccharide (LPS) and detoxified LPS (D-LPS), produced by both alkaline treatment in anhydrous conditions and mild acid hydrolysis, from Escherichia coli 055:B5 bacteria. LPS and D-LPS are separated and readily determined within 25 min on an uncoated fused-silica capillary using normal polarity at 20 kV and detection at 200 nm. A linear relationship (correlation coefficient greater than about 0.97) was found for the LPS and the two D-LPS species over a wide range of concentrations, from approximately 120 to 360 ng, with a detection sensitivity less than about 100 ng. Furthermore, HPCE was able to separate several molecular species mainly due to the presence of populations with O -specific polysaccharides of distinct and increasing mean chain lengths. This approach could be of great importance for the quantitative determination of LPS and D-LPS during the purification and preparation processes, also considering the importance of D-LPS in the preparation of human vaccines, and for the qualitative evaluation of the heterogeneity of LPS and the O -polysaccharide components. [source] Synthesis of New Tetrazole-Substituted Pyroaminoadipic and Pipecolic Acid DerivativesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2005Fatimazohra Lenda Abstract Racemic 5-aryl- and 5-(arylmethyl)tetrazolyl-substituted pyroaminoadipic and pipecolic acid derivatives were diastereoselectively synthesized from dimethyl meso -2,5-dibromoadipate (1) in good yields under mild reaction conditions. The key step of this reaction sequence is the selective N2 -alkylation of 5-substituted tetrazoles with 1. The reactive 2-bromo-5-tetrazolyladipate derivatives 2a,g were generated and treated with sodium azide, followed by Pd/C-catalyzed hydrogenation, to provide lactams 4a,g. The chemoselective reduction of the amide carbonyl group of 4a,g with BH3, followed by acid hydrolysis, provided 5-tetrazolylpipecolic acids in racemic form. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Amino acid 15N in long-term bare fallow soils: influence of annual N fertilizer and manure applicationsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2008R. Bol Summary Long-term dynamics of amino acids (AAs), from a bare fallow soil experiment (established in 1928 at INRA-Versailles, France), were examined in unamended control (Con) plots and plots treated with ammonium sulphate (Amsul), ammonium nitrate (Amnit), sodium nitrate (Nanit) or with animal manure (Man). Topsoil (0,25 cm) from 1929, 1963 and 1997 was analysed for C, N and 15N content and distribution of 18 amino acids recovered after acid hydrolysis with 6 m HCl. With time, soil N, C and AA content were reduced in Con, Amsul, Amnit and Nanit, but increased in Man. However, the absolute N loss was 3,11 times larger in Man than Nanit, Amsul, Amnit and Con, due to the much higher N annual inputs applied to Man. From 1929 to 1997 in Con, Amsul, Amnit and Nanit the whole soil and non-hydrolysable-N pool ,15N increased associated with the loss of N (indicative of Rayleigh 15N/14N fractionation). No ,15N change from 1929 to 1997 was found in the hydrolysable AA-N (HAN) pool. Fertilizer N inputs aided stabilization of soil AA-N, as AA half-life in the mineral N fertilizer treatments increased from 34 years in 1963 to 50 years in 1997. The ,15N values of alanine and leucine reflected both source input and 15N/14N fractionation effects in soils. The ,15N increase of ornithine (,6,) was similar to the whole soil. The ,15N change of phenylalanine in Con (decrease of 7,) was related to its proportional loss since 1929, whereas for Amsul, Amnit, Nanit and Man it was associated with isotope effects caused by the fertilizer inputs. However, the soil ,15N value of most individual amino acids (IAAs) did not significantly change over nearly 70 years, even with mineral or organic N inputs. We conclude for these bare fallow systems that: (i) ,15N changes in the whole soil and non-hydrolysable AA pool were solely driven by microbial processes and not by the nature of fertilizer inputs, and (ii) without plant inputs, the ,15N of the HAN pool and (most) IAAs may reflect the influence of plant,soil interactions from the previous (arable cropping) rather than present (fallow) land use on these soil ,15N values. [source] In search of stable soil organic carbon fractions: a comparison of methods applied to soils labelled with 14C for 40 days or 40 yearsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2008S. Bruun Summary A reliable method for the isolation of a stable fraction of soil organic carbon (SOC) would be very helpful for improving our understanding of the mechanisms responsible for stabilization of SOC and the dynamics of SOC turnover. We tested acid hydrolysis, physical fractionation (particle density/size), photo-oxidation, treatment with chemical oxidants (NaOCl and NaS2O8) and thermal treatment on two soils incubated with 14C-labelled barley straw for either 40 days or 40 years. Different intensities of the treatments were included. Acid hydrolysis, photo-oxidation and treatment with a chemical oxidant consistently removed more 40-year-old C than 40-day-old C, which suggests that the isolated fractions contained a large proportion of material with a relatively rapid turnover. The clay + silt associated SOC fraction contained a small proportion of 40-day-old C and a large proportion of 40-year-old C. This is consistent with a SOC fraction with medium turnover. The thermal treatment removed more 40-year-old C than 40-day-old C. At 400°C there was still a small proportion of the 40-year-old C remaining, whereas almost all the 40-day-old C was removed. This is consistent with a stable SOC fraction. However, because only 2,3% of the C remained after this treatment, the isolated SOC fraction may be of little quantitative importance. Furthermore, the thermally resistant fraction is likely to be heavily altered by the treatment, and therefore unsuitable for further studies of the chemical nature of stable SOC. [source] The structure of the core region of the lipopolysaccharide from Klebsiella pneumoniae O3FEBS JOURNAL, Issue 6 2001-D-manno-octulosonic acid (, -Kdo) residue in the outer part of the core, 3-Deoxy-, O12 lipopolysaccharides, a common structural element of Klebsiella pneumoniae O The structure of lipid A,core region of the lipopolysaccharide (LPS) from Klebsiella pneumoniae serotype O3 was determined using NMR, MS and chemical analysis of the oligosaccharides, obtained by mild acid hydrolysis, alkaline deacylation, and deamination of the LPS:where P is H or ,-Hep; J is H or ,-GalA; R is H or P (in the deacylated oligosaccharides).Screening of the LPS from K. pneumoniae O1, O2, O4, O5, O8, and O12 using deamination showed that they also contain ,-Hep-(1,4)-,-Kdo-(2,6)-GlcN and ,-Kdo-(2,6)-GlcN fragments. [source] Structural analysis of the core region of lipopolysaccharides from Proteus mirabilis serotypes O6, O48 and O57FEBS JOURNAL, Issue 8 2000Evgeny Vinogradov The structure of lipid A core region of the lipopolysaccharides (LPS) from Proteus mirabilis serotypes O6, O57 and O48 was determined using NMR, MS and chemical analysis of the oligosaccharides, obtained by mild acid hydrolysis, alkaline deacylation, and deamination of LPS: Incomplete substitutions are indicated by bold italic type. All sugars are present in pyranose form, ,-Hep is the residue of lglycero -,- dmanno -Hep, ,- dd -Hep is the residue of dglycero -,- dmanno -Hep, l -Ara4N is 4-amino-4-deoxy- l -arabinose, Qui4NAlaAla is the residue of 4- N -(l -alanyl- l -alanyl)-4-amino-4,6-dideoxyglucose. All sugars except l -Ara4N have d -configuration. ,-GalA* is partially present in the form of amide with 1,4-diaminobutane (putrescine)-HN(CH2)4NH2 or spermidine-HN(CH2)3NH(CH2)4NH2. [source] Five New Xanthenone O -Glycosides from the Roots of Polygala sibirica L.HELVETICA CHIMICA ACTA, Issue 5 2008Yu-Hong Zhou Abstract Five new xanthenone O -glycosides, sibiricaxanthone C (1), sibiricaxanthone D (2), sibiricaxanthone E (3), sibiricaxanthone F (4), and sibiricaxanthone G (5) were isolated from the roots of Polygala sibirica L., together with the six known xanthenone glycosides 6,11. The structures of new compounds were elucidated on the basis of spectral data and acid hydrolysis. [source] Photocycloaddition of Six-Membered Cyclic Enones to Propen-2-yl IsocyanateHELVETICA CHIMICA ACTA, Issue 8 2007Maryam Bahaji Abstract On irradiation in the presence of propen-2-yl isocyanate (4), six-membered cyclic enones 3 are converted into regio- and stereoisomeric mixtures of [2+2] cycloadducts 5,10; the preferentially formed HT products, 5,8, can be converted into the corresponding bicyclic amines by acid hydrolysis, whereas, under these conditions, the regioisomeric HH -isocyanato derivatives undergo a retro-Mannich reaction. [source] The Nonchiral Bislactim Diethoxy Ether as a Highly Stereo-Inducing Synthon for Sterically Hindered, , -Branched , -Amino Acids: A Practical, Large-Scale Route to an Intermediate of the Novel Renin Inhibitor AliskirenHELVETICA CHIMICA ACTA, Issue 8 2003Richard Göschke The diastereoselective synthesis of the sterically hindered, , -branched , -amino acid derivative (2S,4S)- 24a and its N -[(tert -butoxy)carbonyl](Boc)-protected alcohol (2S,4S)- 19, both key intermediates of a novel class of nonpeptide renin inhibitors such as aliskiren (1), is described. Initially, the analogous methyl ester (2S,4S)- 17 was obtained by alkylation of the chiral Schöllkopf dihydropyrazine (R)- 12a with the dialkoxy-substituted alkyl bromide (R)- 11a, which proceeded with explicitly high diastereofacial selectivity (ds ,98%) to give (2S,5R,2,S)- 13a (Scheme,4), followed by mild acid hydrolysis and N -Boc protection (Scheme,5). Conversely, the complete lack of stereocontrol and poor yields for the reaction of (R)- 11a with the enantiomeric (S)- 12b suggested, in addition to the anticipated shielding effect by the iPr group at C(2) of the auxiliary, steric repulsion between the MeOC(6) and the bulky residues of (R)- 11a in the proposed transition state, which would strongly disfavor both the Si and Re attack of the electrophile (see Fig.). Based on this rationale, alkylation of the readily accessible achiral diethoxy-dihydropyrazine 21 with (R)- 11a was found to provide a 95,:,5 mixture of diastereoisomers (2S,2,S)- 22a and (2R,2,S)- 23a in high yield (Scheme,6), which afforded in two steps and after recrystallization enantiomerically pure (2S,4S)- 24a. Similarly, the stereochemical course for the alkylation reactions of the related alkyl bromides (S)- 28a and (R)- 28b with both (R)- 12a and (S)- 12b as well as with the achiral 21 was investigated (Schemes,7,9). The precursor bromides (R)- 11a, (S)- 11b, (R)- 28a, and (S)- 28b were efficiently synthesized via the diastereoselective alkylation of the Evans 3-isovaleroyloxazolidin-2-ones (R)- 7a and (S)- 7b either with bromide 6 or with benzyl chloromethyl ether, and subsequent standard transformations (Schemes,3 and 7). A practical and economical protocol of the preparation of (2S,4S)- 24a on a multi-100-g scale is given. This is the first report of the application of an achiral dihydropyrazine, i.e., in form of 21, as a highly stereo-inducing synthon providing rapid access to a N -protected , -branched , -amino acid with (2S) absolute configuration. [source] Simultaneous wet ball milling and mild acid hydrolysis of rice hullJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2010Jinxiang Zhou Abstract BACKGROUND: Rice hull, an abundant residue but a big issue for the rice processing industry, has the potential to serve as a feedstock for production of ethanol because of its lignocellulosic composition. Simultaneous wet ball milling and mild acid hydrolysis of rice hull was studied in this work. RESULTS: Ball milling with 150 small stainless steel beads and rotation speed of 600 rpm in citrate solvent of pH 4 was the optimal condition for hydrolysis, and the yield of sugar increased with increased milling time. Corresponding structure transformations before and after milling analyzed by X-ray diffraction (XRD), environmental scanning electron microscopy (ESEM) and transmission fourier transform infrared spectroscopy (FT-IR) clearly indicate that this hydrolysis could be attributed to the crystalline and chemical structure changes of cellulose in rice hull during ball milling in mild acid solvent. CONCLUSION: This combined treatment of ball milling and citrate solvent greatly changed the crystalline and chemical structure and continuously generated sites accessible to citrate solvent, thus enabling hydrolysis of the rice hull. Copyright © 2009 Society of Chemical Industry [source] FREE RADICAL-SCAVENGING ACTIVITIES OF LOW MOLECULAR WEIGHT CHITIN OLIGOSACCHARIDES LEAD TO ANTIOXIDANT EFFECT IN LIVE CELLSJOURNAL OF FOOD BIOCHEMISTRY, Issue 2010DAI-NGHIEP NGO ABSTRACT Chitin oligosaccharides (NA-COS) with low molecular weight distribution of 229.21,593.12 Da were produced from crab chitin by acid hydrolysis. They showed reducing power and scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) (Sigma Chemical Co., St. Louis, MO), hydroxyl and alkyl radicals. It was observed that the radical-scavenging activity of NA-COS increased in a dose-dependent manner. Their IC50 values for DPPH, hydroxyl and alkyl radicals were 0.8, 1.75 and 1.14 mg/mL, respectively. Furthermore, NA-COS exhibited the inhibitory effect on the oxidative damage of DNA from human lymphoma U937 (American Type Culture Collection, Manassas, VA) and the direct radical-scavenging effect in human fibrosarcoma cells (HT1080) (American Type Culture Collection) in 2,,7,-dichlorofluorescin diacetate (DCFH-DA) assay (Molecular Probes Inc., Eugene, OR). The results suggest that NA-COS can exert antioxidant effect in live cells and have the potential to be applied to food supplements or nutraceuticals. PRACTICAL APPLICATIONS Chitin oligosaccharides (NA-COS) are the hydrolyzed products of chitin (KEUMHO chemical products Co. Ltd., Gyeongbuk, Korea) of which derivatives have shown antioxidant, antimicrobial, anticancer, anti-inflammatory and immunostimulant effects. According to previous studies, NA-COS have beneficial biological activities similar to those of chitin. Furthermore, they are easily soluble in water because of their shorter chain length. Therefore, NA-COS are potentially applicable to improve food quality and human health. [source] BIOCHEMICAL CHARACTERIZATION OF BORAGE (BORAGO OFFICINALIS L.) SEEDSJOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2009BAYA MHAMDI ABSTRACT Gas chromatography,mass spectrometry analysis of seed Borago officinalis essential oil (EO) revealed the presence of 16 volatile components. ,-Caryophyllene (26%) and p-cymene-8-ol (19.7%) represented the major components, while nonadecane (0.7%) and hexanol (0.7%) were the minor ones. The EO composition was characterized by higher abundance of oxygenated monoterpenes (27.7%), followed by sesquiterpenes (26%). Fatty acid composition showed the predominance of linoleic (35.4%), oleic (24.2%) and ,-linolenic (20.4%) acids. Polyphenols were analyzed by reversed-phase high-performance liquid chromatography after acid hydrolysis of phenolic acid esters. Six phenolic acids were identified in seed extract and rosmarinic acid was the predominant one with 1.65 mg/g dry matter weight equivalent to 33% of total phenolic acids. PRACTICAL APPLICATIONS Borage (Borago officinalis L.) is of great interest because of its medicinal and nutritional properties. In fact, thanks to its characteristic composition in fatty acids, particularly high levels of gamma-linolenic acid in its seed oil, borage has gained importance. The potent consumers of this medicinal plant are hypertensive and hypercholesterolemic people. Borage consumption is also recommended for people suffering from rheumatism and eczema. Unfortunately, the knowledge about antioxidative/antiradical properties of borage is very scanty. So, recently, an extensive investigation was focused on the antioxidant properties of borage extracts. These extracts showed excellent antioxidant properties and their effects were attributed to their phenolic constituents. These antioxidants can be concentrated, either as crude extracts or individual phenolic compounds, to be used in highly unsaturated oils such as marine oils. Furthermore, borage consumption has been reported as a possible gastric cancer protective factor. [source] A NEW METHOD FOR ELLAGIC ACID PRODUCTION FROM POMEGRANATE HUSKJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2008JINGJING LU ABSTRACT Pomegranate (Punica granatum L.) husk, a by-product of the pomegranate juice industry, is an inexpensive and abundant source of ellagic acid. Ellagic acid is widely used as functional food for its physiological functions. It is the breakdown product of ellagitannins. To date, the preparation of ellagic acid from pomegranate husk has not been reported. This article reports a new process for ellagic acid production from pomegranate husk by extraction of tannins followed by acid hydrolysis and purification by extraction and recrystallization. Several tests were conducted to obtain optimum conditions including extraction of tannins by varying solvents, acid concentration and reaction time for acid hydrolysis and the volume of methanol used for purification. Ellagic acid (3.5 g) with 90% purity from 100 g pomegranate husk was obtained. This new method is easy to scale up. All equipment used in this production process is widely used in food processing industry. The cost of production is low. It is suitable for industrial applications. PRACTICAL APPLICATIONS The production of ellagic acid is easier and the yield and purity of ellagic acid produced this way are higher than before. This method can be used not only for experiment in laboratory but also for industrial applications. The material , pomegranate husk , is a by-product of the pomegranate juice industry, so it is very cheap and easy to get. High-purity ellagic acid produced this way is sold to many companies back home and abroad. It is used as food additive and cosmetic material because of its antioxidant activity and whiteningfunction. The toxicity of pomegranate husk is lower than that of gallnut, which has been the main material of ellagic acid production in the past. Reagents are common and inexpensive; some of them are reusable. [source] Synthesis of 3,-deoxy-3,-[18F]fluoro-1- , - D -xylofuranosyluracil ([18F]-FMXU) for PETJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 13 2005M. M. Alauddin Abstract The synthesis of a pyrimidine analog, 3,-deoxy-3,-[18F]-fluoro-1- , - D -xylofuranosyluracil ([18F]-FMXU) is reported. 5-Methyluridine 1 was converted to its di-methoxytrityl derivatives 2 and 3 as a mixture. After separation the 2,,5,-di-methoxytrityluridine 2 was converted to its 3,-triflate 4 followed by derivatization to the respective N3 - t -Boc product 5. The triflate 5 was reacted with tetrabutylammonium[18F]fluoride to produce 6, which by acid hydrolysis yielded compound 7. The crude preparation was purified by HPLC to obtain the desired product [18F]-FMXU. The radiochemical yields were 25,40% decay corrected (d. c.) with an average of 33% in four runs. Radiochemical purity was >99% and specific activity was >74 GBq/µmol at the end of synthesis (EOS). The synthesis time was 67,75 min from the end of bombardment (EOB). Copyright © 2005 John Wiley & Sons, Ltd. [source] Novel synthesis of [1- 11C], -vinyl- , -aminobutyric acid ([1,11C]GVG) for pharmacokinetic studies of addiction treatmentJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 3 2002Zongren Zhang Abstract , -Vinyl- , -aminobutyric acid (GVG, Vigabatrin®), a suicide inhibitor of GABA-transaminase (GABA-T), has been suggested as a new drug for the treatment of substance abuse. In order to better understand its pharmacokinetics and potential side effects, we have developed a radiosynthesis of carbon-11 (t1/2=20 min) labeled GVG for positron emission tomographic (PET) studies. We report here a novel synthetic strategy to prepare the precursor and to efficiently label GVG with C-11. 5-Bromo-3-(carbobenzyloxy)amino-1-pentene was synthesized in five steps from homoserine lactone, including reduction and methylenation. This was used in a one-pot, two-step radiosynthesis. Displacement of bromide with no-carrier-added [11C]cyanide followed by acid hydrolysis afforded [1- 11C]GVG with decay corrected radiochemical yields of 27±9% (n=6, not optimized) with respect to [11C]cyanide in a synthesis time of 45 min. Copyright © 2002 John Wiley & Sons, Ltd. [source] Designer drug 2,4,5-trimethoxyamphetamine (TMA-2): Studies on its metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniquesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2006Andreas H. Ewald Abstract Studies are described on the metabolism and the toxicological detection of the amphetamine-derived designer drug 2,4,5-trimethoxyamphetamine (TMA-2) in rat urine using gas chromatographic/mass spectrometric (GC/MS) techniques. The identified metabolites indicated that TMA-2 was metabolized by oxidative deamination to the corresponding ketone followed by reduction to the corresponding alcohol, O -demethylation followed by oxidative deamination, and finally O,O -bis-demethylation. All metabolites carrying hydroxy groups were found to be partly excreted in urine as glucuronides and/or sulfates. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid-liquid extraction, and microwave-assisted acetylation allowed the detection, in rat urine, of an intake of TMA-2 that corresponds to a common drug users' dose. Assuming similar metabolism, the described STA procedure in human urine should be suitable as proof of an intake of TMA-2. Copyright © 2006 John Wiley & Sons, Ltd. [source] New designer drug, 2,5-dimethoxy-4-propylthio-,-phenethylamine (2C-T-7): studies on its metabolism and toxicological detection in rat urine using gas chromatography/mass spectrometry,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2005Denis S. Theobald Abstract Studies are described on the metabolism and toxicological analysis of the phenethylamine-derived designer drug 2,5-dimethoxy-4-propylthio-,-phenethylamine (2C-T-7) in rat urine using gas chromatography/mass spectrometry (GC/MS). The identified metabolites indicated that 2C-T-7 was metabolized by hydroxylation of the propyl side chain followed by N -acetylation and sulfoxidation and also by deamination followed by oxidation to the corresponding acid or by reduction to the corresponding alcohol. To a minor extent, 2C-T-7 was also metabolized by S -dealkylation followed by N -acetylation, S -methylation and sulfoxidation. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid,liquid extraction microwave-assisted acetylation allowed the detection of an intake of a dose of 2C-T-7 in rat urine that corresponds to a common drug users' dose. Assuming similar metabolism, the described STA procedure should be suitable for proof of an intake of 2C-T-7 in human urine. Copyright © 2005 John Wiley & Sons, Ltd. [source] New designer drug 1-(3,4-methylenedioxybenzyl) piperazine (MDBP): studies on its metabolism and toxicological detection in rat urine using gas chromatography/mass spectrometry,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2004Roland F. Staack Abstract Studies are described on the metabolism and toxicological analysis of the piperazine-derived designer drug 1-(3,4-methylenedioxybenzyl)piperazine (MDBP) in rat urine using gas chromatography/mass spectrometry (GC/MS). The identified metabolites indicated that MDBP was metabolized by demethylenation and subsequent methylation to N -(4-hydroxy-3-methoxybenzyl)piperazine followed by partial glucuronidation or sulfation. Additionally, degradation of the piperazine moiety to N -(3,4-methylenedioxybenzyl)ethylenediamine and 3,4-methylenedioxybenzylamine and N -dealkylation to piperazine were observed. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid/liquid extraction and microwave-assisted acetylation allowed the detection of MDBP and its above-mentioned metabolites in rat urine after single administration of a dose calculated from the doses commonly taken by drug users. Assuming similar metabolism, the described STA procedure should be suitable for proof of an intake of MDBP by analysis of human urine. Copyright © 2004 John Wiley & Sons, Ltd. [source] Synthesis of biocompatible and biodegradable block copolymers of polyvinyl alcohol- block -poly(,-caprolactone) using metal-free living cationic polymerizationJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2009Izabela Magdalena Zaleska Abstract Applications of metal-free living cationic polymerization of vinyl ethers using HCl·Et2O are reported. Product of poly(vinyl ether)s possessing functional end groups such as hydroxyethyl groups with predicted molecular weights was used as a macroinitiator in activated monomer cationic polymerization of ,-caprolactone (CL) with HCl·Et2O as a ring-opening polymerization. This combination method is a metal-free polymerization using HCl·Et2O. The formation of poly(isobutyl vinyl ether)- b -poly(,-caprolactone) (PIBVE- b -PCL) and poly(tert -butyl vinyl ether)- b -poly(,-caprolactone) (PTBVE- b -PCL) from two vinyl ethers and CL was successful. Therefore, we synthesized novel amphiphilic, biocompatible, and biodegradable block copolymers comprised polyvinyl alcohol and PCL, namely PVA- b -PCL by transformation of acid hydrolysis of tert -butoxy moiety of PTBVE in PTBVE- b -PCL. The synthesized copolymers showed well-defined structure and narrow molecular weight distribution. The structure of resulting block copolymers was confirmed by 1H NMR, size exclusion chromatography, and differential scanning calorimetry. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5169,5179, 2009 [source] Detection of adulterations in processed coffee with cereals and coffee husks using capillary zone electrophoresisJOURNAL OF SEPARATION SCIENCE, JSS, Issue 20 2009Thiago Nogueira Abstract The proposed method for the identification of adulteration was based on the controlled acid hydrolysis of xylan and starch present in some vegetable adulterants, followed by the analysis of the resulting xylose and glucose, which are the monosaccharides that compose, respectively, the two polysaccharides. The acid hydrolysis with HCl increases the ionic strength of the sample, which impairs the electrophoretic separation. Thus, a neutralization step based on anion exchange resin was necessary. The best separations were obtained in NaOH 80 mmol/L, CTAB 0.5 mmol/L, and methanol 30% v/v. Because of the high value of pH, monosaccharides are separated as anionic species in such running electrolyte. The LOQ for both monosaccharides was 0.2 g for 100 g of dry matter, which conforms to the tolerable limits. [source] Compositional changes induced by UV-B radiation treatment of common bean and soybean seedlings monitored by capillary electrophoresis with diode array detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 4 2007Giovanni Dinelli Abstract In this work, a new CE method with diode array detection (DAD) was developed for the monitoring and quantitation of flavonoids in different beans treated and untreated with UV-B radiation. Flavonoid concentration was monitored in UV-B-treated and untreated sprouts of three common beans (Zolfino ecotype, cv. Verdone, cv. Lingua di Fuoco) and one soybean (cv. Pacific). After acid hydrolysis of extracts, the CE-DAD method provides reproducible quantitative determinations of daidzein, glycitein, genistein, and kaempferol at ppm level in these natural matrices within a relatively short time (less than 16 min). Total flavonoid content determined by CE-DAD was 159 ± 8, 26 ± 2, 13 ± 1, and 1.3 ± 0.3 ,g/g fresh weight for untreated sprouts of Pacific soybean, Verdone bean, Zolfino bean, and Lingua di Fuoco bean, respectively. UV-B treatment caused no significant quantitative effect on Pacific soybean sprouts, whereas it enhanced the total isoflavone content by 1.5, 1.8, and 3.2-fold in Verdone, Zolfino, and Lingua di Fuoco beans, respectively. The proposed method shows (i) the potentialities of bean sprouts as a natural source of bioactive compounds (antioxidants); (ii) the technological role of UV-B treatment for sprout isoflavone enrichment; and (iii) the good capabilities of CE-DAD to monitor this process. [source] Evaluation of lignans and free and linked hydroxy-tyrosol and tyrosol in extra virgin olive oil after hydrolysis processesJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2006Nadia Mulinacci Abstract We describe chemical hydrolytic procedures to evaluate the total amount of tyrosol and hydroxy-tyrosol free and/or linked to secoiridoidic molecules (acid hydrolysis). At the same time a rapid determination of the lignans in complex minor polar compound (MPC) extracts is proposed (alkaline hydrolysis). High-performance liquid chromatography/diode array detection (HPLC/DAD) and HPLC/MS were applied as reference methods to evaluate the quantitative results from the hydrolysis experiments. The optimized acid hydrolysis procedures were first applied to an oleuropein standard and then to MPC fractions extracted from several commercial extra virgin olive oils. The results confirm the applicability of the method, consisting in the acid hydrolysis of complex mixtures of secoiridoidic derivatives, to determine the antioxidant potential in terms of MPC. These data can contribute to forecasting the potential ageing resistance of an extra virgin olive oil in terms of antioxidant potency. Finally, alkaline hydrolysis allows confirmation and easy determination of the amount of lignans, especially in those MPC fractions which are particularly complex. Copyright © 2006 Society of Chemical Industry [source] The Effects of the Modified Starches on the Melting Flow and Biodegradation of the Starch/Glycerol BlendMACROMOLECULAR SYMPOSIA, Issue 1 2008Chia-I Liu Abstract Summary: The purpose of this study was to improve the melting flow of starch/glycerol(GA) blends by modified starches. A variety of modified starches, which was treated by hydrolysis and acid hydrolysis, with and without ultrasonic treatment were used. The MFI (melt flow index) of blends increased from 0.5g/10min to 300g/10min when the addition of acid hydrolysis starch (0.3M CA-starch) was 70wt%. Their crystalline behaviors were analyzed by XRD results. The ultrasonic treatment has been proved to have the effect of hydrolysis without acids and synergistic effect on recrystalline. The SEM micrographs of the blend with the ultrasonic treatment starch gave the cleaving surface with comparison to the other blends. The weight loss of the blends with acid hydrolysis starches reached to 60,80% after one week biodegradation as the ultrasonic treatment was used. [source] Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (Chenopodium pallidicaule): An Andean pseudocerealMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 6 2008J. Mauricio Peńarrieta Abstract Total antioxidant capacity (TAC), total phenolic compounds (TPH), total flavonoids (TF) and individual phenolic compounds were determined in canihua collected at approx. 3850 m altitude. The TAC values varied among samples from 2.7 to 44.7 by the ferric reducing antioxidant power (FRAP) method and from 1.8 to 41 by the 2,2,-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method expressed as ,mol of Trolox equivalents/g dw. The content of TPH was 12.4,71.2 ,mol gallic acid equivalents/g dw and that of the TF ranged between 2.2 and 11.4 ,mol of catechin equivalents/g dw. The data obtained by the four methods showed several significant correlations. Prior to analysis by HPLC, the samples were subjected to acid hydrolysis and in the water-soluble extracts this led to an up to 20-fold increase in the TAC values in comparison with the values of the nonhydrolysed samples. HPLC analysis showed the presence of eight major compounds identified as catechin gallate, catechin, vanillic acid, kaempferol, ferulic acid, quercetin, resorcinol and 4-methylresorcinol. Their estimated contribution to the TAC value (FRAP method) indicated that resorcinols contributed most of the antioxidant capacity of the water-soluble extract. The results show that canihua is a potential source of natural antioxidant compounds and other bioactive compounds which can be important for human health. [source] | |||||||||||||||||||||||||||||||||||||