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Malonic Acid (malonic + acid)
Selected AbstractsMicrowave Assisted Hydrolysis of Meldrum,s Acid Derivatives and Decarboxylation of Derived Malonic Acids.CHEMINFORM, Issue 37 2003V. B. Helavi Abstract For Abstract see ChemInform Abstract in Full Text. [source] The effect of organic acids on base cation leaching from the forest floor under six North American tree speciesEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2001F. A. Dijkstra Summary Organic acidity and its degree of neutralization in the forest floor can have large consequences for base cation leaching under different tree species. We investigated the effect of organic acids on base cation leaching from the forest floor under six common North American tree species. Forest floor samples were analysed for exchangeable cations and forest floor solutions for cations, anions, simple organic acids and acidic properties. Citric and lactic acid were the most common of the acids under all species. Malonic acid was found mainly under Tsuga canadensis (hemlock) and Fagus grandifolia (beech). The organic acids were positively correlated with dissolved organic carbon and contributed significantly to the organic acidity of the solution (up to 26%). Forest floor solutions under Tsuga canadensis contained the most dissolved C and the most weak acidity among the six tree species. Under Tsuga canadensis we also found significant amounts of strong acidity caused by deposition of sulphuric acid from the atmosphere and by strong organic acids. Base cation exchange was the most important mechanism by which acidity was neutralized. Organic acids in solution from Tsuga canadensis, Fagus grandifolia, Acer rubrum (red maple) and Quercus rubra (red oak) were hardly neutralized while much more organic acidity was neutralized for Acer saccharum (sugar maple) and Fraxinus americana (white ash). We conclude that quantity, nature and degree of neutralization of organic acids differ among the different tree species. While the potential for base cation leaching with organic acids from the forest floor is greatest under Tsuga canadensis, actual leaching with organic anions is greatest under Acer saccharum and Fraxinus americana under which the forest floor contains more exchangeable cations than does the strongly acidified forest floor under Tsuga canadensis. [source] A combined computational and experimental approach for investigating a hydrogen-bonded supermolecular compound comprising benzimidazole and malonic acidINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 3 2008Fang-Fang Jian Abstract A hydrogen-bonded tetramer supramolecular motif of 2:2 benzimidazole (BIZ) and malonic acid (MLA) has been synthesized and characterized by elemental analysis, infrared (IR), and X-ray single crystal diffraction. Thermal stability analyses demonstrate that this supramolecular adduct is a new material and it is not the ordinary superposition of the original monomers. Density function theory (DFT) calculations for the models of dimers, trimers, and tetramer comprising BIZ and MLA have been carried out at B3LYP/6-31G* and PBE1PBE/6-31G* levels of theory, respectively. By comparing the calculated results with the experiments (single crystal structure, IR spectra, and thermal analysis) and based on the statistic thermodymnamic calculations, it is concluded that the dimers cannot exist at room temperature and the tetramer can simulate the title supramolecular complex better than the two trimers. Further studies on the model of tetramer indicate that the hydrogen bond of N···HO is stronger than that of O···HN. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Establishment of Azotobacter on plant roots: chemotactic response, development and analysis of root exudates of cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.)JOURNAL OF BASIC MICROBIOLOGY, Issue 5 2007Rakesh Kumar Abstract Biofertilizers contribute in N2 fixation, P solubilization, phytohormone production and thus enhance plant growth. Beneficial plant-microbe interactions and the stability and effectiveness of biofertilizer depend upon the establishment of bacterial strains in the rhizosphere of the plant. This interaction depends upon many factors, one of them being plant exudates. Root exudates are composed of small organic molecules like carbonic acids, amino acids or sugars etc., which are released into the soil and bacteria can be attracted towards these exudates due to chemotaxis. The chemotactic behaviour of Azotobacter strains was studied using cotton (Desi HD 123 and American H 1098) and wheat (WH 711) seedlings and the root exudates of these two plants were chemically characterized. Analysis of the root exudates revealed the presence of sugars and simple polysaccharides (glucose), amino acids (glutamate, lysine) and organic acids (citric acid, succinic acid, maleic acid, malonic acid). Differences between cotton cultivars in root exudates were observed which influenced chemotactic response in Azotobacter. These results indicate colonization with rhizobacteria which implies that optimal symbionts, on the sides of both plant cultivar and bioinoculant bacteria can lead to better plant growth under cultivation conditions. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Mn-peroxidase production by Panus tigrinus CBS 577.79: response surface optimisation and bioreactor comparisonJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2006Daniele Quaratino Abstract This study reports the statistical optimisation through response surface methodology of the growth medium for Panus tigrinus manganese-dependent peroxidase (MnP) production in shaken culture. Three crucial variables, including carbon source, malonic acid and Mn2+, were optimised in a nitrogen-limited medium. Sucrose was the best carbon source for MnP production. Mn2+ ions and malonic acid significantly stimulated MnP production at an optimal concentration of 53 mg dm,3 and 8.2 mmol dm,3, respectively, resulting in 0.83 U cm,3. Further experiments were performed in lab-scale stirred tank (STR) and bubble-column (BCR) reactors using the previously optimised liquid medium. BCR proved to be more adequate than STR in supporting MnP production, leading to 3700 U dm,3 after 144 h with a productivity of 25.7 U dm,3 h,1. On a comparative basis with other production data in lab-scale reactors, these results appear to be compatible with scale transfer. Copyright © 2006 Society of Chemical Industry [source] The synthesis of some 3-acylindoles revisitedJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2007Vedran Hasimbegovic A study probing the scope of acylation of indoles with dicarboxylic acids in acetic anhydride has been performed, resulting in products incorporating 3-acylindole- or 1-acylindole motifs depending on the choice of the acid reactant. Synthetically useful results were only obtained from reactions involving malonic acid or Meldrum's acid. Correlations to previous studies have also been made and discussed. [source] Carbon-14 labelling of selective H3 receptor antagonistsJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 14 2005Steen K. Johansen Abstract The fast and efficient carbon-14 labelling of the three potent H3 antagonists NNC 38-1202, NNC 38-1384, and NNC 38-1401 is reported. The two-step synthetic sequence, which included a Knoevenagel reaction, provided the carbon-14-labelled compounds in 38,55% overall yield starting from [2- 14C]malonic acid. The compounds were all obtained in high radiochemical purity ( > 99%) and with high specific activity (55.8 mCi/mmol). Copyright © 2005 John Wiley & Sons, Ltd. [source] Synthesis of [quinoline-3- 14C]-SSR97193 (ferroquine) from [2- 14C]-malonic acidJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 14 2004Alan McNeill Abstract The antimalarial [quinoline-3- 14C]-SSR97193 (ferroquine) (8), an analogue of chloroquine (CQ) (1), was synthesized from [2- 14C]-malonic acid with an overall radiochemical yield of 15%. The synthetic route via [14C]-Meldrum's acid (9) was designed to minimize the intermediacy of radiolabelled volatiles. This synthesis involves a four-step route to labelled 4,7-dichloroquinoline, which is the key intermediate for the synthesis of many analogues of CQ. Copyright © 2004 John Wiley & Sons, Ltd. [source] Synthesis of carbon-14 labeled [1- 14C]-, and [2- 14C]- L -tyrosineJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2001W. Augustyniak Abstract Two labeled isotopomers of L -tyrosine, L -Tyr, have been synthesized using specific properties of the enzymes phenylanine ammonia lyase, PAL, and L -phenylalanine hydroxylase. In an intermediate step [1- 14C]-, and [2- 14C]- L -phenylalanine, L -Phe, have been obtained from [1- 14C]-, and [2- 14C]cinnamic acid, prepared from potassium [14C]cyanate or [2- 14C]malonic acid, and by addition of ammonia in the presence of enzyme PAL. The labeled isotopomers of L -Phe have been converted into [1- 14C]-, and [2- 14C]- L -Tyr using the enzyme L -phenylalanine hydroxylase. Copyright © 2001 John Wiley & Sons, Ltd. [source] Hypoglycemic effects of malonyl-ginsenosides extracted from roots of Panax ginseng on streptozotocin-induced diabetic micePHYTOTHERAPY RESEARCH, Issue 10 2009Zhi Liu Abstract Hypoglycemic effects of malonyl-ginsenosides (MGR), extracted from roots of Panax ginseng, were examined in streptozotocin- (STZ-) induced diabetic mice. Animals received daily intravenous injections of MGR in doses of 30, 60, 120 mg/kg. At a dose of 120 mg/kg, MGR reduced the fasting blood glucose level of diabetic mice by 77.8% (76.7 ± 8.5 mg/dl versus 345.2 ± 35.8 mg/dl, P < 0.01). The same dose also showed a marked improvement in glucose tolerance of 80% (75.3 ± 10.8 mg/dl versus 375.6 ± 43.3 mg/dl, P < 0.01) in diabetic mice after four days. The alkali hydrolysis productions of MGR, ginseng panaxadiol (PDS), malonic acid and a mixture of malonic acid with PDS, showed no effects on fasting blood glucose levels indicated the hypoglycemic effect of MGR relied on their unique esterified chemical structures. The findings from this study suggest that MGR extracted from Panax ginseng may be prescribed as adjunct to drug treatment for controlling diabetes mellitus. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effects of malonic acid treatment on crystal structure, melting behavior, morphology, and mechanical properties of isotactic poly(propylene)/wollastonite compositesPOLYMER COMPOSITES, Issue 6 2010Lin Li Wollastonite is treated with a new surface modifier (malonic acid). The influence of malonic acid treatment on the crystallization and mechanical properties of polypropylene (PP)/wollastonite composites has been studied. The results of differential scanning calorimetry, wide angle X-ray diffractometry, and polarized light microscopy prove that malonic acid-treated wollastonite increases the relative content of ,-crystal form of PP. The scanning electron microscopy shows that malonic acid-treated wollastonite has better compatibility with PP matrix than the untreated wollastonite. Higher ,-phase contents, smaller spherulite sizes, and better compatibility with PP matrix of the composites containing malonic acid-treated wollastonite result in improved impact strength and tensile strength, but lower flexural modulus. The results of Fourier transform infrared spectroscopy show that malonic acid reacts with the Ca2+ of wollastonite to form the calcium malonate, which acts as an effective ,-nucleating agent. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source] Computerized analysis of cytochemical reactions for dehydrogenases and oxygraphic studies as methods to evaluate the function of the mitochondrial sheath in rat spermatozoaANDROLOGIA, Issue 1 2001M. Piasecka Cytochemical reactions for mitochondrial NADH-dependent dehydrogenases (diaphorase/NADH which is related to flavoprotein), NAD-dependent dehydrogenases (isocitrate, malate) and succinate dehydrogenase were carried out in rat spermatozoa. In addition to a morphological evaluation, the intensity of the reactions was assessed using a computer image analysing system (Quantimet 600 S). The intensity of the reactions was examined in sperm midpieces by measuring integrated optical density (IOD) and mean optical density (MOD). The activity of mitochondrial respiratory chain complexes was also analysed using the polarographic method. In the population of spermatozoa studied, all whole spermatozoa midpieces were completely filled with formazans, the product of the cytochemical reaction. These morphological findings corresponded to the values obtained for IOD and MOD for the given enzymes. In the oxygraphic studies, the spermatozoa demonstrated consumption of oxygen in the presence of substrates for I, II and IV complexes and their mitochondria revealed normal integrity and sensitivity to the substrates and inhibitors. However, the oxygraphic studies revealed differences between the sperm and somatic cells. These differences concerned the stimulation of pyruvate oxidation by malate, the lack of an effect of malonic acid on phenazine methosulphate (an acceptor of electrons) oxidation and the lack of an effect of cytochrome c on ascorbate oxidation. The cytochemical method, together with densitometric measurements, enables: (1) the reaction intensity to be determined objectively; (2) subtle and dramatic differences in reaction intensity to be revealed between spermatozoa that do not differ under morphological evaluation of the intensity; (3) possible defects within the mitochondrial sheath to be located and assessed in a large number of spermatozoa. This method can be used as a screening method alongside the routine morphological examination of spermatozoa. On the other hand, the oxygraphic method in the inner membrane of mitochondria can reveal functional changes which are related to the action of respiratory chain complexes and display characteristic features of mitochondria energy metabolism. The methods used are complementary and allow the complex evaluation of mitochondria in spermatozoa. Both methods can be used in experimental and clinical studies. [source] | |||||||||||||