Morellic acid

Our knowledge of crystallization mechanisms is still quite rudimentary. However, crystal strudures such as 3-nitro-4-hydroxy-p-nitrostyrene quinoxa-line and morellic acid provide snapshot views of some of the events that may occur during crystallization of more normal compounds. One attempts to get a better appredation of the dynamic processes that occur during crystallization events by studying crystal structures which though static as are all crystal structures, are still suggestive... 

Figure 12. Stereoview of the morellic acid pyridine complex showing more explicitly the function of the pyridine molecule. Hydrogen bonds are indicated. Notice the hairpin shape of the acid molecules.

In CA, a-Guttiferin is confused with 03- Guttiferin which is identical with Morellic acid. Constit. of Gamboge the resinous exudation of Garcinia morella. Mp 113-115°. [a]2J -475° (c, 1.5 in CHCI3). 

Xanthones Hydroxanthones Morellic acid From Garcinia spp. 

Garcinia spp. G. hanburyi G. morella Guttiferae Gamboge Gambogic acid Morellic acid IsomoreDic acid Winter (1997) ... 

Fleokl W M and Engel A 1995 Visuaiisation of Nucieic Acids ed G Morel (Booa Raton, FL CRC Press)... 

Gattefoss6 and Morel La Parfumerie Moderne, 1919, 114) describe a method for the production of vanillin by reducing nitrobenzene-sul-phonic acid with iron filings and hydrochloric acid in the presence of guaiacol and formic aldehyde. The first-named body is reduced to phenyl-hydroxylamine-sulphonic acid, which reacts with the guaiacol as follows —... 

A series of derivatives analogous to those from D-glucuronic acid has been made by Morell and Link.68 An important compound is the crystalline methyl ester of methyl a-D-galacturonoside (XXXII) which on alkaline hydrolysis yields methyl a-D-galacturonoside (XXXIII). Since... 

The concentrations of other metals attenuate when the metals sorb onto the surfaces of precipitating minerals (see Chapter 10). Hydrous ferric oxide, the behavior of which is well studied (Dzombak and Morel, 1990), has a large specific surface area and is capable of sorbing metals from solution in considerable amounts, especially at moderate to high pH HAO may behave similarly. The process by which hfo or HAO form and then adsorb metals from solution, known as coprecipitation, represents an important control on the mobility of heavy metals in acid drainages (e.g., Chapman etal., 1983 Johnson, 1986 Davis etal., 1991 Smith et ai, 1992). 

The central ion of a mineral surface (in this case we take for example the surface of a Fe(lll) oxide and S-OH corresponds to =Fe-OH) acts as Lewis acid and exchanges its stuctural OH against other ligands (ligand exchange). Table 2.1 lists the most important adsorption (= surface complex formation) equilibria. The following criteria are characteristic for all surface complexation models (Dzombak and Morel, 1990.)... 

Extensive tabulations on experimentally determined surface equilibrium constants (Schindler and Stumm, 1987 Dzombak and Morel, 1990) reflecting the acid-base characteristic of surface hydroxyl groups and the stability of surface metal com-... 

Concentration versus pH diagrams for weak acids and bases that are most common in natural waters. Note that the concentration axis is in log form. Source From Morel, F. M. M., and J. G. Hering (1993). Principles and Applications of Aquatic Chemistry. Wiley Interscience, p. 160. 

Figure 2.10 Concentrations and fluxes of CH4, CO2 and N2 in anoxic acidic marsh (after Morel and Herring, 1993). Fe and Fd are the fluxes by ebullition and diffusion, respectively Reproduced by permission of Wiley, New York...

Lepidocrocite 8 acid/base titration Waite and Morel, 1984... 

Morel, G., ed. (1995) Visualization of Nucleic Acids, CRC Press, Boca Raton, Florida... 

Data from three separate phytoplankton genera, two prymnesiophyte and one dinoflagellate, indicated that this mechanism may be more general than previously realized (88). The L-amino acid oxidase pathway is related to ammonia uptake and is not light dependent. Thus, this mechanism represents a possible light-independent source of H202. The results reported by Palenik and Morel (88) demonstrated that the addition of 1-5 xM amino acids to cultures results in the fonnation of H202. As yet these experiments have not been extended to natural waters, and the relative contribution of... 

Rueter, 3.G. 3r., Chisholm S.W. and Morel, F.M.M., 1981. Effects of copper toxicity on silicic acid uptake and growth in Thalassiosira pseudonana. 3. Phycol., 17 270-278. 

Waite, T. D., and F. M. M. Morel. 1984b. Ligand exchange and fluorescence quenching studies of the fulvic acid-iron interaction. Analytica Chemica Acta 162 263-274. 

DOM can also act as an electron acceptor for biotically mediated oxidation reactions. Many active microorganisms, particularly phototrophs, produce reductants in excess of metabolic needs that must be regenerated by transfering electrons to acceptors in the environment via membrane-spanning reductases (Price and Morel, 1990). It has been discovered that some iron-reducing bacteria use humic and fulvic acids as terminal electron acceptors for their respiratory transport systems (Coates et al., 1998). 

Buschmann, H. J., Mutihac, L., and Schollmeyer, E. (2003) Complexation of some amino acids and peptides by p- sulfonatocalix[4] arene and hexasodium p-sulfonatocalix[6] arene in aqueous solution, J. Inch Phenom. Macrocycl. Chem. 46, 133-137 see also Douteau-Guevel, N., Perret, F., Coleman, A. W., Morel, J. P., and Morel-Desrosiers, N. (2002) Binding of dipeptides and tripeptides containing lysine or arginine by p-sulfonatocalixarenes in water NMR and microcalorimetric studies, Perkin Trans. 2 524-532. 

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