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Inositol Derivatives (inositol + derivative)
Selected AbstractsA Short Synthesis of Dipalmitoylphosphatidylinositol 4,5-Bisphosphate via 3-O-Selective Phosphorylation of a 3,4-Free Inositol Derivative.CHEMINFORM, Issue 23 2003Fushe Han Abstract For Abstract see ChemInform Abstract in Full Text. [source] 1H chemical shifts in NMR: Part 22,,Prediction of the 1H chemical shifts of alcohols, diols and inositols in solution, a conformational and solvation investigationMAGNETIC RESONANCE IN CHEMISTRY, Issue 8 2005Raymond J. Abraham Abstract The 1H NMR spectra of a number of alcohols, diols and inositols are reported and assigned in CDCl3, D2O and DMSO- d6 (henceforth DMSO) solutions. These data were used to investigate the effects of the OH group on the 1H chemical shifts in these molecules and also the effect of changing the solvent. Inspection of the 1H chemical shifts of those alcohols which were soluble in both CDCl3 and D2O shows that there is no difference in the chemical shifts in the two solvents, provided that the molecules exist in the same conformation in the two solvents. In contrast, DMSO gives rise to significant and specific solvation shifts. The 1H chemical shifts of these compounds in the three solvents were analysed using the CHARGE model. This model incorporates the electric field, magnetic anisotropy and steric effects of the functional group for long-range protons together with functions for the calculation of the two- and three-bond effects. The long-range effect of the OH group was quantitatively explained without the inclusion of either the CO bond anisotropy or the COH electric field. Differential , and , effects for the 1,2-diol group needed to be included to obtain accurate chemical shift predictions. For DMSO solution the differential solvent shifts were calculated in CHARGE on the basis of a similar model, incorporating two-bond, three-bond and long-range effects. The analyses of the 1H spectra of the inositols and their derivatives in D2O and DMSO solution also gave the ring 1H,1H coupling constants and for DMSO solution the CHOH couplings and OH chemical shifts. The 1H,1H coupling constants were calculated in the CHARGE program by an extension of the cos2, equation to include the orientation effects of electronegative atoms and the CHOH couplings by a simple cos2, equation. Comparison of the observed and calculated couplings confirmed the proposed conformations of myo -inositol, chiro -inositol, quebrachitol and allo -inositol. The OH chemical shifts were also calculated in the CHARGE program. Comparison of the observed and calculated OH chemical shifts and CH. OH couplings suggested the existence of intramolecular hydrogen bonding in a myo -inositol derivative. Copyright © 2005 John Wiley & Sons, Ltd. [source] Single crystal structure and molecular dynamics analysis of a myo -inositol derivativeACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2000Jan Dillen The crystal structure of 5- O - tert -butyldimethylsilyl-3,4- O -carbonyl-1,2- O -cyclohexylidene-2-oxo-3-oxa-4-bornanylcarbonyl- d - myo -inositol has been studied by single-crystal X-ray diffraction at both room temperature and 173,K. At room temperature, the tert -butyldimethylsilyl group exhibits dynamical disorder. A molecular dynamics simulation was used to model the disorder and this indicates that the group librates between two stable conformations in the crystal. Approximate relative energies of the different forms and energy barriers for the transition were obtained by empirical force field methods. Calculations of the thermal motion of the atoms are in good qualitative, but fair to poor quantitative agreement with the X-ray data. [source] Small molecule , -amyloid inhibitors that stabilize protofibrillar structures in vitro improve cognition and pathology in a mouse model of Alzheimer's diseaseEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2010Cheryl A. Hawkes Abstract ,-Amyloid (A,) peptides are thought to play a major role in the pathogenesis of Alzheimer's disease. Compounds that disrupt the kinetic pathways of A, aggregation may be useful in elucidating the role of oligomeric, protofibrillar and fibrillar A, in the etiology of the disease. We have previously reported that scyllo -inositol inhibits A,42 fibril formation but the mechanism(s) by which this occurs has not been investigated in detail. Using a series of scyllo -inositol derivatives in which one or two hydroxyl groups were replaced with hydrogen, chlorine or methoxy substituents, we examined the role of hydrogen bonding and hydrophobicity in the structure,function relationship of scyllo -inositol,A, binding. We report here that all scyllo -inositol derivatives demonstrated reduced effectiveness in preventing A,42 fibrillization compared with scyllo -inositol, suggesting that scyllo -inositol interacts with A,42 via key hydrogen bonds that are formed by all hydroxyl groups. Increasing the hydrophobicity of scyllo -inositol by the addition of two methoxy groups (1,4-di- O -methyl- scyllo -inositol) produced a derivative that stabilized A,42 protofibrils in vitro. Prophylactic administration of 1,4-di- O -methyl- scyllo -inositol to TgCRND8 mice attenuated spatial memory impairments and significantly decreased cerebral amyloid pathology. These results suggest that A, aggregation can be targeted at multiple points along the kinetic pathway for the improvement of Alzheimer's disease-like pathology. [source] Structure of Debaryomyces castellii CBS 2923 phytaseACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2009M. Ragon Phytate (myo -inositol hexakisphosphate) is the primary storage form of phosphate in seeds and legumes (Reddy et al., 1982). Phytases are phosphatases that hydrolyze phytate to less phosphorylated myo -inositol derivatives and inorganic phosphate. The crystal structure of phytase from Debaryomyces castellii has been determined at 2.3,Å resolution. The crystals belonged to space group P6522, with unit-cell parameters a = 121.65, c = 332.24,Å. The structure was solved by molecular replacement and refined to a final R factor of 15.7% (Rfree = 20.9%). The final model consists of a dimer (with two monomers of 458 residues), five NAG molecules and 628 water molecules. [source] A Study on the Influence of the Structure of the Glycosyl Acceptors on the Stereochemistry of the Glycosylation Reactions with 2-Azido-2-Deoxy-Hexopyranosyl TrichloroacetimidatesCHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2005M. Belén Cid Dr. Abstract The stereochemical outcome of glycosylations with 2-azido-2-deoxy- D -gluco- and D -galactopyranosyl trichloroacetimidates as glycosyl donors has been investigated by using a series of chiro -inositol derivatives as glycosyl acceptors. The influence of the absolute configuration, the conformation and the conformational flexibility of the glycosyl acceptor has been studied by using different glycosyl donors under similar pre-established experimental conditions. Although the structure of the acceptor may play a role in governing the stereochemistry of these glycosylations, the results show that, in general terms, the relative influence of these factors is difficult to evaluate. For a given set of experimental conditions, the stereochemical course of these glycosylations depends on structural features of both glycosyl donor and glycosyl acceptor. It is a balance of these factors, where the structure of the glycosyl donor always plays a major role, which determines the stereochemistry of the coupling reaction. Therefore, the examples reported in the literature in which the structure of the glycosyl acceptor appears to be crucial in determining the stereochemistry of the reaction constitute particularly favorable cases which do not presently allow any further generalization. [source] | ||||||||||