Glucopyranose Derivatives Research Articles

New isolate from Salvinia molesta with antioxidant and urease inhibitory activity.

Urease plays a significant role in the pathogenesis of urolithiasis pyelonephritis, urinary catheter encrustation, hepatic coma, hepatic encephalopathy, and peptic acid duodenal ulcers. Salvinia molesta was explored to identify new bioactive compounds with particular emphasis on urease inhibitors. The aqueous methanol extract was fractionated using solvents of increasing polarity. A series of column chromatography and later HPLC were performed on butanol extract. The structures of the resulting pure compounds were resolved using NMR (1D and 2D), infrared, and mass spectroscopy. The novel isolate was evaluated for antioxidant activity (using DPPH, superoxide anion radical scavenging, oxidative burst, and Fe+2 chelation assays), anti-glycation behavior, anticancer activity, carbonic anhydrase inhibition, phosphodiesterase inhibition, and urease inhibition. One new glucopyranose derivative 6'-O-(3,4-dihydroxybenzoyl)-4'-O-(4-hydroxybenzoyl)-α/β-D-glucopyranoside (1) and four known glycosides were identified. Glycoside 1 demonstrated promising antioxidant potential with IC50 values of 48.2 ± 0.3, 60.3 ± 0.6, and 42.1 ± 1.8μM against DPPH, superoxide radical, and oxidative burst, respectively. Its IC50 in the Jack bean urease inhibition assay was 99.1 ± 0.8μM. The mechanism-based kinetic studies presented that compound 1 is a mixed-type inhibitor of urease with a Ki value of 91.8 ± 0.1μM. Finally, molecular dynamic simulations exploring the binding mode of compound 1 with urease provided quantitative agreement between estimated binding free energies and the experimental results. The studies corroborate the use of compound 1 as a lead for QSAR studies as an antioxidant and urease inhibitor. Moreover, it needs to be further evaluated through the animal model, that is, in vivo or tissue culture-based ex-vivo studies, to establish their therapeutic potential against oxidative stress phosphodiesterase-II and urease-induced pathologies.

Fluorometric detection of Cu2+ and Ni2+ by a quinoline-based glucopyranose derivative via the excimer of quinoline subunit

Triazole-appended quinoline and naphthyl-based fluorescent sensors 1 and 2 have been developed from D-glucose. The quinoline-based sensor 1 exhibited excimer emission, whereas model compound 2 did not exhibit any excimer emission in MeOH/H2O (7/3, v/v). The excimer emission of quinoline moiety was quenched in the presence of Cu2+ and Ni2+ ions in an aqueous methanolic solution. The sensing ability of sensor 1 for Cu2+ and Ni2+ ions was also established by absorption spectroscopy. Interestingly, sensor 1 exhibited 1:1 stoichiometric ratios for both ions which were further supported by mass spectra of the complexes. The limit of detection (LOD) values of 1 for Cu2+ and Ni2+ were determined as 1.01 µM and 1.46 µM respectively. To the best of our knowledge, this is the first example of a monoquinoline-based sensor that exhibited excimer quenching in the presence of Cu2+ and Ni2+ ions.

A Synthetic Approach to Derive exo-Glucal Derivatives Through the Reaction of a1-C-Vinylated Glucopyranose Derivative with Phenols

A Synthetic Approach to Derive exo-Glucal Derivatives Through the Reaction of a1-C-Vinylated Glucopyranose Derivative with Phenols

Influence of the Anomeric Conformation in the Intermolecular Interactions of Glucose.

Carbohydrates are, together with amino acids, DNA bases, and lipids, the building blocks of living beings. They play a central role in basic functions such as immunity and signaling, which are governed by noncovalent interactions between sugar units and other biomolecules. To get insights into such interactions between monosaccharide units, we used a combination of mass-resolved laser spectroscopy in supersonic expansions and molecular structure calculations. The results obtained clearly demonstrate that the small stability difference between the α/β anomers of glucopyranose derivatives is reversed and amplified during molecular aggregation, making the complexes of the β-anomers significantly more stable. The amplification mechanism seems to be formation of extensive hydrogen-bond networks extending through the two interacting molecules. The same mechanism must be at play in the interactions of biological and synthetic receptors with glycans, which exhibit, in general, a higher affinity for a specific anomer, usually the beta anomer.

Highly Regioselective Monoacylation of Unprotected Glucopyranoside Using Transient Directing‐Protecting Groups

The regioselective functionalization of monosaccharides is notoriously achieved using metal catalysis, lengthy synthetic strategies requiring protection/deprotection, various enzymes, or other methods that target cis‐diols (and thus cannot be used with glucopyranose derivatives), In this paper, we report a new method using selected boronic acids as temporary protecting groups, and describe its application to the regioselective functionalization of methyl α‐d‐glucopyranoside, the most difficult monosaccharide to functionalize regioselectively. Generally, reactions of glucopyranosides may lead to a plethora of mono‐ and polyfunctionalized derivatives, yet our method gave the 3‐O‐acetylated, 2‐O‐benzoylated, and 2‐O‐pivaloylated derivatives of methyl α‐d‐glucopyranoside as major products. We focused on the use of recyclable and green temporary protecting groups (in a one‐pot reaction) and on the modulation of the intramolecular hydrogen‐bonding network using selected arylboronic acids. A complete scalable procedure leading to a single regioisomer from unprotected methyl α‐d‐glucopyranoside is presented.

ChemInform Abstract: Silver‐Mediated Oxidative Trifluoromethylation of Alcohols to Alkyl Trifluoromethyl Ethers.

AbstractThe practical method is efficiently applied to primary, secondary, and tertiary alcohols including natural products such as steroid, amino acid, and glucopyranose derivatives as well as complex pharmacologically relevant compounds.

3′‐Axial CH2OH Substitution on Glucopyranose does not Increase Glycogen Phosphorylase Inhibitory Potency. QM/MM‐PBSA Calculations Suggest Why

Glycogen phosphorylase is a molecular target for the design of potential hypoglycemic agents. Structure-based design pinpointed that the 3'-position of glucopyranose equipped with a suitable group has the potential to form interactions with enzyme's cofactor, pyridoxal 5'-phosphate (PLP), thus enhancing the inhibitory potency. Hence, we have investigated the binding of two ligands, 1-(β-d-glucopyranosyl)5-fluorouracil (GlcFU) and its 3'-CH(2) OH glucopyranose derivative. Both ligands were found to be low micromolar inhibitors with K(i) values of 7.9 and 27.1 μm, respectively. X-ray crystallography revealed that the 3'-CH(2) OH glucopyranose substituent is indeed involved in additional molecular interactions with the PLP γ-phosphate compared with GlcFU. However, it is 3.4 times less potent. To elucidate this discovery, docking followed by postdocking Quantum Mechanics/Molecular Mechanics - Poisson-Boltzmann Surface Area (QM/MM-PBSA) binding affinity calculations were performed. While the docking predictions failed to reflect the kinetic results, the QM/MM-PBSA revealed that the desolvation energy cost for binding of the 3'-CH(2) OH-substituted glucopyranose derivative out-weigh the enthalpy gains from the extra contacts formed. The benefits of performing postdocking calculations employing a more accurate solvation model and the QM/MM-PBSA methodology in lead optimization are therefore highlighted, specifically when the role of a highly polar/charged binding interface is significant.

Stereochemical Differentiation in the Simmons-Smith Reaction for Cyclopropanated Glucopyranose Derivatives as Molecular Probes for Glycosidases

Glucopyranose analogues carrying a bicyclo[4.1.0]heptane framework and the diastereomer of the cyclopropane moiety were synthesized as the unit for molecular probes to mimic the unstable transition state conformation of the glucopyranose ring in enzymatic hydrolysis. The synthesis features differentiation of the α- and β-stereoselectivity in cyclopropanation of the corresponding cyclohexene derivative.

A Synthetic Approach to Anhydroketopyranoses Having a 6,8-Dioxabicyclo[3.2.1]octane Structure from Ketopyranoses

We investigated a synthetic approach to the anhydroketopyranoses having a 6,8-dioxabicyclo[3.2.1]octane structure from D -glucopyranose derivatives. The paper describes the nucleophilic addition of the organometallic reagents RLi or RMgX to the glucono-1,5-lactone derivatives to produce the ketopyranose derivatives having a glucose backbone and their intramolecular cyclization into the desired structural anhydroketopyranoses.

Synthesis of Triazole-Linked Manno- and Glucopyranosyl Amino Acids

The synthesis of two types of triazole-linked glycosyl amino acids, at C-4 and at the anomeric position for mannopyranose and glucopyranose derivatives, respectively, via a copper-catalyzed [3+2] cycloaddition of acetylenic amino acid derivatives and azide-containing glycoside is described.

Saccharide polymers, 2. Synthesis and polymerization of exo‐glucal derivatives

AbstractUnsaturated glucopyranose derivatives such as 1,2,3,4‐tetra‐O‐acetyl‐6‐desoxy‐β‐D‐xylo‐hex‐5‐enopyranose (3) and 1,2,3,4‐tetra‐O‐benzoyl‐6‐desoxy‐β‐D‐xylo‐hex‐5‐enopyranose (6), briefly called “Ac‐exo‐glucal (3)” and “Bz‐exo‐glucal (6)”, were synthesized. These exo‐cyclic sugar vinyl ethers were investigated in polymerization reactions. The corresponding “saccharide polymers”, homo‐ and copolymers, were synthesized under free radical conditions. The structures and the compositions of the soluble “saccharide polymers” were established by elemental analysis, 1H and 13C NMR, and FTIR spectroscopy. Characterization of the polymers, like molecular weights and optical rotations are reported. Saccharide polymers with different sugar content and low as well as high molecular weights were obtained.

The use of 2-deoxy-2-trichloroacetamido-?-glucopyranose derivatives in syntheses of hyaluronic acid-related tetra-, hexa-, and octa-saccharides having a methyl β-?-glucopyranosiduronic acid at the reducing end

The use of 2-deoxy-2-trichloroacetamido-?-glucopyranose derivatives in syntheses of hyaluronic acid-related tetra-, hexa-, and octa-saccharides having a methyl β-?-glucopyranosiduronic acid at the reducing end

Substituent Effect on Ring-Opening Polymerization of Regioselectively Acylated 1,4-Anhydro-α-d-glucopyranose Derivatives

To investigate the substituent effects at the 2-O, 6-O, and 3-O positions on ring-opening polymerization, 1,4-anhydro-2,3-di-O-benzyl-6-O-pivaloyl-α-d-glucopyranose (1), 1,4-anhydro-3,6-di-O-benzyl...

Liquid-crystal properties of octyl 6′- O-alkylmelibiosides

6-O-α- d- Galactopyranosyl- d- glucopyranose (melibiose) derivatives with alkyl groups at the terminal 1- O and 6′- O positions have been synthesized. They show thermotropic and lyotropic liquid-crystal properties. The d-spacings of the strong inner X-ray diffraction rings correspond to ∼ 0.9 times the extended length of the molecule. The molecules are therefore either extended in monomolecular layers or U-shaped in bimolecular layers.

An expeditious and stereocontrolled preparation of 2-azido-2-deoxy-β-D-glucopyranose derivatives fromD-glucal

1,6-Anhydro-2-azido-2-deoxy-β-D-glucopyranose has been prepared by a two-step procedure from D-glucal and transformed into precursors useful in the synthesis of oligosaccharides.

1,6-Anhydro-β-D-glucopyranose derivatives as glycosyl donors for thioglycosidation reactions

1,6-Anhydro derivatives of D-glucopyranose, maltose, and maltotriose reacted at room temperature with trimethylsilylated benzenethiol (2) and cyclohexanethiol (3) in the presence of zinc iodide (Znl2) or trimethylsilyl triflate (TMSOTf), giving the corresponding thioglycosides with predominance of one anomer in high yield. 1,6-Anhydro-2,3,4-tri-O-benzyl-β-D-glucopyranose (1) condensed with a more complex thiol derivative, methyl 2,3,6-tri-O-benzyl-4-thio-4-S-trimethylsilyl-α-D-glucopyranoside (19), to give the 4-thiomaltose derivative (20), whereas no condensation took place between the 1,6-anhydro disaccharide homologue (21) and thiol derivative (19). The difference in reactivity between 1,6-anhydro mono- and di-saccharides was utilized for a specific cross-coupling reaction.

ChemInform Abstract: Synthesis of Oligosaccharide Structures Unique to Pituitary Glycoprotein Hormones.

AbstractThe trisaccharide (VIe) and its sulfate ester (VIf) are synthesized: 1. The component (IVb) is prepared starting from the glucopyranose derivative (Ia) via the intermediates (Ib), (Ic), (IIIa), (IIIb), and (IVa).

Synthesis of some carbon-3 substituted 1,4-benzodiazepin-2-ones and their central nervous system effects.

Starting from 3-hydroxy-1,4-benzodiazepin-2-ones 1--3, via 3-chloro derivatives 4--6, 13 new C(3)-substituted 1,4-benzodiazepin-2-ones were synthesized. Reaction of 4--6 with ethylene glycol yielded 3-(beta-hydroxyethyl) derivatives 7--9. Similar reaction with the isopropylidene derivative of glycerol afforded 10--12, which on hydrolysis of the isopropylidene group hielded glycerol derivatives 13--15. Reaction of trichloroacetyl chloride with oxazepam and temazepam yielded the corresponding trichloroacetyl esters 16 and 17. The beta-hydroxyethyl derivative 7 was conjugated with an acetylated glucopyranose derivative to give isomeric 18 and 19. Partition coefficients (log Poct) and central nervous system activities (in six stranded tests) were determined for 7--15 as well as several standard compounds. Most of the compounds exhibiting beneficial central nervous system activity had Poct values between 1.71 and 2.48. No correlation between lipophilicity and central nervous system activity could be discerned for these compounds.

Dipolar contribution to NMR spin-lattice relaxation of protons

Dipole-dipole interactions between protons in a glucopyranose derivative have been studied by means of the nuclear Overhauser effect and by spin-lattice relaxation experiments. The Overhauser enhancement measurements utilize a new pulse technique which permits the saturating field to have any specified spectral density function so that finite frequency bands in the NMR spectrum can be irradiated. By this method, the dipolar interactions between the various pairs of protons are evaluated. In contrast, the dipolar relaxation of a chosen proton by all other protons in the sample has been determined by comparing the inversion-recovery rates after selective and nonselective 180° pulses. The relaxation measurements indicate that the relaxation in this molecule is purely dipolar in origin. The Overhauser enhancement measurements of one proton are used to determine the contribution to its relaxation from two neighboring protons and, from these results, information about the geometry of the pyranose ring is evaluated.