Anti-Inflammatory Activity of Oxyresveratrol Tetraacetate, an Ester Prodrug of Oxyresveratrol, on Lipopolysaccharide-Stimulated RAW264.7 Macrophage Cells.

Oxyresveratrol (OXY) has been reported for its anti-inflammatory activity; however, the pharmaceutical applications of this compound are limited by its physicochemical properties and poor pharmacokinetic profiles. The use of an ester prodrug is a promising strategy to overcome these obstacles. In previous researches, several carboxylate esters of OXY were synthesized and oxyresveratrol tetraacetate (OXY-TAc) was reported to possess anti-melanogenic and anti-skin-aging properties.

Ratiometric Fluorescent Sensor for Copper(II) and Phosphate Ions from Aminopyrene Derivatives.

Three derivatives of 1-aminopyrene are functionalized with 2-picolyl and 2-picolinyl groups and are tested as fluorescent sensors for metal ions. The target compounds are successfully synthesized in yields of 50-90% and characterized by H-NMR, C-NMR, and HRMS. The compound with an amino picolyl group (P1) exhibits an excellent selectivity toward Cu(II) ion as the fluorescent signal shifts from 433 to 630 nm.

Fluorescent Sensor for Copper(II) and Cyanide Ions via the Complexation-Decomplexation Mechanism with Di(bissulfonamido)spirobifluorene.

A novel spirobifluorene derivative bearing two bissulfonamido groups is successfully synthesized by Sonogashira coupling. This compound exhibits a strong fluorescence quenching by Cu(II) ion in a 50% mixture between acetonitrile and 20 mM pH 7.0 -(2-hydroxyethyl)piperazine-'-ethanesulfonic acid (HEPES) buffer with a detection limit of 98.

Protective Effects of a Lutein Ester Prodrug, Lutein Diglutaric Acid, against HO-Induced Oxidative Stress in Human Retinal Pigment Epithelial Cells.

Oxidative stress-induced cell damage and death of the retinal pigmented epithelium (RPE), a polarized monolayer that maintains retinal health and homeostasis, lead to the development of age-related macular degeneration (AMD). Several studies show that the naturally occurring antioxidant Lutein (Lut) can protect RPE cells from oxidative stress. However, the poor solubility and low oral bioavailability limit the potential of Lut as a therapeutic agent.

Fluorescence Sensors for Bismuth (III) Ion from Pyreno[4,5-d]imidazole Derivatives.

Three pyreno[4,5-d]imidazole derivatives are synthesized and evaluated as fluorescent sensors for bismuth (III) ion. The target compounds are prepared in 55-86% yields from a condensation reaction between pyrene-4,5-dione and aromatic aldehydes. The compound bearing a phenolic group can selectively detect bismuth (III) ion via fluorescence enhancement with a detection limit of 1.

Novel sulfonamidospirobifluorenes as fluorescent sensors for mercury(ii) ion and glutathione.

Novel spirobifluorene derivatives containing two and four sulfonamide groups are successfully synthesized from the commercially available bromo-9,9'-spirobifluorene by Sonogashira couplings. These compounds exhibit an excellent selective fluorescence quenching by Hg(ii) in DMSO/HEPES buffer mixture with three-times-noise detection limits of 10.4 to 103.

Hydrophilic Truxene Derivative as a Fluorescent off-on Sensor for Copper (II) Ion and Phosphate Species.

A new symmetrical truxene derivative (TP3) containing three dipicolylamino peripheral groups is successfully synthesized in four synthetic steps with an overall yield of 42%. This hydrophilic fluorescent compound exhibits a maximum absorption wavelength at 375 nm, an emission maximum at 474 nm with an outstanding 58% quantum efficiency in THF-HEPES buffer mixture. The compound shows a highly selective fluorescence quenching towards Cu(II) ion with a detection limit of 0.

A novel indolium salt as a highly sensitive and selective fluorescent sensor for cyanide detection in water.

A highly sensitive fluorescent turn-on cyanide probe is developed based on benzylidenes containing methylindolium group. Three benzylidene derivatives were synthesized from the condensations of three benzaldehyde derivatives and methyleneindoline. Only one of these three derivatives shows strong blue fluorescent response selectively to CN which can be clearly observed in submicromolar range as the result of the cyanide addition to the indolium group.

A highly selective turn-on fluorescent sensor for glucosamine from amidoquinoline-napthalimide dyads.

Three amidoquinoline-naphthalimide dyads are designed and synthesized in 67-73% overall yields in 3 steps from commercially available starting materials. Compounds with unsubstituted and nitro naphthalimide (1 and 2) show excellent selective fluorescent responses towards glucosamine with the enhancement of fluorescence quantum yields by 14 folds. The determination of HOMO-LUMO levels by linear sweep voltammetry suggests that the sensing mechanism likely involves the inhibition of photo-induced electron transfer (PET) between the aminoquinoline and naphthalimide moieties by glucosamine.

Salicylyl Fluorene Derivatives as Fluorescent Sensors for Cu(II) Ions.

Two derivatives of fluorene containing salicylic acid groups are successfully synthesized by palladium-catalyzed coupling reactions and subsequent hydrolysis of salicylate esters. The compounds are characterized by various spectroscopic methods. In phosphate buffer (pH 8.

New water soluble terphenylene diethynylene fluorophores.

Inspired by our earlier works on sensors from dendritic phenyleneethynylenes, two new star-shaped water-soluble fluorophores containing terphenylene diethynylene units and anionic carboxylate peripheries are successfully synthesized. The convergent synthesis relies on Sonogashira cross-coupling reactions between tris-(4-ethynylphenyl)amine and the iodophenyleneethynylene branches. All of the compounds are characterized by (1)H, (13)C NMR, and mass spectrometry.

Tunable star-shaped triphenylamine fluorophores for fluorescence quenching detection and identification of nitro-aromatic explosives.

Triphenylamine-based fluorophores containing pyrene or corannulene show variable fluorescence quenching sensitivity toward nitro explosives. The most sensitive fluorophore is capable of detecting TNT on the ng cm(-2) scale; the array is useful for identifying nitro aromatics.

Inclusion complexes between amphiphilic phenyleneethynylene fluorophores and cyclodextrins in aqueous media.

Binding events of cyclodextrins (CyD's) in aqueous media are important for designing and explaining the host-guest chemistry applied in sensing and controlled release systems. A water-soluble tricationic compound (3N(+)) with three branches of phenyleneethynylene fluorescent moieties and its related amphiphilic compounds (3C(-), N(0)N(+), N(+), and 2N(+)) are employed as molecular probes in the systematic characterization of the supramolecular interactions with CyD's (α, β, and γ). The strong fluorescence enhancement, combined with induced circular dichroism (CD) signals and (1)H NMR data, is evidence of 1:1 static inclusion complexes of 3N(+)/γ-CyD and 2N(+)/γ-CyD.

FRET detection of DNA sequence via electrostatic interaction of polycationic phenyleneethynylene dendrimer with DNA/PNA hybrid.

Interaction between a polycationic compound and DNA is a useful phenomenon for development of a new DNA sensing system. In this work, dendritic polycationic phenyleneethynylene fluorophores are investigated as a Förster resonance energy transfer (FRET) donor for the detection of DNA hybridization in conjunction with a fluorescein-labeled pyrrolidinyl peptide nucleic acid (Fl-acpcPNA) probe. The first generation dendrimer is an efficient energy donor for the fluorescein acceptor but also shows non-specific FRET signal with Fl-acpcPNA.

Phenylene-ethynylene trication as an efficient fluorescent signal transducer in an aptasensor for potassium ion.

A tricationic phenylene-ethynylene (N(3+)) fluorophore is investigated as a fluorescent transducer in homogeneous aptasensing system for potassium ion (K(+)) assay in aqueous media. The enhancement of the fluorescent signal of N(3+) by three K(+) aptamers consisting of 12, 15, and 21 nucleotides are observed and used for the determination of N(3+)-aptamer binding affinities. The binding affinities increase with the length of the aptameric oligonucleotides and are proven to be important to the sensitivity and selectivity of the aptasensors.

1,3,5-Triphenylbenzene fluorophore as a selective Cu2+ sensor in aqueous media.

Three water-soluble fluorophores are synthesized from 1,3,5-tris-(4'-iodophenyl)benzene. The compound with salicylate groups exhibits a selective fluorescent quenching by Cu(2+)via a static quenching mechanism. The addition of Triton X-100 improves the quantum efficiency of the fluorophore as well as the detection limit for Cu(2+) from 6.

Protein discrimination by fluorescent sensor array constituted of variously charged dendritic phenylene-ethynylene fluorophores.

A protein fluorescent sensor array based on variously charged dendritic fluorophores is developed. The variation of charge is achieved by different combinations of cationic trimethylammonium, anionic carboxylate and non-ionic methyl ester or N,N-dimethylamino on the peripheries of the fluorophores. Nine phenylene-ethynylene dendritic fluorophores, seven zeroth generation bearing charges varied from -3 to +3 and two first generation bearing -6 and +6 charges, are synthesized from triiodotriphenylamine through series of Sonogashira coupling.

UVA absorption and photostability of coumarins.

Various substituted 4-methylcoumarin derivatives were synthesized in order to obtain photostable derivatives with UVA absorption property. It was found that substitution positions affected maximum absorption wavelength, whereas types of substituents, whether hydroxy or alkoxy groups, caused no significant effect. Photostability, however, was affected by both the substitution positions and the types of substituents.

A polyanionic dendritic fluorophore for selective detection of Hg2+ in Triton X-100 aqueous media.

A series of water-soluble fluorescent dendritic compounds composed of phenylene-ethynylene repeating units and anionic carboxylate or cationic ammonium peripheral groups were synthesized. The first generation fluorescent dendrimer containing nine phenylene-ethynylene units and six carboxylate peripheral groups exhibited a highly selective fluorescence quenching by Hg(2+) ions. The Stern-Volmer constant (K(sv)) was 33,700 M(-1) in aqueous media in the presence of Triton X-100 surfactant.

A Rh(II)-catalyzed cycloaddition approach towards the synthesis of komaroviquinone.

Using a rhodium(II)-catalyzed cyclization/cycloaddition sequence as the key reaction step, the icetexane core of komaroviquinone was constructed by an intramolecular dipolar-cycloaddition of a carbonyl ylide dipole across a tethered pi-bond. The ylide was arrived at by cyclization of a rhodium carbenoid intermediate onto a proximal ester group. Efforts towards the preparation of the required precursor for elaboration to the natural product are discussed.

An Approach Toward Oxidopyrylium Ylides Using Rh(II)-Catalyzed Cyclization Chemistry.

The Rh(II)-catalyzed reaction of the E-isomer of 2-diazo-3,6-dioxo-6-phenyl-hex-enoic acid methyl ester was carried out in the presence of various carbonyl compounds and was found to give 1,3-dioxoles in moderate to good yield. In an attempt to prepare the starting -diazo substrate, an unexpected pseudo-dimerization reaction was encountered when 5-phenyl-furan-2,3-dione was heated in the presence of sodium methoxide.

Efficient construction of the oxatricyclo[6.3.1.0(0,0)]dodecane core of komaroviquinone using a cyclization/cycloaddition cascade of a rhodium carbenoid intermediate.

The rhodium(II)-catalyzed cyclization/cycloaddition cascade of a o-carbomethoxyaryl diazo dione is described as a potential route to the oxatricyclo[6.3.1.

A study of vinyl radical cyclization using N-alkenyl-7-bromo-substituted hexahydroindolinones.

A new method for the synthesis of the octahydropyrrolo[3,2,1-ij]quinoline ring system that possesses the characteristic skeleton of the aspidosperma family of alkaloids has been developed. The method utilizes an intramolecular Diels-Alder reaction of an amido-substituted furan across a tethered indole pi-bond. To apply this strategy to the synthesis of the indole alkaloid spegazzinidine, it was necessary to address the problem of assembling the final D-ring of the pentacyclic skeleton.