Indium-Catalyzed Aromative Spiro Coupling of Quinones with Oxindoles for Highly Functionalized Xanthenes as Efficient Fluorophores.

A convenient and an efficient protocol for the assembly of diverse xanthenes bearing a biologically interesting oxindole nucleus is developed by utilizing the In(III)-catalyzed spiro coupling of 1,4-benzoquinones or 1,4-naphthoquinones with oxindoles. This novel protocol proceeds via a cascade of double Michael additions and intramolecular cyclization. The synthesized compounds have potential use as fluorophores for the selective imaging of heavy metals in living cells.

Band-Gap Narrowing of Highly Stable Heterogeneous ZrO -ZnO Nanocomposites for the Reductive Amination of Carbonyl Compounds with Formic Acid and Triethylamine.

The band gap of a material can be affected by factors such as size, doping materials, and oxygen vacancies. The decrease in band gap and change in state of ZrO with the addition of ZnO indicates interfacial interactions between ZrO and ZnO in the nanocomposites (NCs), which is further confirmed by the observed shift of the peaks in the Raman spectra. Heterobimetallic ZrO -ZnO NCs were synthesized through a sustainable green approach by using sucrose isolated from Angelica gigas Nakai root extract.

Silver(i)/base-promoted propargyl alcohol-controlled regio- or stereoselective synthesis of furan-3-carboxamides and (Z)-enaminones.

A novel and facile regioselective synthesis of furan-3-carboxamides by a silver(i)/base-promoted reaction of propargyl alcohol with 3-oxo amides has been demonstrated. This one-pot protocol provides a rapid synthetic approach to diverse trisubstituted furan-3-carboxamides via cascade nucleophilic addition, intramolecular cyclization, elimination, and isomerization reactions. Employing a substituted propargyl alcohol, (Z)-enaminones have been obtained with high stereoselectivities by a Ag2CO3-promoted reaction starting from 3-oxo amides via C-N bond cleavage.

Single electron transfer promoted photoaddition reactions of α-trimethylsilyl substituted secondary N-alkylamines with fullerene C.

Single electron transfer (SET) promoted photoaddition reactions of secondary N-α-trimethylsilyl-N-alkylamines to C were explored to gain a deeper understanding of the mechanistic pathways followed and to expand the library of novel types of organofullerenes that can be generated using this approach. The results show that photoreactions of 10% EtOH-toluene solutions containing C and N-α-trimethylsilyl-N-alkylamines produce either aminomethyl-1,2-dihydrofullerenes or symmetric fulleropyrrolidines as major products depending on the nature of alkyl substituents. In contrast, photoreactions of 10% EtOH-ODCB solutions of these amines with C mainly lead to the formation of symmetric fulleropyrrolidines.

Regioselective Synthesis of Dihydrothiophenes and Thiophenes via the Rhodium-Catalyzed Transannulation of 1,2,3-Thiadiazoles with Alkenes.

A method for the regioselective synthesis of a wide range of dihydrothiophenes was developed from the rhodium-catalyzed transannulation of 1,2,3-thiadiazoles with aliphatic, aromatic, and heteroaromatic alkenes. Tandem rhodium-catalyzed transannulation of 1,2,3-thiadiazoles with alkenes followed by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) oxidation was also demonstrated for the one-pot regioselective synthesis of various thiophenes. Advantages of the present method include a broad substrate scope, wide functional group compatibility, and high regioselectivity.

Iodine-mediated construction of polyfunctionalized arylazopyrazoles from β-ketoesters or 2-arylpyrazol-3-ones and arylhydrazines.

This paper describes step-economic iodine-mediated construction of functionalized arylazopyrazoles in the presence of catalytic AgNO3 starting from simple β-ketoesters and two equivalents of arylhydrazines. This cascade reaction includes in situα-iodination of β-ketoesters, pyrazol-3-one formation, substitution with a nitrogen nucleophile, and oxidation/aromatization.

Synthesis and Evaluation of New Generation Cross-Bridged Bifunctional Chelator for (64)Cu Radiotracers.

Bifunctional chelators have been successfully used to construct (64)Cu-labeled radiopharmaceuticals. Previously reported chelators with cross-bridged cyclam backbones have various essential features such as high stability of the copper(II) complex, high efficiency of radiolabeling at room temperature, and good biological inertness of the radiolabeled complex, along with rapid body clearance. Here, we report a new generation propylene-cross-bridged chelator with hybrid acetate/phosphonate pendant groups (PCB-TE1A1P) developed with the aim of combining these key properties in a single chelator.

Volatile compounds and antioxidant capacity of the bio-oil obtained by pyrolysis of Japanese red pine (pinus densiflora siebold and zucc.).

In the present study, sawdust bio-oil (SBO) manufactured by fast pyrolysis of Japanese red pine (Pinus densiflora Siebold and Zucc.) sawdust was analyzed for its volatile chemical compound composition and evaluated for its free radical scavenging potential, inhibition of lipid peroxidation and reducing power. Gas chromatography and mass spectroscopy revealed 29 volatile compounds, comprising 97.

Anti-tyrosinase, antioxidant, and antibacterial activities of novel 5-hydroxy-4-acetyl-2,3-dihydronaphtho[1,2-b]furans.

Novel 5-hydroxy-4-acetyl-2,3-dihydronaphtho[1,2-b]furans (7a-k) were synthesized using ceric ammonium nitrate (CAN)-catalyzed formal [3 + 2] cycloaddition. Synthesized compounds were evaluated for their tyrosinase inhibitory, antioxidant, and antibacterial activities. A modified spectrophotometric method using l-DOPA as substrate was used to determine tyrosinase inhibitory activities, and a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay was used to evaluate antioxidant properties.

Non-cross-bridged tetraazamacrocyclic chelator for stable (64)cu-based radiopharmaceuticals.

N-mono/dimethylated TE2A tetraazamacrocycles (MM-TE2A and DM-TE2A) were synthesized in high yields. Both Cu-MM/DM-TE2A complexes showed increased kinetic stability compared to that of Cu-TE2A, whereas Cu-DM-TE2A showed even higher in vitro stability than that of Cu-ECB-TE2A. MM-TE2A and DM-TE2A were quantitatively radiolabeled with (64)Cu ions and showed rapid clearance from the body to emerge as a potential efficient bifunctional chelator.

Microwave-assisted synthesis of diverse pyrrolo[3,4-c]quinoline-1,3-diones and their antibacterial activities.

With the aim of developing a general and practical method for library production, a novel and efficient two-phase microwave-assisted cascade reaction between isatins and β-ketoamides in [Bmim]BF4/toluene was developed for the synthesis of pyrrolo[3,4-c]quinoline-1,3-diones. The features of this methodology are, the use of microwave-assisted rapid synthesis, mild reaction conditions, high yields, operational simplicity, facile product separation, and recyclability. Furthermore, the antibacterial activities of the pyrrolo[3,4-c]quinoline-1,3-dione derivatives produced were evaluated against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter aerogenes) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus).

Metabolic engineering of Nicotiana benthamiana for the increased production of taxadiene.

We report the production of taxadiene by transformation of N. benthamiana with a taxadiene synthase gene. The production was significantly increased by an elicitor treatment or metabolic pathway shunting.

Synthesis of novel and diverse mollugin analogues and their antibacterial and antioxidant activities.

Novel and diverse mollugin analogues (1-12) were synthesized using PhB(OH)2/AcOH-mediated electrocyclization reaction as a key step. The newly synthesized compounds were screened for antioxidant and antibacterial activities. Compounds 1, 2, 5, 6, 8, and 10-12 showed high antioxidant activities in DPPH inhibition (IC50=0.

ICl-mediated intramolecular twofold iodoarylation of diynes and diynyl diethers and amines: synthesis of bis(2H-hydronaphthalene and chromene) and 2H-quinoline bearing an alkenyl iodide moiety.

Electrophilic intramolecular twofold iodoarylation was developed from the reaction of diynes and diynyl diethers and amines with iodine monochloride under mild conditions, which produced bis(2H-hydronaphthalene and chromene) and 2H-quinoline bearing an alkenyl iodide moiety in good to excellent yields. These compounds underwent Pd-catalyzed cross-coupling reactions with arylboronic acid and indium tris(arylthiolate) to produce the functionalized styrene derivatives.

Efficient one-pot synthesis of novel and diverse furo[2,3-d] pyrimidinediones and thioxofuro[2,3-d] pyrimidineones by the rhodium (II) pivalate-catalyzed reactions of cyclic diazo compounds.

The rhodium(II)-catalyzed reactions of cyclic diazo compounds derived from barbituric acid or thiobarbituric acid with arylacetylenes and styrenes were examined. These reactions provide a rapid synthetic route to the preparation of a variety of novel and diverse furo [2,3-d pyrimidine-2,4-diones, 2-thioxodihydrofuro [2,3-d pyrimidin-4-ones, dihydrofuro [2,3-d] pyrimidine-2,4-diones, and 2-thioxotetrahydrofuro [2,3-d] pyrimidin-4-ones.

Isolation of a Korean domestic microalga, Chlamydomonas reinhardtii KNUA021, and analysis of its biotechnological potential.

A freshwater microalga, Chlamydomonas reinhardtii KNUA021, was characterized for its potential as a biochemical feedstock. Its optimal growth was observed when the culture was incubated at 25°C and pH 9.4.

Gold-catalyzed sequential alkyne activation for the synthesis of 4,6-disubstituted phosphorus 2-pyrones.

Tandem gold-catalyzed addition of alkynyl phosphonic acid monoethyl esters to terminal alkynes and cyclization were developed for the synthesis of 4,6-disubstituted phosphorus 2-pyrones in one reaction vessel based on the concept of sequential alkyne activation. Alkynyl enol phosphonates were selectively obtained through the gold-catalyzed addition reaction in the presence of a catalytic amount of triethylamine. Also, gold-catalyzed cyclization of alkynyl enol phosphonates was successful in giving a variety of 4,6-disubstituted phosphorus 2-pyrones.

Production of taxadiene from cultured ginseng roots transformed with taxadiene synthase gene.

Paclitaxel is produced by various species of yew trees and has been extensively used to treat tumors. In our research, a taxadiene synthase (TS) gene from Taxus brevifolia was used to transform the roots of cultured ginseng (Panax ginseng C.A.

Enhanced luminescence of lanthanide complexes by silver nanoparticles for ciprofloxacin determination.

We present the enhancement of luminescence of europium complex, Eu(3+)-ciprofloxacin (CIP), in the presence of silver nanoparticles (Ag NPs) for the CIP determination. The increment of the luminescence intensity of the Eu(3+)-CIP complex with Ag NPs was obtained due to the transfer of resonance energy to the fluorophores through the interaction of the excited-state fluorophores and surface plasmon electron in the metal nano surface. The luminescence intensity of Eu3+ was enhanced by complexation with CIP at 614 nm after excitation at 373 nm corresponding to the 5D0-7F2 transitions of Eu3+ ion.

Silver nanoparticles enhanced luminescence of terbium complex in solution for L-dopa determination.

Luminescent properties of a terbium (Tb3+)-L-3, 4-dihydroxyphenylalanine (L-dopa) complex by binding to colloidal silver nanoparticles (Ag NPs) have been presented. Luminescence intensity of the L-dopa complex was dramatically enhanced about 6-7 times by introducing Ag NPs. The Ag NPs concentration on the luminescent intensity was regarded as a main factor that balancing between an enhancing and a quenching effect of the Ag NPs.

(1S,2S)-1-Methylamino-1-phenyl-2-chloropropane: Route specific marker impurity of methamphetamine synthesized from ephedrine via chloroephedrine.

Identification of route specific marker impurities of (S)-(+)-methamphetamine can provide us with very useful information for (S)-(+)-methamphetamine abuse criminal investigation. (1S,2S)-(+)-Chloropseudoephedrine and (1R,2S)-(-)-chloroephedrine are well known impurities of (S)-(+)-methamphetamine synthesized by metal catalyzed hydrogenation of (1R,2S)-(-)-ephedrine or (1S,2S)-(+)-pseudoephedrine. In this report (1S,2S)-1-methylamino-1-phenyl-2-chloropropane is identified as a route specific marker impurity from metal catalyzed hydrogenation method for the synthesis of (1R,2S)-(-)-ephedrine or (1S,2S)-(+)-pseudoephedrine via its chloro-derivative.

Silver nanoparticle-enhanced chemiluminescence method for determining naproxen based on europium(III)-sensitized Ce(IV)-Na2S2O4 reaction.

A simple and sensitive chemiluminescence (CL) method coupled with flow-injection technique is proposed to determine naproxen (NAP). The method is based upon the enhancement of the weak CL signal arising from the reaction of Ce(IV) and Na(2)S(2)O(4) with Eu(3+) to form the Eu(3+)-Ce(IV)-Na(2)S(2)O(4) system. The CL intensity was significantly increased by the introduction of NAP into this system in the presence of silver nanoparticles (Ag NPs).

Spectrofluorimetric study of the interaction between europium(III) and moxifloxacin in micellar solution and its analytical application.

A sensitive spectrofluorimetric method has been developed for the determination of moxifloxacin (MOX) using europium(III)-MOX complex as a fluorescence probe in the presence of an anionic surfactant, sodium dodecyl benzene sulfonate (SDBS). The fluorescence (FL) intensity of Eu(3+) was enhanced by complexation with MOX at 614 nm after excitation at 373 nm. The FL intensity of the Eu(3+)-MOX complex was significantly intensified in the presence of SDBS.

A terbium-sensitized spectrofluorimetric method for determination of catecholamines in a serum sample with micelle medium.

A terbium-sensitized spectrofluorimetric method has been developed for determination of catecholamines such as norepinephrine (NE), epinephrine (EP) and dopamine (DA), using sodium dodecyl benzene sulphonate (SDBS). Fluorescence sensitization of terbium ions (Tb(3+) ) by complexation with catecholamines in the presence of SDBS was observed. The fluorescence intensities of the Tb(3+) -catecholamine complexes were highly enhanced by introducing SDBS with an emission maximum at 545 nm after excitation at 290 nm.

Ultrasensitive study of gatifloxacin based on its enhancing effect on the cerium (IV)-sodium hyposulfite chemiluminescence reaction in a micellar medium.

A sensitive and rapid flow-injection chemiluminescence (CL) method has been developed for the determination of gatifloxacin in pharmaceutical preparations and biological samples. The method is based on the enhancing effect of gatifloxacin on CL emission generated by the interaction of Ce (IV) in sulphuric acid and sodium hyposulphite (Na(2)S(2)O(4)) sensitized by sodium dodecyl benzene sulfonate (SDBS). Strong CL emission was observed when gatifloxacin was injected into the Ce (IV) in sulphuric acid and Na(2)S(2)O(4) solution incorporated with SDBS in a flow-cell.