Synthesis and Electronic Properties of Novel Donor-π-Acceptor-Type Functional Dyes with a Carbonyl-Bridged Bithiophene π-Spacer.

In this study, we synthesized novel donor-π-acceptor (D-π-A) functional dyes bearing a carbonyl-bridged bithiophene as a π-conjugated spacer and evaluated the absorption and fluorescence properties as well as the photostability. The developed dyes - possess an ,-diphenylaminophenyl electron donor unit and an electron acceptor unit such as a formyl group (), an (,-diethylthiobarbituryl)methylene moiety (), or a (3-dicyanomethylidene-1-indanon-2-yl)methylene moiety (). The absorption spectra of - in dichloromethane at room temperature showed absorption maxima at 569 nm, 631 nm, and 667 nm, respectively, and the stronger acceptors in and led to enhancement of the ICT character.

Distribution and Incorporation of Extracellular Vesicles into Chondrocytes and Synoviocytes.

Osteoarthritis (OA) is a chronic disease affecting over 500 million people worldwide. As the population ages and obesity rates rise, the societal burden of OA is increasing. Pro-inflammatory cytokines, particularly interleukin-1β, are implicated in the pathogenesis of OA.

Synthesis, Photoluminescence, and Electroluminescence of Phosphorescent Dipyrido[3,2-;2'3'-]phenazine-Platinum(II) Complexes Bearing Hole-Transporting Acetylide Ligands.

In this study, novel phosphorescent dipyrido[3,2-;2'3'-]phenazine (dppz)-platinum(II)-phenylacetylide complexes were developed to fabricate non-doped organic light-emitting diodes (OLED) by solution-processing. To facilitate the charge carrier injection into the emitting layer (EML), 3,6-di--butylcarbazole-functinalized phenylacetylides were employed. As for the dppz ligand, 9,9-dihexylfluoren-2-yl and 4-hexylthiophen-2-yl side-arms were introduced to the 2,7-positions, which led to reddish orange and red photoluminescence (PL), respectively, in solution and film states (PL wavelength: ca.

Crystal structure of (μ-hydrogen di-sulfato)-μ-oxido-bis-[(4,4'-di--butyl-2,2'-bi-pyridine)-oxidovanadium(IV/V)] aceto-nitrile monosolvate.

The dinuclear oxidovanadium(IV/V) complex, [V(HSO)O(CHN)]·CHCN or [VO(μ-O)(μ-H(SO))(4,4'-Bubpy)]·CHCN (4,4'-Bubpy = 4,4'-di--butyl-2,2'-bi-pyridine), has crystallographic symmetry and exhibits a distorted octa-hedral geometry around the vanadium center, where the two 4,4'-Bubpy ligands are nearly orthogonal to each other. The two vanadium ions are linked by an oxo anion and a unique protonated sulfate anion [H(SO) ]. In the crystal, inter-molecular C-H⋯π and π-π inter-actions between the 4,4'-Bubpy ligands are present, leading to a three-dimensional network.

-Bis[8-(benzyl-sulfan-yl)quinoline-κ ,]di-chlorido-cobalt(II).

The title di-chloro-cobalt(II) complex, -[CoCl()] [ = 8-(benzyl-sulfanyl)-quinoline, CHNS], has a central Co atom (site symmetry ) that exhibits a distorted octa-hedral coordination geometry and is coordinated by two N and two S atoms from the bidentate ,-ligand () situated in an equatorial plane and two Cl atoms in the axial positions. Complexes are linked by weak inter-molecular C-H⋯π inter-actions between the 8-(benzyl-sulfanyl)-quinoline ligands, forming a chain extending along the -axis direction.

Innovative green oxidation of amines to imines under atmospheric oxygen.

In recent years, the development of environmentally benign molecular construction methods has been of great importance, and especially, resource recycling, high atomic efficiency, and low environmental impact are in high demand. From this point of view, attention has also been focused on the development of one-pot synthesis of pharmaceuticals and functional molecules. Imines are excellent synthetic intermediates of these useful molecules, and the environmentally friendly oxidative synthesis of imines from amines has been energetically developed using oxygen (or air), which is abundantly available on the Earth, as an oxidant.

Metal-Free Synthesis of 2-Substituted Quinazolines Green Oxidation of -Aminobenzylamines: Practical Construction of -Containing Heterocycles Based on a Salicylic Acid-Catalyzed Oxidation System.

Conventional quinazoline synthesis methods involve a highly multistep reaction, and often require excess amounts of substrate to control the product selectivity, leading to significant resource wastage. Hence, in this study, from the viewpoint of green chemistry, we developed a novel metal-free synthetic method for 2-substituted quinazoline derivatives by the 4,6-dihydroxysalicylic acid-catalyzed oxidative condensation of -aminobenzylamines and benzylamines using atmospheric oxygen. In this system, the use of a catalytic amount of BF‧EtO (10 mol%) as a Lewis acid successfully led to the efficient oxidative condensation and intramolecular cyclization of these amines, followed by aromatization to afford the corresponding 2-arylquinazolines in up to 81% yield with excellent atom economy and environmental factor.

Potential of a Novel Chemical Compound Targeting Matrix Metalloprotease-13 for Early Osteoarthritis: An In Vitro Study.

Osteoarthritis is a progressive disease characterized by cartilage destruction in the joints. Matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) play key roles in osteoarthritis progression. In this study, we screened a chemical compound library to identify new drug candidates that target MMP and ADAMTS using a cytokine-stimulated OUMS-27 chondrosarcoma cells.

Photoinduced Bisphosphination of Alkynes with Phosphorus Interelement Compounds and Its Application to Double-Bond Isomerization.

The addition of interelement compounds with heteroatom-heteroatom single bonds to carbon-carbon unsaturated bonds under light irradiation is believed to be an atomically efficient method to procure materials with carbon-heteroatom bonds. In this study, we achieved the photoinduced bisphosphination of alkynes using the phosphorus interelement compound, tetraphenyldiphosphine monosulfide (), to stereoselectively obtain the corresponding ()--1,2-bisphosphinoalkenes, which are important transition-metal ligands. The bisphosphination reaction was performed by mixing and various alkynes and then exposing the mixture to light irradiation.

Transition-Metal-Free Synthesis of Unsymmetrical Diaryl Tellurides via S2 Reaction of Aryl Radicals on Tellurium.

Although diaryl tellurides are parent organotellurium compounds, their synthesis methods, especially for unsymmetrical ones, are limited. This may be due to the instability of diaryl tellurides and their synthesis intermediates under reaction conditions. Radical reactions are known to exhibit excellent functional group selectivity; therefore, we focused on a bimolecular homolytic substitution (S2) reaction between the aryl radical and diaryl ditelluride.

Excellent Catalytic Performances of a Au/C-CuO Binary System in the Selective Oxidation of Benzylamines to Imines under Atmospheric Oxygen.

A green method of the oxidation of benzylamines to imines was developed using a novel binary system of Au/C-CuO. This system was evaluated under atmospheric oxygen, and the corresponding imines were obtained in up to 100% yields by loading 0.006 mol % of Au/C and 1.

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones.

A simple and efficient method for α-brominating lactones that affords αbromolactones under mild conditions using tetraalkylammonium hydroxide (RNOH) as a base was developed. Lactones are ring-opened with Br and a substoichiometric amount of PBr, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (HO/CHCl) containing RNOH afforded α-bromo lactones in good yields.

Clarification on the Reactivity of Diaryl Diselenides toward Hexacyclohexyldilead under Light.

In this study, the reactivity of organochalcogen compounds toward a representative alkyl-lead bond compound under light was investigated in detail. Under light irradiation, the Cy-Pb bond of CyPb (Cy = cyclohexyl) undergoes homolytic cleavage to generate a cyclohexyl radical (Cy•). This radical can be successfully captured by diphenyl diselenide, which exhibits excellent carbon-radical-capturing ability.

Oxidative Synthesis of Acid Blue 7 Dye Catalyzed by CuO/Silicotungstic Acid in Water-Phase.

A catalytic oxidation reaction for Acid Blue 7 dye synthesis was evaluated in water. Without lead oxide or manganese oxide derivatives as oxidants, polyoxometalate catalysts were investigated to reduce the usage of harmful heavy metal. A catalyst was prepared by mixing silicotungstic acid with copper oxide, and aqueous hydrogen peroxide (30%) was used as an oxidizing agent.

Transition-Metal-Catalyzed Diarylation of Isocyanides with Triarylbismuthines for the Selective Synthesis of Imine Derivatives.

The transition-metal-catalyzed diarylation of isocyanides with triarylbismuthines was investigated in detail, and rhodium catalysts such as [RhCl(nbd)] were found to selectively afford -alkyl diaryl ketimines. On the other hand, palladium-catalyzed diarylation proceeded with the incorporation of two molecules of isocyanide, preferentially yielding ,-dialkyl or ,-diaryl -diimines. In addition, a cascade synthesis of 2,3-diarylquinoxalines starting from the palladium-catalyzed diarylation of isocyanides with triarylbismuthines was successfully achieved.

One-Pot Construction of Diverse β-Lactam Scaffolds via the Green Oxidation of Amines and Its Application to the Diastereoselective Synthesis of β-Amino Acids.

In this study, a simple one-pot construction of β-lactam scaffolds was successfully achieved via 4,6-dihydroxysalicylic acid-catalyzed organocatalytic oxidation of amines to imines using molecular oxygen. Although some imines are highly unstable and difficult to isolate by conventional methods, the organocatalytic oxidation of amines described herein, followed by their direct reaction with acyl chlorides in the presence of a base, afforded a series of new β-lactam derivatives with excellent selectivity, which could not be synthesized and isolated by previously reported methods. Thus, this one-pot protocol will be one of the powerful methods applicable to the synthesis of various potential drug candidates and functional molecules.

Au/Ag/Cu-Mixed Catalysts for the Eco-Friendly Oxidation of 5-Hydroxymethylfurfural and Related Compounds to Carboxylic Acids under Atmospheric Oxygen in Water.

A green method for the oxidation of alcohols to carboxylic acids was developed using a novel co-catalytic system based on gold, silver, and copper catalysts. This reaction system was conducted under atmospheric oxygen in water and mild conditions to selectively oxidize 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid, as a building block for polyethylene furanoate, which is a 100% bio-based, future alternative to the petroleum-based polyethylene terephthalate. Furthermore, various primary alcohols were conveniently oxidized to their corresponding carboxylic acids in up to quantitative yields.

Photoinduced Syntheses and Reactivities of Phosphorus-Containing Interelement Compounds.

The photoinduced reactions of tetraphenyldiphosphine disulfide with a range of organic dichalcogenides successfully afforded a series of phosphorus(V)-chalcogen interelement compounds via a radical process. The relative reactivities of the organic dichalcogenides (i.e.

Tris-(4,4'-di--butyl-2,2'-bi-pyridine)(-4--butyl-cyclo-hexa-nolato)-deca-μ-oxido-hepta-oxido-hepta-vanadium aceto-nitrile monosolvate including another unknown solvent mol-ecule.

The title hepta-nuclear alkoxido(oxido)vanadium(V) oxide cluster complex, [V(CHO)O(CHN)]·CHCN, was obtained by the reaction of [VO(CHN)] with 4--butyl-cyclo-hexa-nol (mixture of and ) in a mixed CHCl/CHCN solvent. The complex has a VON core with approximately symmetry, which is composed of two VO tetra-hedra, two VO octa-hedra and three VON octa-hedra. In the crystal, these complexes are linked together by weak inter-molecular C-H⋯O hydrogen bonds between the 4,4'-di--butyl-2,2'-bi-pyridine ligand and the VON core, forming a one-dimensional network along the -axis direction.

4,6-Dihydroxysalicylic Acid-Catalyzed Oxidative Condensation of Benzylic Amines and Aromatic Ketones for the Preparation of 2,4,6-Trisubstituted Pyridines and Its Application to Metal-Free Synthesis of G-Quadruplex Binding Ligands.

4,6-Dihydroxysalicylic acid was activated under air to catalyze the one-pot oxidative condensation reaction of benzylamines with acetophenones in the presence of BF·EtO, affording 2,4,6-trisubstituted pyridines in yields of 59-91%. During this metal-free oxidative condensation reaction, the benzylamines not only provided the aryl moiety at the 4-position of the pyridines but also acted as the nitrogen donor. This method can be applied to the metal-free synthesis of G-quadruplex binding ligands by the sequential addition of 4-chlorobutyryl chloride and pyrrolidine to the reaction system of the 2,4,6-trisubstituted pyridine synthesis.

Synthesis of Aryl Iodides from Arylhydrazines and Iodine.

A metal- and base-free method is developed for the synthesis of aryl iodides from arylhydrazine hydrochlorides and iodine. A wide variety of aryl iodides can be conveniently synthesized by an equimolar reaction of arylhydrazine hydrochlorides and I in dimethyl sulfoxide at 60 °C for 6 h. In the iodination step, arylhydrazines are oxidized by iodine to form arenediazonium salts, which undergo single-electron transfer from iodide anion to give aryl and iodine radicals; subsequent combination of them affords the corresponding aryl iodides.

Palladium-Catalyzed Diarylation of Isocyanides with Tetraarylleads for the Selective Synthesis of Imines and α-Diimines.

Using tetraaryllead compounds (PbAr) as arylating reagents, isocyanides undergo selective diarylation in the presence of palladium catalysts such as Pd(OAc) or Pd(PPh) to afford imines and/or α-diimines based on the isocyanide employed. With aliphatic isocyanides, imines are obtained preferentially, whereas α-diimines are formed in the case of electron-rich aromatic isocyanides. The differences in imine/α-diimine selectivity can be attributed to the stability of imidoylpalladium intermediates formed in this catalytic reaction.

2,4,6-Trihydroxybenzoic Acid-Catalyzed Oxidative Ugi Reactions with Molecular Oxygen via Homo- and Cross-Coupling of Amines.

Metal-free, oxidative four-component Ugi reactions (U-4CRs) were conducted to synthesize dipeptides from two different amines, isocyanides, and carboxylic acids using 2,4,6-trihydroxybenzoic acid catalyst in O atmosphere. The organocatalytic U-4CRs proceed via oxidative cross-coupling of benzylamines with other aliphatic or aromatic amines to form imines, followed by condensation with isocyanides and carboxylic acids. The U-4CRs via cross-coupling of amines are rare, and the simple, metal-free procedures are advantageous for further applications in drug and heterocycle syntheses.

Reductive Formation of a Vanadium(IV/V) Oxide Cluster Complex [VO(4,4'- Bubpy)] Having a C-Symmetric Propeller-Shaped Nonionic VO Core.

A novel C-symmetric propeller-shaped vanadium(IV/V) oxide cluster complex, [VO(4,4'- Bubpy)] (V'), has been synthesized from the reaction of the windmill-shaped vanadium(V) oxide cluster complex [VO(4,4'- Bubpy)] (V) with PPh under N, whereas refluxing V in methanol or ethanol under N provides tetranuclear oxido(alkoxido)vanadium(IV/V) complexes [VO(OR)(4,4'- Bubpy)] [R = Me (V'-Me) and Et (V'-Et)]. The mixed-valent vanadium(IV/V) clusters V' and V' are converted back to V under O. Interconversions of V' and the oxido(alkoxido)vanadium(V) complexes [VO(OMe)(4,4'- Bubpy)] (V) and [VO(OEt)(4,4'- Bubpy)] (V-Et) are also presented.