One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes

β-Nitrostyrenes underwent a Diels–Alder reaction with Danishefsky’s diene to afford cyclohexenes together with the corresponding hydrolyzed products, 3-arylated-5-methoxy-4-nitrocyclohexanones. When the reaction was conducted in the presence of water, the cyclohexenes were efficiently hydrolyzed into cyclohexanones. Subsequent aromatization by heating the cyclohexanone with a catalytic amount of iodine in dimethyl sulfoxide gave 3-arylated-4-nitrophenols. The reaction of nitrostyrenes with Danishefsky’s diene could be conducted in one pot to directly afford the corresponding nitrophenols. Moreover, a heteroaryl group, e.g., a thienyl group could be introduced into the nitrophenol framework.

One-Pot and Metal-Free Synthesis of 3-Arylated 4-Nitrophenols via Polyfunctionalized Cyclohexanones from β-Nitrostyrenes

β-Nitrostyrenes underwent the Diels-Alder reaction with Danishefsky’s diene to afford cyclohexenes together with the corresponding hydrolyzed products, 3-arylated 5-methoxy-4-nitrocyclohexanones. When the reaction was conducted in the presence of water, the cyclohexenes were efficiently hydrolyzed into cyclohexanones. Subsequent aromatization by heating the cyclohexanone with a catalytic amount of iodine in dimethyl sulfoxide gave 3-arylated 4-nitrophenols. The reaction of nitrostyrenes with Danishefsky’s diene could be conducted in one-pot to directly afford the corresponding nitrophenols. Moreover, a heteroaryl group such as a thienyl group could be introduced into the nitrophenol framework.

Dihydrooxazolones and dihydroimidazolones derived from acylglycines: syntheses, molecular structures and supramolecular assembly

Syntheses and structures are described for some alkylidene-substituted dihydrooxazolones and dihydroimidazoles derived from simple acylglycines. A second, triclinic, polymorph of 4-benzylidene-2-(4-methylphenyl)-1,3-oxazol-5(4H)-one, C17H13NO2, (I), has been identified and the structure of 2-methyl-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one, C9H7NO2S, (II), has been rerefined taking into account the orientational disorder of the thienyl group in each of the two independent molecules. The reactions of phenylhydrazine with 2-phenyl-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one or 2-(4-methylphenyl)-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one yield, respectively, 3-anilino-2-phenyl-5-[(thiophen-2-yl)methylidene]-3,5-dihydro-4H-imidazol-4-one, C10H15N3OS, (III), and 3-anilino-2-(4-methylphenyl)-5-[(thiophen-2-yl)methylidene]-3,5-dihydro-4H-imidazol-4-one, C21H17N3OS, (IV), which both exhibit orientational disorder in their thienyl groups. The reactions of 2-phenyl-4-[(thiophen-2-yl)methylidene]-1,3-oxazol-5(4H)-one with hydrazine hydrate or with water yield, respectively,N-[3-hydrazinyl-3-oxo-1-(thiophen-2-yl)prop-1-en-2-yl]benzamide and 2-(benzoylamino)-3-(thiophen-2-yl)prop-2-enoic acid, which in turn react, respectively, with thiophene-2-carbaldehyde to form 2-phenyl-5-[(thiophen-2-yl)methylidene]-3-{[(E)-(thiophen-2-yl)methylidene]amino}-3,5-dihydro-4H-imidazol-4-one, C19H13N3OS2, (V), which exhibits orientational disorder in only one of its thienyl groups, and with methanol to give methyl (2Z)-2-(benzoylamino)-3-(thiophen-2-yl)prop-2-enoate, C15H13NO3S, (VI). There are no direction-specific intermolecular interactions in the crystal structure of the triclinic polymorph of (I), but the molecules of (II) are linked by two independent C—H...O hydrogen bonds to formC22(14) chains. Compounds (III) and (IV) both form centrosymmetricR22(10) dimers built from N—H...O hydrogen bonds, while compound (V) forms a centrosymmetricR22(10) dimer built from C—H...O hydrogen bonds. In the structure of compound (VI), a combination of N—H...O and C—H...π(arene) hydrogen bonds links the molecules into sheets. Comparisons are made with some similar compounds.

Probing surface−complex interactions with the bis(4-thienylterpyridine)iron(II) complex anchored on TiO2 and gold nanoparticles

The bis(4-thienylterpyridine)iron(II) complex was employed, in comparison with the 4-phenylterpyridine analogue, as a molecular probe for monitoring the surface plasmon interactions with gold nanoparticles. The two complexes exhibited distinct SERS responses, confirming the binding of the thienyl group to the gold nanoparticles. Their inclusion into β-cyclodextrin anchored on TiO2 surfaces provided a useful system for applications in UV dosimetry, based on the gradual bleaching of the violet-blue color under sunlight and air.

The Electrosynthesis and Characterization of Thienyl-Group-Bearing Acrylic Polymer as Precursor for Electrochemical Reaction of Thiophene Side-Chain

The precursor thienyl-group-bearing acrylic polymer (TE-PAA-co-PMMA), obtained with 3-Ethyl acrylate-thiophene (TE-AA) and methyl methacrylate through free radical polymerization, was prepared electrochemically to free-standing, processible and conducting conjugated PTE-PAA-co-PMMA film by direct anodic oxidation in CH2Cl2 containing 50% boron trifluoride diethyl etherate (BFEE). The structure, electrochemical, optical, thermal properties and morphology of as-formed electropolymer were systematically investigated by FT-IR, cyclic voltammetry, UV-vis, thermogravimetry and scanning electron microscopy. Cyclic voltammetry studies demonstrated that the precursor can be reversibly oxidized and reduced accompanied by obvious color changes from dark blue to transmissive yellow-green and the electropolymer has good redox activity as well as excellent electrochemical stability. Additionally, fluorescence spectra show that the so-obtained crosslinked polymer is still good blue-light emitter.

Efficient Synthesis, Properties of a Novel Unsymmetrical Photochromic Diarylethene Based on Benzothiophene and Thienyl Group

An unsymmetrical diarylethene derivative was synthesized, and its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 548 nm in hexane and at 558 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The PMMA film of the diarylethene 1a exhibited relatively strong fluorescence at 413 nm when excited at 311 nm. The fluorscence intensity is highest at the concentration of 1.0×10-4 mol/L when excited at 311 nm.

Efficient, Synthesis, Properties of a Novel Unsymmetrical Photochromic Diarylethene Having Phenyl and Thienyl Group

An unsymmetrical diarylethene derivative was synthesized and its photochromic properties and fluorescence switch were investigated in detail. The results showed that this compound exhibited reversible photochromism, undergoing reversible cyclization and cycloreversion reactions upon alternating irradiation with UV and visible light both in solution and in PMMA film, and its absorption maxima were observed at 524 nm in hexane and at 532 nm in PMMA amorphous film, respectively, upon irradiation with 297 nm UV light. The PMMA film of the diarylethene 1a exhibited relatively strong fluorescence at 415 nm when excited at 318 nm. The fluorscence intensity is highest at the concentration of 1.0×10-4 mol/L when excited at 300 nm.