481-39-0Relevant articles and documents
Synthesis and photosensitizing properties of porphycene with imidazolium tag
Shimakoshi, Hisashi,Sasaki, Kenichi,Iseki, Yusuke,Hisaeda, Yoshio
, p. 530 - 536 (2012)
Porphycene having an imidazolium cation tag was synthesized and characterized by elemental analysis, UV-vis, NMR and ESI-mass spectroscopies. This porphycene derivative easily dissolves in various ionic liquids and produces singlet oxygen under irradiation by visible light (λ 460 nm). The photophysical parameters of the porphycene in ionic liquids were determined and the values were compared to those in acetonitrile. Photosensitizing reactions using this new porphycene for the oxidation of 1,5-dihydroxynaphthalene in ionic liquids were investigated and found to form 5-hydroxy-1,4-naphthoquinone. The recycled use of the porphycene was efficiently achieved in N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)amide ([TMPA][TFSA]) and N-methyl-N-propyl-piperidinium bis(trifluoromethanesulfonyl) amide ([P13][TFSA]).
(-)-REGIOLONE, AN α-TETRALONE FROM JUGLANS REGIA: STRUCTURE, STEREOCHEMISTRY AND CONFORMATION
Talapatra, Sunil K.,Karmacharya, Bimala,De, Shambhu C.,Talapatra, Bani
, p. 3929 - 3932 (1988)
A new α-tetralone derivative designated (-)-regiolone has been isolated with juglone, betullic acid and sitosterol from the stem-bark of Juglans regia. (-)-Regiolone has been shown to be 4,8-dihydroxy-1-tetralone on the basis of its spectral data and chemical transformation to juglone.Its conformation has been deduced from the 1H NMR spectral data.The absolute stereochemistry of its only chiral centre has been shown to be S by the application of the dibenzoate chirality rule.
Directing energy transfer in panchromatic platinum complexes for dual Vis-Near-IR or dual visible emission from σ-bonded BODIPY dyes
Geist, Fabian,Jackel, Andrej,Irmler, Peter,Linseis, Michael,Malzkuhn, Sabine,Kuss-Petermann, Martin,Wenger, Oliver S.,Winter, Rainer F.
, p. 914 - 930 (2017)
We report on the platinum complexes trans- Pt(BODIPY)(8-ethynyl-BODIPY)(PEt3)2 (EtBPtB) and trans-Pt(BODIPY)(4-ethynyl-1,8-naphthalimide)(PR3)2 (R = Et, EtNIPtB-1; R = Ph, EtNIPtB-2), which all contain two diffe
Structure-property relationships and 1O2 photosensitisation in sterically encumbered diimine PtII acetylide complexes
Nolan, Deanne,Gil, Belen,Wang, Longsheng,Zhao, Jianzhang,Draper, Sylvia M.
, p. 15615 - 15626 (2013)
A series of sterically encumbered [Pt(L)(σ-acetylide)2] complexes were prepared in which L, a dendritic polyaromatic diimine ligand, was held constant (L=1-(2,2′-bipyrid-6-yl)-2,3,4,5-tetrakis(4-tert- butylphenyl)benzene) and the cis ethynyl co-ligands were varied. The optical properties of the complexes were tuned by changing the electronic character, extent of π conjugation and steric bulk of the ethynyl ligands. Replacing electron-withdrawing phenyl-CF3 substituents (4) with electron-donating pyrenes (5) resulted in a red shift of both the lowest-energy absorption (ΔE=3300cm-1, 61nm) and emission bands (ΔE=1930cm-1, 64nm). The emission, assigned in each case as phosphorescence on the basis of the excited-state lifetimes, switched from being 3MMLL′CT-derived (mixed metal-ligand-to-ligand charge transfer) when phenyl/polyphenylene substituents (3, 4, 6) were present, to ligand-centred 3ππ* when the substituents were more conjugated aromatic platforms [pyrene (5) or hexa-peri-hexabenzocoronene (7)]. The novel PtII acetylide complexes 5 and 7 absorb strongly in the visible region of the electromagnetic spectrum, which along with their long triplet excited-state lifetimes suggested they would be good candidates for use as singlet-oxygen photosensitisers. Determined by in situ photooxidation of 1,5-dihydroxynaphthalene (DHN), the photooxidation rate with pyrenyl-5 as sensitiser (kobs=39.3×10-3min-1) was over half that of the known 1O2 sensitiser tetraphenylporphyrin (kobs=78.6×10-3min -1) under the same conditions. Measured 1O2 quantum yields of complexes 5 and 7 were half and one-third, respectively, of that of TPP, and thus reveal an efficient triplet-triplet energy-transfer process in both cases. A polyarylated bipyridine ligand was used to prepare a series of sterically encumbered [Pt(L)(σ-acetylide)2] complexes (L=1-(2,2′-bipyrid-6-yl)-2,3,4,5-tetrakis(4-tert-butylphenyl)benzene), the optical properties of which were tuned effectively by changing the electronic character, extent of π-conjugation, and steric bulk of the cis ethynyl co-ligands. Singlet-oxygen photosensitising properties were also explored (see figure). Copyright
Green synthetic approaches to furoylnaphthohydroquinone and juglone
Benites, Julio,Cortes, Michael,Miranda, Luis,Estela, Cynthia,Rios, David,Valderrama, Jaime A.,Arenas, Jorge
, p. 2455 - 2457 (2014)
The synthesis of two valuable precursors of biological active compounds named 2-(furan-2-yl)-1,4-dihydroxynapthohydroquinone 2 and 5-hydroxy-1,4-naphthoquinone (4, juglone) via solar photo-induced reactions from 1,4-naphthoquinone 1 and 1,5-dihydroxynaphthalene 3 in green solvent media is reported. When t-butyl alcohol and the binary t-ButOH/DMK and ternary i-PrOAc/DMK/MEK solvent mixtures were used, acylhydroquinone 2 was isolated in yields of 80, 83 and 77%, respectively. The sensitized photooxygenation of 3 "on water" and in water containing sodium dodecyl sulfate produce juglone 4 in 81 and 39% yields respectively.
Photophysical and photosensitizing properties of brominated porphycenes
Shimakoshi, Hisashi,Baba, Tatsushi,Iseki, Yusuke,Aritome, Isao,Endo, Ayataka,Adachi, Chihaya,Hisaeda, Yoshio
, p. 2882 - 2884 (2008)
A heavy atom, bromine, was directly substituted into the porphycene macrocycle to promote intersystem crossing by way of spin-orbit coupling. The singlet oxygen production ability of the porphycene is dramatically enhanced, and the highest value of 0.95 for the quantum yield of singlet oxygen generation (ΦΔ) was obtained for the dibrominated porphycene by visible light excitation. The Royal Society of Chemistry.
On the biogenesis of 5-hydroxy-1,4-napthoquinone (juglone) in Juglans regia L
Leistner,Zenk
, (1968)
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Oxidative phenylamination of 5-substituted 1-hydroxynaphthalenes to N-phenyl-1,4-naphthoquinone monoimines by air and light "on water"
Benites, Julio,Melndez, Juan,Estela, Cynthia,Ros, David,Espinoza, Luis,Brito, Ivn,Valderrama, Jaime A.
, p. 2448 - 2452 (2014)
A number of N-phenyl-1,4-naphthoquinone monoimines 6 - 10 were prepared by on-water oxidative phenylamination of 1,5-dihydroxynaphthalene (1 ) and 5-acetylamino-1-hydroxynaphthalene ( 5 ) with oxygen-substituted phenylamines under aerobic conditions and e
SPIO@SiO2-Re@PEG nanoparticles as magneto-optical dual probes and sensitizers for photodynamic therapy
Galli, Marco,Moschini, Elisa,Dozzi, Maria Vittoria,Arosio, Paolo,Panigati, Monica,D'Alfonso, Laura,Mantecca, Paride,Lascialfari, Alessandro,D'Alfonso, Giuseppe,Maggioni, Daniela
, p. 38521 - 38532 (2016)
A dual magneto-optical nanoprobe, endowed with properties useful for photodynamic therapy, has been prepared. It is constituted by a superparamagnetic iron oxide (SPIO) core (diameter size distribution centered at ca. 10 nm), obtained by thermal decomposition of iron oleate, coated by a compact silica shell, grown in a reverse microemulsion environment. Luminescent [Re(phen)(CO)3(py)]CF3SO3 complexes were covalently anchored to the silica shell, by functionalizing the pyridine ligand with a triethoxysilane moiety. Finally, the surface of the nanoparticles (NPs) was coated with a layer of polyethylene glycol (PEG), functionalized with triethoxysilane, to improve stability and stealthiness in physiological conditions. Transmission electron microscopy of these SPIO@SiO2-Re@PEG nanocomposites showed a single population, with size distribution centered at ca. 40 nm. NPs showed nuclear relaxivity values that guarantee an appreciable contrast in magnetic resonance imaging (r2 > 30 s-1 mM-1 at frequencies higher than 5 MHz). The presence of the Re complexes imparted photoluminescence to the NPs, with blue shifted emission and higher photoluminescence quantum yields with respect to the free [Re(phen)(CO)3(py-upts)]+ complex (λem 553 vs. 580 nm, Φ 0.060 vs. 0.038, in aerated water solution). The complexes embedded into the NPs maintained a satisfactory efficiency toward 1O2 generation (quantum yields 0.21 vs. 0.26 for the free complex, as assessed using 1,5-dihydroxynaphthalene as indirect marker of the 1O2 presence). Preliminary cell penetration tests were performed on human lung adenocarcinoma A549 cells. Two photon excitation confocal microscopy showed that the NPs were easily internalized and accumulated in the perinuclear region of the cells already after 4 h of incubation. Increased cytotoxicity upon irradiation with respect to the dark was also observed, showing the potential of the nanocomposite for photodynamic therapy applications.
An efficient multigram synthesis of juglone methyl ether
Cui, Jia-Hua,Cui, Qing,Zhang, Qi-Jing,Li, Shao-Shun
, p. 553 - 554 (2015)
Based on the regioselective oxidation of 1,4,5-trimethoxynaphthalene by cerium (IV) ammonium nitrate, an efficient synthesis of juglone methyl ether has been achieved with high overall yield (74%) and good purity (98.6%). Compared with the reported methods, the reaction conditions are milder and the work-up of each step is much simpler. Moreover, the new strategy considerably reduces the cost in the synthesis of juglone methyl ether and is suitable for large-scale preparations.
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Goldstein,Grandjean
, p. 181,184 (1943)
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σ-Pt-BODIPY Complexes with Platinum Attachment to Carbon Atoms C2 or C3: Spectroscopic, Structural, and (Spectro)Electrochemical Studies and Photocatalysis
Irmler, Peter,Winter, Rainer F.
, p. 235 - 253 (2018)
In this work we discuss five new complexes with the general formula trans-Pt(bodipy)I(PEt3)2, where differently substituted bodipy dyes attach to the coordination center via a direct Pt-C σ-bond to the pyrrolic carbon atom C2 or C3. We also report an isolable intermediate of the oxidative addition step where the bodipy is 2-bonded to the cis-Pt(0)(PEt3)2 moiety. Comparison between the new complexes, meso-platinated analogue 8-Pt, and the parent dyes reveals that the site of platinum attachment influences the spectroscopic, photophysical, electrochemical, and electronic properties. In contrast to 8-Pt, absorption and emission bands are red-shifted with respect to the parent dyes. 2-Platinated bodipy dyes 2-Pt-6H, 2-Pt-6I, 2-Pt-Mes-6I, and 2-Pt-6Et exhibit dual fluorescence and NIR phosphorescence emissions, with low quantum yields, whereas 3-Pt emits solely by fluorescence (I:Fl = 52.7%). The complexes are modestly efficient sensitizers for photochemical 1O2 production but outperform methylene blue. They also undergo one reversible one-electron reduction and oxidation as indicated by cyclic voltammetry. Half-wave potentials are cathodically shifted by 340-510 mV with respect to the parent dyes. The one-electron reduced and some of the one-electron oxidized forms were generated and investigated by UV/vis/NIR and EPR spectroscopy as well as TD-DFT calculations. The similarity of their spectra to those of the one-electron reduced or oxidized forms of other bodipy dyes as well as the richly structured EPR spectra and g-values close to ge attest to a dominant bodipy character of the relevant frontier MOs.
Organophotocatalytic Aerobic Oxygenation of Phenols in a Visible-Light Continuous-Flow Photoreactor
Wellauer, Jo?l,Miladinov, Dragan,Buchholz, Thomas,Schütz, Jan,Stemmler, René T.,Medlock, Jonathan A.,Bonrath, Werner,Sparr, Christof
supporting information, p. 9748 - 9752 (2021/05/27)
A mild photocatalytic phenol oxygenation enabled by a continuous-flow photoreactor using visible light and pressurized air is described herein. Products for wide-ranging applications, including the synthesis of vitamins, were obtained in high yields by precisely controlling principal process parameters. The reactor design permits low organophotocatalyst loadings to generate singlet oxygen. It is anticipated that the efficient aerobic phenol oxygenation to benzoquinones and p-quinols contributes to sustainable synthesis.
Synthetic Studies of the Rubellin Natural Products: Development of a Stereoselective Strategy and Total Synthesis of (+)-Rubellin C
Gartman, Jackson A.,Tambar, Uttam K.
, p. 11237 - 11262 (2021/08/16)
This manuscript describes our studies of the class of natural products known as the rubellins, culminating in the total synthesis of (+)-rubellin C. These anthraquinone-based natural products contain a variety of stereochemical and architectural motifs, including a 6-5-6-fused ring system, 5 stereogenic centers, and a central quaternary center. Herein, we report our development of a strategy to target the stereochemically dense core and anthraquinone nucleus, including approaches such as a bifunctional allylboron and vinyl triflate reagent, an anthraquinone benzylic metalation strategy, and a late-stage anthraquinone introduction strategy. Our studies culminate in a successful route to highly functionalized anthraquinone-based natural product scaffolds and a stereoselective total synthesis of (+)-rubellin C. These strategies and outcomes will aid in synthetic planning toward anthraquinone-based natural products of high interest.
Oxidative Dearomatization of Phenols and Polycyclic Aromatics with Hydrogen Peroxide Triggered by Heterogeneous Sulfonic Acids
Pancrazzi, Francesco,Maestri, Giovanni,Maggi, Raimondo,Viscardi, Rosanna
supporting information, p. 5407 - 5414 (2021/10/25)
We report herein a method for the oxidative dearomatization of phenols and bare polycyclic arenes into the corresponding quinoid derivatives using hydrogen peroxide. The reaction is catalyzed by sulfonic acids and best results were achieved using heterogenized species. The best results using phenols were achieved using a hybrid material, namely a perfluorinated polymer functionalized with sulfonic acid groups supported on silica. The dearomatization of polycyclic aromatic hydrocarbons performed better using the polymeric acid catalyst. These methods operate under mild conditions, using mild and benign oxidants and thus minimizing the formation of waste.
