- Sterically driven metal-free oxidation of 2,7-di-tert-butylpyrene
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We disclose an unprecedented single-step metal-free green oxidation of 2,7-di-tert-butylpyrene selectively into either the corresponding 4,5-dione or 4,5,9,10-tetraone, two key building blocks used for organic optoelectronic applications using hypervalent
- Cesario, Marcello F.,El-Assaad, Tarek H.,McGrath, Dominic V.,Parida, Keshaba N.
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p. 5966 - 5971
(2020/10/18)
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- Pyrenediones as versatile photocatalysts for oxygenation reactions with: In situ generation of hydrogen peroxide under visible light
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Pyrenediones (PYDs) are efficient photocatalysts for three oxygenation reactions: Epoxidation of electron deficient olefins, oxidative hydroxylation of organoborons, and oxidation of sulfides via in situ generation of H2O2 under visible light irradiation, using oxygen as a terminal oxidant and IPA as a solvent and a hydrogen donor.
- Zhang, Yuannian,Yang, Xin,Tang, Haidi,Liang, Dong,Wu, Jie,Huang, Dejian
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supporting information
p. 22 - 27
(2020/01/13)
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- Aerobic C-H Functionalization Using Pyrenedione as the Photocatalyst
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We disclose a visible-light-promoted aerobic alkylation of activated C(sp 3)-H bonds using pyrenedione (PYD) as the photocatalyst. Direct C-H bond alkylation of tetrahydrofuran with alkylidenemalononitriles is accomplished in over 90% yield in the presence of 5 mol% of PYD and 18 W blue LED light under ambient conditions. The substrate scope is extended to ethers, thioethers, and allylic C-H bonds in reactions with various electrophilic Michael acceptors. The catalytic turnover process is facilitated by oxygen. Our work represents the first example of using PYD as a photocatalyst to promote C(sp 3)-H alkylation, revealing the unique character of PYD as a novel organophotocatalyst.
- Zhang, Yuannian,Yang, Xin,Wu, Jie,Huang, Dejiang
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supporting information
p. 2512 - 2520
(2020/09/03)
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- Copper(i)-based oxidation of polycyclic aromatic hydrocarbons and product elucidation using vacuum ultraviolet spectroscopy and theoretical spectral calculations
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Copper(i) complexes supported by fluorinated 1,3,5-triazapentadienyl ligands have been used as catalysts for the oxidation of anthracene, naphthalene, and pyrene to the corresponding quinones, using H2O2 as an oxidant under mild conditions without an acid co-catalyst. Gas chromatography-vacuum ultraviolet spectroscopy (GC-VUV) combined with time-dependent density functional theory theoretical computations of absorption spectra was demonstrated as a new and useful tool-set for unknown determination in complex reaction mixtures, especially when standards are not available for spectral comparisons and product mixtures involve closely related isomers. The anthracene has been converted to 9,10-anthraquinone in quantitative yield using this copper catalyzed process. The oxidation of naphthalene afforded 1,4-naphthoquinone as the major product, and 1-naphthol and 2-naphthol as minor products. The pyrene oxidation resulted in 4,5-, 1,6-, and 1,8-pyrenequinones, among other products. The X-ray crystal structure of [N{(CF3)C(C6F5)N}2]CuNCCH3 is also reported.
- Ponduru, Tharun T.,Qiu, Changling,Mao, James X.,Leghissa, Allegra,Smuts, Jonathan,Schug, Kevin A.,Dias, H. V. Rasika
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supporting information
p. 19442 - 19449
(2018/12/13)
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- A comparison of optical, electrochemical and self-assembling properties of two structural isomers based on 1,6- and 1,8-pyrenedione chromophores
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Two isomeric donor-acceptor-donor (DAD) pyrene chromophores were synthesized and their optical, electrochemical and solid-state properties were investigated. Both chromophores showed similar light absorption profiles that spanned the visible region from 3
- Keller, Samantha N.,Sutherland, Todd C.
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p. 2970 - 2978
(2018/02/19)
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- Synthesis of o-Carboxyarylacrylic Acids by Room Temperature Oxidative Cleavage of Hydroxynaphthalenes and Higher Aromatics with Oxone
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A simple procedure for the synthesis of a variety of o-carboxyarylacrylic acids has been developed with Oxone (2KHSO5·KHSO4·K2SO4); the oxidation reaction involves the stirring of methoxy/hydroxy-substituted naphthalenes, phenanthrenes, anthracenes, etc. with Oxone in an acetonitrile-water mixture (1:1, v/v) at rt. Mechanistically, the reaction proceeds via initial oxidation of naphthalene to o-quinone, which undergoes cleavage to the corresponding o-carboxyarylacrylic acid. The higher aromatics are found to yield carboxymethyl lactones derived from the initially formed o-carboxyarylacrylic acids.
- Parida, Keshaba Nanda,Moorthy, Jarugu Narasimha
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p. 8354 - 8360
(2015/09/01)
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- Biomimetic oxidation of pyrene and related aromatic hydrocarbons. Unexpected electron accepting abilities of pyrenequinones
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We present a mild catalytic method to oxidize PAHs and, in particular, pyrene. The pyrenediones are much better electron acceptors than benzoquinone in the gas phase and present similar accepting abilities in solution.
- López-Moreno, Alejandro,Clemente-Tejeda, David,Calbo, Joaquín,Naeimi, Atena,Bermejo, Francisco A.,Ortí, Enrique,Pérez, Emilio M.
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supporting information
p. 9372 - 9375
(2014/08/05)
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- Photodegradation mechanisms of 1-nitropyrene, an environmental pollutant: The effect of organic solvents, water, oxygen, phenols, and polycyclic aromatics on the destruction and product yields
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This work describes studies of the photodegradation mechanism of 1-nitropyrene (1-NO2Py) in a chemical model system consisting of an organic solvent and known constituents of an aerosol particle. Photoproducts such as 1-hydroxypyrene (1-OHPy),
- Garcia-Berrios, Zulma I.,Arce, Rafael
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experimental part
p. 3662 - 3664
(2012/06/30)
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- Regiospecific oxidation of polycyclic aromatic phenols to quinones by hypervalent iodine reagents
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The hypervalent iodine reagents o-iodoxybenzoic acid (IBX) and bis(trifluoro-acetoxy)iodobenzene (BTI) are shown to be general reagents for regio-controlled oxidation of polycyclic aromatic phenols (PAPs) to specific isomers (ortho, para, or remote) of polycyclic aromatic quinones (PAQs). The oxidations of a series of PAPs with IBX take place under mild conditions to furnish the corresponding ortho-PAQs. In contrast, oxidations of the same series of PAPs with BTI exhibit variable regiospecificity, affording para-PAQs where structurally feasible and ortho-PAQs or remote PAQ isomers in other cases. The structures of the specific PAQ isomers formed are predictable on the basis of the inherent regioselectivities of the hypervalent iodine reagents in combination with the structural requirements of the phenol precursors. IBX and BTI are recommended as the preferred reagents for regio-controlled oxidation of PAPs to PAQs.
- Wu, Anhui,Duan, Yazhen,Xu, Daiwang,Penning, Trevor M.,Harvey, Ronald G.
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experimental part
p. 2111 - 2118
(2010/04/26)
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- Photoinduced electron-transfer systems consisting of electron-donating pyrenes or anthracenes and benzimidazolines for reductive transformation of carbonyl compounds
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Photoinduced electron-transfer reactions of several ketone substrates were studied to evaluate the utilities of 1,6-bis(dimethylamino)pyrene (BDMAP), 1,6-dimethoxypyrene (DMP), 9,10-bis(dimethylamino)anthracene (BDMAA), and 9,10-dimethoxyanthracene (DMA) as electron-donating sensitizers cooperating with 2-aryl-1,3-dimethylbenzimidazolines. BDMAP and DMP generally led higher conversion of ketones and better yield of reduction products compared to BDMAA and DMA.
- Hasegawa, Eietsu,Takizawa, Shinya,Seida, Takayuki,Yamaguchi, Akira,Yamaguchi, Naoto,Chiba, Naoki,Takahashi, Tomoya,Ikeda, Hiroshi,Akiyama, Kimio
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p. 6581 - 6588
(2007/10/03)
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- Abnormal orientation in nitration of anthracene, pyrene, and perylene with pyridinium nitrate. 2-Nitroanthracene and 4-nitropyrene
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Nitration by undissociated nitric acid which presumably forms at thermolysis (115°C) of pyridinium nitrate in pyridine selectively proceeds with respect to aromatic substrates and nonselectively with respect to various positions in aromatic rings. Whereas in electrophilic nitration forms a single isomer of mononitro products, the process under study yields two mononitro isomers, and nitration occurs only with polycyclic hydrocarbons containing a butadiene fragment included into neighboring rings (anthracene, naphthacene, pyrene, and perylene). On the contrary, benzene and its derivatives, naphthalene, phenanthrene, and triphenylene are not nitrated. Beside pyridinium nitrate as nitrating agents giving two isomeric mononitro arenes from polycyclic compounds are used tetranitromethane in pyridine and ammonium nitrate in a mixture pyridine-acetic anhydride. The side products of the reaction are biaryls, quinones (in particular, with unusually located carbonyl groups), and dyes containing aci-nitro and oxo groups.
- Nefedov
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p. 1165 - 1171
(2007/10/03)
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- DERIVATIVES OF 1,4,5,8-NAPHTHALENETETRACARBOXYLIC ACID. IV. SOME RELATIONSHIPS GOVERNING THE OXIDATION OF 1,6- AND 1,8-PYRENEQUINONES BY ALKALI-METAL HYPOCHLORITES
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The oxidation of 1,6- and 1,8-pyrenequinones by alkali-metal hypochlorites to 1,4,5,8-naphthalenetetracarboxylic acid is preceded by the entry of not less than two hydroxyl groups into the molecule of the quinones. 1,3,6-Pyrenetrione is oxidized by hypochlorites with transfer of the reaction center to position 2.The 1,6- and 1,8-pyrenequinones and their monohalogen and 3-methoxy-substituted derivatives are converted into 1,4,5,8-naphthalenetetracarboxylic acid with yields of 50percent, but the corresponding quinones disubstituted at positions 3 and 8 do not react under these conditions.Quantum-chemical calculations of the electronic strucutre by the Hueckel method were used in the interpretation of the results.
- Shigalevskii, V. A.,Chesnovskii, V. S.,Filippov, M. P.,Solomatin, G. G.
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p. 1373 - 1379
(2007/10/02)
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- IODOXYBENZENE A REMARKABLY CLOSE OZONE EQUIVALENT
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Iodoxybenzene is isoelectronic to ozone and several of its reactions proceed via pathways remarkably similar to that of ozone.An attractive feature of iodoxybenzene mediated reactions is the direct formation of products and the transformation of the reagent to iodobenzene.The formation of benzil and iodobenzene in good yields from diphenylacetylene provides support for the anticipated intermediate arising from ?4s+?2s addition.Iodoxybenzene transforms phenanthrene to phenanthrenequinone as a result of the initially formed 4+2 adduct undergoing C-H rupture, in preference to the C-C rupture.This change is parallel to the transformation of phenanthrene 9-carboxylic acid to phenanthrenequinone with ozone.The expected C-C rupture of the initially formed adduct does take place with acenaphthylene leading to naphthalic anhydride.The reaction of pyrene with iodoxybenzene leads to nearly equal amounts of the 4-5, 1-6 and 3-6 quinones involving attack on the bond of the lowest bond localisation energy and the atom of the lowest atom localization energy.This behaviour is similar to the action of ozone on benzopyrene.Iodoxybenzene transforms anthracene, just like ozone, to anthraquinone, in good yields.The involvement of transannular addition of iodoxybenzene, as is partly the case with ozone, is proved unlikely by reaction with 9, 10 dimethylanthracene which gave 10-methyl 9-anthraldehyde and 10-carboxy 9-anthraldehyde, involving the insertion of elements of iodoxybenzene to the aryl C-H bond.This tendency of iodoxybenzene has been further demonstrated by the following changes: diphenylmethane-->benzophenone; fluorene-->fluorenone and tetralin-->α-tetralone.Several of the transformations brought about with iodoxybenzene provide attractive synthetic routes, particularly to phenanthrenequinone, pyrenequinones and tetralone.Finally, just like the 2O3 --> 3O2 change, iodoxybenzene, and even more so, 4-iodoxybiphenyl, thermally fragment to iodobenzene and 4-iodobiphenyl.
- Ranganathan, S.,Ranganathan, D.,Ramachandran, P. V.
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p. 3145 - 3152
(2007/10/02)
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