- Selective Formation of 4,4′-Biphenols by Anodic Dehydrogenative Cross- and Homo-Coupling Reaction
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A simple and selective electrochemical synthesis by dehydrogenative coupling of unprotected 2,6- or 2,5-substituted phenols to the desired 4,4′-biphenols is reported. Using electricity as the oxidizing reagent avoids pre-functionalization of the starting materials, since a selective activation of the substrates takes place. Without the necessity for metal-catalysts or the use of stoichiometric reagents it is an economic and environmentally friendly transformation. The elaborated electrochemical protocol leads to a broad variety of the desired 4,4′-biphenols in a very simplified manner compared to classical approaches. This is particular the case for the cross-coupled products.
- Dahms, Benedikt,Kohlpaintner, Philipp J.,Wiebe, Anton,Breinbauer, Rolf,Schollmeyer, Dieter,Waldvogel, Siegfried R.
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supporting information
p. 2713 - 2716
(2019/02/05)
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- THE USE OF DIPHENOL IN PREPARATION OF MEDICINES FOR PREVENTION AND TREATMENT OF CEREBRAL ISCHEMIA
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The present invention relates to use of biphenols in the preparation of a medicament for the prevention and treatment of ischemic stroke, specifically to use of 3,3′,5,5′-tetraisopropyl-4,4′-biphenol and salt, ester, or solvate thereof in the preparation of a medicament for the prevention and treatment of ischemic stroke injury.
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- A dual-functional heterogeneous ruthenium catalyst for the green one-pot synthesis of biphenols
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A green one-pot synthesis of biphenols using O2 and H2 was achieved using a magadiite-supported Ru nanoparticle catalyst. This catalyst selectively promoted the oxidative coupling of phenols to diphenoquinones with O2, followed by the successive reduction of these diphenoquinones to biphenols using H2 in a single reactor.
- Maeno, Zen,Mitsudome, Takato,Mizugaki, Tomoo,Jitsukawa, Koichiro
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p. 3205 - 3209
(2017/08/16)
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- Selective oxidative homo-and cross-coupling of phenols with aerobic catalysts
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Simple catalysts that use atom-economical oxygen as the terminal oxidant to accomplish selective ortho-ortho, ortho-para, or para-para homo-couplings of phenols are described. In addition, chromium salen catalysts have been discovered as uniquely effective in the cross-coupling of different phenols with high chemo-and regioselectivity.
- Lee, Young Eun,Cao, Trung,Torruellas, Carilyn,Kozlowski, Marisa C.
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supporting information
p. 6782 - 6785
(2014/06/09)
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- Commercial manufacturing of propofol: Simplifying the isolation process and control on related substances
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A commercially viable manufacturing process for propofol (1) is described. The process avoids acid-base neutralization events during isolation of intermediate, 2,6-di-isopropylbenzoic acid (3) and crude propofol, and thus simplifies the synthesis on industrial scale to a considerable extent. Syntheses of five impurities/related substances (USP and EP) are also described.
- Pramanik, Chinmoy,Kotharkar, Sandeep,Patil, Pradip,Gotrane, Dinkar,More, Yogesh,Borhade, Ajit,Chaugule, Balaji,Khaladkar, Tushar,Neelakandan,Chaudhari, Ashok,Kulkarni, Mukund G.,Tripathy, Narendra K.,Gurjar, Mukund K.
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supporting information
p. 152 - 156
(2014/05/20)
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- Carbonic anhydrase inhibitors. Inhibition of human erythrocyte isozymes I and II with a series of antioxidant phenols
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The inhibition of two human cytosolic carbonic anhydrase (hCA, EC 4.2.1.1) isozymes I and II, with a series of phenol derivatives was investigated by using the esterase assay, with 4-nitrophenyl acetate as substrate. 2,6-Dimethylphenol, 2,6-diisopropylphenol (propofol), 2,6-di-t-butylphenol, butylated hydroxytoluene, butylated hydroxyanisole, vanillin, guaiacol, di(2,6-dimethylphenol), di(2,6-diisopropylphenol), di(2,6-di-t-butylphenol), and acetazolamide showed KI values in the range of 37.5-274.5 μM for hCA I and of 0.29-113.5 μM against hCA II, respectively. All these phenols were non-competitive inhibitors with 4-nitrophenylacetate as substrate. Some antioxidant phenol derivatives investigated here showed effective hCA II inhibitory effects, in the same range as the clinically used sulfonamide acetazolamide, and might be used as leads for generating enzyme inhibitors possibly targeting other CA isoforms which have not been yet assayed for their interactions with such agents.
- Sentuerk, Murat,Guelcin, Ilhami,Dastan, Arif,Irfan Kuefrevioglu, Oe.,Supuran, Claudiu T.
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experimental part
p. 3207 - 3211
(2009/09/08)
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- Solubilization of dipropofol, an antibacterial agent, using saccharide and ascorbic acid
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Dipropofol has a strong antibacterial activity against Gram-positive bacteria. However, it lacked the solubility in water and this property was supposed to limit its efficacy. We tried to improve the solubility and found a new solubilization method of dipropofol in water by the addition of a monosaccharide or ascorbic acid.
- Ogata, Masahiro,Oka,Seki, Masako,Hoshi, Midori,Takatsu, Hirokatsu,Mashino, Tadahiko,Urano, Shiro,Endo, Toyoshige
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p. 1565 - 1568
(2008/03/12)
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- Antioxidant activity of propofol and related monomeric and dimeric compounds
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This study was carried out to investigate the antioxidant activity of propofol (2,6-diisopropylphenol) and its related compounds, butylated hydroxyanisole (BHA), 2,6-dimethylphenol, 2,6-di-t-butylphenol, and their dimeric compounds. The degree of antioxidant activity was evaluated based on the degree of peroxidation induced with Fe-ascorbic acid in egg phosphatidylcholine through the determination of thiobarbituric acid-reactive substances (TBARS) formed during peroxidation. Their antioxidant activities were in the order of dipropofol>di(2,6-di-t-butylphenol)>diBHA>di(2,6-dimethylphenol). Dipropofol, a dimeric compound of propofol, showed the highest antioxidant activities. Dimeric compounds had higher activities than monomeric compounds, and the 1,1-diphenyl-p-picryhydrazyl-trapping ability of dimeric compounds was also greater than those of monomeric compounds (4-10-fold). These results suggest that dimeric phenols may increase their antioxidant activities along with increments in the conjugation system and play a inhibitory role in the propagation of free radical chain reactions.
- Ogata, Masahiro,Shin-Ya, Kazuo,Urano, Shiro,Endo, Toyoshige
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p. 344 - 346
(2007/10/03)
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- Antibacterial activity of dipropofol and related compounds
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Phenolic compounds, in general, exhibit antioxidant and antibacterial activities. We studied antimicrobial activity of the phenolic antioxidants, propofol (2,6-diisopropylphenol), tocopherol, eugenol, butylated hydroxyanisole (BHA), and several of their dimer compounds. Dipropofol (dimer of 2,6-diisopropylphenol) showed strong antibacterial activity against gram-positive strains including methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococci (VRE), while propofol and other monomeric and dimeric phenols having methyl or tert-butyl groups showed no remarkable activity. The results indicated that the dimeric structure of 2,6-diisopropylphenol moiety may play an important role in the antibacterial activity.
- Ogata, Masahiro,Sato, Kanae Tutumimoto,Kunikane, Takao,Oka, Kentaro,Seki, Masako,Urano, Shiro,Hiramatsu, Keiichi,Endo, Toyoshige
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p. 1120 - 1122
(2007/10/03)
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- Novel photochemical coupling of hindered phenols in the presence of acridine mechanistically probed by CIDEP
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Irradiation of hindered phenols in the presence of acridine as a light absorber gives bisphenols and biacridane.CIDEP study establishes the path of hydrogen abstraction by the triplet acridine.The overall mechanism is proposed by the product analysis and the CIDEP studies.
- Okada, Keiji,Okubo, Katsura,Oda, Masaji,Murai, Hisano
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p. 845 - 846
(2007/10/03)
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- Choice of Manganese(III) Complexes for the Synthesis of 4,4'-Biphenyldiols and 4,4'-Diphenoquinones
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2,6-Disubstituted phenols are oxidized with tris(2,4-pentanedionato)manganese(III), , in glacial acetic acid to give the corresponding 4,4'-biphenyldiols in high yields, whereas similar reactions using manganase(III) acetate, , instead of quantitatively yield the corresponding 4,4'-diphenoquinones.Cross-coupling reactions of 2,6-di-t-butylphenol and other substituted phenols afford the corresponding cross-coupled 4,4'-biphenyldiols and 4,4'-diphenoquinones together with oxidation products derived from them starting phenols themselves.The advantageous use of and Mn(OAc)3> in the ubiqitous phenol coupling reaction is discussed.
- Nishino, Hiroshi,Nobuyuki, Itoh,Nagashima, Makiko,Kurosawa, Kazu
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p. 620 - 622
(2007/10/02)
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- Mushroom tyrosinase catalysed coupling of hindered phenols: A novel approach for the synthesis of diphenoquinones and bisphenols
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An efficient oxidative carbon-carbon coupling of hindered phenols leading to diphenoquinones and bisphenols by mushroom tyrosinase is reported.
- Pandey,Muralikrishna,Bhalerao
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p. 3771 - 3774
(2007/10/02)
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