- Toluene dioxygenase-catalyzed synthesis and reactions of cis -diol metabolites derived from 2- and 3-methoxyphenols
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Using toluene dioxygenase as biocatalyst, enantiopure cis-dihydrodiol and cis-tetrahydrodiol metabolites, isolated as their ketone tautomers, were obtained from meta and ortho methoxyphenols. Although these isomeric phenol substrates are structurally similar, the major bioproducts from each of these biotransformations were found at different oxidation levels. The relatively stable cyclohexenone cis-diol metabolite from meta methoxyphenol was isolated, while the corresponding metabolite from ortho methoxyphenol was rapidly bioreduced to a cyclohexanone cis-diol. The chemistry of the 3-methoxycyclohexenone cis-diol product was investigated and elimination, aromatization, hydrogenation, regioselective O-exchange, Stork-Danheiser transposition and O-methylation reactions were observed. An offshoot of this technology provided a two-step chemoenzymatic synthesis, from meta methoxyphenol, of a recently reported chiral fungal metabolite; this synthesis also established the previously unassigned absolute configuration.
- Boyd, Derek R.,Sharma, Narain D.,Malone, John F.,McIntyre, Peter B. A.,McRoberts, Colin,Floyd, Stewart,Allen, Christopher C. R.,Gohil, Amit,Coles, Simon J.,Horton, Peter N.,Stevenson, Paul J.
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- Tripodal O-N-O Bis-Phenolato Amine Titanium(IV) Complexes Show High in vitro Anti-Cancer Activity
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The octahedral titanium(IV) complexes trans,mer-[Ti{R3N(CH2C6H2-2-O-4-R2-6-R1)2}2] (R1 = Me, OMe, Cl; R2 = Me, OMe, F, Cl; R3 = Me, Et; not all combinations) are synthesised in two steps from simple phenols in 36–53 % overall yield. The highly crystalline (4 X-ray structures) complexes are active against MCF-7 (breast) and HCT-116 (colon) cancer cell lines showing widely varying GI50 values in the range 1–100 μM depending on R1–R3. Highest activities are realised when R1 = OMe and R2, R3 = Me (GI50 ca. 1 μM for MCF-7 and 2–3 μM for HCT-116). These are respectively 8× and 3× times greater than the activities of cisplatin in the same cell lines. These titanium complexes show some significant selectivity for cancer cell lines; up to 7× higher in MCF-7 compared to non-cancer (MRC-5) fibroblast cells. Details of cellular mode of action indicators (cell cycle perturbation, Annexin V, γ-H2AX, and caspase studies) that point to an apoptosis mode for the most active compound (R1 = OMe and R2, R3 = Me) are also reported.||||||.
- Abid, Mohammed,Nouch, Ryan,Bradshaw, Tracey D.,Lewis, William,Woodward, Simon
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Read Online
- Anodic coupling of guaiacol derivatives on boron-doped diamond electrodes
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The anodic treatment of guaiacol derivatives on boron-doped diamond electrodes (BDD) provides a direct access to nonsymmetrical biphenols, which would require a multistep sequence by conventional methods. Despite the destructive nature of BDD anodes they
- Kirste, Axel,Schnakenburg, Gregor,Waldvogel, Siegfried R.
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Read Online
- Galactose oxidase models: Solution chemistry, and phenoxyl radical generation mediated by the copper status
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Galactose oxidase (GO) is an enzyme that catalyzes two-electron oxidations. Its active site contains a copper atom coordinated to a tyrosyl radical, the biogenesis of which requires copper and dioxygen. We have recently studied the properties of electrochemically generated mononuclear CuII-phenoxyl radical systems as model compounds of GO. We present here the solution chemistry of these ligands under various copper and dioxygen statuses: N3O ligands first chelate CuII, leading, in the presence of base, to [CuII(ligand)(CH3CN)]+ complexes (ortho-tert-butylated ligands) or [(CuII)2(ligand) 2]2+ complexes (orthomethoxylated ligands). Excess copper-(II) then oxidizes the complex to the corresponding mononuclear Cu II-phenoxyl radical species. N2O2 tripodal ligands. in the presence of copper(II), afford directly a copper(II)-phenoxyl radical species. Addition of more than two molar equivalents of copper( II) affords a CuII-bis(phenoxyl) diradical species. The donor set of the ligand directs the reaction towards comproportionation for ligands possessing an N3O donor set, while disproportionation is observed for ligands possessing an N2O2 donor set. These results are discussed in the light of recent results concerning the self-processing of GO. A path involving copper(II) disproportionation is proposed for oxidation of the crosslinked tyrosinate of GO, supporting the fact that both copper(I) and copper(II) activate the enzyme.
- Michel, Fabien,Thomas, Fabrice,Hamman, Sylvain,Saint-Aman, Eric,Bucher, Christophe,Pierre, Jean-Louis
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- Selective monoalkylation of hydroquinone in the presence of SO3H-functionalized ionic liquids as catalysts
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A process aiming at O-alkylation of hydroquinone (HQ), where ionic liquids (ILs) act as catalyst is objectively described. Five SO3H-functionalized ILs having different cations were prepared and characterized by NMR and FTIR techniques. The acidity and thermal stability of ILs were determined by Hammett function and thermogravimetric analysis (TGA), respectively. The catalytic activity of these ILs were tested for O-alkylation of HQ with methanol in 4-methoxyphenol (4MP) in the presence of small amount of benzoquinone (BQ). The effect of reaction parameters such as temperature, time, catalyst loading and substrate concentration on the conversion of HQ and product distribution was examined and optimized to maximize the yield of 4MP using 1,3-disulfonic acid imidazolium hydrogen sulfate (IL2) catalyst. Maximum yield of desired product 4MP 93.79percent was obtained at 338?K temperature, 5.45 × 10–2?mol HQ, 8.33 × 10–3?mol BQ, and 10.37?molpercent catalyst loading in 120?min reaction time. Single-product formation was observed up to 338?K temperature but higher temperature (above 338?K) and longer reaction time resulted in the formation of 2,4-dimethoxyphenol (24DMP) as a by-product. Catalyst recyclability was also established up to the fifth run which showed no declination in its activity.
- Bhongale, Priyanka V.,Joshi, Sunil S.,Mali, Nilesh A.
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Read Online
- Reusable and Efficient Polystyrene Immobilized Ionic Liquid Catalyst for Batch and Flow Methylation of Hydroquinone
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An environmentally benign process for synthesizing 4-methoxyphenol through methylation of hydroquinone using polystyrene immobilized Bronsted acidic ionic liquid is presented. The catalyst has been characterized by several techniques, such as solid-state NMR, FTIR, and XRD. The morphological properties were analyzed through SEM and TEM analysis. The elemental analysis was performed using EDS and XPS techniques. The catalyst was thermally stable up to 603?K, which was confirmed by TGA. The chemical interaction between ionic liquid and polystyrene was confirmed by measuring the glass transition temperature of pure polystyrene and catalyst. The BET analysis was performed to estimate the catalyst’s surface area, pore size, and pore volume. The recyclability of the proposed new catalyst was established up to five recycle runs in the batch mode. In addition, continuous flow experiments were conducted to test the catalytic activity in terms of catalyst life span and showed excellent stability up to 20?h. The rapid separation, long-term stability, and efficient recycling of synthesized polymeric catalysts make an excellent alternative to the commonly used homogeneous catalysts for selective O-methylation of hydroquinone reaction. The newly developed continuous process for synthesizing 4-methoxyphenol with 100% selectivity suggests good opportunities to reduce energy consumption, which designates a cost-effective process. Graphical Abstract: [Figure not available: see fulltext.]
- Bhongale, Priyanka V.,Joshi, Sunil S.,Mali, Nilesh A.
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- Synthetic method 4 - alkoxyphenol compounds
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The invention discloses a synthetic method of 4 - alkoxyphenol compounds, and belongs to the field of organic chemical synthesis. The method is as follows: An aryl alkyl ether compound is added to the sealing tube. The catalyst dimerization acetic acid rhodium and the oxidizing agent iodobenzene diethyl ester are added, a solvent trifluoroacetic anhydride is added, and the 4 -alkoxyphenol compound is prepared by heating reaction. To the invention, high regioselectivity direct hydroxylation of the aryl alkyl ether compound is realized, the application range of the substrate is wide, the yield is high, the activity after amplification reaction does not significantly decay, and higher yield is still obtained. The utility model has good practicability and industrial application prospect.
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Paragraph 0082-0084
(2021/09/29)
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- Para -Selective hydroxylation of alkyl aryl ethers
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para-Selective hydroxylation of alkyl aryl ethers is established, which proceeds with a ruthenium(ii) catalyst, hypervalent iodine(iii) and trifluoroacetic anhydride via a radical mechanism. This protocol tolerates a wide scope of substrates and provides a facile and efficient method for preparing clinical drugs monobenzone and pramocaine on a gram scale.
- Zhu, Runqing,Sun, Qianqian,Li, Jing,Li, Luohao,Gao, Qinghe,Wang, Yakun,Fang, Lizhen
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supporting information
p. 13190 - 13193
(2021/12/16)
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- Synthesis, antiepileptic effects, and structure-activity relationships of α-asarone derivatives: In vitro and in vivo neuroprotective effect of selected derivatives
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In the present study, we compared the antiepileptic effects of α-asarone derivatives to explore their structure-activity relationships using the PTZ-induced seizure model. Our research revealed that electron-donating methoxy groups in the 3,4,5-position on phenyl ring increased antiepileptic potency but the placement of other groups at different positions decreased activity. Besides, in allyl moiety, the optimal activity was reached with either an allyl or a 1-butenyl group in conjugation with the benzene ring. The compounds 5 and 19 exerted better neuroprotective effects against epilepsy in vitro (cell) and in vivo (mouse) models. This study provides valuable data for further exploration and application of these compounds as potential anti-seizure medicines.
- Zhang, Jian,Mu, Keman,Yang, Peng,Feng, Xinqian,Zhang, Di,Fan, Xiangyu,Wang, Qiantao,Mao, Shengjun
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- Bimetallic photoredox catalysis: Visible light-promoted aerobic hydroxylation of arylboronic acids with a dirhodium(ii) catalyst
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We report the use of a rhodium(II) dimer in visible light photoredox catalysis for the aerobic oxidation of arylboronic acids to phenols under mild conditions. Spectroscopic and computational studies indicate that the catalyst Rh2(bpy)2(OAc)4 (1) undergoes metal-metal to ligand charge transfer upon visible light irradiation, which is responsible for catalytic activity. Further reactivity studies demonstrate that 1 is a general photoredox catalyst for diverse oxidation reactions.
- Campbell, Michael G.,Chuang, Gary Jing,Liu, Ming-Lun,Miura-Stempel, Emily,Tu, Jing-Wen,Yang, Hsiang-Ming
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p. 2040 - 2047
(2020/03/13)
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- Oxidation of Electron-Rich Arenes Using HFIP-UHP System
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The straightforward oxidation of electron-rich arenes, namely, phenols, naphthols, and anisole derivatives, under mild reaction conditions, is described by means of the use of an environmentally benign HFIP-UHP system. The corresponding quinones or hydroxylated arenes were obtained in moderate to good yields.
- Llopis, Natalia,Baeza, Alejandro
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p. 6159 - 6164
(2020/05/20)
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- Tuning the Reactivity of Peroxo Anhydrides for Aromatic C-H Bond Oxidation
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Phenol moieties are key structural motifs in many areas of chemical research from polymers to pharmaceuticals. Herein, we report on the design and use of a structurally demanding cyclic peroxide (spiro[bicyclo[2.2.1]heptane-2,4′-[1,2]dioxolane]-3′,5′-dione, P4) for the direct hydroxylation of aromatic substrates. The new peroxide benefits from high thermal stability and can be synthesized from readily available starting materials. The aromatic C-H oxidation using P4 exhibits generally good yields (up to 96%) and appreciable regioselectivities.
- Pilevar, Afsaneh,Hosseini, Abolfazl,?ekutor, Marina,Hausmann, Heike,Becker, Jonathan,Turke, Kevin,Schreiner, Peter R.
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p. 10070 - 10079
(2018/09/06)
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- METHOD FOR SYNTHESIZING PHENOL USING METAL CATALYST
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The present invention relates to a method for synthesizing phenol using a metal catalyst and, more specifically, to a method for preparing phenol, which is a product of cross-coupling reaction by performing reaction of aryl halide and 2-dimethylaminoethanol in the presence of a metal catalyst. According to the present invention, phenol, as a product of cross-coupling reaction by performing reaction of aryl halide and 2-dimethylaminoethanol in the presence of a metal catalyst, can be synthesized with high yield. Also, various phenols having substituents can be synthesized.COPYRIGHT KIPO 2017
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Paragraph 0058; 0060
(2017/10/26)
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- Reaction of 1,2-difunctionalized ethanes with aryl iodides in copper-catalyzed cross-coupling: Application to synthesis of phenols
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A series of 1,2-difunctionalized ethanes, such as ethylene glycol, 2-aminoethanol, 1,2-diaminoethane, 2-dimethylaminoethanol N',N'-dimethylethane-1,2-diamine, were investigated to test the reactivity with aryl iodides in the presence of copper catalysts. Under the reaction conditions, they produce the various Cheteroatom cross-coupled products. Interestingly, ethylene glycol and 2-dimethylaminoethanol afforded mainly the phenolic compounds while the others produced different cross-coupled products. Although ethylene glycol and 2-dimethylaminoethanol resulted in the same product, their behaviors in the reaction were quite different: ethylene glycol appears to mostly act as the ligand and 2-dimethylaminoethanol appears to serve as both the ligand and reactant. This finding led to a copper-catalyzed synthesis of phenols using either ethylene glycol or 2-dimethylaminoethanol, which can be applied to a variety of aryl iodides, providing an alternative synthetic route to phenols.
- Kim, Jihye,Battsengel, Oyunsaikhan,Liu, Yajun,Chae, Junghyun
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supporting information
p. 2833 - 2840
(2016/02/05)
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- Ortho-and para-selective ruthenium-catalyzed C(sp2)-H oxygenations of phenol derivatives
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Versatile ruthenium catalysts allowed for efficient direct oxygenations of aryl carbamates under remarkably mild reaction conditions. In addition to chelation-assisted C-H activation, the optimized ruthenium catalyst proved amenable to para-selective hydroxylations of anisoles without Lewis basic directing groups.
- Liu, Weiping,Ackermann, Lutz
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supporting information
p. 3484 - 3486
(2013/07/26)
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- Pyranoxanthones: Synthesis, growth inhibitory activity on human tumor cell lines and determination of their lipophilicity in two membrane models
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The benzopyran and dihydrobenzopyran moieties can be considered as "privileged motifs" in drug discovery being good platforms for the search of new bioactive compounds. These moieties are commonly found fused to the xanthonic scaffold belonging to the bio
- Azevedo, Carlos M.G.,Afonso, Carlos M.M.,Soares, José X.,Reis, Salette,Sousa, Diana,Lima, Raquel T.,Vasconcelos, M. Helena,Pedro, Madalena,Barbosa, Jo?o,Gales, Luís,Pinto, Madalena M.M.
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p. 798 - 816
(2013/10/22)
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- Synthetic models related to methoxalen - CYP2A6 interactions. Dimethoxybenzofuran derivatives as potent and selective inhibitors of cyp2a6
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The human CYP2A6 enzyme metabolizes several xenobiotics including nicotine, the addictive component in tobacco. Reduced activity of CYP2A6, either for genetic reasons or by administering inhibitors of CYP2A6, reduces tobacco smoking. The reported compound
- Yamaguchi, Yuki,Akimoto, Ichie,Motegi, Kyoko,Yoshimura, Teruki,Wada, Keiji,Nishizono, Naozumi,Oda, Kazuaki
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p. 1727 - 1739
(2013/09/12)
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- Chemo- and regioselective direct hydroxylation of arenes with hydrogen peroxide catalyzed by a divanadium-substituted phosphotungstate
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Peroxide in, phenol out: The catalyst [-PW10O38V 2(μ-OH)2]3- showed high activity in the hydroxylation of various aromatic compounds with aqueous H2O 2. The system was regioselective, producing para-phenols from monosubstituted benzene derivatives. Furthermore, alkylarenes with reactive side-chain Ca spa 3-H bonds could be chemoselectively hydroxylated without significant formation of side-chain oxygenated products. Copyright
- Kamata, Keigo,Yamaura, Taiyo,Mizuno, Noritaka
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supporting information; experimental part
p. 7275 - 7278
(2012/08/28)
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- Organocatalytic Dakin oxidation by nucleophilic flavin catalysts
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Flavin catalysts perform the first organocatalytic Dakin oxidation of electron-rich arylaldehydes to phenols under mild, basic conditions. Catechols are readily prepared, and the oxidation of 2-hydroxyacetophenone was achieved. Aerobic oxidation is displayed in the presence of Zn(0) as a reducing agent. This reactivity broadens the scope of biomimetic flavin catalysis in the realm of nucleophilic oxidations, providing a framework for mechanistic investigations for related oxidations, such as the Baeyer-Villiger oxidation and Weitz-Scheffer epoxidation.
- Chen, Shuai,Hossain, Mohammad S.,Foss, Frank W.
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supporting information; experimental part
p. 2806 - 2809
(2012/08/07)
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- Efficient anodic and direct phenol-arene C,C cross-coupling: The benign role of water or methanol
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C,C cross-coupling reactions for the synthesis of nonsymmetrical biaryls represent one of the most significant transformations in contemporary organic chemistry. A variety of useful synthetic methods have been developed in recent decades, since nonsymmetrical biaryls play an evident role in natural product synthesis, as ligand systems in homogeneous catalysis and materials science. Transformation of simple arenes by direct C,H activation belongs to the cutting-edge strategies for creating biaryls; in particular the 2-fold C,H activation is of significant interest. However, in most examples very costly noble metal catalysts, ligand systems, and significant amount of waste-producing oxidants are required. Electrochemical procedures are considered as inherently "green" methods, because only electrons are required and therefore, no reagent waste is produced. Here, we report a metal-free electrochemical method for cross-coupling between phenols and arenes using boron-doped diamond (BDD) anodes in fluorinated media. Our sustainable approach requires no leaving functionalities. Employing water or methanol as mediator represents the key improvement for achieving nonsymmetrical biaryls with superb selectivity and synthetic attractive yields.
- Kirste, Axel,Elsler, Bernd,Schnakenburg, Gregor,Waldvogel, Siegfried R.
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supporting information; experimental part
p. 3571 - 3576
(2012/04/10)
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- Oxidation of organotrifluoroborates via oxone
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A method for the oxidation of organotrifluoroborates using Oxone was developed. A variety of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates were converted into the corresponding oxidized products in excellent yields. This method proved to be tolerant of a broad range of functional groups, and in secondary alkyl substrates it was demonstrated to be completely stereospecific.
- Molander, Gary A.,Cavalcanti, Livia N.
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experimental part
p. 623 - 630
(2011/03/20)
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- Anti-inflammatory and antimalarial meroterpenoids from the New Zealand ascidian aplidium scabellum
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Bioassay-directed fractionation of an extract of the New Zealand ascidian Aplidium scabellum has afforded the anti-inflammatory secondary metabolite 2-geranyl-6-methoxy-1,4-hydroquinone-4-sulfate (1) and a family of pseudodimeric meroterpenoids scabellone
- Chan, Susanna T. S.,Pearce, A. Norrie,Januario, Ana H.,Page, Michael J.,Kaiser, Marcel,McLaughlin, Rene J.,Harper, Jacquie L.,Webb, Victoria L.,Barker, David,Copp, Brent R.
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body text
p. 9151 - 9156
(2011/12/16)
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- PRODRUGS OF OXAZOLIDINONE CETP INHIBITORS
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The compounds of Formula I are prodrugs of CETP inhibitors having a central oxazolidinone ring. The compounds cyclize by the elimination of HX to form an oxazolidinone ring after administration to a patient.
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Page/Page column 9
(2010/04/27)
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- A new method for halogenation of aromatic compounds by using dimethyldioxirane and tetrabutylammonium halides
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In this presentation the novel regioselective halogenation of arenes or phenols with dimethyldioxirane and Bu4NX is described. The results showed that a new, versatile and mild method can be utilized for preparation of aryl halides starting with arenes or phenols. Finally, this aryl halide forming methodology is applicable to structurally more complex flavonoids.
- Lee, Yean-Jang,Wu, Huan-Ting,Lin, Chia-Ning
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scheme or table
p. 585 - 587
(2010/04/23)
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- Towards an asymmetric synthesis of the bacterial peptide deformylase (PDF) inhibitor fumimycin
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Studies towards the synthesis of the bacterial peptide deformylase (PDF) inhibitor fumimycin are reported. The synthetic approach features an organocatalytic access to the α,α-disubstituted amino acid unit and results in the synthesis of an advanced inter
- Hartmann, Caroline E.,Gross, Patrick J.,Nieger, Martin,Braese, Stefan
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supporting information; experimental part
p. 5059 - 5062
(2010/04/04)
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- Reaction of phenols with the 2,2-diphenyl-1-picrylhydrazyl radical. Kinetics and DFT calculations applied to determine ArO-H bond dissociation enthalpies and reaction mechanism
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(Figure Presented) The formal H-atom abstraction by the 2,2-diphenyl-1-picrylhydrazyl (dpph?) radical from 27 phenols and two unsaturated hydrocarbons has been investigated by a combination of kinetic measurements in apolar solvents and density functional theory (DFT). The computed minimum energy structure of dpph? shows that the access to its divalent N is strongly hindered by an ortho H atom on each of the phenyl rings and by the o-NO2 groups of the picryl ring. Remarkably small Arrhenius pre-exponential factors for the phenols [range (1.3-19) × 105 M-1 s-1] are attributed to steric effects. Indeed, the entropy barrier accounts for up to ca. 70% of the free-energy barrier to reaction. Nevertheless, rate differences for different phenols are largely due to differences in the activation energy, Ea,1 (range 2 to 10 kcal/mol). In phenols, electronic effects of the substituents and intramolecular H-bonds have a large influence on the activation energies and on the ArO-H BDEs. There is a linear Evans-Polanyi relationship between E a,1 and the ArO-H BDEs: Ea,1/kcal x mol-1 = 0.918 BDE(ArO-H)/kcal x mol-1 - 70.273. The proportionality constant, 0.918, is large and implies a "late" or "product-like" transition state (TS), a conclusion that is congruent with the small deuterium kinetic isotope effects (range 1.3-3.3). This Evans-Polanyi relationship, though questionable on theoretical grounds, has profitably been used to estimate several ArO-H BDEs. Experimental ArO-H BDEs are generally in good agreement with the DFT calculations. Significant deviations between experimental and DFT calculated ArO-H BDEs were found, however, when an intramolecular H-bond to the O? center was present in the phenoxyl radical, e.g., in ortho semiquinone radicals. In these cases, the coupled cluster with single and double excitations correlated wave function technique with complete basis set extrapolation gave excellent results. The TSs for the reactions of dpph ? with phenol, 3- and 4-methoxyphenol, and 1,4-cyclohexadiene were also computed. Surprisingly, these TS structures for the phenols show that the reactions cannot be described as occurring exclusively by either a HAT or a PCET mechanism, while with 1,4-cyclohexadiene the PCET character in the reaction coordinate is much better defined and shows a strong π-π stacking interaction between the incipient cyclohexadienyl radical and a phenyl ring of the dpph? radical.
- Foti, Mario C.,Daquino, Carmelo,Mackie, Iain D.,DiLabio, Gino A.,Ingold
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experimental part
p. 9270 - 9282
(2009/04/07)
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- Selective Synthesis of the para-Quinone Region of Geldanamycin
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(Matrix presented) The quinone portion of the ansamycin geldanamycin was made with complete selectivity from the 1,4-dihydroquinone generated from a 1,4-bis-methoxymethyl (MOM) ether intermediate. Palladium catalysis with air gave the desired product in 9
- Andrus, Merritt B.,Hicken, Erik J.,Meredith, Erik L.,Simmons, Bryon L.,Cannon, John F.
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p. 3859 - 3862
(2007/10/03)
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- Syntheses of isochromane analogues of the michellamines and korupensamines
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Syntheses of the oxygen analogues 6, 7 and 8 of the michellamines 1 and korupensamines 2 are described. Racemic 5-iodo-6,8-dimethoxy-trans-1,3-dimethylisochromane 10 was synthesised in eleven steps from 2,4-dimethoxybenzaldehyde in an overall yield of 51%
- De Koning, Charles B.,Michael, Joseph P.,Van Otterlo, Willem A.L.
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p. 799 - 811
(2007/10/03)
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- Polyphenolic glycosides from african proteaceae
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The phytochemical investigation of members of the genus Protea afforded a series of polyphenolic compounds (1-5) that were identified by 1D and 2D NMR experiments. Of these, 2-5 are new compounds. Chemical syntheses of 1-3 were performed in order to confirm the structures and to prepare additional material for biological evaluation.
- Verotta,Orsini,Pelizzoni,Torri,Rogers
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p. 1526 - 1531
(2007/10/03)
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- Synthesis of an isochroman analogue of the michellamines
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The synthesis of racemic 5-iodo-6,8-dimethoxy-1,3-trans- dimethylisochroman (16) in eleven steps from 2,4-dimethoxybenzaldehyde is outlined. Compound (16) was coupled by means of Suzuki methodology with 4- isopropoxy-5-methoxy-7-methylnaphthaleneboronic a
- De Koning, Charles B.,Michael, Joseph P.,Van Otterlo, Willem A.L.
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p. 3037 - 3040
(2007/10/03)
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- Phenol compound having antioxidative activity and the process for preparing the same
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Disclosed are a phenol compound represented by the formula (1): STR1 wherein R0 represents H, alkyl or alkyloxy; R1 represents alkyl; R2 represents alkyl or alkyloxy; OR3 represents OH; R4 represents H, lower alkyl or acyl, each of the above substituents may be substituted; W represents O, S or NR7 ; where R7 represents H, alkyl, aryl, OH or alkyloxy, a group of the formula (2): STR2 represents an amino which may be mono- or di-substituted or heterocyclic group containing N atom, or a pharmaceutically acceptable salt thereof, and a process for preparing the same.
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- Method for the production of alkoxy- and aryloxy-phenols
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Alkoxybenzaldehydes and aryloxybenzaldehydes are converted to the corresponding phenols by reacting the benzaldehydes in an organic solvent phase with formic acid and hydrogen peroxide in an aqueous solvent phase to produce the corresponding formate ester. The formate ester is then saponified to produce the corresponding phenol.
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- Oxidation of Benzaldehydes Catalyzed by Methyltrioxorhenium with Hydrogen Peroxide
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Methyltrioxorhenium-catalyzed oxidation of benzaldehydes with hydrogen peroxide gives corresponding phenols in good yield.Benzaldehydes substituted with methoxy or hydroxyl groups at 2- and/or 4-position are good substrates for this reaction.
- Yamazaki, Shigekazu
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p. 127 - 128
(2007/10/02)
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- Preparation of methoxyphenols by oxidation of methoxybenzaldehydes with hydrogen peroxide in presence of p-toluenesulphonic acid
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Methoxyphenols have been prepared efficiently from the corresponding methoxybenzaldehydes by oxidation with hydrogen peroxide at room temperature in the presence of p-toluenesulphonic acid in methanol.
- Baruah, Robindra N.
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p. 1103 - 1104
(2007/10/02)
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- (Z)-2,2',4,4'-Tetramethoxystilbene-5,5'-diol and its Oxidation
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In an attempt to isolate a phenanthrene-4,5-quinone the title stilbenediol (24) was prepared by a Wittig reaction.Deisopropylation of a (Z)-diisopropyloxystilbene with boron trichloride resulted in isomerization to the (E) diol (15), but the required (Z)
- Hewgill, Frank R.
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p. 461 - 470
(2007/10/02)
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- Sodium perborate: A convenient reagent for benzylic hydroperoxide rearrangement
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Sodium perborate in boron trifluoride etherate has been found to be an effective reagent for the hydroperoxide rearrangement of electron rich and highly substituted benzylic tertiary alcohols to phenols in good yields.
- Kabalka,Reddy,Narayana
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p. 7667 - 7668
(2007/10/02)
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- Phenolic Constituents of Glycyrrhiza Species. Part 10. Glyasperin E, a New 3-Phenoxychromen-4-one Derivative from the Roots pf Glycyrrhiza aspera
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Glyasperin E 1, a new 3-phenoxychromen-4-one derivative, has been isolated from the roots of Glycyrrhiza aspera.The structure of glyasperin E 1 was established first on the basis of spectroscopic evidence and then confirmed by synthesis.Glyasperin E dimet
- Zeng, Lu,Fukai, Toshio,Nomura, Taro,Zhang, Ru-Yi,Lou, Zhi-Cen
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p. 1153 - 1160
(2007/10/02)
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- Selective Oxidation of Alcohols and Aldehydes with Hydrogen Peroxide Catalyzed by Methyltrioctylammonium Tetrakis(oxodiperoxotungsto)phosphate(3-) under Two-Phase Conditions
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The use of methyltrioctylammonium tetrakis(oxodiperoxotungsto)phosphate(3-) (1c) in combination with hydrogen peroxide as the primary oxidant in an aqueous/organic biphase system provides a cheap, efficient, and versatile catalytic method for alcohol and aldehyde oxidation.By this method, a variety of water-insoluble primary and secondary alcohols and aldehydes were oxidized to carboxylic acids and ketones in good yields under mild conditions and after relatively short reaction times.
- Venturello, Carlo,Gambaro, Mario
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p. 5924 - 5931
(2007/10/02)
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- 29Si and 13C NMR Spectra of 4-Substituted 2-Methoxytrimethylsiloxybenzenes. Factors Determining the Chemical Shifts in Models of Lignin Constituents
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29Si and 13C NMR chemical shifts are reported for a series of twenty 4-substituted 2-methoxytrimethylsiloxybenzenes; the set of substituents incorporates a basic set of ten substituents differing in their relative polar and resonance effects and ten other
- Schraml, Jan,Kvicalova, Magdalena,Chvalovsky, Vaclav,Elder, Thomas,Brezny, Robert
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p. 973 - 978
(2007/10/02)
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- The Baeyer-Villiger Oxidation of Aromatic Aldehydes and Ketones with Hydrogen Peroxide Catalyzed by Selenium Compounds
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A series of organoselenium compounds was investigated as activators of hydrogen peroxide in the Baeyer-Villiger oxidation.As a result, a convenient and cheap method for transformation of aromatic aldehydes, having polycondensed ring systems or electron-donating substituents, and polymethoxy derivatives of acetophenone, into phenols was elaborated.This method utilizes hydrogen peroxide activated by areneseleninic acids, as oxidizing agent.
- Syper, Ludwik
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p. 167 - 172
(2007/10/02)
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- Further Syntheses of C-Branched α-Deoxycyclitols Starting from 1,6-Anhydrohexopyranoses
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1,6-Anhydro-3,4-O-isopropylidene-β-D-altropyranose (4) reacts with n-butyllithium to give 1L-1-C-butyl-2,3-O-isopropylidene-1,2,3,5/4-cyclohexanepentol (5a).The analogous reaction with methyllithium yields the C-methyl-branched cyclitols 5b, 6, and 7.Reaction of 2,7-anhydro-4,5-O-isopropylidene-β-D-sedoheptulopyranose (8) with n-butyllithium gives the di-C-branched cyclitol 9a, whereas with methyllithium the two isomers 9b and 10 are isolated. 1,6-Anhydro-2,3,4-tri-O-methyl-β-D-glucopyranose (11) produces a considerable amount of 2,4-dimethoxyphenol (13) besides the expected C-branched cyclitol 12.The enantiomer of 5a, in terms of the 4-O-methyl derivative 15a, is formed by the reaction of 1,6-anhydro-2-O-methyl-3,4-O-isopropylidene-β-D-galactopyranose (14) with n-butyllithium.Starting from 15a, some additional reactions for C-branched unsaturated cyclitols as well as for aminodeoxycyclitols are described.
- Klemer, Almuth,Kohla, Monika
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p. 967 - 979
(2007/10/02)
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- Preparation of Regioselectively Protected Hydroquinones by Phosphorylation of p-Benzoquinones with Trialkyl Phosphites
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The title reaction has been applied to 10 monosubstituted p-benzoquinones (Scheme 2, Table).The regioselectivity of the O-phosphorylation is influenced by bulky substituents (t-butyl and trimethylsilyl) and, electronically, by the methoxy group.The regioselectivity, which is high in nonpolar media (benzene), is lower in polar solvents (CH2Cl2 and CH3CN).The synthetic potential of this transformation, exemplified by the preparation of compounds 29 (Scheme 3) and 32 (Scheme 4), is considerably extended by applying milder methods for the phosphate hydrolysis and by using the reagent couple P(OCH3)3/trimethylsilyl chloride, which gives clean access to p-hydroxyphenyl phosphates. p-Benzoquinones 4h and 4i with strong ?-acceptor substituents react in a different way, giving phosphonates.The electronically induced regioselectivity of the O- and C-phosphorylation is in accordance with the preferences expected for the attack by a nucleophilic phosphorylation agent.
- Duthaler, Rudolf O.,Lyle, Paulette A.,Heuberger, Christoph
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p. 1406 - 1426
(2007/10/02)
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- Acid-Catalyzed Oxidation of Benzaldehydes to Phenols by Hydrogen Peroxide
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A wide variety of benzaldehydes were oxidized to phenols by hydrogen peroxide in acidic methanol.
- Matsumoto, Masakatsu,Kobayashi, Hisako,Hotta, Yasushi
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p. 4740 - 4741
(2007/10/02)
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