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TEMPO-mediated late stage photochemical hydroxylation of biaryl sulfonium salts
The late stage photochemical hydroxylation of biaryl sulfonium salts was enabled with a TEMPO derivative as a simple oxygen source, in metal free conditions. The scope and mechanism of this exceptionally simple synthetic method, which constructs important arylated phenols from aromatic C-H bonds, are herein discussed.
Atodiresei, Iuliana L.,Liang, Wenjing,Patureau, Frederic W.,Yu, Congjun,Zhao, Yue
p. 2846 - 2849
(2022/03/09)

Substituent and Surfactant Effects on the Photochemical Reaction of Some Aryl Benzoates in Micellar Green Environment?
In this study, we carried out preparative and mechanistic studies on the photochemical reaction of a series of p-substituted phenyl benzoates in confined and sustainable micellar environment. The aim of this work is mainly focused to show whether the nature of the surfactant (ionic or nonionic) leads to noticeable selectivity in the photoproduct formation and whether the electronic effects of the substituents affect the chemical yields and the rate of formation of the 5-substituted-2-hydroxybenzophenone derivatives. Application of the Hammett linear free energy relationship (LFER) on the rate of formation of benzophenone derivatives, on the lower energy band of the UV-visible absorption spectra of the aryl benzoates and 5-substituted-2-hydroxybenzophenone derivatives allows a satisfactory quantification of the substituent effects. Furthermore, UV-visible and 2D-NMR (NOESY) spectroscopies have been employed to measure the binding constant Kb and the location of the aryl benzoates within the hydrophobic core of the micelle. Finally, TD-DFT calculations have been carried out to estimate the energies of the absorption bands of p-substituted phenyl benzoates and 5-substituted-2-hydroxybenzophenone derivatives providing good linear correlation with those values measured experimentally.
Siano, Gastón,Crespi, Stefano,Bonesi, Sergio M.
p. 1298 - 1309
(2021/05/07)

Palladium-Catalyzed Hydroxylation of Aryl Halides with Boric Acid
Boric acid, B(OH)3, is proved to be an efficient hydroxide reagent in converting (hetero)aryl halides to the corresponding phenols with a Pd catalyst under mild conditions. Various phenol products were obtained in good to excellent yields. This transformation tolerates a broad range of functional groups and molecules, including base-sensitive substituents and complicated pharmaceutical (hetero)aryl halide molecules.
Song, Zhi-Qiang,Wang, Dong-Hui
supporting information
p. 8470 - 8474
(2020/11/18)

Method for preparing alcohol and phenol through aerobic hydroxylation reaction of boric acid derivative in absence of photocatalyst
The invention discloses a method for preparing alcohol and phenol through aerobic hydroxylation reaction of a boric acid derivative in the absence of a photocatalyst, wherein the boric acid derivativeis aryl boronic acid or alkyl boronic acid, and the corresponding target compounds are respectively a phenol-based compound and an alcohol-based compound. According to the method, by using a boric acid derivative as a reaction substrate, an additive is added under a solvent condition, and a hydroxylation reaction is performed under aerobic and illumination conditions to obtain a corresponding target compound. According to the invention, the new strategy is provided for the synthesis of phenols through aerobic hydroxylation of aryl boronic acid without a photocatalyst; the catalyst-free aerobic hydroxylation method for photocatalysis of aryl boronic acid or alkyl boronic acid by using triethylamine as an additive is firstly disclosed; and the new method has advantages of photocatalyst-freecondition, wide substrate range and good functional group compatibility.
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Paragraph 0025-0028; 0030-0032

(2020/01/25)

Method for selectively preparing hydroquinone monoether compound or quinol compound (by machine translation)
The method comprises the following steps: taking an organic boric acid compound and a p-benzoquinone compound as a reaction raw material, under the action of a copper catalyst, selectively reacting to obtain a hydroquinone monoether compound or a quinol compound. Compared with the prior art, the method disclosed by the invention adopts a one-pot reaction, can selectively obtain two products through solvent control, is suitable for preparing various types of hydroquinone monoether compounds and quinol compounds, and has wide applicability. The substrate functional group is high in tolerance and wide in substrate range. The raw material and the catalyst are cheap and easily available, the reaction conditions are mild, the reaction solvent is green and environment-friendly, the post-treatment is simple, and the yield and purity of the product are high. The preparation method is convenient. The method is rapid and efficient, and has a good application prospect in drug molecule synthesis. (by machine translation)
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Paragraph 0046-0049

(2020/12/30)

Bimetallic photoredox catalysis: Visible light-promoted aerobic hydroxylation of arylboronic acids with a dirhodium(ii) catalyst
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
p. 2040 - 2047
(2020/03/13)

Nickel-catalyzed oxidative hydroxylation of arylboronic acid: Ni(HBTC)BPY MOF as an efficient and ligand-free catalyst to access phenolic motifs
A straightforward and mild oxidative ipso-hydroxylation of arylboronic acids has been achieved using a simple and non-noble metal, nickel-based reusable heterogeneous catalyst Ni(HBTC)BPY MOF (HBTC = benzene-1,3,5-tricarboxylate, BPY = 4,4′-bipyridine) in the presence of benign hydrogen peroxide as an oxidant under ambient reaction condition. The Ni(HBTC)BPY MOF exhibits excellent catalytic activity towards the formation of phenols from diverse arylboronic acids within short time and can be reused up to five times without any notable loss in its activity as well as shown high functional group tolerance even in the presence of sensitive functionalities and useful to achieve hydroxyl group in heterocycles.
Latha, Ganesapandian,Devarajan, Nainamalai,Karthik, Murugan,Suresh, Palaniswamy
(2020/01/08)

CoII Immobilized on Aminated Magnetic-Based Metal–Organic Framework: An Efficient Heterogeneous Nanostructured Catalyst for the C–O Cross-Coupling Reaction in Solvent-Free Conditions
Abstract: In this paper, we report the synthesis of Fe3O4?AMCA-MIL53(Al)-NH2-CoII NPs based on the metal–organic framework structures as a magnetically separable and environmentally friendly heterogeneous nanocatalyst. The prepared nanostructured catalyst efficiently promotes the C–O cross-coupling reaction in solvent-free conditions without the need for using toxic solvents and/or expensive palladium catalyst. Graphic Abstract: [Figure not available: see fulltext.].
Mohammadinezhad, Arezou,Akhlaghinia, Batool
p. 332 - 352
(2020/01/11)

Preparation method of diphenyl ether structural compound (by machine translation)
The invention discloses a preparation method of a diphenyl ether structural compound, and belongs to the technical field of chemical engineering. The synthesis conditions are mild, water is used as a solvent, a one-pot method is used for synthesizing a target product, and the yield is high. Compared with the traditional Ullmann reaction, the method has the advantages of wide raw material source, low reaction temperature, pure product and high yield, and can be used as a preferred method for synthesizing important medicines and pesticide products or organic intermediates. (by machine translation)
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Paragraph 0014

(2020/06/05)

Photoinduced hydroxylation of arylboronic acids with molecular oxygen under photocatalyst-free conditions
Photoinduced hydroxylation of boronic acids with molecular oxygen under photocatalyst-free conditions is reported, providing a green entry to a variety of phenols and aliphatic alcohols in a highly concise fashion. This new protocol features photocatalyst-free conditions, wide substrate scope and excellent functional group compatibility.
Xu, Yu-Ting,Li, Chen-Yuan,Huang, Xiao-Bo,Gao, Wen-Xia,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
supporting information
p. 4971 - 4975
(2019/09/30)

Trichloroacetonitrile as an efficient activating agent for the: Ipso -hydroxylation of arylboronic acids to phenolic compounds
A metal-free and base-free Cl3CCN mediated method was developed for the ipso-hydroxylation of aryl boronic acids to their corresponding phenols, which was promoted by a key unstable Lewis adduct intermediate. This transformation has broad functional group tolerance, and late-stage functionalization was successful as well. After simple investigation, two pathways (radical/ionic mechanism) were suggested, and the beneficial action of blue light needs to be further studied.
Fang, Yuanding,Zhao, Rong,Yao, Yuan,Liu, Yang,Chang, Denghu,Yao, Ming,Shi, Lei
p. 7558 - 7563
(2019/08/20)

A new strategy to design a graphene oxide supported palladium complex as a new heterogeneous nanocatalyst and application in carbon–carbon and carbon-heteroatom cross-coupling reactions
The palladium nanoparticles were successfully stabilized with an average diameter of 6–7?nm through the coordination of palladium and terpyridine-based ligands grafted on graphene oxide surface. The graphene oxide supported palladium nanoparticles were thoroughly characterized and applied as an efficient heterogeneous catalyst in carbon–carbon (Suzuki-Miyaura, Mizoroki-Heck coupling reactions) and carbon–heteroatom (C-N and C-O) bond-forming reactions. The catalyst was simply recycled from the reaction mixture and was reused consecutive four times with small drop in catalytic activity.
Bahrami, Kiumars,Targhan, Homa
(2019/04/01)

Palladium-Mediated Site-Selective C-H Radio-iodination
The palladium-mediated C-H radio-iodination of arenes using sodium iodide as the primary isotopic source is reported and performed without chemical know-how in 30 min and applied to the synthesis of complex radio-iodinated compounds of biological interest.
Dubost, Emmanuelle,Babin, Victor,Benoist, Florian,Hébert, Alexandra,Barbey, Pierre,Chollet, Céline,Bouillon, Jean-Philippe,Manrique, Alain,Pieters, Grégory,Fabis, Frédéric,Cailly, Thomas
supporting information
p. 6302 - 6305
(2018/10/02)

Bactericidal compound and bactericide composition and preparation and application thereof
The invention relates to the field of agricultural bactericides, and discloses a compound with the bactericidal activity and a bactericide composition and preparation which take the compound as an active ingredient and application of the bactericide composition and preparation.The structure of the bactericidal compound is shown as a formula (I) or a formula (II) (please see the formulas in the description).The bactericidal compound and the preparation containing the bactericidal compound have the significant prevention and control effect on cucumber downy mildew and rice sheath blight.
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Paragraph 0080; 0081

(2016/12/12)

Formation of 2,2-dimethylchroman-4-ones during the photoinduced rearrangement of some aryl 3-methyl-2-butenoate esters. A mechanistic insight
Several aryl 3-methyl-2-butenoate esters upon irradiation lead to the formation of [1,3]-migrated photoproducts, phenol and, surprisingly 2,2-dimethylchroman-4-one derivatives. The starting photochemical reaction takes place from the singlet excited state of the ester and as a total mechanism two consecutive reaction pathways are proposed. The former involves the photo-Fries rearrangement of the esters in all the solvents studied and, depending on the proticity of the solvent, the latter involves an ESIPT process followed by thermal 6π-electrocyclic reaction and/or thermal (intramolecular oxa-Michael addition) cyclization of the ortho regioisomers photoformed. This second pathway is responsible of the formation of the 2,2-dimethylchroman-4-one derivatives.
Iguchi, Daniela,Erra-Balsells, Rosa,Bonesi, Sergio M.
p. 1903 - 1910
(2016/04/05)

Catalytic decomposition of 1,3-diphenoxybenzene to monomeric cyclic compounds over palladium catalysts supported on acidic activated carbon aerogels
Activated carbon aerogel (ACA) was prepared by a chemical activation of carbon aerogel using phosphoric acid (H3PO4). Activated carbon aerogel bearing sulfonic acid (ACA-SO3H), Cs 2.5H0.5PW12O40-impregnated activated carbon aerogel (Cs2.5H0.5PW12O 40/ACA), and Cs2.5H0.5PW12O 40-impregnated activated carbon aerogel bearing sulfonic acid (Cs2.5H0.5PW12O40/ACA-SO 3H) were prepared in order to provide acid sites to ACA. Palladium catalysts were then supported on ACA, ACA-SO3H, Cs 2.5H0.5PW12O40/ACA, and Cs 2.5H0.5PW12O40/ACA-SO3H by an incipient wetness impregnation method. The prepared Pd/ACA, Pd/ACA-SO 3H, Pd/Cs2.5H0.5PW12O 40/ACA, and Pd/Cs2.5H0.5PW12O 40/ACA-SO3H catalysts were applied to the decomposition of 1,3-diphenoxybenzene. 1,3-Diphenoxybenzene was used as a trimeric lignin model compound for representing C-O bond in lignin. Cyclohexanol, benzene, and phenol were mainly produced by the decomposition of 1,3-diphenoxybenzene. 4-Phenoxyphenol was also produced as an intermediate by the decomposition of 1,3-diphenoxybenzene. Conversion of 1,3-diphenoxybenzene and total yield for main products (cyclohexanol, benzene, and phenol) increased with increasing acidity of the catalysts. Among the catalysts tested, Pd/Cs2.5H 0.5PW12O40/ACA-SO3H with the largest acidity showed the highest conversion of 1,3-diphenoxybenzene and total yield for main products. Pd/Cs2.5H0.5PW12O 40/ACA-SO3H also served as a stable and reusable catalyst in the decomposition of 1,3-diphenoxybenzene.
Park, Hai Woong,Kim, Jeong Kwon,Hong, Ung Gi,Lee, Yoon Jae,Choi, Jung Ho,Bang, Yongju,Song, In Kyu
p. 59 - 66
(2013/06/26)

Efficient microwave-assisted Pd-catalyzed hydroxylation of aryl chlorides in the presence of carbonate
An efficient microwave-assisted, palladium-catalyzed hydroxylation of aryl chlorides in the presence of a weak base carbonate was developed, which rapidly converts aryl and heteroaryl chlorides to phenols, and can be used when the aryl chloride is functionalized with a ketone, aldehyde, ester, nitrile, or amide.
Yu, Chao-Wu,Chen, Grace S.,Huang, Chen-Wei,Chern, Ji-Wang
supporting information; experimental part
p. 3688 - 3691
(2012/08/28)

PROCESS FOR PRODUCING 4-HYDROXYDIPHENYL ETHER
A method for producing 4-hydroxydiphenyl ether, characterized by reacting diphenyl ether with an acylating agent in the presence of an acid catalyst to obtain a 4-acyldiphenyl ether represented by the formula (1): wherein R represents a substituted or unsubstituted alkyl or aryl group, reacting the 4-acyldiphenyl ether with a peroxide to obtain a 4-acyloxydiphenyl ether represented by the formula (2): wherein R has the same meaning as defined above, and solvolyzing the ester bond of the 4-acyloxydiphenyl ether, is provided.
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Page/Page column 6

(2008/06/13)

Selective displacement of aryl fluorides with hydroquinone: Synthesis of 4-phenoxyphenols
The selective displacement of a variety of aryl fluorides with hydroquinone has been achieved to give substituted 4-phenoxyphenols 3. In some cases the addition of 18-crown-6 resulted in a significant rate enhancement, and the reactions could be carried out at lower temperature. One of these derivatives, 3a (X = Cl) was converted to 2-propyl-4-(4-chlorophenoxy)phenol 2a, a precursor to the PPARγ receptor agonist 1.
Marcune, Benjamin F.,Hillier, Michael C.,Marcoux, Jean-Fran?ois,Humphrey, Guy R.
p. 7823 - 7826
(2007/10/03)

One-pot synthesis of phenols from aromatic aldehydes by Baeyer-Villiger oxidation with H2O2 using water-tolerant Lewis acids in molecular sieves
The heterogeneous oxidation systems Sn-Beta/H2O2 and Al-Beta/H2O2 were both active for the Baeyer-Villiger oxidation of aromatic aldehydes. With alkoxy substituents in ortho and especially in para position, the corresponding formate ester was the primary reaction product with excellent selectivity. The highest selectivity toward the ester was obtained with the Sn-Beta catalyst in dioxane as solvent. High selectivities of the corresponding phenol could be obtained by employing ethanol or aqueous acetonitrile as solvent with Sn-Beta. Al-Beta was more efficient as catalyst for both Baeyer-Villiger oxidation and ester hydrolysis and, thus achieved high yields for the corresponding alcohol. However, this was a less selective catalyst than Sn-Beta zeolite. Sn-Beta was a chemoselective catalyst when the aldehyde reactant contained olefinic groups in an alkyl chain. With these reactants, the Al-zeolite gave no activity. Other classical BV oxidants, e.g., peracids, also yielded the epoxidation products. Thus, Sn-Beta catalysts open a new entry to aromatic phenols with unsaturated alkyl substituents that are interesting intermediates in the chemical industry.
Corma, Avelino,Fornes, Vicente,Iborra, Sara,Mifsud, Maria,Renz, Michael
p. 67 - 76
(2007/10/03)

PROCESS FOR PREPARING ALKOXY- AND ARYLOXY-PHENOLS
Process for preparing alkoxy- and aryloxy-phenols, comprising oxidizing the ketone of formula (I) with peracids to give the corresponding ester of formula (II) which is then hydrolysed to give the corresponding aryloxy- or alkoxy-phenol.
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Page 11

(2008/06/13)

Zinc-catalyzed Williamson ether synthesis in the absence of base
A zinc-catalyzed Williamson ether synthesis is described with microwave heating in the presence of DMF or stirring in an oil-bath using THF as solvent and in the absence of base. Zinc powder was found to be a highly efficient catalyst for the synthesis of aromatic ethers using microwave heating in the presence of N,N-dimethylformamide as well as under stirring in an oil-bath using tetrahydrofuran as solvent without any inorganic base. This method can be used for selective mono-, di- or tri-O-alkylations.
Paul, Satya,Gupta, Monika
p. 8825 - 8829
(2007/10/03)

5-Aryl thiazolidine-2,4-diones: Discovery of PPAR dual α/γ agonists as antidiabetic agents
A novel series of 5-aryl thiazolidine-2,4-diones based dual PPARα/γ agonists was identified. A number of highly potent and orally bioavailable analogues were synthesized. Efficacy study results of some of these analogues in the db/db mice model of type 2 diabetes showed them superior to rosiglitazone in correcting hyperglycemia and hypertriglyceridemia.
Desai, Ranjit C.,Han, Wei,Metzger, Edward J.,Bergman, Jeffrey P.,Gratale, Dominick F.,MacNaul, Karen L.,Berger, Joel P.,Doebber, Thomas W.,Leung, Kwan,Moller, David E.,Heck, James V.,Sahoo, Soumya P.
p. 2795 - 2798
(2007/10/03)

Atmospheric chemistry of the phenoxy radical, C6H5O(?): UV spectrum and kinetics of its reaction with NO, NO2, and O2
Pulse radiolysis and FT-IR smog chamber experiments were used to investigate the atmospheric fate of C6H5O(?) radicals. Pulse radiolysis experiments gave σ(C6H5O(?))235 nm = (3.82 ± 0.48) × 10-17 cm2 molecule-1, k(C6H5O(?) + NO) = (1.88 ± 0.16) × 10-12, and k(C6H5O(?) + NO2) = (2.08 ± 0.15) × 10-12 cm3 molecule-1 s-1 at 296 K in 1000 mbar of SF6 diluent. No discernible reaction of C6H5O(?) radicals with O2 was observed in smog chamber experiments, and we derive an upper limit of k(C6H5O(?) + O2) -21 cm3 molecule-1 s-1 at 296 K. These results imply that the atmospheric fate of phenoxy radicals in urban air masses is reaction with NOx. Density functional calculations and gas chromatography-mass spectrometry are used to identify 4-phenoxyphenol as the major product of the self-reaction of C6H5O(?) radicals. As part of this study, relative rate techniques were used to measure rate constants for reaction of Cl atoms with phenol [k(Cl + C6H5OH) = (1.93 ± 0.36) × 10-10], several chlorophenols [k(Cl + 2-chlorophenol) = (7.32 ± 1.30) × 10-12, k(Cl + 3-chlorophenol) = (1.56 ± 0.21) × 10-10, and k(Cl + 4-chlorophenol) = (2.37 ± 0.30) × 10-10], and benzoquinone [k(Cl + benzoquinone) = (1.94 ± 0.35) × 10-10], all in units of cm3 molecule-1 s-1. A reaction between molecular chlorine and C6H5OH to produce 2- and 4-chlorophenol in yields of (28 ± 3)% and (75 ± 4)% was observed. This reaction is probably heterogeneous in nature, and an upper limit of k(Cl2 + C6H5OH) ≤ 1.9 × 10-20 cm3 molecule-1 s-1 was established for the homogeneous component. These results are discussed with respect to the previous literature data and to the atmospheric chemistry of aromatic compounds.
Platz,Nielsen,Wallington,Ball,Hurley,Straccia,Schneider,Sehested
p. 7964 - 7974
(2007/10/03)

Sodium Bis(trimethylsily)amide and Lithium Diisopropylamide in Deprotection of Alkyl Aryl Ethers: α-Effect of Silicon
Removal of methyl, benzyl, and methylene groups from alkyl aryl ethers is among the most popular deprotecting methods in organic synthesis. Alkali organoamides NaN(SiMe3)2 and LiN(i-Pr)2, often used as organic bases, have been developed as efficient deprotecting agents. Treatment of aryl methyl ethers with 1.5 equiv of NaN(SiMe3)2 or LiN(i-Pr)2 in THF and 1,3-dimethyl-2-imidazolidinone in a sealed tube at 185 °C produced the corresponding phenol derivatives in good to excellent yields (80-97percent). Removal of the methylene unit from benzodioxole derivatives was also accomplished by use of 2.5 equiv of these alkali organoamides. The corresponding catechols were obtained in 93-99percent yields. The activity of NaN(SiMe3)2 was proven lower than that of LiN(i-Pr)2; it is due to the steric congestion and the α-stabilizing effect of the silyl groups. Thus selective mono-O-demethylation of o-dimethoxybenzenes can be achieved by the use of NaN(SiMe3)2 but not LiN(i-Pr)2. O-Debenzylation of aryl benzyl ethers, however, can be accomplished by the use of LiN(i-Pr)2.
Hwu, Jih Ru,Wong, Fung Fuh,Huang, Jiann-Jyh,Tsay, Shwu-Chen
p. 4097 - 4104
(2007/10/03)

Pair Formation of Phenol in the Vicinity of an Aqueous Solution Surface Studied by Means of Liquid Beam Multiphoton Ionization Mass Spectrometry
An aqueous solution of phenol was introduced into vacuum as a continuous liquid flow (liquid beam) and was irradiated with a laser beam at a wavelength of 272 nm.Ions produced by multiphoton ionization in the liquid beam and ejected from it were analyzed by a time-of-flight mass spectrometer.The mass spectrum of ions ejected from the liquid beam exhibits peaks assignable to C6H5OH+(H2O)n, H3O+(H2O)n, and C6H5O+C6H5OH.The ions C6H5OH+ and H3O+ are considered to be produced in the liquid beam by multiphoton ionization of phenol and proton transfer from phenol to a water molecule, respectively; these ions are ejected into vacuum with the solvent water molecules.On the other hand, C6H5O+C6H5OH is considered to be produced mainly from a pair of phenol molecules in the vicinity of the solution surface.This ion is regarded as the precursor for formation of phenoxyphenol, C6H5OC6H4OH, which is known as a product of the ion-molecule reaction of C6H5O+ + C6H5OH in the liquid.An abrupt rise in the abundance of C6H5O+C6H5OH above 0.55 M indicates that the surface structure starts to change at this concentration to a new one where two phenol molecules are paired.
Mafune, Fumitaka,Hashimoto, Yuichiro,Hashimoto, Mitsuo,Kondow, Tamotsu
p. 13814 - 13818
(2007/10/02)

Products of oxidative coupllng of phenol by horseradish peroxidase
The oxidation and coupling of phenol by horseradish peroxidase in the presence of hydrogen peroxide yielded dimers trimers and higher molecular weight polymers which are mostly insoluble in water, so the products may be removed by centrifugation. However we discovered some products, such as dimers o,o'-biphenol, p,p'-biphenol, o,p'-biphenol, o-phenoxyphenol and p-phenoxyphenol, even though trimer 4-(4-phenoxyphenoxy)phenol were present in the aqueous phase at a very low concentration.
Huixian,Taylor
p. 1807 - 1817
(2007/10/03)

Phenol conversion and dimeric intermediates in horseradish peroxidase-catalyzed phenol removal from water
Phenol was removed from water by horseradish peroxidase-catalyzed polymerization. Five dimeric and one trimeric products from the reaction were identified in the aqueous solution. A peroxidase inactivation model for the reaction in the presence of poly(et
Jian Yu,Taylor,Huixian Zou,Biswas,Bewtra
p. 2154 - 2160
(2007/10/03)

A convenient method for the preparation of 4-aryloxyphenols
A convenient method for the preparation of 4-aryloxyphenols via the homologation of preformed phenols is described. Condensation of various 4-substituted phenols with either 4-fluorobenzaldehyde (8) or 4-fluoroacetophenone (9) yielded the corresponding 4-aryl-oxybenzaldehydes, 10, and acetophenones, 11, in 70-93% yield. Baeyer-Villiger oxidation of these materials with 3-chloroperoxybenzoic acid (MCPBA) yielded the corresponding 4-formyloxy and 4-acetoxyphenyl ethers which were hydrolyzed without purification to the desired 4-aryloxyphenols 12 in 72-94% yield. Both 4-fluorobenzaldehyde (8) and 4-fluoroacetophenone (9) are synthetically equivalent to the a4 umpoled synthon 6. Extension of this methodology of the preparation of 4,4'-[arylbis(oxy)]bisphenols from aromatic diols is also described. Condensation of various aromatic diols with 8 or 9 yielded the corresponding 4,4'-[arylbis(oxy)]bisbenzaldehydes 15 and acetophenones 16 in 71-89% yield. Baeyer-Villiger oxidation of these compounds with MCPBA yielded the desired 4,4'-[arylbis(oxy)]bisphenyl bisformates 17 and bisacetates 18 in 67-84% yield. Hydrolysis of these compounds afforded the desired 4,4'-[arylbis(oxy)bisphenols 19 in 70-91% yield.
Yeager,Schissel
p. 63 - 68
(2007/10/02)

Multiphoton Ionization of Phenol in Nonaqueous Solutions: Characterization of the Cation and Ion-Molecule Chemistry
The phenoxy cation has been generated in polar and nonpolar solutions by two-photon ionization of phenol by using 2.5-ns pulses of 266 nm light.The ions have been characterized by pulsed conductivity (ion mobility) measurements and transient absorption spectroscopy with λmax = 290 - 300 nm and an estimated extinction coefficient of 1300 M-1 cm-1.The involvement of the phenoxy ion in ion-molecule chemistry with either neutral solute or solvent molecules has been observed.The kinetics of these processes as well as a proposed reaction mechanism are presented.
Siuzdak, G.,North, S.,BelBruno, J. J.
p. 5186 - 5190
(2007/10/02)

Herbicidally active phenoxyalkanecarboxylic acid derivatives
A compound of the formula: STR1 wherein Q1 is CH or N; R is H or C1 -C5 alkyl; X is H, halogen, CF3, or NO2 ; Y is H or halogen; Z is --O-- or --NH--; A is STR2 wherein Q2, and Q3 are each CH or N; R1 and R2 are each H, C1 -C5 alkyl, C1 -C5 alkoxy, or C2 -C6 alkxoycarobnyl; R3, R4, and R5 are each H or C1 -C5 alkyl; R6 is H, halogen, or C1 -C5 alkyl; R7, R8, R9, and R10 are each H or C1 -C5 alkyl; R11 is H, C1 -C5 alkyl, C1 -C5 alkoxy, C2 -C6 alkenyl, C6 -C10 aryl, C7 -C15 aryloxyalkyl, or C7 -C15 aralkyl; R12 and R13 are each H or C1 -C5 alkyl; R14 is C1 -C5 alkyl, C2 -C6 alkenyl, C5 -C10 aryl, or C7 -C15 aralkyl; or R13 and R14 taken together form C3 -C4 alkylene, V1 and V2 are each H, halogen, NO2, CN, or CF3 ; V3 is halogen or CF3 ; W1 is --O-- or --NH--; W2 is --(CH2)n -- wherein n is 0 or 1, or CO; X1 is halogen, or a salt thereof, which is effective as a herbicidal agent.
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(2008/06/13)

SECOND-ORDER COMBINATION REACTION OF PHENOXYL RADICALS
Phenoxy radicals, when produced pulse radiolytically at concentrations > 1E-4 M, combine in second-order processes to give 2,2'-, 2,4', and 4,4'-dihydroxybiphenyl as the predominant products.The ratios of these products observed under a variety of conditi
Ye, Mingyu,Schuler, Robert H.
p. 1898 - 1902
(2007/10/02)

Polimerisation and Related Reactions involving Nucleophilic Aromatic Substitution. Part 2. The Rates of Reaction of Substituted 4-Halogenobenzophenones with the Salts of Substituted Hydroquinones
4-X-4'-fluorobenzophenones undergo the expected nucleophilic substitution reactions with the alkali metal salts of 4-Y-4'-hydroxydiphenyl ethers at 140 deg C in diphenyl sulphone as solvent: the Hammett ρ value is 1.02 for the X substituents and -0.34 for the Y substituents.The order of reactivity of the alkali metal salts is Cs > K > Na.The related reaction of fluorobenzophenone with potassium 4-Z-phenolates under the same conditions gives a ρ value of -2.28.This result has been used to calculate the corresponding rate coefficients for the reaction of the mono- and di-potassium salts of hydroquinone with fluorobenzophenone.
Lovering, Jonathan R.,Ridd, John H.,Parker, David G.,Rose, John B.
p. 1735 - 1738
(2007/10/02)

Fluoran colorants for recording systems
Fluorans of the formula (I) STR1 where R1 is hydrogen or methyl, R2 is hydrogen or unsubstituted or substituted alkyl, R3 is hydrogen, unsubstituted or substituted alkyl, cycloalkyl or unsubstituted or substituted phenyl, or STR2 is a 5-membered or 6-membered saturated heterocyclic radical, R4 and R5 independently of one another are each hydrogen, alkyl, alkoxy or halogen, R6 is hydrogen, halogen, alkyl, alkoxy, phenylalkoxy, phenoxy, phenyl or unsubstituted or substituted amino, or is pyrrolidinyl, piperidinyl or morpholinyl, R7 is hydrogen, alkyl or halogen, R8 is C1 -C5 -alkyl, and the radicals R4 and R5 and/or R6 and R7 together may furthermore each be a --CH=CH--CH=CH-- bridge, and the fused-on benzo ring may be further substituted, are used for the preparation of pressure-sensitive and heat-sensitive recording materials.
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(2008/06/13)

Oxidativ Coupling of Phenols. Part 6. A Study of the Role of Spin Density Factors on the Product Composition in the Oxidations of 3,5-Dimethylphenol and Phenol
Oxidations of both 3,5-dimethyphenol and phenol with di-t-butyl peroxide at 140 degC gave as the major product the ortho-ortho-C-C coupled dimer, while oxidations with di-t-butyl peroxyoxalate at room temperature give much more of the ortho-para-C-C dimer.The results are not consistent either with the spin density distribution in the phenoxyl radical intermediates or with steric effects being the major factor which determines the product composition.It is proposed that the two phenoxyl radicals involved in coupling preferentially approach each other in a 'sandwich like' manner with the oxigens in a 1,3-relationship.
Armstrong, David R.,Cameron, Colin,Nonhebel, Derek C.,Perkins, Peter G.
p. 563 - 568
(2007/10/02)

THE ROLE OF STEREOELECTRONIC FACTORS IN THE OXIDATION OF PHENOLS
The oxidative coupling of both 3,5-dimethylphenol and phenol leads to the ortho-ortho and ortho-para coupled products as the predominant C-C dimers: stereoelectronic factors determine the preferred mode of approach of the phenoxyl radicals.
Armstrong, David R.,Breckenridge, Robin J.,Cameron, Colin,Nonhebel, Derek C.,Pauson, Peter L.,Perkins, Peter G.
p. 1071 - 1074
(2007/10/02)

Acid and Polarity Effects in Benzene Photoreactions with Alkenes and Alkynes
The effects of polar solvents and proton donors on various photoreactions of the benzene ring with electron-acceptor alkenes and alkynes are described and discussed in relation to the various electronic excitation mechanisms involved.Proton donors prove valuable as mechanistic probes for polar intermediates in such processes, and can in some systems both initiate and divert reaction pathways. - Key words: Photoreactions, Benzene, Alkenes, Alkynes, Acid Effects
Bryce-Smith, D.,Gilbert, A.,Al-Jalal, N.,Deshpande, R.R.,Grzonka, J.,et al.
p. 1101 - 1112
(2007/10/02)

Process for the production of 2-aryl-2H-benzotriazoles
A process for the production of 2-aryl-2H-benzotriazoles comprises reducing and cyclizing the corresponding o-nitroazobenzenes with hydrogen at a temperature in the range of about 20° C. to about 100° C. and at a pressure in the range of about 15 psia (1 atmosphere) to about 1000 psia (66 atmospheres) in an alkaline medium at a pH over 10 in the presence of a nickel catalyst, preferably molybdenum-promoted Raney nickel. High yields of pure product are obtained directly with a concomitant reduction of undesired by-product and a reduction in effluent pollution problems.
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(2008/06/13)

Process for the production of 2-aryl-2H-benzotriazoles
A process for the production of 2-aryl-2H-benzotriazoles comprises reducing and cyclizing the corresponding o-nitroazobenzenes with carbon monoxide at a temperature in the range of about 20° C. to about 150° C. and at a pressure in the range of about 15 psia (1 atmosphere) to about 1000 psia (66 atmospheres) in an alkaline medium at a pH over 10 in the presence of a copper-amine complex catalyst. High yields of pure product are obtained with a concomitant reduction of undesired by-products and a reduction in effluent pollution problems.
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(2008/06/13)

Process for the production of 2-aryl-2H-benzotriazoles
An improved process for the production of 2-aryl-2H-benzotriazoles by the reduction of o-nitroazobenzene intermediates with zinc in alkaline medium comprises employing a ratio of moles of alkali to moles of o-nitroazobenzene intermediate in the range of 0.2-1.7/1 in the presence of less than 150 ppm of iron based on zinc used. The improved process results in higher yields of high purity products with a concomitant reduction in the amount of undesired cleavage amine by-products and a reduction in effluent pollution problems. The process is carried out in a polar/non-polar solvent mixture.
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(2008/06/13)

Method for manufacture of dihydric phenols
Dihydric phenols are produced preferentially in high yields by having monohydric phenols or phenyl ethers oxidized by an organic peracid using, as a catalyst, at least one member selected from the group consisting of peracid stabilizers, polycarboxylic acids containing N or OH and possessed of a structure from which heavy metal ion-chelating property can theoretically be assumed, magnesium salts, sodium salts and potassium salts thereof, sodium salt, potassium salt and lower alkyl esters of phosphoric acid, and sodium salt and lower alkyl esters of pyrophosphoric acid.
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(2008/06/13)