- Unexpected 2,4,6-trimethylphenol oxidation in the presence of Fe(III) aquacomplexes
-
2,4,6-Trimethylphenol (TMP) was efficiently oxidised by Fe(III) aquacomplexes. HPLC analysis was used to follow the kinetics of the redox process. Two degradation products were detected and identified: 2,6-dimethyl-4-(hydroxymethyl)phenol (P1) and 3,5-dimethyl-4-hydroxybenzaldehyde (P2) accounting for 100% of TMP degradation in the early stages of the reaction. The formation of the products was concomitant with the reduction of Fe(III) into Fe(II). The direct relation between TMP oxidation and the concentration of the monomeric species {Fe(H2O)5(OH)} 2+ gives evidence for the initial reaction to take place between TMP and this particular species. Moreover, the correlation between P2 formation and P1 disappearance during the reaction implies the sequence of reactions: TMP → P1 → P2. A mechanism leading to the two degradation products is proposed. the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006.
- Aguer, Jean-Pierre,Mailhot, Gilles,Bolte, Michele
-
-
Read Online
- A highly sensitive fluorescent probe that quantifies transthyretin in human plasma as an early diagnostic tool of Alzheimer's disease
-
The development of sensitive and reliable fluorescent probes for the early diagnosis of Alzheimer's disease (AD) is highly challenging and plays an important role in achieving effective treatments. Herein, we designed and synthesized an indole-based fluorophore for TTR in human plasma, an important hallmark of AD pathogenesis. This robust and simple fluorescent method allows quantification of TTR in the complex biological matrix.
- Lim, Hye Rim,Kim, Seo Yun,Jeon, Eun Hee,Kim, Yun Lan,Shin, Yu Mi,Koo, Tae-Sung,Park, Sung Jean,Hong, Ki Bum,Choi, Sungwook
-
-
Read Online
- A NOVEL OXYGENATION OF 2,4,6-TRIMETHYLPHENOL TO 3,5-DIMETHYL-4-HYDROXYBENZALDEHYDE BY DIOXYGEN WITH COPPER(II)-AMINE COMPLEX CATALYST
-
2,4,6-Trimethylphenol was efficiently oxagenated to 3,5-dimethyl-4-hydroxybenzaldehyde by molecular oxagen in the presence of catalytic amount of copper(II)chloride/amine (1/1) complex in alcoholic solvent at ambient temperature.
- Takehira, Katsuomi,Shimizu, Masao,Watanabe, Yoshihito,Orita, Hideo,Hayakawa, Takashi
-
-
Read Online
- 5-Hydroxy-2,3-dihydrobenzofuran-derived polyfunctional antioxidants: 1. Synthesis of 2-dodecylthiomethyl-5-hydroxy-2,3-dihydrobenzofurans
-
2-Dodecylthiomethyl-5-hydroxy-2,3-dihydrobenzofurans, new sulfur-containing analogs of tocopherols, were synthesized based on methylphenols through the intermediate preparation of 4-alkoxy-2-allylphenols and then 5-alkoxy-2-iodomethyl-2,3-dihydrobenzofura
- Yagunov,Kholshin,Kandalintseva,Prosenko
-
-
Read Online
- 5-Aryl-2-(3,5-dialkyl-4-hydroxyphenyl)-4,4-dimethyl- 4H-imidazole 3-oxides and their redox species: How antioxidant activity of 1-hydroxy-2,5-dihydro- 1h-imidazoles correlates with the stability of hybrid phenoxyl-nitroxides
-
Cyclic nitrones of the imidazole series, containing a sterically hindered phenol group, are promising objects for studying antioxidant activity; on the other hand, they can form persistent hybrid phenoxyl-nitroxyl radicals (HPNs) upon oxidation. Here, a series of 5-aryl-4,4-dimethyl- 4H-imidazole 3-oxides was obtained by condensation of aromatic 2-hydroxylaminoketones with 4-formyl-2,6-dialkylphenols followed by oxidation of the initially formed N-hydroxy derivatives. It was shown that the antioxidant activity of both 1-hydroxy-2,5-dihydroimidazoles and 4H-imidazole 3-oxides increases with a decrease in steric volume of the alkyl substituent in the phenol group, while the stability of the corresponding HPNs generated from 4H-imidazole 3-oxides reveals the opposite tendency.
- Amitina, Svetlana A.,Artamonov, Ilya A.,Dmitrieva, Natalya A.,Kandalintseva, Natalya V.,Lomanovich, Alyona V.,Markov, Alexander F.,Mazhukin, Dmitrii G.,Ten, Yury A.,Zaytseva, Elena V.
-
-
- Activating a Peroxo Ligand for C?O Bond Formation
-
Dioxygen activation for effective C?O bond formation in the coordination sphere of a metal is a long-standing challenge in chemistry for which the design of catalysts for oxygenations is slowed down by the complicated, and sometimes poorly understood, mechanistic panorama. In this context, olefin–peroxide complexes could be valuable models for the study of such reactions. Herein, we showcase the isolation of rare “Ir(cod)(peroxide)” complexes (cod=1,5-cyclooctadiene) from reactions with oxygen, and then the activation of the peroxide ligand for O?O bond cleavage and C?O bond formation by transfer of a hydrogen atom through proton transfer/electron transfer reactions to give 2-iradaoxetane complexes and water. 2,4,6-Trimethylphenol, 1,4-hydroquinone, and 1,4-cyclohexadiene were used as hydrogen atom donors. These reactions can be key steps in the oxy-functionalization of olefins with oxygen, and they constitute a novel mechanistic pathway for iridium, whose full reaction profile is supported by DFT calculations.
- del Río, M. Pilar,Abril, Paula,López, José A.,Sodupe, Mariona,Lledós, Agustí,Ciriano, Miguel A.,Tejel, Cristina
-
supporting information
p. 3037 - 3041
(2019/01/24)
-
- Phenolic Oxidation Using H2O2 via in Situ Generated para-Quinone Methides for the Preparation of para-Spiroepoxydienones
-
Phenols are attractive starting materials for the preparation of highly substituted cyclohexane rings via dearomative processes. Herein we report an efficient preparation of dearomatized 1-oxaspiro[2.5]octa-4,7-dien-6-ones (para-spiroepoxydienones) via the nucleophilic epoxidation of in situ generated para-quinone methides from 4-(hydroxymethyl)phenols using aqueous H2O2. The developed protocol bypasses the need for stoichiometric bismuth reagents or diazomethane, which are frequently deployed for p-spiroepoxydienone preparation. The p-spiroepoxydienones are further elaborated in numerous downstream complexity-building transformations.
- McLaughlin, Michael F.,Massolo, Elisabetta,Cope, Thomas A.,Johnson, Jeffrey S.
-
supporting information
p. 6504 - 6507
(2019/09/04)
-
- Magnetic nano-structured cobalt-cobalt oxide/nitrogen-doped carbon material as an efficient catalyst for aerobic oxidation of p-cresols
-
Efficient aerobic oxidation has been developed for the selective preparation of a sequence of valuable p-hydroxybenzaldehydes from corresponding p-cresols, using a new magnetically separable catalyst of nano-structured cobalt-cobalt oxide/nitrogen-doped carbon (CoOx@CN) material. CoOx@CN showed high activity for the 2-methoxy-4-cresol oxidation to vanillin, giving great yield (90%) and with good turnover number (210), as well as other p-cresols in good to great yields. The catalytic performance was investigated and related to the structural, chemical and magnetic properties which determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The effects of base to substrate molar ratio, catalyst concentration, temperature, and solvent on the conversion and selectivity patterns also have been studied. The investigation revealed that remarkable catalytic properties of CoOx@CN could be ascribed to the active species cobalt oxide, doped nitrogen and porous carbon with large surface area. The size of the catalyst is a key factor for catalyst performance. The ferromagnetic property of catalyst enables to recycle easily by an external magnetic field and reuse six successive times without significant activity loss.
- Liang, Cheng,Li, Xuefeng,Su, Diefeng,Ma, Qiyi,Mao, Jianyong,Chen, Zhirong,Wang, Yong,Yao, Jia,Li, Haoran
-
p. 121 - 131
(2018/05/22)
-
- Exploration of phenylpropanoic acids as agonists of the free fatty acid receptor 4 (FFA4): Identification of an orally efficacious FFA4 agonist
-
The long chain free fatty acid receptor 4 (FFA4/GPR120) has recently been recognized as lipid sensor playing important roles in nutrient sensing and inflammation and thus holds potential as a therapeutic target for type 2 diabetes and metabolic syndrome. To explore the effects of stimulating this receptor in animal models of metabolic disease, we initiated work to identify agonists with appropriate pharmacokinetic properties to support progression into in vivo studies. Extensive SAR studies of a series of phenylpropanoic acids led to the identification of compound 29, a FFA4 agonist which lowers plasma glucose in two preclinical models of type 2 diabetes.
- Sparks, Steven M.,Aquino, Christopher,Banker, Pierette,Collins, Jon L.,Cowan, David,Diaz, Caroline,Dock, Steven T.,Hertzog, Donald L.,Liang, Xi,Swiger, Erin D.,Yuen, Josephine,Chen, Grace,Jayawickreme, Channa,Moncol, David,Nystrom, Christopher,Rash, Vincent,Rimele, Thomas,Roller, Shane,Ross, Sean
-
p. 1278 - 1283
(2017/06/19)
-
- Cu(OAc)2-catalyzed remote benzylic C(sp3)-H oxyfunctionalization for C=O formation directed by the hindered para-hydroxyl group with ambient air as the terminal oxidant under ligand- and additive-free conditions
-
A hindered para-hydroxyl group-directed remote benzylic C(sp3)-H oxyfunctionalization has been developed for the straightforward transformation of 2,6-disubstituted 4-cresols, 4-alkylphenols, 4-hydroxybenzyl alcohols and 4-hydroxybenzyl alkyl ethers into various aromatic carbonyl compounds. The ligand- and additive-free Cu(OAc)2-catalyzed atmospheric oxidation mediated by ethylene glycol unlocks a facile, atom-economical, and environmentally benign C=O formation for the functionalization of primary and secondary benzyl groups. Due to the pharmaceutical importance of 4-hydroxybenzaldehydes and 4-hydroxyphenones, the methodology is expected to be of significant value for both fundamental research and practical applications.
- Jiang, Jian-An,Chen, Cheng,Huang, Jian-Gang,Liu, Hong-Wei,Cao, Song,Ji, Ya-Fei
-
supporting information
p. 1248 - 1254
(2014/03/21)
-
- Environmentally friendly and highly efficient Co(OAc)2-catalyzed aerobic oxidation to access 2,6-di-electron-donating group substituted 4-hydroxybenzaldehydes
-
A highly efficient and green aerobic oxidation has been developed for selectively preparing a series of valuable 2,6-dialkyl-, dialkoxyl-, and alkoxylalkyl-substituted 4-hydroxybenzaldehydes from corresponding 4-cresols in good to excellent yields, using a catalytic system of Co(OAc)24H2O (1.0 mol%)-NaOH (1.0 equiv)-O2(1.0 atm) in aqueous ethylene glycol (EG/H2O = 20/1, v/v) at 50 °C. Furthermore, a plausible mechanism was proposed for the direct oxyfunctionalization of the aromatic methyl group into the aldehyde group.
- Jiang, Jian-An,Du, Jia-Lei,Zhang, Zhong-Nan,Zhai, Jiao-Jiao,Ji, Ya-Fei
-
supporting information
p. 1430 - 1440
(2016/09/23)
-
- A convenient synthesis of tri- and tetramethylbenzaldehydes from readily available phenols
-
This letter describes a convenient synthesis of the six isomeric tri- and tetramethylbenzaldehydes, which are not readily available from major chemical suppliers. Formylation of readily available phenols via electrophilic aromatic substitution provides compounds containing the correct aromatic substitution pattern. ?Suzuki cross-coupling of the corresponding trifluoromethanesulfonates with methylboronic acid then provides the benzaldehydes as single isomers. Georg Thieme Verlag Stuttgart. New York.
- Dhankher, Persis,Sheppard, Tom D.
-
supporting information
p. 381 - 384
(2014/03/21)
-
- Electronic-state switching strategy in the photochemical synthesis of indanones from o-methyl phenacyl epoxides
-
An electronic excited-state switching strategy has been utilized to control the selectivity of a key photochemical step in the total synthesis of indanorine. The excited-state character of 4, 5-dimethoxy-2-methylphenacyl epoxide was changed from an unfavorable 3φ , φ * state to a productive 3n, φ * state by a temporary structural modification, resulting in a relatively efficient and high-yielding formation of an indanone derivative. The corresponding structural modification was selected on the basis of quantum chemical calculations prior to the synthesis.
- Stacko, Peter,Solomek, Tomas,Klan, Petr
-
supporting information; experimental part
p. 6556 - 6559
(2012/02/15)
-
- DERIVATIVES OF SUBSTITUTED 3-PHENYL-1-(PHENYLTHIENYL)PROPAN-1-ONES AND OF 3-PHENYL-1-(PHENYLFURANYL) PROPAN-1-ONES, PREPARATION AND USE
-
The present invention relates to compounds derived from substituted 3-phenyl-1-(thien-2-yl)propan-1-ones, pharmaceutical compositions comprising them as well as their therapeutic applications, notably in the field of human and animal health.
- -
-
Page/Page column 13
(2010/03/02)
-
- Selective benzylic C-C coupling catalyzed by a bioinspired dicopper complex
-
A highly preorganized bioinspired dicopper complex with imidazole ligation catalyzes the selective benzylic para-C-H activation of 2,4,6-trimethylphenol under aerobic conditions, yielding either the stilbenequinone or 4-methoxymethyl-2,6-dimethylphenol depending on the solvent used. The Royal Society of Chemistry.
- Prokofieva, Angelina,Prikhod'ko, Alexander I.,Dechert, Sebastian,Meyer, Franc
-
p. 1005 - 1007
(2008/09/21)
-
- An unusual reaction of benzalaminoacetals in trifluoroacetic acid: Facile synthesis of 2-benzylpyrazines
-
(Chemical Equation Presented) Benzalaminoacetals (1), upon refluxing with trifluoroacetic acid, lead to 2-benzylpyrazines, rather than the expected isoquinolines. This unusual reaction represents another useful way to prepare a variety of 2-benzylpyrazines from the corresponding benzaldehydes.
- Augustine, John Kallikat,Naik, Yanjerappa Arthoba,Mandal, Ashis Baran,Kundapur, Umesha
-
p. 1176 - 1179
(2008/09/18)
-
- Copper-mediated selective oxidation of a C-H bond
-
(Chemical Equation Presented) An environmentally friendly procedure has been developed for the oxidation of 2,4,6-trimethylpheriol (TMP) at the para Csp3-H bond. Upon reaction with H2O2 in the presence of catalytic amounts of CuII and neocuproine in methanol at 65°C, 4-(methoxymethyl)-2,6-dimethylphenol (MDP) or 4-hydroxy-3,5- dimethylbenzaldehyde (HDB) is formed (see reaction).
- Boldron, Christophe,Gamez, Patrick,Tooke, Duncan M.,Spek, Anthony L.,Reedijk, Jan
-
p. 3585 - 3587
(2007/10/03)
-
- Selective copper(II)-mediated oxidative coupling of a nucleophilic reagent to the para-methyl group of 2,4,6-trimethylphenol
-
A copper(II) neocuproine system has been developed for the efficient and very selective 1,6-addition of a nucleophile to the para-methyl group of 2,4,6-trimethylphenol. Crystallographic and spectroscopic data point towards the involvement of a μ-methoxo-μ-phenoxo-bridged copper species which appears to generate a highly reactive quinone methide intermediate that can be attacked by a nucleophilic reagent. The Royal Society of Chemistry 2005.
- Boldron, Christophe,Oezalp-Yaman, Seniz,Gamez, Patrick,Tooke, Duncan M.,Spek, Anthony L.,Reedijk, Jan
-
p. 3535 - 3541
(2007/10/03)
-
- Selective oxidation of phenols to hydroxybenzaldehydes and benzoquinones with dioxygen catalyzed by polymer-supported copper
-
Oxidation of 2,6-disubstituted 4-methylphenols with dioxygen by using a CuCl2-poly(4-methyl-4′-vinyl-2,2′-bipyridine) catalyst gave the corresponding 4-hydroxybenzaldehydes in high yields. The activity of the catalyst and the selectivity of the products significantly depended on the reaction conditions and the composition of the catalyst. When the molar ratio of the bipyridine unit of the polymer ligand to Cu was unity, i.e., N/Cu = 2, the best results were obtained. Moreover, the reaction is likely to be promoted by coordination of the products to the catalyst. Similarly, 2,3,6-trimethylphenol and related compounds were converted to p-benzoquinones selectively with a CuCl2-poly(4-vinylpyridine) catalyst. These polymer-supported catalysts were readily recovered and are reusable without noticeable decrease of their activity.
- Takaki, Ken,Shimasaki, Yohei,Shishido, Tetsuya,Takehira, Katsuomi
-
p. 311 - 317
(2007/10/03)
-
- NBS-Promoted Reactions of Symmetrically Hindered Methylphenols via p-Benzoquinone Methide
-
Symmetrically hindered methylphenols 1 react smoothly with NBS to form transient intermediates, p-benzoquinone methides (BM), which can be further processed to give hydroxybenzaldehydes in the presence of DMSO. This reaction is initiated by the formation of the phenoxy radical, followed by disproportionation to afford BM. None of the side-chain-brominated product is observed. The existence of BM is supported by the following observations: the formation of BM in solution can be monitored by GC and GC-MS; the electrophilic methine part participates in electrophilic aromatic substitution with anisoles to give hydroxybenzylated products 15; and the double bond character of the exocyclic methine plays a role in [4 + 2] cycloaddition with diene to afford Diels-Alder adducts. In contrast, unsymmetrically hindered or simple methylphenol (p-cresol) with NBS gives the nuclear brominated products, as usual. The energies of symmetrically hindered BMs, unsymmetrically hindered BM, and simple BM were calculated using density functional theories. Relative stabilization energies calculated at the B3LYP/6-31G*//B3LYP/6-31G* level by an isodesmic equation are enhanced 3-6 kcal/mol for symmetrically hindered BMs.
- Baik, Woonphil,Lee, Hyun Joo,Jang, Jung Min,Koo, Sangho,Kim, Byeong Hyo
-
p. 108 - 115
(2007/10/03)
-
- Isoquinoline compound melanocortin receptor ligands and methods of using same
-
The invention relates to melanocortin receptor ligands and methods of using the ligands to alter or regulate the activity of a melanocortin receptor. The invention further relates to tetrahydroisoquinoline aromatic amines that function as melanocortin receptor ligands and as agents for controlling cytokine-regulated physiologic processes and pathologies, and combinatorial libraries thereof.
- -
-
-
- Oxidative demethylation of 4-methylphenols to 1,4-benzoquinones with hydrogen peroxide, catalyzed by K10 montmorillonite
-
2,4,6-Trimethylphenol and pentamethylphenol react with hydrogen peroxide in the presence of K10 montmorillonite (22°C, CCl4, 2 h) to afford, respectively, 2,6-dimethyl-1,4-benzoquinone and 2,3,5,6-tetramethyl-1,4-benzoquinone. 2,6-Di-tert-butyl-4-methylphenol and 4-methylphenol do not react under the same conditions. The mechanism of this reaction is discussed.
- Bushmelev,Genaev,Shubin
-
-
- Indirect oxidations using electrogenerated hydrogen peroxide
-
Hydrogen peroxide is a unique redox reagent in that it may be produced from air and after use in synthesis, manufacturing technology or effluent treatment, it leaves no residual chemicals. New concepts in cell technology for in situ generation of hydrogen peroxide, as well as recent developments in its chemistry, have made more attractive the use of hydrogen peroxide as a mediator in indirect electrolysis. This review discusses some of the factors contributing to these developments.
- Pletcher, Derek
-
p. 745 - 750
(2007/10/03)
-
- Cobalt-Schiff Base Complex Catalyzed Oxidation of Para-Substituted Phenolics. Preparation of Benzoquinones
-
Para-substituted phenolics, serving as models for lignin (a renewable source of carbon), are oxidized to the corresponding benzoquinone with oxygen in the presence of catalytic amounts of Co-Schiff base complexes.The reaction products observed depend on the structure of the catalyst.The 5-coordinate catalysts (pyridine)cobalt and amine>cobalt convert syringyl alcohol (3,5-dimethoxy-4-hydroxybenzyl alcohol) to 2,6-dimethoxybenzoquinone in high yield.In contrast, syringaldehyde (3,5-dimethoxy-4-hydroxybenzaldehyde) is unreactive toward these catalysts.However, the 4-coordinate Co(salen) converts syringaldehyde to 2,6-dimethoxybenzoquinone in 72percent isolated yield.Phenols bearing a single methoxy group on the ring are unreactive toward any catalyst in MeOH.However, vanillyl alcohol (3-methoxy-4-hydroxybenzyl alcohol) is converted to 2-methoxybenzoquinone with Co(N-Me salpr) and oxygen in 43percent yield in CH2Cl2, and 58percent yield in CH2Cl2 in the presence of 1percent CuCl2.The success of the oxidations appears to be related to the ease of removal of the phenolic hydrogen by the Co/O2 complex.Competitive deactivation of the catalyst occurs with substrates of lower reactivity.
- Bozell, Joseph J.,Hames, Bonnie R.,Dimmel, Donald R.
-
p. 2398 - 2404
(2007/10/02)
-
- Process for selective preparation of hydroxybenzaldehydes
-
Process for preparing hydroxybenzaldehydes of the formula (1) STR1 in which R1 -R4 are hydrogen, fluorine, chlorine, bromine, alkyl, alkoxy, phenyl, naphthyl, phenylalkyl, naphthylalkyl, phenoxy or saturated or unsaturated cyclopentane or cyclohexane radicals, and R1 -R4 may with the hydroxybenzene ring carbon atoms on which they are located form 1 or 2 saturated or unsaturated isocyclic or heterocyclic rings, by admixing 1 mol of a phenol of the formula (2) STR2 in which R1 -R4 have the stated meanings, in a pressure vessel with from 5 to 100 mol of hydrogen fluoride and from 0.5+x to 1.5+x mol of boron trifluoride, where x is the number of oxygen atoms contained in the starting compound (formula (2)), setting the mixture to from -10° to 100° C. and then passing carbon monoxide into this mixture until a pressure of from 10 to 150 bar is reached and allowing the mixture to react at the desired pressure reached.
- -
-
-
- The Oxidation of 2,4,6-Trimethylphenol with Molecular Oxygen Catalyzed by a Copper(II)-Oxime or Copper(II)-Amine System
-
2,4,6-Trimethylphenol (1a) was selectively oxidized to 3,5-dimethyl-4-hydroxybenzaldehyde (2a) by molecular oxygen in the presence of a copper(II) chloride-oxime or copper(II) chloride-amine catalyst in alcohol at ambient temperature.When an acid was present in the catalyst system, the formation of both 2,6-dimethyl-p-benzoquinone (3) and a formaldehyde dialkyl acetal was accelerated.It is likely that 2a is produced by way of the formation of a quinonemethide intermediate, followed by a repeated 1,6-addition of alcohol on the intermediate to form a 4-(alkoxymethyl)-2,6-dimethylphenol (5a), and then 3,5-dimethyl-4-hydroxybenzaldehyde dialkyl acetal, which would be hydrolyzed to 2a.When the reaction time was shortened, 5a was isolated in good yield.Oxidations of the other p-methyl-substituted phenols were also examined using the present oxidation system.
- Shimizu, Masao,Watanabe, Yoshihito,Orita, Hideo,Hayakawa, Takashi,Takehira, Katsuomi
-
p. 251 - 257
(2007/10/02)
-
- 4-oxy-substituted phenoxyalkyl carboxylic acid, ester, and alcohol derivatives as antihyper-cholesterolemic and antiatherosclerotic agents
-
Novel 4-oxy substituted phenoxyalkyl carboxylic acid, ester and alcohol derivatives are described, as well as methods for the preparation and pharmaceutical composition of same, which are useful in preventing the intestinal absorption of cholesterol and thus are useful in the treatment of hypercholesterolemia and atherosclerosis.
- -
-
-
- A Facile Synthesis of 4-Alkoxymethylphenols by a Copper(II)-Acetoxime Catalyst/O2 System
-
4-Alkoxymethyl-2,6-dimethylphenols were synthesized from 2,4,6-trimethylphenol in good yields by a copper(II) chloride-acetoxime catalyst/molecular oxygen system in alcohols at ambient temperature.The oxidation of the other p-methylsubstituted phenols were also examined.
- Shimizu, Masao,Watanabe, Yoshihito,Orita, Hideo,Hayakawa, Takashi,Takehira, Katsuomi
-
p. 2053 - 2056
(2007/10/02)
-
- Oxidation by Cobalt(III) Acetate. Part 13. Oxidation of Substituted Phenols with Cobalt(III) Acetate in Acetic Acid
-
The oxidation of 2,6-di- and 2,4,6-tri-substituted phenols with cobalt(III) acetate has been investigated in acetic acid under an inert atmosphere; the former gave the corresponding diphenoquinones in excellent yields, and the latter yielded side-chain or nuclear acetoxylated products in moderate to good yields.
- Hirano, Masao,Ishii, Tadamichi,Morimoto, Takashi
-
p. 1434 - 1436
(2007/10/02)
-
- Oxidation products of paramethyl-substituted hindered phenols
-
Paramethyl-substituted hindered phenols are selectively oxidized by contacting with an oxidizing agent at elevated temperatures in the presence of a heterogeneous oxidative coupling catalyst. In the absence of an optional nucleophile the products comprise carbon-carbon oxidative coupling products. In the presence of a nucleophile, addition products result that may be further oxidized by continued exposure to the oxidizing agent to yield substituted p-hydroxybenzaldehydes.
- -
-
-
- Process for production of aromatic aldehydes
-
Aromatic aldehydes are produced by oxidation with oxygen of a para-cresol derivative in a solvent, in the presence of a base and a catalytic amount of a cobalt compound. The catalyst is a chelated complex of cobalt with a rigid structure that is slightly oxidizable selected from the group consisting of bis-(4-methylpyridine isoindolinato)cobalt(II) acetate, phthalocyaninatocobalt(II), and sulfophthalocyaninanatocobalt(II). The process is particularly suited to the production of p-hydroxy benzaldehydes.
- -
-
-
- Compounds for inhibiting the biosynthesis of lipoxygenase-derived metabolites of arachidonic acid
-
Compounds having the formula inhibit 5-lypoxyogenase and are useful in the treatment of inflammation.
- -
-
-
- Potential antisecretory antidiarrheals. 1. α2-Adrenergic aromatic aminoguanidine hydrazones
-
Guanabenz, a centrally acting antihypertensive agent, has been shown to have intestinal antisecretory properties. A series of aromatic aminoguanidine hydrazones was made in an effort to separate the antisecretory and cardiovascular activities. Benzaldehyde, naphthaldehyde, and tetralone derivatives were synthesized. The compounds were evaluated in the cholera toxin treated ligated jejunum of the rat and in the Ussing chamber using a rabbit ileum preparation. A number of compounds, including members of each structural class, were active upon subcutaneous administration in the rat. Active compounds were determined to be α2-adrenergic agonists by yohimbine reversals of their Ussing chamber activities. The compound displaying the best separation of activities was the aminoguanidine hydrazone of 2,6-dimethyl-4-hydroxybenzaldehyde (20).
- Pitzele,Moormann,Gullikson,Albin,Bianchi,Palicharla,Sanguinetti,Walters
-
p. 138 - 144
(2007/10/02)
-
- OXYGENATION OF (E)-4-STILBENOLS CATALYSED BY COBALT(II) SCHIFF BASE CHELATES
-
Cobalt(II) Schiff base chelate, CoSMDPT (1), catalysed the oxygenation of (E)-4-stilbenols (2a-2d), to give two molecules of aldehydes.Both the oxygen atoms of dioxygen are incorporated into the substrate, providing a good chemical model for dioxygenase reactions.
- Ganeshpure, P. A.,Satish, S.
-
p. 6629 - 6632
(2007/10/02)
-
- A SIMPLE SINTHESIS OF TROPONES AND RELATED COMPOUNDS
-
Cyclohexa-2,4- and 2,5-dienones bearing position 2 or 4 a dihalomethyl group (halogen = chlorine or bromine) are smoothly reduced by tri-butyltin hydride to furnish appropriately substituted tropones.Modification of the substituents permits access to a tropolone and to less substituted tropones.The mechanism of this ring expansion process has been discussed.
- Barbier, Michael,Barton, Derek H. R.,Devys, Michel,Topgi, Ravindra Satish
-
p. 5031 - 5038
(2007/10/02)
-
- Oxidation of Phenols with Iodine in Alkaline Methanol
-
The use of iodine as an oxidizing agent for phenolic compounds has been explored.The reaction has been conducted in methanol containing such alkali as potassium hydroxide and, depending on the nature of the substituents and on the amount of iodine employed, leads to iodination, oxidation to give a stable phenoxy radical, oxidative dimerization, or benzylic oxidation.In general the reaction proceeds smoothly at room temperature, and under appropriate conditions yields of products are good to excellent.Oxidative dimerization of 2,4- and 2,6-di-tert-butylphenols invol-ves iodination followed by iodine-catalyzed dimerization.The oxidation of 4-methylphenols with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in methanol has been carried out for comparison.
- Omura, Kanji
-
p. 3046 - 3050
(2007/10/02)
-
- Migrations in Oxidations of Mesidine
-
The oxidation of mesidine in methanolic media by ferricyanide, dichromate, and persulfate afforded an anil 4 containing a shifted methoxymethyl group in addition to the principal anil 3 formed by oxidative dealkylation.Possible intermediates 6, 7, and 8 were prepared and oxidized to the product anils.Oxidations of related anilines 9, 10, and 13 did not parallel those of mesidine but afforded analogues of 3.There is significant spectral evidence for anils with alkyl shifts but little for anils analogous to 4.
- Goldstein, Stephen L.,McNelis, Edward
-
p. 1613 - 1620
(2007/10/02)
-
- Process for producing 4-hydroxy-2,4,6-trimethylcyclohexa-2,5-diene-1-one
-
A process for the preparation of 4-hydroxy-2,4,6-trimethylcyclohexa-2,5-diene-1-one from 2,4,6-trimethylphenol is disclosed, comprising reacting 2,4,6-trimethylphenol with an aqueous solution or suspension of hypohalogenous acid or salt thereof in an aqueous medium or mixed medium of water and specific organic solvents. This process enables to prepare 4-hydroxy-2,4,6-trimethylcyclohexa-2,5-diene-1-one, which is a precursor for 2,3,5-trimethylhydroquinone, a starting material for the preparation of vitamin E, by a simplified operation, safely and at high yields.
- -
-
-