- Reaction of sterically congested phenols and quinones with organic radicals
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In the course of radiation-induced free-radical transformations of hexane and ethanol, pyrocatechol and hydroquinone derivatives, as well as their respective quinones, are more effective than phenol and resorcinol derivatives in controlling reactions that involve alkyl and hydroxyalkyl radicals. The opposite result takes place in the inhibition by phenols of hexane oxidation in which the key role belongs to the peroxyl radicals generated from the starting compounds. 2005 Pleiades Publishing, Inc.
- Edimecheva,Ostrovskaya,Polozov,Shadyro
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- Alkylation of resorcinol with tertiary butanol over zeolite catalysts: Shape selectivity vs acidity
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The catalytic performance of various zeolites such as H-ZSM-5, H-Y, H-beta, H-Mordenite in resorcinol alkylation with tertiary butanol demonstrated that pore characteristics have major influence on product selectivity, whereas acid strength and number of acid sites influenced resorcinol conversion. The passivation of external surface of H-beta zeolite by silylation and amine poisoning produced shape selectively O-alkylated resorcinol methyl tert butyl ether (RMTBE) and 4-tert butyl resorcinol (4-TBR). We propose that 4-TBR formation goes over external acid sites through RMTBE isomerization, whereas formation of 4-TBR takes place inside the pores through direct C-alkylation mechanism.
- Marakatti, Vijaykumar S.,Gaigneaux, Eric M.
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- Preparation method of large-steric-hindrance biphenyl tetra-phenol skeleton and phosphite ligand thereof
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The invention discloses a large-steric-hindrance biphenyl tetra-phenol skeleton and a phosphite ligand thereof, which have good conversion rate and normal paraffin isomerization in hydroformylation reaction between 2,2',6,6'-tetra[(1,1,3-butadiene) and C5-C10 or above olefin.
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Paragraph 0027-0030
(2021/01/24)
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- Synthesis method of novel large-steric-hindrance biphenol skeleton and tridentate phosphite ligand thereof
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The invention discloses a synthesis method of a novel large-steric-hindrance biphenol skeleton 2, 2', 6-trihydroxy-3, 3', 5, 5'-tetra-tert-butyl-1, 1'-biphenyl and a tridentate phosphite ligand thereof. The novel biphenyl tridentate phosphite ligand has a structure as shown in a general formula I, and a substituent R in the general formula I can be a cyclic phosphine structure. The novel biphenyltridentate phosphite ligand has good conversion rate and normal-to-isomeric ratio in a mixed/etherified C4(butylene) hydroformylation reaction system.
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Paragraph 0029-0032
(2021/02/10)
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- Role of Lewis and Br?nsted acid sites in resorcinol: Tert-butylation over heteropolyacid-based catalysts
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The role of Br?nsted and Lewis acid sites at the surface of heteropolyacid-based catalysts was studied in resorcinol alkylation with methyl-Tert-butylether. Three sets of catalysts, SiO2/HPW, TiO2/HPW and ZrO2/HPW (where HPW stands for phosphotungstic acid hydrate), synthesized by the hydrolytic sol-gel method were investigated. The surface total acidity was characterized by ammonia chemisorption and thermo-programmed desorption. In addition, infrared analysis of adsorbed pyridine was performed to distinguish between Br?nsted and Lewis sites. The resorcinol conversion was correlated to the fraction of Br?nsted sites present at the catalyst surface based on the total acidity. The results pointed out the importance of considering both Br?nsted and Lewis sites as active players in the mechanism of resorcinol alkylation: Lewis sites have the role of adsorbing the substrate close to the tert-butyl cation, which is formed on Br?nsted sites. Resorcinol conversion can be increased to a maximum if the right Br?nsted/Lewis ratio is attained at the catalyst surface.
- Gaigneaux, Eric M.,Marakatti, Vijaykumar S.,Pezzotta, Chiara
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p. 7984 - 7997
(2020/12/28)
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- Biphenol compound as well as preparation method and application thereof
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The invention discloses a biphenyl triphenol compound. The compound has a structure as shown in the following formula (I). The biphenyl triphenol compound provided by the invention is an important intermediate for synthesizing a tridentate phosphite ligand of a biphenyl frame, and plays an important role in hydroformylation reaction and industrial application thereof. The invention also provides preparation methods of various biphenol compounds, including an oxidative coupling method; the oxidative coupling method provided by the invention can be used for synthesizing the biphenol compounds inone step; and the method has the advantages of cheap and easily available catalyst, simple operation, good yield, low cost and large-scale preparation.
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Paragraph 0106-0110
(2020/10/20)
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- Biphenyltridentate phosphite ligand and preparation method and application thereof (by machine translation)
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The invention discloses a biphenyl tridentate phosphite ligand and a preparation method and application thereof, wherein the biphenyltridentate phosphite ligand has the structure shown in a formula (I), and the ligand has extremely stable water oxygen. The catalyst is not easy to decompose and has good catalytic activity. (by machine translation)
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Paragraph 0096-0100
(2020/11/10)
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- Preparation of novel biphenyl tetradentate phosphite ligand and application of novel biphenyl tetradentate phosphite ligand in mixed/etherified C4 hydroformylation reaction
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The invention discloses a preparation method of a novel biphenyl tetradentate phosphite ligand 2, 2 ', 6, 6'-tetra [(1, 1 'biphenyl-2, 2'-diyl) phosphite]-3, 3 ', 5, 5'- tetra-tert-butyl -1, 1- 'biphenyl and derivatives thereof. The novel biphenyl tetradentate phosphite ligand has a structure as shown in general formula I, wherein a substituent R in the general formula I can be a cyclic phosphinestructure. Meanwhile, the invention discloses an application in a mixed/etherified C4 (butene) hydroformylation reaction system taking a novel biphenyl tetradentate phosphite ligand as a ligand.
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Paragraph 0026-0029
(2020/11/23)
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- Cambiarenes: Single-Step Synthesis and Selective Zwitterion Binding of a Clip-Shaped Macrocycle with a Redox-Active Core
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A novel macrocyclic host molecule was synthesized that forms in a single step from commercially available starting materials. The core of the macrocycle backbone possesses two quinone rings and, thus, it is redox-active. Host–guest binding involving the clip-shaped cavity indicates selective binding of pyridine N-oxides based on the electron density of and steric bulk around the anionic oxygen.
- Petersen, Riley J.,Rozeboom, Brett J.,Oburn, Shalisa M.,Blythe, Nolan J.,Rathje, Tanner L.,Luna, Javier A.,Kibby, Steven K.,O'Brien, Emily A.,Rohr, Kayleigh G.,Carpenter, Joshua R.,Sanders, Taylor L.,Johnson, Andrew M.,Hutchins, Kristin M.,Shaw, Scott K.,MacGillivray, Leonard R.,Wackerly, Jay Wm.
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supporting information
p. 1928 - 1930
(2020/02/11)
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- Sulfated zirconia: An efficient catalyst for the Friedel-Crafts monoalkylation of resorcinol with methyl tertiary butyl ether to 4-tertiary butylresorcinol
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Friedel-Crafts alkylation of resorcinol with methyl tertiary butyl ether was carried out over sulfated zirconia (SZ) catalysts in the liquid phase. The SZ catalysts were synthesized by an impregnation method with different sulfur amounts and characterized by XRD, FT-IR, nitrogen sorption, XPS, SEM, pyridine-FTIR, and NH3-TPD. The effect of the sulfur loading on the total acidity and catalytic activity was investigated. The influence of the nature of the solvents on the alkylation reaction was inspected in terms of their acceptor and donor numbers. The sulfur loading, amount of solvent, temperature, catalyst amount, mole ratio and reusability of the catalyst were examined. The SZ catalyst synthesized by impregnating 1 N sulfuric acid was found to be highly selective for the monoalkylation to 4-tertiary butyl resorcinol (72%) with a resorcinol conversion of ～70%. The catalyst was recycled thrice with a negligible decrease in the yield for 4-tertiary butylresorcinol. The SZ exhibited the best performance at low temperature (60 °C) among the different types of solid acid catalysts studied so far.
- Marakatti, Vijaykumar S.,Marappa, Shivanna,Gaigneaux, Eric M.
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supporting information
p. 7733 - 7742
(2019/05/27)
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- Dual oxidase/oxygenase reactivity and resonance Raman spectra of {Cu3O2} moiety with perfluoro-: T -butoxide ligands
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A Cu(i) fully fluorinated O-donor monodentate alkoxide complex, K[Cu(OC4F9)2], was previously shown to form a trinuclear copper-dioxygen species with a {Cu3(μ3-O)2} core, TOC4F9, upon reactivity with O2 at low temperature. Herein is reported a significantly expanded kinetic and mechanistic study of TOC4F9 formation using stopped-flow spectroscopy. The TOC4F9 complex performs catalytic oxidase conversion of hydroquinone (H2Q) to benzoquinone (Q). TOC4F9 also demonstrated hydroxylation of 2,4-di-tert-butylphenolate (DBP) to catecholate, making TOC4F9 the first trinuclear species to perform tyrosinase (both monooxygenase and oxidase) chemistry. Resonance Raman spectra were also obtained for TOC4F9, to our knowledge, the first such spectra for any T species. The mechanism and substrate reactivity of TOC4F9 are compared to those of its bidentate counterpart, TpinF, formed from K[Cu(pinF)(PR3)]. The monodentate derivative has both faster initial formation and more diverse substrate reactivity.
- Brazeau, Sarah E. N.,Norwine, Emily E.,Hannigan, Steven F.,Orth, Nicole,Ivanovi?-Burmazovi?, Ivana,Rukser, Dieter,Biebl, Florian,Grimm-Lebsanft, Benjamin,Praedel, Gregor,Teubner, Melissa,Rübhausen, Michael,Liebh?user, Patricia,R?sener, Thomas,Stanek, Julia,Hoffmann, Alexander,Herres-Pawlis, Sonja,Doerrer, Linda H.
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p. 6899 - 6909
(2019/05/27)
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- Synergistic role of Lewis and Br?nsted acidities in Friedel-Crafts alkylation of resorcinol over gallium-zeolite beta
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The role of Lewis and Br?nsted acidities in alkylation of resorcinol is demonstrated through the gallium-zeolite beta by varying the amount of Lewis and Br?nsted acid sites. The synergism of Lewis and Br?nsted acid sites takes place heterogeneously in Friedel-Crafts alkylation of resorcinol with methyl tert-butyl ether to produce 4-tert-butyl resorcinol and 4,6-di-tert-butyl resorcinol as the major and minor products, respectively.
- Nur, Hadi,Ramli, Zainab,Efendi, Jon,Rahman, Aiman Najati Akmar,Chandren, Sheela,Yuan, Lai Sin
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experimental part
p. 822 - 825
(2012/01/03)
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- Chemical double mutant cycles for the quantification of cooperativity in H-bonded complexes
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Chemical double mutant cycles have been used in conjunction with new H-bonding motifs for the quantification of chelate cooperativity in multiply H-bonded complexes. The double mutant cycle approach specifically deals with the effects of substituents, sec
- Camara-Campos, Amaya,Musumeci, Daniele,Hunter, Christopher A.,Turega, Simon
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scheme or table
p. 18518 - 18524
(2010/04/24)
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- Synthesis and solid state structure of oxacalix[4]arenes bearing four nitro groups and four tert-butyl groups at their extra-annular positions
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Four oxacalix[4]arene derivatives, in which 1,3-dinitrobenzene units and 1,3-di-tert-butylbenzene units are incorporated in alternating order, were synthesized by aromatic nucleophilic substitution. The introduction of the tert-butyl groups increased the stability of the macrocycles against nucleophilic C-O bond cleavage. X-ray crystal structure analyses reveal that the oxacalixarenes adopt an unsymmetrical 1,3-alternate conformation. The bulky substituents did not disturb the conjugation between the bridging oxygen atoms and the dinitrobenzene rings.
- Akagi, Shuichiro,Yasukawa, Yusuke,Kobayashi, Kazuhiro,Konishi, Hisatoshi
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supporting information; experimental part
p. 9983 - 9988
(2010/02/27)
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- DENDRON AND DENDRIMER, METHOD OF PRODUCING THE SAME, AND METHOD OF PRODUCING A THIOACETAL COMPOUND
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A dendron or dendrimer, which has, as a recurring unit of each branch, a structure of formula (I): Wherein TC designates a linkage to a former generation in the direction to a focal point of the dendron or a core of the dendrimer; TT designates a linkage to a next generation in the direction to a terminal; X is a divalent group comprised of at least one heteroatom; L?1#191 and L?2#191 each are a divalent linking group; R is a hydrogen atom or a substituent; and a method of producing a dendron or a dendrimer; and a method of producing a thioacetal compound.
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Page/Page column 26
(2008/06/13)
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- Copper(II)-mediated autoxidation of tert-butylresorcinols
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Although copper(II)-mediated oxidation of phenols results in oxidative coupling rather than in oxygenation, it was recently reported that naturally occurring 5-alkylresorcinols undergo oxygenation in the presence of copper(II). To explore the generality of this reaction, the copper(II)-mediated autoxidation of 4-tert-butylresorcinol and 4,6-di-tert-butylresorcinol was investigated and was found to result in direct oxygenation at open activated positions and, at the tert-butyl-substituted positions, in oxygenation with competing loss of (as isobutylene) and 1,2-rearrangement of the tert-butyl group. 5-tert-Butyl-2-hydroxy-1,4-benzoquinone is the major product from both starting materials, and the final product mixture reflects, in part, coupling of metastable initially formed electrophilic and nucleophilic side products. Mechanisms that are consistent with the observed products and control reactions are proposed. The key step appears to be equilibration of a copper(II)-resorcinolate with a charge-transfer radical form that reacts regioselectively with O2 as prescribed by resonance.
- Ling, Ke-Qing,Lee, Younghee,Macikenas, Dainius,Protasiewicz, John D.,Sayre, Lawrence M.
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p. 1358 - 1366
(2007/10/03)
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- Method for producing hydroxy-containing alkylated aromatic compounds
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Process for producing hydroxy-containing alkylated aromatic compounds by the liquid phase reaction of an aromatic compound having at least one hydroxyl group with an alkylating agent in the presence of a heteropoly acid and water.
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- ALKYLATION OF RESORCINOL BY TERTIARY ALCOHOLS
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The initial product from the alkylation of resorcinol by tert-butyl alcohol in the presence of phosphoric or sulfuric acids is 4-tert-butylresorcinol, which is then converted into 4,6-disubstituted resorcinol.The optimum yields of 4,6-di-tert-alkylresorcinols are obtained with sulfuric acid as catalyst with the resorcinol, tertiary alcohol, and acid in molar ratios of 1:3:0.5.
- Korneev, S. M.,Nikolaev, V. A.
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p. 1493 - 1495
(2007/10/02)
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- SYNTHESIS OF ANALOGUES OF PRECOCENES CONTAINING 6-CHLORO- OR 6-TERT-BUTYL SUBSTITUENTS
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The synthesis of benzopyran compounds (XIV and XVI), analogues of precocenes (I and II) containing 6-chloro- or 6-tert-butyl substituents, is described .
- Seboek, Peter,Timar, Tibor,Jaszberenyi, J. Csaba,Jekoe, Jozsef
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p. 471 - 486
(2007/10/02)
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- Silica Gel as an Effective Catalyst for the Alkylation of Phenols and Some Heterocyclic Compounds
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In the presence of silica gel, the reaction of phenol with t-BuBr was examined under a variety of conditions and it was found that silica gel is an effective catalyst for the alkylation.As a result of this work 2-tert-butyl-, 2,6-di-tert-butyl-, and 2,4,6-tri-tert-butylphenols, all of which are hard to obtain directly by the Friedel-Crafts process, could be prepared easily by this one-step reaction.Several other alkyl halides were also used in this reaction.The alkylations of some heterocyclic aromatic compounds which cannot be alkylated by the conventional Friedel-Crafts method were also succesfully performed by this reaction.
- Kamitori, Yasuhiro,Hojo, Masaru,Masuda, Ryoichi,Izumi, Tatsuo,Tsukamoto, Shuichi
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p. 4161 - 4165
(2007/10/02)
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- PHOSPHORORGANISCHE VERBINDUNGEN 101. TERTIAERE PHOSPHINE MIT ORTHOALKOXYPHENYL-GRUPPEN. Synthese und Eigenschaften
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Alkylphenylethers, ortho-lithiated in good yields, are transformed according to scheme (1) to the triarylphosphines ArPPh2, Ar2PPh and Ar3P (Ar contains in all cases an ortho-alkoxy group) (Table 1.).Hydroquinonedialkylethers can be lithiated twice, forming the compounds 102 and 103.Table 2 summarizes some arylalkylethers (71 - 101) which were lithiated; table 7 presents 12 new arylalkylethers.The syntheses of triarylphosphines with one or two bulky groups (105 - 110) and of triarylphosphines with one or two 3,4-dialkoxyphenyl groups (111 - 114) are reported.The 31P-spectra of the compounds prepared are discussed with respect to the validity of the Tolman-rule.
- Horner, L.,Simons, G.
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p. 189 - 210
(2007/10/02)
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