- Diazaborines oxidize slowly with H2O2 but rapidly with peroxynitrite in aqueous buffer
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Reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) and peroxynitrite (ONOO?) oxidize arylboronic acids to their corresponding phenols. When used in molecular imaging probes and in ROS-responsive molecules, however, simple arylboronic acids struggle to discriminate between H2O2 and ONOO? because of their fast rate of reaction with both ROS. Here, we show that diazaborines (DABs) react slowly with H2O2 but rapidly with peroxynitrite in an aqueous buffer. In addition to their slow reaction with H2O2, the immediate product of DAB oxidation with H2O2 and ONOO? can yield a kinetically trapped CN Z-isomer that slowly equilibrates with its E-isomer. Taken together, our work shows that diazaborines exhibit enhanced kinetic discrimination between H2O2 and ONOO? compared to arylboronic acids, opening up new opportunities for diazaborine-based tools in chemical biology.
- Domaille, Dylan W.,Golzwarden, Julian V. A.,Haggett, Jack G.,Han, Gun Su,Moser, Angela R.,Vyas, Shubham
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supporting information
p. 995 - 999
(2022/02/16)
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- Fabricating Bifunctional Co?Al2O3@USY Catalyst via In-Situ Growth Method for Mild Hydrodeoxygenation of Lignin to Naphthenes
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To enhance the catalytic activity and stability of metal catalysts in the hydrodeoxygenation of lignin derivatives into naphthenes, a bifunctional Co?Al2O3@USY catalyst was fabricated by the reduction of CoAl layered double hydroxide in-situ grown on the USY zeolite. In the hydrodeoxygenation of guaiacol, a 100.0 % conversion with cyclohexane yield up to 93.6 % was achieved at 180 °C, 3 MPa for 4 h, which should be the hitherto lowest reaction temperature that has been reported over Co-based metal catalysts. This catalyst was also relatively stable with 5 runs and exhibited excellent catalytic performance in the hydrodeoxygenation of other lignin model compounds and even real lignin feedstock into naphthenes. The high-efficiency of Co?Al2O3@USY was attributed to the synergistic effect between well-dispersed small Co nanoparticles and abundant acidic sites on the USY surface, while the outstanding stability was attributed to the anchoring effect of Al2O3 matrix to Co nanoparticles which avoided the leaching of Co species and particle agglomeration. This work provides a potential strategy for the design of an efficient and stable catalyst for lignin utilization.
- Cheng, Shuai,Diao, Xinyong,Ji, Na,Jia, Zhichao,Li, Hanyang,Ri, Poknam,Wang, Shurong
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- A cascade mechanism for a simple reaction: The gas-phase methylation of phenol with methanol
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The gas-phase alkylation of phenol with methanol, a reaction triggered for the production of o-cresol and 2,6-xylenol, is catalysed by MgO-based catalysts. Despite the industrial use of this process, the mechanism of the reaction – which is commonly believed to be based on a classical electrophilic attack of activated methanol onto the aromatic ring – is far from being fully understood. In some previous studies we reported that the reaction intermediate is salicylic alcohol, which is formed by the reaction between the adsorbed phenolate and formaldehyde, the latter being formed in-situ by methanol dehydrogenation. Here we elucidate the following steps of the reaction mechanism, by combining reactivity experiments and DFT calculation, with MgO as a model catalyst. It was found that salicylic alcohol dehydrates into quinone methide, which is then reduced via H-transfer by methanol to o-cresol. Moreover, a dehydrogenation/hydrogenation equilibrium is established between salicylic alcohol and salicylic aldehyde. The methide can also react with methanol to form 2-methoxymethylphenol, which may decompose into o-cresol, thus providing an alternative pathway for the formation of the alkylated compound.
- Tabanelli, Tommaso,Passeri, Sauro,Guidetti, Stefania,Cavani, Fabrizio,Lucarelli, Carlo,Cargnoni, Fausto,Mella, Massimo
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p. 447 - 460
(2019/01/30)
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- A naphthoquine phosphate process impurity and its synthesis method
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The invention discloses a compound of formula (I) reported shown naphthoquine phosphate has not seen the structure of process impurities, and provides a alkyl aminomethyl phenol is converted into the corresponding alkyl ethoxy methyl phenol, or substitute
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Paragraph 0045-0047
(2019/04/04)
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- PROCESS FOR THE PREPARATION OF 2-METHOXYMETHYL-1,4-BENZENEDIAMINE, ITS DERIVATIVES THEREOF AND THE SALTS THEREOF
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A process for synthesizing 2-methoxymethyl-1,4-benzenediamine, its derivatives of formula (IV) and the salts thereof, which comprises a reductive amination step. The preferred final product is 2-methoxymethyl-1,4-benzenediamine of formula (IV-a). (Formula
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Page/Page column 19
(2012/06/16)
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- Copper(I)-catalyzed hydroalkoxylation/hydrogen-bonding-induced asymmetric hetero-diels-alder cycloaddition cascade: An approach to aromatic spiroketals
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One thing leads to another: Bis(benzannelated) 5,6-spiroketal skeletons can be constructed by an efficient cascade process involving an unprecedented CuI-catalyzed intramolecular alkyne hydroalkoxylation and an asymmetric hetero-Diels-Alder cyc
- Li, Xin,Xue, Jijun,Huang, Chusheng,Li, Ying
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supporting information; experimental part
p. 903 - 906
(2012/07/03)
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- Mild and rapid method for the generation of ortho -(naphtho)quinone methide intermediates
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A new mild method has been devised for generating o-(naphtho)quinone methides via fluoride-induced desilylation of silyl derivatives of o-hydroxybenzyl(or 1-naphthylmethyl) nitrate. The reactive o-(naphtho)quinone methide intermediates were trapped by C,
- Shaikh, Abdul Kadar,Cobb, Alexander J. A.,Varvounis, George
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p. 584 - 587
(2012/03/10)
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- Substituted triazole derivatives as oxytocin antagonists
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The present invention relates to substituted triazoles of formula (I), uses thereof, processes for the preparation thereof and compositions containing said compounds. These inhibitors have utility in a variety of therapeutic areas including sexual dysfunction.
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Page/Page column 37
(2008/06/13)
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- Rare earth metal trifluoromethanesulfonates catalyzed benzyl-etherification.
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Rare earth metal trifluoromethanesulfonates [rare earth metal triflate, RE(OTf)3] were found to be efficient catalyst for benzyl-etherification. In the presence of a catalytic amount of RE(OTf)3, condensation of benzyl alcohols and aliphatic alcohols proceeded smoothly to afford the benzyl ethers. The condensation between benzyl alcohols and thiols also proceeded, and thio ethers were obtained in good yield. In these reactions, RE(OTf)3 could be recovered easily after the reactions were completed and could be reused without loss of activity.
- Kawada, Atsushi,Yasuda, Kayo,Abe, Hitoshi,Harayama, Takashi
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p. 380 - 383
(2007/10/03)
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- Reductive etherification of aromatic aldehydes with decaborane
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Aromatic aldehydes were easily convened to the corresponding ethers in methanol or ethanol using decaborane at r.t. under nitrogen in high yields.
- Lee, Seung Hwan,Park, Yong June,Yoon, Cheol Min
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p. 6049 - 6050
(2007/10/03)
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- Convenient Method for the ortho-Formylation of Phenols
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Phenolic derivatives are formylated selectively ortho to the hydroxy group by paraformaldehyde with magnesium dichloride-triethylamine as base. With alkyl-substituted phenols excellent yields of the corresponding salicylaldehyde derivatives were obtained. Similar results were obtained with chloro-substituted phenols and with 3- and 4-methoxyphenol, while 2-methoxyphenol was unreactive. A good yield of methyl 3-formyl-4-hydroxybenzoate was obtained by this method as well, but generally phenols with electron-attracting groups reacted sluggishly; the long reaction times required caused the formation of by-products, particularly MOM-derivatives of the phenols.
- Hofslokken, Nini U.,Skattebol, Lars
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p. 258 - 262
(2007/10/03)
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- The reactivity of o-hydroxybenzyl alcohol and derivatives in solution at elevated temperatures
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The reactivity of o-hydroxybenzyl alcohol (o-HBA, 1), as a model compound for lignin, has been studied in various solvents between 390 and 560 K. Both in polar and apolar solvents the benzylic cation is the reactive intermediate. In alcoholic solvents, the benzylic cation reacts with the solvent to give the corresponding ethers. Relative reaction rates have been determined for different alcohols; a factor of 14 is encountered between the most (methanol) and least (tert-butyl alcohol) reactive ones. The etherification is reversible, in contrast to the electrophilic aromatic substitution with phenol and anisole, for which k(PhOH) = 1 X 105 M-1 s- 1 and k(anisole) = 1 x 104 M-1 s-1, at 424 K. In apolar hydroaromatic solvents, 7H-benz[de]anthracene, 9,10-dihydroanthracene, and 9,10- dihydrophenanthrene, the formation of o-cresol proceeds via hydride transfer from the solvent to the benzylic cation; rate constants at 555 K are 2 x 106, 5 x 104, and 5 x 103 M-1 s-1, respectively.
- Dorrestijn, Edwin,Kranenburg, Marieke,Ciriano, Maria Victoria,Mulder, Peter
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p. 3012 - 3018
(2007/10/03)
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- A New Synthesis of 2,2'-Disubstituted Unsymmetrical Biphenyls Based on the Intramolecular Ullmann Coupling Reaction Utilising Salicyl Alcohol as a Template
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A synthesis of 2,2'-disubstituted unsymmetrical biphenyls was examined by using the template-directed intramolecular Ullmann coupling reaction as a key step.The Ullmann coupling reaction of the diesters 1-5 showed that the most suitable ring size for the intramolecular Ullmann coupling reaction is an eleven-membered ring.On the basis of these results, salicyl alcohol was selected as a template.Acylations of salicyl alcohol by two different aroyl chlorides proceeded regioselectively in a one-pot procedure to afford the diesters 18 in good yields.The intramolecular Ullmann coupling reaction of 18 by the dropwise-addition method gave the cyclisation products 19 in high yields.Hydrogenolysis of 19 proceeded regioselectively to afford the unsymmetrical biphenyls 21 in quantitative yields, while the regioselective cleavage of the ester bonds of 19 by nucleophilic substitution reactions gave the corresponding 2,2'-disubstituted unsymmetrical biphenyls 22 and 24 in good yields.
- Takahashi, Masami,Ogiku, Tsuyosi,Okamura, Kimio,Da-te, Tadamasa,Ohmizu, Hiroshi,et al.
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p. 1473 - 1480
(2007/10/02)
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- A FACILE SYNTHESIS OF HOGHLY FUNCTIONALIZED UNSYMMETRICAL HETEROBIARYLS UTILIZING THE INTRAMOLECULAR ULLMANN COUPLING REACTION DIRECTED BY SALICYL ALCOHOL AS A TEMPLATE
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The cyclic heterobiaryls (3) containing a thenoyl of furoyl group were synthesized in good yields by regioselective acylations of salicyl alcohol (1), followed by the intramolecular Ullmann coupling reaction of the diesters (2).The cleavage of the two est
- Takahashi, Masami,Kuroda, Tooru,Ogiku, Tsuyoshi,Ohmizu, Hiroshi,Kondo, Kazuhiko,Iwasaki, Tameo
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p. 1867 - 1882
(2007/10/02)
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- A FACILE SYNTHESIS OF HIGHLY FUNCTIONALIZED UNSYMMETRICAL HETEROBIARYLS UTILIZING THE INTRAMOLECULAR ULLMANN COUPLING REACTION DIRECTED BY SALICYL ALCOHOL AS A TEMPLATE
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Heterobiaryls (4) were synthesized in good yields utilizing intramolecular Ullman couplig reaction directed by salicyl alcohol as a template.The regioselective cleavage of the two ester bonds of 4 gave the highly functionalized unsymmetrical heterobiaryls
- Takahashi, Masami,Kuroda, Tooru,Ogiku, Tsuyoshi,Ohmizu, Hiroshi,Kondo, Kazuhiko,Iwasaki, Tameo
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p. 2061 - 2064
(2007/10/02)
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- An Efficient Synthesis of Highly Functionalized Unsymmetrical Biphenyls Having Substituents on the Ortho Positions
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The highly functionalized unsymmetrical biphenyls having electron-donating and/or electron-withdrawing substituents on the ortho positions were effectively synthesized based on the intramolecular Ullmann coupling reaction directed by salicyl alcohol as a
- Takahashi, Masami,Moritani, Yasunori,Ogiku, Tsuyoshi,Ohmizu, Hiroshi,Kondo, Kazuhiko,Iwasaki, Tameo
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p. 5103 - 5104
(2007/10/02)
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New oxygen-activating systems for dehydrogenation of 2-hydroxymethyl phenols 1 (a: R = tBu ; b: R = CH3; c : R = H) to the corresponding salicylaldehydes 3 are described. These systems are composed of a transition metal (M0 = Fe0 or Cu0), a transition metal ion (MnCln=Fe11Cl2 or Cu1Cl) in catalytic amount and molecular oxygen. The most active systems are Fe0FeCl2O2CH3OH and Cu0CuCl + FeCl2O2CH3OH. Based on all the results so far obtained a mechanistic hypothesis is proposed.
- Sparfel, Daniel,Baranne-Lafont, Joele,Cuong, Nguyen Kim,Capdevielle, Patrice,Maumy, Michel
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p. 793 - 802
(2007/10/02)
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- Photocondensation of o-Hydroxybenzyl Alcohol in an Alkaline Medium: Synthesis of Phenol-Formaldehyde Resins
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A new method for the synthesis of phenol-formaldehyde (Bakelite) resins via a new photochemical reaction, the photocondensation of o-hydroxybenzyl alcohol (saligenin) in an alkaline medium, is reported.
- Wan, Peter,Hennig, Darren
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p. 939 - 941
(2007/10/02)
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- An Application of nJ(CH2,H) and 5J(OH,H) Long-Range Couplings in the Conformational Analysis of 2-Hydroxybenzyl Methyl Ether in Various Solvents. Computational Strategies for Spectral Analysis and Determination of Association Thermod
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1H NMR spectra of 2-hydroxy- and 2-methoxy-benzyl methyl ethers were measured in various solvents and solvent mixtures.Precise nJ(CH2,H), where n = 4, 5 or 6, and 5J(OH,H) long-range couplings were applied to the characterization of
- Laatikainen, Reino
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p. 588 - 594
(2007/10/02)
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- Structure-Reactivity Studies and Catalytic Effects in the Photosolvolysis of Methoxy-substituted Benzyl Alcohols
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The photosolvolysis of several methoxy-, dimethoxy-, and hydroxy-substituted benzyl alcohols has been studied in aqueous solution.The primary photochemical event is photodehydroxylation, to give a benzyl cation intermediate, which can be trapped by added external nucleophiles.The reaction is via the singlet excited state, based on observation of fluorescence quenching by hydronium ion in a complementary manner with acid catalysis of reaction observed for several derivatives.Solvent isotope effects on fluorescence efficiency and reaction for (7) and (8) provide additional support of singlet-state reactivity for these compounds.Dimethoxy-substituted alcohols are more reactive than monosubstituted compounds, with quantum yields of methanolysis of up to 0.31 for the most reactive compound, 2,6-dimethoxybenzyl alcohol (8).Using a kinetic argument, the quantum yields of the primary photodehydroxylation process has been estimated to be 1.0 +/- 0.1 for this compound.The results observed for the dimethoxy-substituted derivatives suggest the existence of additivity of substituent effects in these photodehydroxylation reactions.
- Wan, Peter,Chak, Becky
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p. 1751 - 1756
(2007/10/02)
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- Immonium salts and derivatives thereof
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There are provided: novel aryloxy immonium salts, prepared by the reaction of their corresponding haloformates with amides; and phenolic compositions corresponding to the aryloxy immonium salts. These novel aryloxy immonium salts and their corresponding phenolic compositions have utility as chemical intermediates, antioxidants, stabilizers and antibacterials.
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- Immonium salts and derivatives thereof
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There are provided: novel aryloxy immonium salts, prepared by the reaction of their corresponding haloformates with amides; and phenolic compositions corresponding to the aryloxy immonium salts. These novel aryloxy immonium salts and their corresponding phenolic compositions have utility as chemical intermediates, antioxidants, stabilizers and antibacterials.
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