- Macroporous silica microcapsules immobilizing esterase with high hydrolysis reactivity
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An esterase, 3,4-dihydrocoumarin hydrolase, was directly immobilized into silica microcapsules. The hydrolysis reaction of 3,4-dihydrocoumarin by a macroporous silica microcapsule immobilizing the esterase was faster than those by mesoporous ones. Using t
- Fujiwara, Masahiro,Shoji, Shigeru,Murakami, Yuka,Ishikawa, Kazuhiko
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Read Online
- Industrial production method of 4-hydroxy-1-indanone
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The invention discloses an industrial production method of 4-hydroxy-1-indanone, and relates to the technical field of organic chemistry, the industrial production method comprises the following steps: taking dihydrocoumarin as a raw material, carrying out hydrolysis reaction on the dihydrocoumarin under the catalysis of hydrochloric acid to obtain an intermediate 1, and carrying out cyclization reaction on the intermediate 1 and polyphosphoric acid under the catalysis of strongly acidic resin to obtain the 4-hydroxy-1-indanone. The preparation method disclosed by the invention is short in route, easily available in raw materials, high in yield, moderate in reaction condition, suitable for industrial production, less in three wastes, more environment-friendly, easier to operate and stable in process.
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Paragraph 0019; 0040-0042; 0045-0047; 0050-0052; 0062-0064
(2021/08/14)
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- Ruthenium-catalyzed intramolecular arene C(sp2)-H amidation for synthesis of 3,4-dihydroquinolin-2(1 H)-ones
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We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp2)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.
- Au, Chi-Ming,Ling, Cho-Hon,Sun, Wenlong,Yu, Wing-Yiu
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p. 3310 - 3314
(2021/05/29)
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- Scalable and safe synthetic organic electroreduction inspired by Li-ion battery chemistry
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Reductive electrosynthesis has faced long-standing challenges in applications to complex organic substrates at scale. Here, we show how decades of research in lithium-ion battery materials, electrolytes, and additives can serve as an inspiration for achieving practically scalable reductive electrosynthetic conditions for the Birch reduction. Specifically, we demonstrate that using a sacrificial anode material (magnesium or aluminum), combined with a cheap, nontoxic, and water-soluble proton source (dimethylurea), and an overcharge protectant inspired by battery technology [tris(pyrrolidino)phosphoramide] can allow for multigram-scale synthesis of pharmaceutically relevant building blocks. We show how these conditions have a very high level of functional-group tolerance relative to classical electrochemical and chemical dissolving-metal reductions. Finally, we demonstrate that the same electrochemical conditions can be applied to other dissolving metal-type reductive transformations, including McMurry couplings, reductive ketone deoxygenations, and epoxide openings.
- Peters, Byron K.,Rodriguez, Kevin X.,Reisberg, Solomon H.,Beil, Sebastian B.,Kawamata, Yu,Baran, Phil S.,Hickey, David P.,Klunder, Kevin,Gorey, Timothy J.,Anderson, Scott L.,Minteer, Shelley D.,Collins, Michael,Starr, Jeremy,Chen, Longrui,Udyavara, Sagar,Neurock, Matthew
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p. 838 - 845
(2019/04/30)
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- Pd nanoparticles on reverse phase silica gel as recyclable catalyst for Suzuki-Miyaura cross coupling reaction and hydrogenation in water
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Two catalytic systems, consisting of palladium nanoparticles supported by reverse phase amino functionalized silica are utilized as catalysts for Suzuki-Miyaura reaction and hydrogenation in water. The catalysts were developed by modifying silica into bidentate ligands, using either 2-pyridinecarboxaldehyde or 2,2′-bipyridine-4,4′-dicarboxylic acid. The synthesized catalysts showed quantitative reaction yields and recyclability with negligible leaching of Pd nanoparticles. Various characterization techniques including XPS, ICP-MS, SEM, BET, XRD, TEM, 1H- and 13C- NMR are used to verify the efficiency of the catalysts.
- Shabbir, Saira,Lee, Sinyoung,Lim, Minkyung,Lee, Heejin,Ko, Hyeji,Lee, Youngbok,Rhee, Hakjune
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p. 296 - 304
(2017/07/12)
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- Catalytic hydrolysis of hydrophobic esters on/in water by high-silica large pore zeolites
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Hydrolysis of water-insoluble esters is an industrially important but challenging reaction, because the esters are mostly present in oil droplets on water during the reaction. On the basis of the screening results for hydrolysis of a water-insoluble ester, 3-phenylpropionate, on/in water by 25 types of heterogeneous and homogenous catalysts, we have found that Hβ zeolite with a moderate Si/Al ratio (Si/Al = 75), Hβ-75, is an effective and reusable catalyst for hydrolysis of hydrophobic esters. The hydrolysis of esters with different sizes is studied by Hβ and HZSM5 zeolites with different Si/Al ratios, and the results show the hydrophobicity, pore size and number of Br?nsted acid sites are critical factors affecting the catalytic activity for this system. Kinetic and adsorption studies show that the high yields by Hβ-75 are due to preferential interaction of the hydrophobic zeolite pore with hydrophobic esters over polar molecules (carboxylic acids, water, alcohols) and transfer of the carboxylic acids to the oil droplets on water, both of which inhibit the reverse reaction (esterification of the carboxylic acids).
- Siddiki,Toyao, Takashi,Kon, Kenichi,Touchy, Abeda S.,Shimizu, Ken-ichi
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p. 741 - 748
(2016/12/09)
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- Computational and Experimental Studies of Phthaloyl Peroxide-Mediated Hydroxylation of Arenes Yield a More Reactive Derivative, 4,5-Dichlorophthaloyl Peroxide
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The oxidation of arenes by the reagent phthaloyl peroxide provides a new method for the synthesis of phenols. A new, more reactive arene oxidizing reagent, 4,5-dichlorophthaloyl peroxide, computationally predicted and experimentally determined to possess enhanced reactivity, has expanded the scope of the reaction while maintaining a high level of tolerance for diverse functional groups. The reaction proceeds through a novel "reverse-rebound" mechanism with diradical intermediates. Mechanistic insight was achieved through isolation and characterization of minor byproducts, determination of linear free energy correlations, and computational analysis of substituent effects of arenes, each of which provided additional support for the reaction proceeding through the diradical pathway.
- Camelio, Andrew M.,Liang, Yong,Eliasen, Anders M.,Johnson, Trevor C.,Yuan, Changxia,Schuppe, Alex W.,Houk,Siegel, Dionicio
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p. 8084 - 8095
(2015/09/01)
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- CYCLIC PEROXIDE OXIDATION OF AROMATIC COMPOUND PRODUCTION AND USE THEREOF
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The present invention provides a method for converting an aromatic hydrocarbon to a phenol by providing an aromatic hydrocarbon comprising one or more aromatic C-H bonds and one or more activated C-H bonds in a solvent; adding a phthaloyl peroxide to the solvent; converting the phthaloyl peroxide to a di-radical; contacting the di-radical with the one or more aromatic C-H bonds; oxidizing selectively one of the one or more aromatic C-H bonds in preference to the one or more activated C-H bonds; adding a hydroxyl group to the one of the one or more aromatic C-H bonds to form one or more phenols; and purifying the one or more phenols.
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Page/Page column 10
(2014/10/15)
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- Raney nickel-catalyzed hydrogenation of unsaturated carboxylic acids with sodium borohydride in water
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A mild, selective, and green method for the reduction of unsaturated carboxylic acids with sodium borohydride-Raney nickel (W6) system in water is reported. This method is practical and safe and avoids use of organic solvents. Taylor & Francis Group, LLC.
- Rao, Gopal Krishna,Gowda, Narendra B.,Ramakrishna, Ramesha A.
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experimental part
p. 893 - 904
(2012/02/01)
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- Microbial reduction of coumarin, psoralen, and xanthyletin by Glomerella cingulata
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Microbial transformation of coumarin, psoralen, and xanthyletin was performed with the fungus Glomerella cingulata. The main reaction pathways involved reduction at α,β-unsaturated δ-lactone ring on coumarin analogue. Coumarin was metabolized by G. cingul
- Marumoto, Shinsuke,Miyazawa, Mitsuo
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experimental part
p. 495 - 500
(2011/03/19)
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- Biotransformation of dihydrocoumarin by Aspergillus niger ATCC 11394
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Aspergillus niger ATCC 11394 was used to catalyze the biotransformation of dihydrocoumarin using two experimental conditions: growing and resting cells. Six biotransformation products (2- 7) were purified from the bio-reaction media and their structures e
- Aguirre-Pranzoni, Celeste B.,Furque, Gabriela I.,Ardanaz, Carlos E.,Pacciaroni, Adriana,Sosa, Virginia,Tonn, Carlos E.,Kurina-Sanz, Marcela
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experimental part
p. 170 - 181
(2011/05/17)
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- Pd nanoparticles dispersed on solid supports: Synthesis, characterization and catalytic activity on selective hydrogenation of olefins in aqueous media
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Two types of Pd nanoparticle catalysts were prepared having 2-4 nm particle size using silica gel and porous polymer beads as solid supports. 2-Pyridinecarboxaldehyde ligand was anchored on commercially available 3-aminopropyl-functionalized silica gel followed by Pd metal dispersion. Bead-shaped cross-linked poly(4-vinylpyridine-co-styrene) gel was prepared by an emulsifier-free emulsion polymerization of 4-vinylpyridine, styrene and divinylbenzene in the presence of ammonium persulfate and subsequently dispersing the Pd metal on the synthesized polymer. These catalysts were characterized by SEM, TEM and ICP techiniques with respect to appearance, size and possible leaching out, respectively. Furthermore, the reactivity of these catalysts was tested on hydrogenation of various α,β-unsaturated carbonyl compounds using aqueous solvent under a hydrogen balloon (1 atm). The results showed that the Pd dispersed on silica was a more efficient catalyst than Pd dispersed on polymer and the former could be recycled more than 10 times without considerable loss in activity. Copyright
- Lim, Minkyung,De Castro, Kathlia A.,Oh, Seungchan,Lee, Kangsuk,Chang, Young-Wook,Kim, Hokun,Rhee, Hakjune
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scheme or table
p. 1 - 8
(2011/09/14)
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- A chemoselective hydrogenation of the olefinic bond of α,β- unsaturated carbonyl compounds in aqueous medium under microwave irradiation
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A microwave-assisted mild and ecofriendly catalytic transfer hydrogenation process was developed to reduce various α,β-unsaturated carbonyl compounds into the corresponding saturated carbonyl compounds in the presence of silica-supported palladium chloride as catalyst and a combination of MeOH/HCOOH/H2O (1:2:3) as hydrogen source within 22-55 minutes in moderate to excellent yields with 100% chemoselectivity.
- Sharma, Anuj,Kumar, Vinod,Sinha, Arun K.
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p. 354 - 360
(2007/10/03)
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- Solid-supported green synthesis of substituted hydrocinnamic esters by focused microwave irradiation
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An efficient chemoselective hydrogenation protocol for substituted cinnamic esters is developed for the synthesis in quantitative yield of corresponding bioactive dihydrocinnamic esters with solid-supported palladium chloride/ammonium formate (cat.) in HCOOH/H2O 1:2 as a hydrogenating agent under focused-microwave irradiation for 10 min.
- Kumar, Vinod,Sharma, Anuj,Sinha, Arun K.
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p. 483 - 495
(2007/10/03)
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- Azobenzene derivatives as labeling agents and intermediates thereof
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A compound of the formula I: wherein R is H or —N═N-2-carboxyphenyl; A is (CH2)nor —CH═CH—, wherein n is an integer from 0 to 10, or A may also be —CH(COOH)— when R is —N═N-2-carboxyphenyl; and X is a radical selected from the group consisting of: (i) Cl; (ii) COOR1, wherein R1is p-nitrophenyl or N-succinimidyl; (iii) CONH—NHR2, wherein R2is H, COO(t-butyl) or COObenzyl; (iv) CONH—[B]—NHR3, wherein R3is H, COOR1, or CO—[B′]—maleimido, wherein R1is t-butyl, p-nitrophenyl or N-succinimidyl, and B and B′, the same or different, are (CH2)nwherein n is an integer from 2 to 10; (v) CONH—[B]—COOR4, wherein R4is H, C1-C8alkyl, N-succinimidyl; (vi) CONH—[B]—OH; (vii) CONH—[B]—CONH—NHR2, wherein R2is H, COO(t-butyl) or COObenzyl; and (viii) NHR2, wherein R2is H, COO(t-butyl) or COObenzyl, when A is —CH(COOH)— and R is —N═N-2-carboxyphenyl. The 4′-hydroxyazobenzene-2-carboxylic acid (HABA) compounds are novel reagents for labeling, isolation and detection of biological molecules.
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- Regioselective intramolecular oxidation of phenols and anisoles by dioxiranes generated in situ
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A novel method for regioselective oxidation of phenols and anisoles has been developed in which dioxiranes, generated in situ from ketones and Ozone, oxidize phenol derivatives in an intramolecular fashion. A series of ketones with electron-withdrawing groups, such as CF3, COOMe, and CH2Cl, were attached to phenols, anisoles, or aryl rings via a C2 or C3 methylene linker. In a homogeneous solvent system of CH3CN and H2O, oxidation of phenol derivatives 1-10 afforded spiro 2-hydroxydienones in 24-55% yields regardless of the presence of other substituents (ortho Me, meta Me or Br) on the aryl ring and the length of the linker. Experimental evidences were provided to support the mechanism that involves a regioselective π bond epoxidation of aryl rings followed by epoxide rearrangement and hemiketal formation.
- Yang, Dan,Wong, Man-Kin,Yan, Zheng
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p. 4179 - 4184
(2007/10/03)
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- Acid-promoted fries rearrangements of benzannulated lactones
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The scope of acid-promoted Fries rearrangements of benzannulated lactones has been examined. The reaction is applicable to seven-membered lactones possessing a sufficiently activated aromatic ring but not to six-membered lactones, and it proceeds in higher yield for diterpenoid lactones than for lower molecular weight lactones. The structures of the 2,6-methano-bridged benzoxocin side products (23), (24), and (25) from rearrangement of the diterpenoid lactone (11) have been assigned.
- Cambie, Richard C.,Mitchell, Lorna H.,Rutledge, Peter S.
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p. 1167 - 1174
(2007/10/03)
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- Selectivity in sodium borohydride reduction of coumarin encapsulated in β-cyclodextrin
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The sodium borohydride reduction of coumarin to the corresponding alkanol and alkenol has been investigated in the presence and absence of β-cyclodextrin (β-CD). Excellent selectivity is observed when β-CD-coumarin complex is reduced in solid state at 0°C and the alkenol, cis-o-hydroxycinnamyl alcohol is the major product. Complex formation and the mode of substrate insertion into the CD cavity have been analysed using various physical methods.
- Pitchumani, Kasi,Velusamy, Ponnusamy,Srinivasan, Chockalingam
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p. 12979 - 12988
(2007/10/02)
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- The Lactonization of 2'-Hydroxyhydrocinnamic Acid Amides: A Potential Prodrug for Amines
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The lactoniaztion of two hydroxy amides - 4-methoxyaniline 3-(2'-hydroxyphenyl)-3,3-dimethylpropionic acid amide (2b) and 4-methoxyaniline 3-(2'-hydroxy-4',6'-dimethylphenyl)-3,3-dimethylpropionic acid amide (3b) - was studied over a pH range of 1-8.Due to the slowness of its reaction, a third hydroxy amide - 4-methoxyaniline 3-(2'-hydroxyphenyl)propionic acid amide (1b) - was investigated only at pH values of 7.5 and 10.The lactonization of 2b and 3b, which was found to be subject to general catalysis by buffer components, was observed to be catalyzed concurrently but not concertedly by both the acidic and basic forms of the buffer.The buffer-independent pH rate profiles for the lactonization of 2b and 3b were found to obey the equation k0 = kH++> + kH2O + kOH-->, indicating that the reaction is also subject to specific catalysis by hydronium and hydroxide ions.A Broenstedt analysis of the rate constants for buffer catalysis gave α and β values of 0.30 +/- 0.02 and 0.54 +/- 0.04, respectively, for 3b.The rate constants for the accelerated lactonization of 1b at 50, 70, and 90 deg C and pH 10 were used to calculate values of 14.7 +/- 0.8 kcal/mol and -9.5 +/- 2.3 eu for the activation parameters, ΔH(excit.) and ΔS(excit.), respectively.Comparison of the observed rates of lactonization at pH 7.5 and 30 deg C for the three hydroxy amides allowed an estimate of the extent of rate enhancement provided by addition of a partial or total "trimethyl lock" for the hydroxy amide lactonization reaction under near physiological conditions.The order of reactivity of the three hydroxy amides was found to be 3b >> 2b > 1b with rate enhancement factors of 2.5E4, 44, and 1, respectively.This study was begun with the objective of generating a hydroxy amide of very high reactivity at physiological pH for development into amine prodrug forms. 3b, which exhibited a half-life of 65 s at pH 7.5, has been chosen for further development as an amine prodrug.
- Amsberry, Kent L.,Borchardt, Ronald T.
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p. 5867 - 5877
(2007/10/02)
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- Tetrahedral Intermediate in Acyl Transfer Reactions. A Revaluation of the Significance of Rate Data Used in Deriving Fundamental Linear Free Energy Relationships
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A theoretical investigation of model mechanisms applicable to acyl transfer reactions in solution has shown that the interpretations of experimental rate constants in terms of mechanistic constants are all subject to an ambiguity that is well-known in principle but usually ignored or incorrectly evaluated in practice.For all models involving reversibly formed tetrahedral intermediates, the experimental constants are products of the form kffp in which kf is equal to ki+>n or to ki and fp is a product distribution fraction.Each assesible pH range can give a maximum of one constant that depends on the pH; there is no way to dissect out the desired mechanistic constants or the equilibrium constants for several tetrahedral intermediates unless some independent means can be developed to measure the fp.These conclusions are of major concern to all studies that attempt to relate reactivity to structure.Representative acyl transfer reactions have been reinterpreted.One example of the so-called trialkyl lock acceleration is now shown to amount to a factor of about 4000 for the mechanistic rates in contrast to the factor of 5*1010 originally proposed.Most of the decrease in estimate arises from recent reevaluations on observed rates, but there is a further decrease by a factor of 100 in the mechanistic rates due to considerations treated in present study.Evidence is also presented that certain acyl transfer reactions in solution may proceed by direct displacement rather than though a reversibly formed tetrahedral intermediate.
- DeTar, DeLos F.
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p. 7205 - 7212
(2007/10/02)
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- Synthesis of 7,8,9,10,11,12,20,21,22,23,24,25-Dodecahydrodibenzotetraoxacyclodocosin, a Crown Ether
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A number of symmetrical diesters and an unsymmetrical type have been synthesised from pyrocatechol.Under conditions in which intramolecular acyloin formation was anticipated the product from one symmetrical compound, ethyl 4-(o-ethoxycarbonylpropoxyphenoxy)butyrate, was a cyclic bis-β-keto-ester resulting in reasonable yield from intermolecular Dieckmann cyclisation.Hydrolysis to the 9,22 diketone, and its reduction to 7,8,9,10,11,12,20,21,22,23,24,25-dodecahydrodibenzotetraoxacyclodocosin 'dibenzo-22-crown-4', proceeded smoothly.An unsymmetrical intermediate, methyl 4-(o-ethoxycarbonylmethoxypropylphenoxy)butyrate, was prepared for similar cyclisation and in preliminary experiments appeared to give acyloin and β-keto-ester products.The method represents a different approach to crown ether systems of certain types.
- Tyman, John H. P.,Grundy, Jesse,Brown, George R.
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p. 336 - 343
(2007/10/02)
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- Formation and Hydrolysis of Lactones of Phenolic Acids
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The lactonization of 2'-hydroxybiphenyl-2-carboxylic acid to 3,4-benzocoumarin has been studied in aqueous solution, 30 deg C, in the range of pH 0-6.5.As with simpler coumarinic acids, the rate-determining step changes from the breakdown of tetrahedral intermediates in the neutral or weakly acidic pH range to formation of intermediates below pH 2.In contrast, the lactonization of methyl-substituted dihydrocoumarinic acids shows no eviednce for a change in rate-limiting step over a wide pH range.The hydrolysis of 8-hydroxy-1-naphthoic acid lactone in the range of pH 0-10 also does not undergo a transition in rate-limiting step.These results suggest that conjugation of the phenolic oxygen with the carbonyl carbon atom through an extended double-bond system may be necessary for the expulsion of water from a cationic tetrahedral intermediate and hence for the change in the rate-determining step.Revision of the rate constants for the acid-catalyzed lactonization of dihydrocoumarinic acid and of 4,4,5,7-tetramethyldihydrocoumarinic acid indicates that the rate-enhancing effect of the "trimethyl lock" is significantly smaller than previously believed.
- Caswell, Michael,Schmir, Gaston L.
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p. 4815 - 4821
(2007/10/02)
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