- Iron-catalyzed arene C-H hydroxylation
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The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
- Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
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- Room temperature depolymerization of lignin using a protic and metal based ionic liquid system: an efficient method of catalytic conversion and value addition
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Lignin is one of the most abundant biopolymer which can be utilized to synthesize various chemicalsviaits depolymerization. However, depolymerization of lignin generally occurs under very harsh conditions. Herein, we report the efficient depolymerization of ligninviadissolution in a mixed ionic liquid system: ethyl ammonium nitrate (EAN) + prolinium tetrachloromanganate(ii) [Pro]2[MnCl4] at 35 °C and under atmospheric pressure conditions. The high dissolution of lignin in ethyl ammonium nitrate provided a large number of H-bonding sites leading to the cracking of lignin and subsequent oxidative conversion by [Pro]2[MnCl4]viathe formation of metal-oxo bonding between Mn and lignin molecules. The extracted yield of vanillin was found to be 18-20% on lignin weight basisviaGC-MS analysis. The depolymerization of lignin was confirmed by SEM, FT-IR and PXRD analysis. Since lignin contains UV-absorbing functional groups, the regenerated biomass after the recovery of the depolymerized products was further utilized to synthesize a UV-shielding material. The constructed films from such a material exhibited a high SPF value of 22 and were found to be very effective by limiting the UV degradation of rhodamine B thus making the lignin valorization process economically viable and environmentally sustainable.
- Mehta, Mohit J.,Kulshrestha, Akshay,Sharma, Shweta,Kumar, Arvind
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p. 1240 - 1247
(2021/02/26)
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- Structural features and antioxidant activities of Chinese quince (Chaenomeles sinensis) fruits lignin during auto-catalyzed ethanol organosolv pretreatment
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Chinese quince fruits (Chaenomeles sinensis) have an abundance of lignins with antioxidant activities. To facilitate the utilization of Chinese quince fruits, lignin was isolated from it by auto-catalyzed ethanol organosolv pretreatment. The effects of three processing conditions (temperature, time, and ethanol concentration) on yield, structural features and antioxidant activities of the auto-catalyzed ethanol organosolv lignin samples were assessed individually. Results showed the pretreatment temperature was the most significant factor; it affected the molecular weight, S/G ratio, number of β-O-4′ linkages, thermal stability, and antioxidant activities of lignin samples. According to the GPC analyses, the molecular weight of lignin samples had a negative correlation with pretreatment temperature. 2D-HSQC NMR and Py-GC/MS results revealed that the S/G ratios of lignin samples increased with temperature, while total phenolic hydroxyl content of lignin samples decreased. The structural characterization clearly indicated that the various pretreatment conditions affected the structures of organosolv lignin, which further resulted in differences in the antioxidant activities of the lignin samples. These results can be helpful for controlling and optimizing delignification during auto-catalyzed ethanol organosolv pretreatment, and they provide theoretical support for the potential applications of Chinese quince fruits lignin as a natural antioxidant in the food industry.
- Cheng, Xi-Chuang,Guo, Xin-Ran,Liu, Hua-Min,Liu, Yu-Lan,Qin, Zhao,Wang, Xue-De
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p. 4348 - 4358
(2020/09/22)
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- Synthesis of aryl-substituted 2-methoxyphenol derivatives from maltol-derived oxidopyrylium cycloadducts through an acid-mediated ring contraction cascade
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Oxidopyrylium cycloadducts derived from maltol and aryl acetylenes undergo acid-mediated rearrangements to generate aryl-substituted 2-methoxyphenol (guaiacol) derivatives. Specifically, the cycloadducts react with boron trichloride to form 2-methoxy-5-ar
- Bejcek, Lauren P.,Murelli, Ryan P.
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supporting information
p. 3203 - 3205
(2020/03/23)
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- A convenient synthetic approach to dioncoquinone B and related compounds
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A total synthesis of dioncoquinone B and related compounds, including ancistroquinones B, C and malvon A, is presented. The strategy is based on available reagents and can be used as a preparative synthesis of a number of natural and synthetic biologically active (3-alkyl)-2,7,8-di(tri)methoxy(hydroxy)-1,4-naphthoquinones.
- Khmelevskaya, Ekaterina A.,Pelageev, Dmitry N.
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supporting information
p. 1022 - 1024
(2019/03/13)
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- Synthesis of N-Substituted Condensed Tetrahydropyridine-Based Enaminones via Palladium-Catalyzed Intramolecular C–N Cross-coupling
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A number of β-enaminones with secondary amino group (alkyl, cyclopropyl, and aryl) were prepared from corresponding β-diketones. Two general protocols for their palladium-catalyzed intramolecular C–N cross-coupling were established to give corresponding N-substituted condensed tetrahydropyridines in good yields. The methodology is applicable for a wide variety of structural motifs. The work also extends the applicability of novel, recently established, palladium precatalysts to new substrates.
- Dou?ová, Hana,R??i?ková, Zdeňka,?im?nek, Petr
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supporting information
p. 670 - 684
(2018/01/22)
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- Rh/DuanPhos-Catalyzed Asymmetric Hydrogenation of β-Acetylamino Vinylsulfides: An Approach to Chiral β-Acetylamino Sulfides
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Rh/DuanPhos-catalyzed asymmetric hydrogenation of challenging β-acetylamino vinylsulfides has been developed, affording chiral β-acetylamino sulfides with high yields and excellent ee's (up to 99% ee). This novel methodology provides an efficient and concise synthetic route to chiral β-acetylamino sulfides. The potential utility of this protocol in the synthesis of Apremilast has also been disclosed.
- Gao, Wenchao,Lv, Hui,Zhang, Xumu
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supporting information
p. 2877 - 2880
(2017/06/07)
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- PROCESSES FOR THE PREPARATION OF APREMILAST AND INTERMEDIATES THEREOF
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Disclosed are processes for the preparation of Apremilast and intermediates for its preparation.
- -
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Paragraph 0076
(2017/07/29)
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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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- An intramolecular C-N cross-coupling of β-enaminones: A simple and efficient way to precursors of some alkaloids of Galipea officinalis
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2-Aroylmethylidene-1,2,3,4-tetrahydroquinolines with the appropriate substituents can be suitable precursors for the synthesis of alkaloids from Galipea officinalis (cuspareine, galipeine, galipinine, angustureine). However, only two, rather low-yielding procedures for their synthesis are described in the literature. We have developed a simple and efficient protocol for an intramolecular, palladium or copper-catalysed amination of both chloro- and bromo-substituted 3-amino-1,5-diphenylpent-2-en-1-ones leading to the above-mentioned tetrahydroquinoline moiety. The methodology is superior to the methods published to date.
- Douov, Hana,Hork, Radim,Ruikov, Zdeka,imunek, Petr
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supporting information
p. 884 - 892
(2015/08/24)
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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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- A boronic acid chalcone analog of combretastatin A-4 as a potent anti-proliferation agent
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Chalcones represent a class of natural products that inhibits tubulin assembly. In this study we designed and synthesized boronic acid analogs of chalcones in an effort to compare biological activities with combretastatin A-4, a potent inhibitor of tubuli
- Kong, Yali,Wang, Kan,Edler, Michael C.,Hamel, Ernest,Mooberry, Susan L.,Paige, Mikell A.,Brown, Milton L.
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experimental part
p. 971 - 977
(2010/05/02)
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- NON-STEROIDAL COMPOUNDS
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The present invention relates to non-steroidal compounds useful in the treatment of inflammatory conditions and pharmaceutical compositions comprising them. A representative example of these compounds is formula (III).
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Page/Page column 38
(2008/12/08)
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- Novel 3-Thia-10-Aza-Phenanthrene Derivatives
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The compounds of formula I in which A, R1, R2 and R3 have the meanings as given in the description, are novel effective PDE4 inhibitors.
- -
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Page/Page column 19
(2008/06/13)
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- Novel 3-Oxa-10-Aza-Phenanthrenes
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The compounds of formula I in which R1, R2 and R3 have the meanings as given in the description, are novel effective PDE4 inhibitors.
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Page/Page column 16
(2010/11/28)
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- Enantioselective synthesis of 1,4-dihydrobenzoxathiins via sulfoxide-directed borane reduction
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A novel sulfoxide-directed borane reduction was shown to give a variety of 2-substituted 1,4-dihydrobenzoxathiins. For all substrates evaluated, the reaction is completely stereospecific. Application of this methodology to the chiral synthesis of an artif
- Waters, Marjorie S.,Onofiok, Ekama,Tellers, David M.,Chilenski, Jennifer R.,Song, Zhiguo Jake
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p. 3389 - 3396
(2008/02/11)
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- A NEW PROCESS FOR THE PREPARATION OF PHENOLIC HYDROXY-SUBSTITUTED COMPOUNDS
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The invention relates to a process for the preparation of a phenolic hydroxy-substituted compound of the general formula (I) by desalkylation of an alkyl aryl ether of the general formula (II) by treatment with a thiourea/aluminium chloride reagent pair, in said general formulae R1 stands for straight chain or branched C1-6 alkyl group; R2, R3, R4, R5 , and R6 have the same or different meanings and stand for hydrogen or halogen atom, hydroxy, carboxy, nitro, oxo, C1-6 alkylcarbonyl, straight chain or branched alkyl or - alkoxy, or aryl group, or R2 and R3 together stand for a 5-7 membered ring or fused ring system; said 5-7 membered ring may be a partially saturated ring optionally substituted with an oxo group or can be an unsaturated ring; or said fused ring system may constitute with the first ring a steroid, preferably an estratriene derivative optionally substituted with an oxo or C1-6 alkylcarbonyloxy group in the 17 position -.
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Page/Page column 22-23
(2008/06/13)
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- Synthesis of tetrahydropyran-4-ones and thiopyran-4-ones from donor-substituted α-bromostyrene derivatives
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Tetrahydropyran-4-one and tetrahydrothiopyran-4-one derivatives with a 3-aryl substituent were synthesized by double-conjugate addition of water or H2S to divinyl ketones. These starting materials were prepared in two steps by conversion of lit
- Rosiak, Anna,Frey, Wolfgang,Christoffers, Jens
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p. 4044 - 4054
(2007/10/03)
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- QUINOLINE DERIVATIVES AND QUINAZOLINE DERIVATIVES INHIBITING AUTOPHOSPHORYLATION OF Flt3 AND MEDICINAL COMPOSITIONS CONTAINING THE SAME
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An objective of the present invention is to provide compounds and pharmaceticals useful for the treatment of disease where the inhibition of autophosphorylation of FMS-like tyrosine kinase 3(Flt3) is therapeutically effective. The present invention relates to a pharmaceutical composition for use in the treatment or prevention of diseases where the inhibition of autophosphorylation of Flt3 therapeutically or prophylactically effective, which comprises a compound represented by formula (I) or a pharmaceutically acceptable salt or solvate thereof: wherein X represents CH or N; Z represents O or S; R1, R2, and R3 represent H, OH, or optionally substituted alkoxy; R4 represents H; R5, R6, R7, and R8 represent H, Hal, alkyl or the like; and R9 represents, e.g., alkyl substituted by t-butyl or the like.
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Page/Page column 21
(2010/02/13)
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- QUINOLINE OR QUINAZOLINE DERIVATIVES INHIBITING AUTO-PHOSPHORYLATION OF FIBROBLAST GROWTH FACTOR RECEPTORS
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An objective of the present invention is to provide novel compounds which have inhibitory activity against autophosphorylation of an FGF receptor family and, when orally or intraveneously administered, can suppress the growth of cancer cells. The compounds of the present invention are represented by formula (I) or a pharmaceutically acceptable salt or solvate thereof: wherein X represents CH or N; Z represents 0 or S; Q represents NR10, CR11R12, carbonyl, O, S(=O)m, wherein m is 0 to 2, or urea; R1 to R3 each independently represent H, OH, halogen, nitro, amino, alkyl, alkoxy or the like in which the alkyl and alkoxy groups are optionally substituted; R4 represents H; R5 to R8 each independently represent H, halogen, alkyl, or alkoxy; and R9 represents an optionally substituted carbocyclic or heterocyclic group.
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- 6-acetyl-8-hydroxy-2,2-dimethylchromene, an antioxidant in sunflower seeds; Its isolation and synthesis and antioxidant activity of its derivatives
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By the guide of assay toward inhibition of photooxidation of β-carotene, 6-acetyl-8-hydroxy-2,2-dimethylchromene (1) was isolated from sunflower seeds. In addition to 1, the analogous compounds possessing the chromene (chromane) skeleton were synthesized and their antioxidant activities were examined.
- Tsuda, Hideyuki,Ishitani, Youichi,Takemura, Yoshiyuki,Suzuki, Yoshiaki,Kato, Tadahiro
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p. 139 - 142
(2007/10/03)
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- SYNTHESIS OF 4-PHENYLCOUMARINS FROM DALBERGIA VOLUBILIS AND EXOSTEMA CARIBAEUM
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Two isomeric 4-phenyl coumarins, 3',7-dihydroxy-4',5-dimethoxy-4-phenylcoumarin (seshadrin) from Dalbergia volubilis and 3',5-dihydroxy-4',7-dimethoxy-4-phenylcoumarin from Exostema caribaeum have been synthesized.However, the spectral properties of the f
- Bose, P.,Banerji, J.
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p. 2438 - 2439
(2007/10/02)
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- SELECTIVE ALKYLATIONS OF CERTAIN PHENOLIC AND ENOLIC FUNCTIONS WITH LITHIUM CARBONATE/ALKYL HALIDE
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Phenolic groups with pKaa's(ca.10), they can be alkylated with this reagent combination.
- Wymann, Walter E.,Davis, Roman,Patterson, John W.,Pfister, Juerg R.
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p. 1379 - 1384
(2007/10/02)
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- SUBSTITUENT EFFECTS IN AROMATIC PHOTOCHEMISTRY: UV IRRADIATION OF 3,4-DIMETHOXYBENZONITRILE AND 3,4-DIMETHOXYACETOPHENONE IN THE PRESENCE OF INORGANIC ANIONS
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Ultraviolet photolysis of 3,4-dimethoxybenzonitrile (Ia) and 3,4-dimethoxyacetophenone (IIa) in the presence of the hydroxide or cyanide anions leads to nucleophilic displacement of either the para or the meta methoxy substituent.The ratio of isomeric photoproducts is dependent upon the nature of the nucleophile.Photoreactions with the OH(-) anion leads exclusively to the substitution at C-3.On the other hand, both isomers are formed when acetophenone IIa is irradiated in the presence of CN(-), with the C-3/C-4 ratio ranging from 1:2 to 1:6 in dependence on the nucleophile concentration.These difference between the OH(-) and CN(-) anion are related to the results of a fluorescence quenching study which has revealed that only the observed for the quenching of the second excited state of Ia by the cyanide anion.This indicates several distinct quenching modes, in relation to the concentration dependence of regioselectivity.The activating power of -H, -CN, -COCH3, and -NO2 substituents, as measured by relative quantum yields of disappearance for 3,4-dimethoxy-R-substituted benzenes, is 1 : 2.5 : 5 : 580 and 1 : 1.5 : 6 : 1000 in their photoreactions with OH(-) and CN(-) anions, respectively.
- Kuzmic, Petr,Soucek, Milan
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p. 980 - 988
(2007/10/02)
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- Cleavage of the Methylenedioxy Ring. III. Cleavage with Sodium Benzyloxide in Dimethyl Sulfoxide
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Cleavage of the methylenedioxy ring in aromatic formyl (1-3), nitro (4 and 5), and acetyl (30) compounds with N-sodium benzyloxide-benzyl alcohol in dimethyl sulfoxide gave 3-hydroxybenzene derivatives (19, 22-24, 26, 27, and 33).In the case of the acetyl compound 30, the 4-hydroxybenzene derivative (34) was also obtained as a minor product.Regioselective cleavage of the ring in aromatic compounds having electronwithdrawing groups with nucleophilic oxide anions is discussed.Cleavage of the ring in 1-5 and 30 with 2 N sodium methoxide in dimethyl sulfoxide-dimethylformamide was found to be useful for the practical preparation of 3-hydroxybenzene derivatives (6-10 and 31).Keywords - Cleavage of methylenedioxy ring; regioselectivity; piperonals; 3,4-methylenedioxy-nitrobenzene; 3,4-methylenedioxy-acetophenone; sodium methoxide; sodium phenoxide; sodium benzyloxide; dimethyl sulfoxide; dimethylformamide
- Kobayashi, Shigeru,Okimoto, Kazuto,Imakura, Yasuhiro
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p. 1567 - 1573
(2007/10/02)
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- An Unambiguous Synthesis of Melannein
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Melannein (6-hydroxy-7-methoxy-4-(3'-hydroxy-4'-methoxyphenyl)coumarin, I) and its O,O-diethyl ether (II) have been synthesised.The steps involved in the synthesis of I and II are the respective condensation of o-methoxyhydroquinone with ethyl m-benzyloxy-p-methoxybenzoylacetate (XI) and ethyl m-ethoxy-p-methoxybenzoylacetate (III) in absolute ethyl alcohol in the presence of dry hydrogen chloride gas.The isomeric O,O-diethyl ether of melannein, viz. 6-ethoxy-7-methoxy-4(4'-ethoxy-3'-methoxyphenyl)coumarin (VI) has also been prepared by the condensation of o-methoxyhydroquinone with ethyl p-ethoxy-m-methoxybenzoylacetate (VII).The esters (III), (VII) and (XI) have been prepared by the reaction of the appropriate acetophenone derivatives with diethyl carbonate in the presence of sodium hydride.
- Ahluwalia, V. K.,Kapur, Kanchan,Manchanda, Saroj
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p. 186 - 188
(2007/10/02)
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- Dependence of Aryl Ether Acylation upon Lewis Acid Stoichiometry
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Acylation of alkyl aryl ethers has been observed to be uniquely dependent on the stoichiometry of the Friedel-Crafts catalyst.With 100 molpercent catalyst, acylation proceeds rapidly and in high yield; with large molar excesses of catalyst, the reaction is essentially completely arrested.This inhibition can be reversed by using sterically bulky alkyl groups which effectively prevent complexing between catalyst and aryl ether.Based on these observations, we have developed processes for regioselective intramolecular acylation of either a phenyl or an alkoxylated phenyl ring when both are present.
- Buckley, Thomas F.,Rapoport, Henry
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p. 3056 - 3062
(2007/10/02)
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