- Benzoflavone derivatives as potent antihyperuricemic agents
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Two series of benzoflavone derivatives were rationally designed, synthesized and evaluated for their xanthine oxidase (XO) inhibitory potential. Among both series, eight compounds (NF-2, NF-4, NF-9, NF-12, NF-16, NF-25, NF-28, and NF-32) were found to exert significant XO inhibition with IC50 values lower than 10 μM. Enzyme kinetic studies revealed that the most potent benzoflavone derivatives (NF-4 and NF-28) are mixed type inhibitors of the XO enzyme. Molecular modeling studies were also performed to investigate the binding interactions of these molecules (NF-4 and NF-28) with the amino acid residues present in the active site of the enzyme. Docking results confirmed that their favorable binding conformations in the active site of XO can completely block the catalytic activity of the enzyme. Benzoflavone derivatives exhibiting potent XO enzyme inhibition also showed promising results in a hyperuricemic mice model when tested in vivo.
- Singh, Jatinder V.,Mal, Gurbachan,Kaur, Gurleen,Gupta, Manish K.,Singh, Amritpal,Nepali, Kunal,Singh, Harbinder,Sharma, Sahil,Bedi, S. Preet Mohinder
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p. 128 - 147
(2019/01/30)
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- 5,6-Benzoflavones as cholesterol esterase inhibitors: Synthesis, biological evaluation and docking studies
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In a continued effort to develop potent cholesterol esterase (CEase) inhibitors, a series of 5,6-benzoflavone derivatives was rationally designed and synthesized by changing the position of the benzene ring attached to the flavone skeleton in previously reported 7,8-benzoflavones. All the synthesized compounds were checked for their inhibitory potential against cholesterol esterase (CEase) using a spectrophotometric assay. Among the series of forty compounds, seven derivatives (B-10 to B-16) exhibited above 90 percent inhibition against CEase in an in vitro enzymatic assay. Compound B-16 showed the most promising activity with an IC50 value of 0.73 nM against cholesterol esterase. To determine the type of inhibition, enzyme kinetic studies were carried out for B-16, which revealed its mixed-type inhibition approach. Moreover, to figure out the key binding interactions of B-16 with the amino acid residues of the enzyme's active site, molecular protein-ligand docking studies were also performed. B-16 completely blocks the catalytic assembly of CEase and prevents it from participating in the ester hydrolysis mechanism. The favorable binding conformation of B-16 suggests its prevailing role as a CEase inhibitor. Overall, the study showed that the cisorientation of ring A with respect to the carbonyl group of ring C is responsible for the potent CEase inhibitory activity of the newly synthesized compounds.
- Singh, Jatinder V.,Kaur, Anumeet,Bhagat, Kavita,Gupta, Manish K.,Singh, Manwinder,Singh, Harbinder,Bedi, Preet Mohinder S.
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p. 490 - 502
(2018/03/28)
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- Asymmetric Alkynylation of β-Ketoesters and Naphthols Promoted by New Chiral Biphenylic Iodanes
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The preparation of new chiral biphenylic λ3-iodane reagents bearing transferable alkynyl ligands is described. These reagents transfer their carbon-based ligands onto β-ketoesters with an enantiomeric excess (ee) up to 68 %, and most remarkably, enable the dearomative alkynylation of naphthols in good to high yields up to 84 % ee.
- Companys, Simon,Peixoto, Philippe A.,Bosset, Cyril,Chassaing, Stefan,Miqueu, Karinne,Sotiropoulos, Jean-Marc,Pouységu, Laurent,Quideau, Stéphane
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supporting information
p. 13309 - 13313
(2017/10/05)
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- MONOMER, ORGANIC LAYER COMPOSITION, ORGANIC LAYER, AND METHOD OF FORMING PATTERNS
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The present invention relates to a monomer represented by chemical formula 1, an organic membrane composition including the monomer, an organic membrane produced using the organic membrane composition, and a pattern forming method using the organic membrane composition. The chemical formula 1 is the same as defined in the present specification.
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Paragraph 0176-0178
(2017/04/05)
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- Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
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Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
- Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
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experimental part
p. 641 - 649
(2011/03/19)
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- A facile demethylation of ortho substituted aryl methyl ethers promoted by AlCl3
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An efficient and practical demethylation of ortho substituted aryl methyl ethers using AlCl3 has been developed. This method gives a high conversion, is simple to operate and is cost-effective. A mechanism involving the complexation of AlCl3 with the OMe and the adjacent electron withdrawing group is proposed. Many functional groups can be tolerated in the demethylation process, and 29 examples gave a demethylated product in a yield of 90-98%.
- Du, Zhen-Ting,Lu, Jing,Yu, Hong-Rui,Xu, Yan,Li, An-Pai
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experimental part
p. 222 - 227
(2010/08/04)
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- Regioselective ortho-acylation of phenol and naphthol derivatives catalyzed by FeCl3 under microwave conditions
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Phenol and naphthol derivatives were subjected to regioselective solvent-free ortho-acylation with organic acids in the presence of FeCl 3 under microwave irradiation. The reactions were complete in a short time, and the products were obtained in high yields.
- Naeimi,Moradi
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body text
p. 1757 - 1759
(2009/09/29)
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- Solvent affected facile synthesis of hydroxynaphthyl ketones: Lewis acids promoted Friedel-Crafts and demethylation reaction
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Hydroxynaphthyl ketones were obtained with high yields under very mild conditions in the presence of AlCl3 via Friedel-Crafts acylation and demethylation from naphthyl ethers. Several Lewis acids were tested, and AlCl3 was the most efficient catalyst. Copyright Taylor & Francis Group, LLC.
- Li, Wan-Mei,Lai, Hu-Qin,Ge, Zhong-Hua,Ding, Cheng-Rong,Zhou, Ying
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p. 1595 - 1601
(2008/02/01)
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- Microwave assisted direct ortho-acylation of phenol and naphthol derivatives by BF3·(C2H5)2O
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The solventless acylation of phenol and naphthol derivatives with various organic acids and BF3·(C2H5) 2O, under microwave conditions, was studied. High yields of the o-acylated products were achieved in a very short time.
- Naeimi, Hossein,Moradi, Leila
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p. 284 - 287
(2008/02/04)
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- Selective fries rearrangement catalyzed by zinc powder
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Zinc powder in the presence of N,N-dimethylformamide efficiently catalyzes the selective Fries rearrangement of acetylated phenols under microwave heating or with conventional heating using an oil bath. In some cases different products were obtained using microwave heating and conventional heating. Selective migration of the acyl group has been noted with good yields.
- Paul, Satya,Gupta, Monika
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p. 1789 - 1792
(2007/10/03)
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- Formylchromone derivatives as a novel class of protein tyrosine phosphatase 1B inhibitors
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Formylchromone inhibits a human protein tyrosine phosphatase PTP1B with a IC50 value of 73 μM. The chemical reactivity of formylchromone was adjusted by substitution at various positions of the formylchromone skeleton. In an initial assessment of the structure-activity relationship, the most potent inhibitor showed an IC50 of 4.3 μM against PTP1B and strong or medium selectivity against other human PTPases, LAR and TC-PTP. This compound, however, was not selective against microbial PTPases, YPTP1 and YOP. The potency and selectivity of the formylchromone derivatives expecting further improvements provides a novel pharmacophore for the design of drugs for the treatmenrt of type 2 diabetes and obesity.
- Shim, Yi Sup,Kim, Ki Chul,Chi, Dae Yoon,Lee, Keun-Hyeung,Cho, Hyeongjin
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p. 2561 - 2563
(2007/10/03)
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- Thermal cross fries acyl and benzoyl migrations from aromatic diesters to phenols
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A study of boron trifluoride etherate catalyzed thermal cross Fries reaction is reported in this paper. Acyl and benzoyl migrations from various aromatic diesters to phenols in dry benzene as solvent takes place selectively and in this, way offers an alternative route to the preparation of different hydroxy acetophenones and benzophenones.
- Thapliyal,Aggarwal
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p. 706 - 708
(2007/10/03)
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- Effect of cyclodextrin complexation on photo-fries rearrangement of naphthyl esters
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Photolysis of β-cyclodextrin inclusion complexes of 1- and 2-naphthyl esters (acetates and benzoates) in aqueous medium, results in rearrangement to give one isomer of acylnaphthol in excess, whereas the solid state irradiation of the cyclodextrin complexes yields selectively one isomer. In addition, formation of cleavage product is totally suppressed. This remarkable selectivity is attributed to specific modes of the complexation of the esters into the β-CD cavity.
- Banu, Habeeb Shayira,Pitchumani, Kasi,Srinivasan, Chockalingam
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p. 9601 - 9610
(2007/10/03)
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- Tandem Fries Reaction-Conjugate Addition under Microwave Irradiation in Dry Media; One-pot Synthesis of Flavanones
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An AlCl3-ZnCl2 mixture supported on silica gel is found to be an efficient medium for the Fries rearrangement of acyloxybenzene or naphthalene derivatives in solvent-free conditions under microwave irradiation.
- Moghaddam, Firouz Matloubi,Ghaffarzadeh, Mohammad,Abdi-Oskoui, Seyed Hossein
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p. 574 - 575
(2007/10/03)
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- Investigation of the photo-fries rearrangements of two 2-naphthyl alkanoates by experiment and theory. Comparison with the acid-catalyzed reactions
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A detailed investigation of the photochemistry of 2-naphthyl acetate (1a) and 2-naphthyl myristate (1b) has been conducted under a variety of conditions. Factors related to the reactions such as temperature and solvent type have been explored. The results, most easily interpreted by photo-Fries type processes, are contrasted with those from the Lewis-acid catalyzed (dark) Fries reactions of 1a. They are also compared to the predictions of semiempirical and ab initio calculations using 2-naphthyl propanoate (1c) and species derived from it as models. Unsuccessful triplet sensitization experiments with benzophenone and calculations point to the excited singlet states of 1 as the immediate precursor to the acyl/2-naphthoxy radical pairs that recombine to form keto intermediates 2, reform 1, or diffuse apart and eventually yield 2-naphthol (4); enolization of 2 results in the isolated rearrangement products, n-acyl-2-naphthols (n-3). Static and dynamic fluorescence studies provide some insights into the nature of the lysis process. Irradiation of a mixture of appropriately labeled derivatives of 1 led to none of the expected "cross-over" products, indicating that the intermediates 2 arise from recombination of radical pairs from the same parent molecule. Irradiation of 1b in ethanol and 1-octanol provides no evidence for the intermediacy of dodecylketene and supports out-of-cage mechanisms as the exclusive source of 4. There are indications of subtle solvent effects and a conformational dependence on the distribution of photoproducts.
- Cui, Changxing,Wang, Xiaochun,Weiss, Richard G.
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p. 1962 - 1974
(2007/10/03)
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- Photo-Fries reaction of naphthyl esters within zeolites
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Photolysis of naphthyl esters within zeolites leads to the photo-Fries rearrangements as in isotropic solution. However, a high level of product selectivity is obtained using 'cation as the key'. A key component for predicting the selectivity of photoreactions within zeolites, namely the location of reactants, is missing at this stage.
- Pitchumani,Warrier,Cui,Weiss,Ramamurthy
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p. 6251 - 6254
(2007/10/03)
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- Microwave-induced rate enhancement of Fries rearrangement
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Rate enhancement in several Fries rearrangements has been observed under microwave irradiation.Thus, 2-naphthyl acetate provides exclusively 1-acetyl 2-naphthol in 70percent yield within 2 min.
- Sridar, V.,Rao, V. S. Sundara
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p. 184 - 185
(2007/10/02)
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- Claisen Rearrangement of Prenyl Ethers of Isomeric Acetylnaphthols and Bisprenyl Ethers of 4,6- and 2,4-Diacetylresorcinols
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Claisen rearrangements of the 3-methylbut-2-enyl(prenyl)ethers 3 and 9 of 2-acetyl-1-hydroxy- and 1-acetyl-2-hydroxynaphthalenes 1 and 2 and the bis(3-methylbut-2-enyl)ethers 12 and 18 of 2,4- and 4,6-diacetylresorcinols 11 and 17 have been studied under a variety of thermal and catalytic conditions. 2-Acetyl-4-(3-methylbut-2-enyl)naphthalene-1-ol 4 was the sole product on rearrangement of compound 3, in DMA or neat.Under catalytic conditions 3,4-dihydro-2,2-dimethyl-2H-naphthopyran 7 was obtained in poor yield.An isomeric pyran, 1,2-dihydro-3,3-dimethyl-3H-naphthopyran 10 (25-43percent) was obtained under both thermal and catalytic conditions from 9.The rearrangement of 12 under thermal conditions (DMA and neat) furnished 3-acetyl-2,4-dihydroxy-5-(3-methylbut-2-enyl)acetophenone 13 and 3,8-diisopropylbenzodifuran 14.Pd'' mediated rearrangement of 12 gave only the partially deprenylated ether, 3-acetyl-4-hydroxy-2-(3-methylbut-2-enyloxy)acetophenone 15 (29percent).While the isomeric ether 18 gave the monoprenyl ether, 5-acetyl-4-hydroxy-2-(3-methylbut-2-enyloxy)acetophenone 19 in quantitative yield (95percent).The rearrangment products were characterised and their formation rationalised in terms of allowed sigmatropic shifts( prenyl and H) followed by loss of prenyl or acetyl groups.The reactions of prenyl ethers are both comparable to those of the corresponding allyl ethers and consistent with the greater fixed double-bond character of the naphthalene system compared to that of benzene.Prenyl derivatives of benzene and naphthalene containing ortho - hydroxyacetophenone units were formed which have potential in synthesis.
- Anjaneyulu, Ammanamanchi S. R.,Isaa, Balagopala M.
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p. 2089 - 2094
(2007/10/02)
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- Photochromic spiropyran compounds
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A series of novel photochromic spiropyrans are disclosed in which a spiro-adamantane group is introduced into the 2-position of the benzopyran or naphthopyran ring. The spiropyran compounds of the invention exhibit heliochromic properties, i.e. they color in sunlight and fade rapidly at ambient temperatures in the absence of U.V. light, making them good candidates for use in the manufacture of sunglasses. The invention includes lenses which darken in sunlight and incorporate the novel spiropyrans and a process for the preparation of the spiropyran compounds.
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- Reactions of Carbonyl Compounds in Basic Solutions. Part 11. The Baker-Venkataraman Rearrangement
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The detailed mechanism of the Baker-Venkataraman rearrangement has been studied.The kinetics of the rearrangement of a series of 2-acetylphenyl 3- or 4-substituted benzoates and acetylnaphthyl benzoates catalysed by a basic 'non-nucleophilic' buffer in dimethyl sulphoxide have been measured.Studies of substituent effects, kinetic isotope effects, and acidity function correlations indicate a pathway involving pre-equilibrium formation of the carbanion, followed by rate-determining intramolecular nucleophilic attack.The methanolysis of the 2-acetylphenyl benzoates catalysed by methoxide in methanolic dimethyl sulphoxide has been similary investigated.In this case the pathway appears to involve neighbouring group participation by the ketonic carbonyl group.
- Bowden, Keith,Chehel-Amiran, Mohsen
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p. 2039 - 2044
(2007/10/02)
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- α-HALO KETONES IX.1 A NEW FURAN-FORMING REACTION
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Some α-halo ketones react with 2-naphthol in the presence of strong acids to give naphthofurans.A hydroxyallylic catin may be an intermediate in the reaction.
- Warnhoff, E.W.,Yerhoff, F.W.
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p. 777 - 784
(2007/10/02)
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