- Preparation method for 4-methoxy-1,3-phthalic acid
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The invention provides a preparation method for 4-methoxy-1,3-phthalic acid. 4-methoxy-1,3-phthalic acid is key intermediate for preparation of an anti-platelet aggregation drug picotamide (with a trade name of plactidil). According to the preparation method, 4-methoxy-1,3-phthalic acid is prepared from the starting raw material p-methylphenol or o-methylphenol through esterification, Fries rearrangement, methylation, oxidation and acidification. Compared with traditional preparation methods, the preparation method provided by the invention has the advantages of low equipment investment, simple operation, quick reaction, high yield, low synthesis cost, greatly reduced environmental pollution and the like, and is particularly suitable for large-scale industrial production.
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Paragraph 0039; 0040; 0041; 0042
(2017/12/04)
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- Submicron ZnO raspberries as effective catalysts for Fries rearrangement
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o-Xylene-in-water emulsion droplets have been exploited as soft templates for the synthesis of submicrometer-sized raspberry-like ZnO morphologies. The optical properties, structure and morphology of the microstructures have been characterised by absorption and fluorescence spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and selected area electron diffraction analysis. It has been found that the microstructures could act as an environmentally benign and cost-effective alternative to conventional Lewis acid catalysts for the illustrious Fries rearrangement of o-methylphenyl acetate to 3-methyl-4-hydroxyacetophenone, employed as the model reaction and which has been probed by NMR spectroscopic studies.
- Ali, Mohammed,Rahaman, Hasimur,Pal, Sudip Kumar,Kar, Nikita,Ghosh, Sujit Kumar
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p. 41780 - 41785
(2015/05/27)
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- The phase change storage element and its manufacturing method
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Disclosed are a phase change RAM device and a method for fabricating a phase change RAM device, which can efficiently lower intensity of current required for changing a phase of a phase change layer. The method includes the steps of providing a semiconductor substrate formed with an insulating interlayer including a tungsten plug, forming a first oxide layer on the semiconductor substrate, forming a pad-type bottom electrode, which makes contact with the tungsten plug, in the first oxide layer, forming a second oxide layer on the first oxide layer including the bottom electrode, and forming a porous polystyrene pattern on the second oxide layer such that a predetermined portion of the second oxide layer corresponding to a center portion of the bottom electrode is covered with the porous polystyrene pattern.
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- Investigation on the substitution effects of the flavonoids as potent anticancer agents: A structure-activity relationships study
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Three series of flavonoid analogues substituted with different aminomethyl substitutions at C-6, C-7, and C-8 were designed and synthesized for the structure-activity relationship studies as potent anticancer agents. The prepared analogues were evaluated for their in vitro inhibitory activity against the growth of the hepatic cancer cell lines HepG2 and SMMC-7721. Structure-activity relationships indicated that not only the compounds with amino methyl groups were more active than those without the groups in the same series but also the compounds substituted by aminomethyl groups at position C-8 were more active than those at positions C-6 and C-7.
- Wang, Xiao-Bing,Yang, Lei,Kong, Ling-Yi,Liu, Wei,Guo, Qing-Long
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p. 1833 - 1849,17
(2020/07/30)
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- Effect of structurally constrained oxime-ether linker on PPAR subtype selectivity: Discovery of a novel and potent series of PPAR-pan agonists
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A novel series of thaizole and oxazole containing phenoxy acetic acid derivatives is reported as PPAR-pan agonists. Incorporation of structurally constrained oxime-ether based linker in the chemotype of a potent PPARδ selective agonist GW-501516 was adapted as designing strategy. In vitro, selected test compounds 12a, 12c, 17a and 18a showed PPAR-pan agonists activities and among these four compounds tested, 12a emerged as highly potent and efficacious compound, while 17a exhibited moderate and balanced PPAR-pan agonistic activity. In vivo, selected test compounds 12a and 17a exhibited significant anti-hyperglycemic and anti-hyperlipidemic activities in relevant animal models. These results support our hypothesis that the introduction of structurally constrained oxime-ether linker between lipophilic tail and acidic head plays an important role in modulating subtype selectivity and subsequently led to the discovery of potent PPAR-pan agonists.
- Makadia, Pankaj,Shah, Shailesh R.,Pingali, Harikishore,Zaware, Pandurang,Patel, Darshit,Pola, Suresh,Thube, Baban,Priyadarshini, Priyanka,Suthar, Dinesh,Shah, Maanan,Giri, Suresh,Trivedi, Chitrang,Jain, Mukul,Patel, Pankaj,Bahekar, Rajesh
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experimental part
p. 771 - 782
(2011/03/18)
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- Improved alkylation and product stability in phosphotriester formation through quinone methide reactions with dialkyl phosphates
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Investigating reactions of functionalized p-quinone methides continues to advance our design of a reagent being developed for controlled, in situ modification of DNA via phosphodiester alkylation. Previously reported investigations of p-quinone methides derived from catechols allowed for trapping of isolable trialkyl phosphates for characterization and mechanistic information. However, lactone formation with these derivatives required long reaction times, resulting in an unfavorable mixture of trialkyl phosphate and hydrolysis products. To enhance the rate and efficacy of trialkyl phosphate formation and trapping, a phenol derived p-quinone methide has been designed to enforce a conformation favoring lactonization of the dialkyl phosphate alkylated intermediate. The relative rates of phosphodiester alkylation and subsequent trapping of the phosphotriester adduct have been examined by UV and 1H NMR analysis for p-quinone methide precursor 1 and the corresponding control, 1′. The incorporation of a methyl group at the meta-position of 1 (relative to 1′) significantly improves the rate of lactionization to provide a much higher yield of the desired product, lactonized phosphotriester 5. The control reaction with 1′ afforded only a minor amount of the corresponding lactonized trialkyl phosphate 5′.
- Bakke, Brian A.,McIntosh, Matthias C.,Turnbull, Kenneth D.
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p. 4338 - 4345
(2007/10/03)
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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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- 2-aminopyridine derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminopyridine derivative compounds of the following formula: wherein R1to R5have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminopyridine derivative compounds.
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- Alumina in Methanesulfonic Acid (AMA) as a New Efficient Reagent for Direct Acylation of Phenol Derivatives and Fries Rearrangement. A Convenient Synthesis of o-Hydroxyarylketones
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Alumina in methanesulfonic acid (AMA) is used to prepare o-hydroxyaryl ketones by acylation of phenol and naphthol derivatives with carboxylic acids and the Fries rearrangement of phenolic esters. Mechanistic studies show that the acylation reaction in AMA occurred through an esterification followed by a Fries rearrangement of the phenolic ester by an intermolecular mechanism.
- Sharghi, Hashem,Kaboudin, Babak
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p. 2678 - 2695
(2007/10/03)
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- Zirconium tetrachloride as a mediator for ambient temperature ortho-Fries rearrangements
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Zirconium tetrachloride has been found to be an excellent mediator of the Fries reaction. Rearrangements occur at ambient temperature and are highly selective; giving the acetophenone derived from acetyl migration to the sterically least encumbered adjacent carbon.
- Harrowven, David C.,Dainty, Richard F.
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p. 7659 - 7660
(2007/10/03)
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- The Photo-Fries Rearrangement in the Presence of Potassium Carbonate: A Convenient Synthesis of ortho-Hydroxyacetophenones
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Phenyl acetates 1 are converted into o-hydroxyacetophenones 2 in 78-90percent yields by photolysis in hexane solution in the presence of potassium carbonate.
- Garcia, Hermenegildo,Primo, Jaime,Miranda, Miguel Angel
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p. 901 - 902
(2007/10/02)
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- ipso Nitration. XXIII. Reactions of cyclohexadiene adducts from nitration of 4-ethyltoluene in acetic anhydride
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The diastereoisomers of 4-ethyl-1-methyl-4-nitrocyclohexa-2,5-dienyl acetate (1) and 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetate (2) are stereospecifically reduced to the corresponding nitrocyclohexadienols with aluminum hydride.Each dienol is stereospecifically methylated to the corresponding methyl ether with methyl iodide, silver oxide, and potassium hydroxide.Acid-catalysed solvolysis of the acetates 1 and 2 results in the substitution of the acetate moiety by other nucleophiles and these reactions are not stereospecific.The products of rearomatization of dienyl acetates, dienols and dienyl methyl ethers depend on the acidity and ionizing power of the solvents and are readily explained in terms of reactions involving a nitrocyclohexadienyl cation or acetoxy- (hydroxy-, methoxy-)cyclohexadienyl cation as key intermediates.In the 4-acetoxy-4-alkylcyclohexadienyl cation 1,2-migration of the acetoxyl group is more rapid then alkyl migration, but 1,2-alkyl migration is faster then migration of the hydroxyl or methoxyl groups in the corresponding cations. 1-Ethyl-4-methoxy-4-methylcyclohexa-2,5-dien-1-ol and 4-ethyl-3-nitrotoluene are significant minor products in the solvolysis of 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dien-1-ol in aqueous methanol.Nitration of p-ethyltoluene in the presence of sulfuric acid or in trifluoracetic anhydride gives a mixture of 4-ethyl-2-nitro- and 4-ethyl-3-nitrotoluene in a 2:1 ratio.
- Fischer, Alfred,Henderson, George N.
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p. 2314 - 2327
(2007/10/02)
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- The Chemistry of Nitrilium Salts. Part 1. Acylation of Phenols and Phenol Ethers with Nitriles and Trifluoromethanesulphonic Acid
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Aliphatic nitriles, RCN (R = Me, n-Pr, CH2Cl, and CCl3), in the presence of trifluoromethanesulphonic acid have been found to react with a number of mono-, di-, and tri-substituted phenols and phenol ethers at room temperature to give ketones after hydrolysis of the reaction mixture.Moderate to good yields of acylation products are obtained in the majority of these reactions.The yield with malononitrile and succinonitrile, which are only slightly soluble in the reaction medium, are generally poor, and reaction involves only one of the available nitrile groups.Attempts to use diethyl ether and dichloromethane as solvents for some of these reactions were unsuccessful, but limited success was achieved with nitromethane.
- Booth, Brian L.,Noori, Ghazi F.M.
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p. 2894 - 2900
(2007/10/02)
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- Synthesis and Structure-Activity Relationships among α-Adrenergic Receptor Agonists of the Phenylethanolamine Type
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Nineteen arylethanolamine derivatives related to norepinephrine were prepared and tested for α-adrenergic stimulant activity.In one series the analogues possess a p-hydroxy function, while the meta position is substituted by methyl, ethyl, isopropyl, cyclohexyl, fluoro, chloro, iodo, carboxy, carbomethoxy, and methylsulfamido groups.The other series is meta hydroxylated with the para position substituted by the same groups.The influence of these groups upon the α-adrenergic activity is discussed, and the compounds are compared to octopamine, normetanephrine,norepinephrine, and norphenylephrine.It has been found that the introduction of an isopropyl, cyclohexyl, and fluoro group in the meta position of octopamine improves its affinity by three, five, and six times, respectively, whereas when these groups are introduced in the para position of norphenylephrine their effects are always detrimental.The most active compound, α-(aminomethyl)-(4-fluoro-3-hydroxyphenyl)methanol (44), has about one-hundreth the affinity and the same intrinsic activity as norepinephrine.
- Leclerc, Gerard,Bizec, Jean Claude,Bieth, Nicole,Schwartz, Jean
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p. 738 - 744
(2007/10/02)
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