- AN OCTAMETHOXYFLAVONE FROM POGOSTEMON PURPURASCENS
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3,5,6,7,8,2',4',5'-octamethoxyflavone has been isolated from the whole plant of Pogostemon purpurascens.Key Word Index-Pogostemon purpurascens; Labiatae; purpurascenin; 3,5,6,7,8,2',4',5'-octamethoxyflavone
- Patwardhan, S. A.,Gupta, A. S.
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Read Online
- Synthesis method of pharmaceutical intermediate 2,4,5-trimethoxybenzoic acid
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The invention discloses a synthesis method of a pharmaceutical intermediate 2,4,5-trimethoxybenzoic acid. The synthesis method takes 1,2,4-trimethoxybenzene, DMF (Dimethyl Formamide), phosphoryl chloride, 2,4,5-trimethoxybenzaldehyde, silver nitrate, acetonitrile, hydrogen peroxide, zirconium oxide and MCM-41 as main raw materials, and MCM-41 zeolite powder is subjected to short-chain modificationby adopting tetraethyl orthosilicate TEOS; ultrasonic treatment is carried out on a mixed alkali solution and metal ion frameworks of nickel nitrate and aluminum nitrate are used for replacing to form a unique space three-dimensional framework structure with catalytic activity. According to the synthesis method disclosed by the invention, the disadvantages that products are complicated, the products are difficultly completely purified and the like, caused by drastic oxidization reaction of traditional benzaldehyde, are overcome by an intermediate catalyst, and the intermediate catalyst has anexcellent catalysis effect on synthesis reaction of the 2,4,5-trimethoxybenzoic acid.
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Paragraph 0008; 0010-0018; 0023; 0024
(2018/09/08)
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- Acceptorless dehydrogenation and aerobic oxidation of alcohols with a reusable binuclear rhodium(II) catalyst in water
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A water-soluble binuclear rhodium(ii) complex was found to be an efficient catalyst for both acceptorless dehydrogenation and aerobic oxidation of alcohols under air to produce carboxylic acids or ketones in water. The catalyst is highly efficient with substrate/catalyst ratios up to 5 × 103 being feasible, and could be recycled 19 times without significant loss of activity.
- Wang, Xuewei,Wang, Chao,Liu, Yuxuan,Xiao, Jianliang
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supporting information
p. 4605 - 4610
(2016/09/04)
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- Mohr's salt catalyzed oxidation of aldehydes with t-BuOOH
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Various aromatic, aliphatic and conjugated aldehydes were transformed to the corresponding carboxylic acids with 70% t-BuOOH solution (water) in the presence of catalytic amounts (10 mol%) of Mohr's salt. This method possesses functional group compatibility, does not involve cumbersome work-up, exhibits chemoselectivity since other functional groups remain intact and proceeds under mild conditions. The resulting products are obtained in good yields within reasonable times. Copyright
- Chakraborty, Debashis,Majumder, Chandrima,Malik, Payal
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experimental part
p. 487 - 490
(2012/04/04)
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- Ceric ammonium nitrate catalyzed oxidation of aldehydes and alcohols
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A variety of aromatic, aliphatic and conjugated aldehydes and alcohols were transformed to the corresponding carboxylic acids and ketones with a quantitative conversion in high yields with 70% t-BuOOH solution in water in the presence of catalytic amounts of ceric ammonium nitrate [Ce(NH 4)2(NO3)6] (CAN) under room temperature conditions. The scope of our catalytic system is applicable for a wide range of aromatic, conjugated and aliphatic substrates. These aldehydes were converted to the corresponding carboxylic acids in good isolated yields in reasonable times. This method possesses a wide range of capabilities since it can be used with other functional groups which may not tolerate oxidative conditions, involves fairly simple method for work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time.
- Gowda, Ravikumar R.,Chakraborty, Debashis
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experimental part
p. 2379 - 2384
(2012/02/15)
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- Bi2O3-catalyzed oxidation of aldehydes with t-BuOOH
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A variety of aromatic, aliphatic and conjugated aldehydes were transformed to the corresponding carboxylic acids with 70% t-BuOOH solution (water) in the presence of catalytic amounts of Bi2O3. This method possesses a wide range of capabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under mild conditions. The resulting products are obtained in good yields within reasonable time. The overall method is green.
- Malik, Payal,Chakraborty, Debashis
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supporting information; experimental part
p. 3521 - 3523
(2010/08/22)
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- Bismuth(III) oxide catalyzed oxidation of alcohols with tert-butyl hydroperoxide
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A variety of aromatic, aliphatic and conjugated alcohols were transformed into the corresponding carboxylic acids and ketones with aq 70% t-BuOOH in the presence of catalytic amounts of bismuth(III) oxide. This method possesses a wide range of capabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under ambient conditions. The resulting products are obtained in good yields within reasonable time. The overall method is green.
- Malik, Payal,Chakraborty, Debashis
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experimental part
p. 3736 - 3740
(2011/01/03)
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- Silver nitrate-catalyzed oxidation of aldehydes to carboxylic acids by H2O2
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A variety of aromatic, aliphatic and conjugated aldehydes were converted to the corresponding carboxylic acid derivatives with 30% H2O 2 as the oxidant in the presence of catalytic amounts of AgNO 3. The method described has wide range of applicabilities, does not involve cumbersome work-up, exhibits chemoselectivity and proceeds under mild reaction conditions, and the resulting products are obtained in good yields within reasonable time.
- Chakraborty, Debashis,Gowda, Ravikumar R.,Malik, Payal
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experimental part
p. 6553 - 6556
(2011/02/21)
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- CuCl catalyzed oxidation of aldehydes to carboxylic acids with aqueous tert-butyl hydroperoxide under mild conditions
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Oxidation of aldehydes to the corresponding carboxylic acids can be performed highly efficiently at room temperature with 70% tert-butyl hydroperoxide (in water) in the presence of a catalytic amount of easily available ligand free CuCl in acetonitrile as solvent under very mild conditions. This oxidation protocol works well for various aldehydes including aliphatic aldehydes and aliphatic dialdehydes.
- Mannam, Sreedevi,Sekar
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p. 1083 - 1086
(2008/09/18)
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- Efficient and rapid method for the oxidation of electron-rich aromatic aldehydes to carboxylic acids using improved basic hydrogen peroxide
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An efficient and rapid method for oxidation of electron-rich aromatic aldehydes to their corresponding carboxylic acids in excellent yields was developed. It is based on the oxidation of methoxy-substituted benzaldehydes in methanol with an improved aqueous basic hydrogen peroxide system. Benzaldehydes with electronwithdrawing substituents are oxidized to the corresponding carboxylic acid in excellent yields under mild reaction conditions. Copyright Taylor & Francis Group, LLC.
- Cong, Zhi-Qi,Wang, Chun-Ian,Chen, Tie,Yin, Bing-Zhu
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p. 679 - 683
(2007/10/03)
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- Total syntheses of (±) cervinomycins A1 and A2
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Regiocontrolled total syntheses of cervinomycins A1 (1) and A2 (2_have been achieved from easily accessible 6-acetyl-2-bromo-1,4,-dimethoxynaphthalene (4).
- Rama Rao,Yadav,Kishta Reddy,Upender, Velaparthi
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p. 5199 - 5202
(2007/10/02)
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- Diels-Alder Approaches to Model Compounds Related to Fredericamycin A
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A series of model compounds related to the antitumor and antibiotic compound fredericamycin A has been prepared.Spiro-2,5-dione (2) has been prepared and established as a novel spiro dienophile in the Diels-Alder reaction with 1,3-butadiene, Danishefsky's diene, a triacetoxy-substituted o-quinodimethane, and two isobenzofuran intermediates.Thus, the cycloaddition of 3-cyano-4,5,7-trimethoxy-1(3H)-isobenzofuranone (35) and 2 afforded 4,9-dihydroxy-5,6,8-trimethoxyspiroindene-2,1'-indan>-1,3-dione (38) in 62percent yield.This methodology provides a viable synthetic route to the quinone portion of fredericamycin A that contains the seven requisite oxygens.
- Evans, Jonathan C.,Klix, Russell C.,Bach, Robert D.
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p. 5519 - 5527
(2007/10/02)
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- FURTHER POLYSUBSTITUTED FLAVONES FROM AGERATUM HOUSTONIANUM
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The aerial parts of Ageratum houstonianum afforded three new flavones, 5-hydroxy-6,7,8,2',4',5'-hexamethoxyflavone; 5,2'-dihydroxy-6,7,8,4',5'-pentamethoxyflavone and 5-hydroxy-6,7,2',4',5'-pentamethoxyflavone.The known 5,6,7,3',4',5'-hexamethoxyflavone was also isolated.Structural determinations involved spectral methods and chemical degradations. - Key Word Index: Ageratum houstonianum; Asteraceae; Eupatorieae; heptasubstituted and hexasubstituted flavones; structure determination.
- Quijano, Leovigildo,Calderon, Jose S.,Garibay, Frederico Gomez,Escobar, Edgar,Rios, Tirso
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p. 2075 - 2078
(2007/10/02)
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