- BENZYLATED PHENANTHRENES FROM EULOPHIA NUDA
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From the tubers of Eulophia nuda, further phenanthrene derivatives have been isolated: 9,10-dihydro-1-(4'-hydroxybenzyl)-4,7-dimethoxyphenanthene-2,8-diol, 1-(4'-hydroxybenzyl)-4,8-dimethoxyphenanthrene-2,7-diol.In addition, 3,4'-dihydroxy-3',5,5'-trimethoxybibenzyl and bis(4-hydroxybenzyl) ether were obtained.The structures were assigned by spectroscopic methods.The structure of the penultimate compound mentioned above was also confirmed by synthesis.Key Word Index-Eulophia nuda; Orhidaceae; benzylated phenanthrenes; bibenzyls.
- Tuchinda, Patoomratana,Udchachon, Jinda,Khumtaveeporn, Kanjai,Taylor, Walter C.
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- Na 2 CO 3-Catalyzed O-Acylation of Phenols for the Synthesis of Aryl Carboxylates with Use of Alkenyl Carboxylates
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Inorganic base-catalyzed O-acylation of phenol and its derivatives has been developed. The procedure provides an efficient catalysis system for the preparation of aryl carboxylates with alkenyl carboxylates as acyl reagents. The reaction proceeded smoothly by using ?-Na 2 CO 3 as the catalyst in MeCN to produce the corresponding aryl carboxylates in good to excellent yields.
- Zhou, Xiao-Yu,Chen, Xia
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supporting information
p. 2321 - 2325
(2018/10/20)
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- Highly efficient and recyclable acetylation of phenols and alcohols by nickel zirconium phosphate under solvent-free conditions
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Nickel zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma optical emission spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity.
- Hajipour, Abdol Reza,Karimi, Hirbod,Kohi, Afshin
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- Acetylation of alcohols and phenols under solvent-free conditions using iron zirconium phosphate
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Iron zirconium phosphate (ZPFe) nanoparticles were found to function as an efficient catalyst for the acetylation of a wide range of alcohols and phenols using acetic anhydride, generating good to excellent yields under solvent-free conditions. The steric and electronic properties of various substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma-optical emission spectrometry, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 9.3 ? when Fe3+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several important advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up.
- Hajipour, Abdol R.,Karimi, Hirbod,Masti, Amir
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p. 595 - 602
(2015/09/28)
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- Catalysis of reaction between ozone and 4-hydroxytoluene in acetic anhydride
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Kinetics and products of 4-hydroxytoluene oxidation with ozone-air mixture in the presence of transition metal acetates as catalysts have been studied. Main steps of the catalytic series have been considered, and a mechanism of redox catalysis has been proposed which conforms to the experimental data and enables control over the direction, depth, and selectivity of the oxidation. Only manganese(II) acetate has been found to exhibit high catalytic activity in the presence of catalytic amounts of mineral acids. Manganese(II) acetate largely suppresses electrophilic reaction of ozone with the aromatic ring, so that the main reaction direction is oxidation of the methyl group with formation of 4-acetoxybenzyl acetate as the major product (62.6%) and 4-acetoxybenzylidene diacetate as a minor one (10.2%).
- Galstyan, A. G.,Sedykh, A. A.,Galstyan, G. A.
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p. 1510 - 1514
(2014/12/10)
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- Acetylation of alcohols and phenols under solvent-free conditions using copper zirconium phosphate
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Copper zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively-coupled plasma optical emission spectroscopy, energy dispersive spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 8.0 ? when Cu2+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several key advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up.
- Hajipour, Abdol R.,Karimi, Hirbod
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p. 1982 - 1989
(2015/09/28)
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- Selective acylation of the phenolic hydroxyl of (hydroxyalkyl)phenols by using vinyl carboxylates as acyl donors in the presence of rubidium fluoride
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Highly selective acylation of the phenolic hydroxy group can be achieved with (hydroxyalkyl)phenols carrying both alcoholic and phenolic hydroxyls by the use of vinyl carboxylates as acyl donors in the presence of rubidium fluoride.
- Miyazawa, Toshifumi,Yamamoto, Masato,Danjo, Hiroshi
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p. 1351 - 1354
(2013/10/01)
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- Facile synthesis of diarylmethanes via quinone methides
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A novel acid-mediated generation of quinone methides followed by nucleophilic addition of electronrich aromatic compounds to furnish diarylmethanes has been developed. A wide range of electronrich aromatic compounds including some heterocycles can be employed for this reaction to provide the corresponding diarylmethanes in good yields and regioselectivities.
- Tangdenpaisal, Kassrin,Phakhodee, Wong,Ruchirawat, Somsak,Ploypradith, Poonsakdi
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p. 933 - 941
(2013/07/25)
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- Electron-deficient [TiIV(salophen)(OTf)2]: A new and highly efficient catalyst for the acetylation of alcohols and phenols with acetic anhydride
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In the present work, a highly efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by high-valent [Ti IV(salophen)(OTf)2] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were acetylated with short reaction times and high yields. The catalyst was reused several times without loss of its catalytic activity.
- Yadegari, Maryam,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 2237 - 2243
(2011/10/03)
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- Study of reaction of isomeric acetoxytoluenes with ozone in liquid phase in the presence of manganese bromide catalyst
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The kinetics of the ozone reaction with isomeric acetoxytoluenes in acetic anhydride in the presence of sulfuric acid and mixed manganese bromide catalyst was studied. Under these conditions it is possible to stop the oxidation process at the stage of formation of hydroxybenzaldehydes in the form of the respective acetoxybenzylidendiacetates (63-70%). The reaction products contain also acetoxybenzyl acetate (16-18%) and a small amount of acetoxybenzyl bromide (2%). The mechanism of oxidation-reduction catalysis with manganese bromide complex explaining the experimental data was considered. Pleiades Publishing, Ltd., 2010.
- Galstyan,Sedykh
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scheme or table
p. 948 - 952
(2011/01/07)
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- Liquid-phase reactions of isomeric methylphenols with ozone
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Ozonation of isomeric methylphenols in acetic anhydride was studied. Here, acetic anhydride acts simultaneously as solvent and acylating agent. In the presence of a mineral acid methylphenols were converted into methylphenyl acetates during preparation of solutions for ozonation. The major products in the oxidation of isomeric methylphenyl acetates with ozone were aliphatic peroxides (80-90%); oxidation of the methyl group gave rise to the corresponding acetoxybenzyl acetates (7-14%) and acetoxybenzylidene diacetates (3-6%). A probable scheme for the liquid-phase oxidation of methylphenyl acetates with ozone in acetic anhydride was proposed.
- Galstyan
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scheme or table
p. 15 - 19
(2010/05/01)
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- Simple and efficient method for acetylation of alcohols, phenols, amines, and thiols using anhydrous NiCl2 under solvent-free conditions
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Solvent-free acetylation of alcohols, phenols, amines, and thiols with acetic anhydride (Ac2O) in the presence of 0.1mol% (13mg) anhydrous NiCl2, an inexpensive and easily available catalyst, is described. Excellent yields, short reaction time, and mild reaction conditions are important features of this method.
- Meshram, Gangadhar,Patil, Vishvanath D.
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experimental part
p. 4384 - 4395
(2010/04/29)
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- Oxidation of p-cresol with ozone in acetic anhydride
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Preparation of aromatic alcohols and aldehydes by oxidation of p-cresol with ozone in acetic anhydride in the presence of sulfuric acid, manganese acetate, and potassium bromide was studied. The optimal oxidation conditions were determined. Pleiades Publishing, Inc., 2006.
- Sedykh,Galstyan
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p. 123 - 126
(2008/02/04)
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- A simple and efficient radical reduction using water-soluble radical initiator and hypophosphorous acid in aqueous alcohol
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A simple, mild and high-yielding procedure for the reduction of various halogenated compounds using a combination of the water-soluble radical initiater (VA-061), hypophosphorous acid and triethylamine in aqueous alcohol is reported. A simple, mild, and high-yielding procedure for the reduction of various halogenated compounds using a combination of the water-soluble radical initiator, 2,2′-azobis[2-(2-imidazolin-2-yl)propane] (VA-061), a water-soluble chain carrier, hypophosphorous acid, and the base, triethylamine, in aqueous alcohol is described. The reagents used in this method are all water soluble, and therefore, an almost pure desired product can be readily obtained using only an extraction procedure.
- Nambu, Hisanori,Alinejad, Anahita Hessamian,Hata, Kayoko,Fujioka, Hiromichi,Kita, Yasuyuki
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p. 8927 - 8929
(2007/10/03)
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- Synthesis and antimycobacterial activity of pyrazine and quinoxaline derivatives
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A series of pyrazine and quinoxaline derivatives have been synthesized, and their activity against M. tuberculosis (Mtb) and Mycobacterium avium (MAC) are reported. The 4-acetoxy-benzyl ester of pyrazinoic acid and 4′-acetoxybenzyl 2-quinoxalinecarboxylate showed excellent activity against Mtb (MIC ranges of less than 1-6.25 μg/mL) but only modest activity against MAC (MICs of 4-32 μg/mL).
- Seitz, Lainne E.,Suling, William J.,Reynolds, Robert C.
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p. 5604 - 5606
(2007/10/03)
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- Regio- and Chemo-selective Properties of Lipase from Candida cylindracea
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Lipase from Candida cylindracea allows discrimination between the two connectively non-equivalent hydroxy groups in primary diols or their esters via acylation-hydrolysis, with high regioselectivity.The same technique is used to distinguish between hydroxy groups of different nature in phenolic compounds.
- Pedrocchi-Fantoni, Giuseppe,Servi, Stefano
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p. 1029 - 1034
(2007/10/02)
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- Process for the preparation of α-halogenated cresol esters
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Process for the preparation of Compound I by treating Compound II with X2 or SO2 X2 in the presence of a free radical initiator and an anhydride having the formula (RCO)2 O while eliminating the acid halide form
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- Electrophilic Aromatic Substitution of Catechins: Bromination and Benzylation
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Relative yields of C-6, C-8, and C-6 and C-8 substituted catechins obtained from the reaction of (+)-catechin or 3',4',5,7-tetra-O-methyl-(+)-catechin with pyridinium hydrobromide-perbromide, bromine, p-hydroxybenzyl alcohol, or o-hydroxybenzyl alcohol sh
- McGraw, Gerald W.,Hemingway, Richard W.
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p. 973 - 978
(2007/10/02)
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- A USEFUL METHOD FOR SELECTIVE ACYLATION OF ALCOHOLS USING 2,2'-BIPYRIDYL-6-YL CARBOXYLATE AND CESIUM FLUORIDE
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Primary and secondary alcohols are acylated under mild conditions by the of use 2,2'-bipyridyl-6-yl carboxylates and cesium fluoride.Furthermore, the reaction is successfully applied to selective acylation of a primary carbinol group of diols containing primary and secondary carbinol groups or exclusive O-acylation of aromatic amino alcohols.
- Mukaiyama, Teruaki,Pai, Fong-Chang,Onaka, Makoto,Narasaka, Koichi
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p. 563 - 566
(2007/10/02)
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