- Graphite oxide-catalyzed acetylation of alcohols and phenols
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Graphite oxide (GO) was used as a catalyst for the reactions of alcohols and phenols with acetic anhydride. The acetates of primary and secondary alcohols were prepared in good to excellent yields in short reaction time under mild conditions. Electron deficient phenols could be converted to the corresponding acetates steadily. As an efficient catalyst, GO is easily available, cheap, moderately toxic and weakly acidic.
- Liu, Yuan-Yuan,Qi, Jun-Mei,Bai, Li-Sha,Xu, Yue-Long,Ma, Ning,Sun, Fei-Fei
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supporting information
p. 726 - 730
(2016/05/19)
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- Iron-Catalyzed Cross-Coupling of Alkenyl Acetates
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Stable C-O linkages are generally unreactive in cross-coupling reactions which mostly employ more electrophilic halides or activated esters (triflates, tosylates). Acetates are cheap and easily accessible electrophiles but have not been used in cross-couplings because the strong C-O bond and high propensity to engage in unwanted acetylation and deprotonation. Reported herein is a selective iron-catalyzed cross-coupling of diverse alkenyl acetates, and it operates under mild reaction conditions (0 C, 2 h) with a ligand-free catalyst (1-2 mol%). Iron clad: Acetates are underutilized electrophiles in metal-catalyzed cross-coupling reactions because of the strong alkenyl C-O bond and their propensity to engage in unwanted reactions. Combination of a ligand-free low-valent Fe catalyst with nucleophilic organomagnesium reagents, low temperature, and short reaction times results in highly selective cross-couplings with alkenyl acetates.
- G?rtner, Dominik,Stein, André Luiz,Grupe, Sabine,Arp, Johannes,Von Wangelin, Axel Jacobi
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supporting information
p. 10545 - 10549
(2015/09/02)
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- Palladium-catalyzed acetoxylation of arenes by novel sulfinyl n-heterocyclic carbene ligand complexes
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A series of novel ligands based on N-heterocyclic carbene and sulfoxide functionalities have been prepared and characterized. Pd(II) complexes have been synthesized by transmetalation from the corresponding NHC-Ag derivatives, and their behavior as catalysts has been studied in arene C-H bond oxidative activation. Studies conducted toward the elucidation of the reaction mechanism of the acetoxylation suggest a C-H activation step at Pd(IV) rather than Pd(II) intermediates.
- Tato, Francisco,Garcia-Dominguez, Andres,Cardenas, Diego J.
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supporting information
p. 7487 - 7494
(2014/04/03)
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- An imidazolium tosylate salt as efficient and recyclable catalyst for acetylation in an ionic liquid
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A novel non-metallic salt, 1-butyl-3-methylimidazolium tosylate ([bmim][OTs]) dissolved in the ambient temperature ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), was found to be the efficient catalyst for acetylation with the advantages of good recyclability, avoidance of metal contamination, mild reaction conditions, and wide availability for substrates (alcohols, phenols, and amines), could completely replace organic bases, metal Lewis acids, or metallic triflates to fulfill acetylation by a nucleophilic catalytic mechanism, which was supported by 13C NMR analysis.
- Liu, Ye,Liu, Lu,Lu, Yong,Cai, Yue-Qin
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experimental part
p. 633 - 638
(2009/08/07)
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- Facile and regioselective dealkylation of alkyl aryl ethers using niobium(V) pentachloride
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A simple and facile method for the cleavage of carbon-oxygen bonds promoted by niobium pentachloride(V) is described. Excellent yields and regioselectivities were observed with various alkyl aryl ethers to give the phenols. NMR studies revealed the formation of monoaryloxy niobium salt(V), and a neighboring-group effect may play a significant role in the regioselectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Sudo, Yukinori,Arai, Shigeru,Nishida, Atsushi
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p. 752 - 758
(2007/10/03)
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- Facile catalyzed acylation of alcohols, phenols, amines and thiols based on ZrOCl2·8H2O and acetyl chloride in solution and in solvent-free conditions
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Acylation of heteroatoms (O, N and S) with acetyl chloride based on the use of a catalytic amount of the moisture stable, inexpensive ZrOCl 2?8H2O, proceeds efficiently producing the corresponding acylated products in excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
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p. 147 - 151
(2007/10/03)
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- Facile catalyzed acylation of heteroatoms using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride
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Acylation of a variety of alcohols, phenols, aliphatic and aromatic amines, a thiol and a thiophenol proceeds efficiently using BiCl3 generated in situ from the procatalyst BiOCl and acetyl chloride in a solvent or under solventless conditions, furnishing the corresponding acylated derivatives in very good to excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
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p. 6775 - 6778
(2007/10/03)
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- An efficient method for acylation reactions
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Cu(OTf)2 was found to be an efficient catalyst in the acylation reaction of alcohols, phenols, amines and thiols with acetic arthydride in CH2Cl2 or acetic acid. A catalytic cycle has been proposed for the acylation reaction.
- Saravanan, Parthasarathy,Singh, Vinod K.
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p. 2611 - 2614
(2007/10/03)
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- Novel chemoselective de-esterification of esters of polyacetoxy aromatic acids by lipases
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Candida cylindracea lipase (CCL) and porcine pancreatic lipase (PPL) have been used for deacetylation of peracetates of methyl and ethyl esters of six different polyphenolic acids in organic solvents. Exclusive de-esterification of the ester groups derived from the phenolic hydroxy and aliphatic acid over the ester group of the aromatic acid and aliphatic alcohol has been achieved affording the corresponding esters of phenolic acids in as high yields as 90-97%. The results have been corroborated with the mechanism of lipase action.
- Parmar, Virinder S.,Kumar, Ajay,Bicht, Kirpal S.,Mukherjee, Shubhasish,Prasad, Ashok K.,Sharma, Sunil K.,Wengel, Jesper,Olsen, Carl E.
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p. 2163 - 2176
(2007/10/03)
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- Retention behavior of compounds with active hydrogen atoms and their acetylated derivatives in reversed-phase HPLC
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In view of poor interlaboratory reproducibility of retention indices I in reversed-phase high-performance liquid chromatography, not the indices themselves but their differences for reactants and products of interaction with various reagents can be used to identify compounds with active hydrogen atoms. For acetylated derivatives of phenols and aromatic amines, the quantity ?I = I(ArXH) -I(ArXCOCH3), where X = O or NH. has statistically significant distinguishable values of 126 ± 15 and 70 ± 20, respectively. The additivity of the parameters ?I is first revealed for the polyfunctional compounds of these classes that are incapable of intramolecular hydrogen bonding. Abnormal ?I values and deviations from the additivity rule are observed only for substances with intramolecular hydrogen bonding. This finding can be used to confirm the presence of relevant structural units in molecules.
- Zenkevich,Kosman
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p. 1173 - 1176
(2007/10/03)
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