- Amino-polystyrene supported hexaethylene glycol-bridged ionic liquid as an efficient heterogeneous catalyst for water-mediated nucleophilic hydroxylation
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We report a simple and eco-friendly method for producing an amino-polystyrene supported hexaethylene glycol-bridged ionic liquid (APS-HEGBIL) based on the copolymerization of amino-styrene with 1-vinyl imidazolium ionic liquid bearing hexaethylene glycol moieties, and its characterization by several analytical techniques. The resulting APS-HEGBIL catalyst was found to be remarkably efficient at catalyzing the selective nucleophilic hydroxylation of alkyl halides to produce the corresponding alcohols in water, which acted as a solvent and a nucleophilic hydroxide source. The catalyst was easily recycled and maintained its catalytic activity and stability after ten cycles with excellent yields. The main attributes of the catalyst were that it significantly enhanced the nucleophilicity of water during reactions and promoted the rapid conversions of polar and base-sensitive alkyl halide reactants to alcohols in excellent yields. The combination of ionic liquids and polymeric materials afforded quasi-homogeneous catalysts that were recycled by simple filtration and provided environmentally benign means for conducted catalytic procedures.
- Reddy, Mudumala Veeranarayana,Kang, Seok Min,Yoo, Suah,Woo, Sang Sik,Kim, Dong Wook
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p. 9435 - 9442
(2019/04/01)
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- Nucleophilic Hydroxylation in Water Media Promoted by a Hexa-Ethylene Glycol-Bridged Dicationic Ionic Liquid
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Hexaethylene glycol bis(3-hexaethylene glycol imidazolium) dimesylate ionic liquid (hexaEG-DHIM) was designed and prepared as a highly efficient promoter for the nucleophilic hydroxylation of alkyl halides to the corresponding alcohol products in neat water media. It was observed that hexaEG-DHIM promoter enhanced the nucleophilicity of water significantly in the reaction. In addition, the hexaEG-DHIM could be reused several times without loss of activity. Moreover, the hydroxylation reactions of base-sensitive and/or polar alkyl halide substrates proceeded highly chemoselectively in excellent yields.
- Jadhav, Vinod H.,Kim, Jin Gwan,Jeong, Hyeon Jin,Kim, Dong Wook
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p. 7275 - 7280
(2015/07/28)
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- The Mechanism of the Reaction of Nicotinic Acid 1-Oxide with Acetic Anhydride
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In order to elucidate the mechanism of the 2-acetylation in the reaction of nicotinic acid 1-oxide (2a) with boiling acetic anhydride, thermal reactions and reactions with hot acetic anhydride have been explored with 3-X-pyridine 1-oxides (2).The former reactions of 2d (X = CONHAc), 2f (X = CONMeAc), 2h (X = CH2OAc) and 2j result in recovery or decomposition.The latter reactions of 2c (X = CONH2), 2d, 2e (X = CONHMe), 2h and 2j bring about mainly deoxygenative α-acetoxylation, no 2-acetylation being noticed.However, the reaction of 2f with acetic anhydride affords 6,7-dihydro-6-methyl-7-methylene-5H-pyrrolopyridin-5-one 1-oxide (7) as an initial product, which further undergoes deoxygenative β-acetoxylation to give 7-acetoxy-7-acetoxymethyl-6,7-dihydro-6-methyl-5H-pyrrolopyridin-5-one (8) and 7-acetoxymethylene-6,7-dihydro-6-methyl-5H-pyrrolopyridin-5-one (9).On the basis of the results we propose a new electrophilic pathway for the 2-acetylation of 2a and 2f.Keywords - pyridine 1-oxide 3-substituted; nicotinic acid 1-oxide; nicotinamide 1-oxide N-acetyl-N-methyl; pyrrolopyridine; 2-acetylation; pyridone formation
- Nagano, Hiroyuki,Nawata, Yoshiharu,Hamana, Masatomo
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p. 4068 - 4077
(2007/10/02)
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