- Investigation of carbon-2 substituted imidazoles and their corresponding ionic liquids
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The functionality at the C-2 position of the imidazole ring plays a key role in defining the chemical properties of the imidazoles and their corresponding ionic liquids. Imidazoles 1-6 with different C-2 functionality were synthesized and their corresponding ionic liquids were systematically investigated. Based on their physical properties the six imidazoles can be divided into three groups. (1) The imidazoles 2 and 3 are capable of self-polymerization to form poly(ionic liquid)s, and they are characterized with a strong leaving group at the C-2 position. (2) The imidazoles 4 and 5 can form ionic liquids, but they are very sensitive to moisture. (3) The imidazoles 1 and 6 can form stable ionic liquids, and their stabilities were influenced by the electronic effects of the substituents at the C-2 position.
- Liao, Chen,Zhu, Xiang,Sun, Xiao-Guang,Dai, Sheng
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supporting information; experimental part
p. 5308 - 5310
(2011/10/30)
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- N-phosphorylated imidazolium salts as precursors to 2- and 5-phosphorylated imidazoles and new imidazol-2-ylidenes featuring the PNCN unit
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It has been experimentally proven that the reaction of 1- or 1,2-disubstituted imidazoles with diorganylphosphorus(III) halides proceeds via initial formation of N-phosporylated imidazolium salts. Treatment of these salts with strong bases results in phosphorylation of the parent imidazoles at the 2- or 5-positions, correspondingly. In a previous case, imidazol-2-ylidenes are formed as intermediates. With both N1 and N3 atoms bearing sterically demanding or/and π-donating groups, deprotonation of 1,3-disubstituted imidazolium salts with NaN(SiMe3)2 afforded new stable N-phosphorus-substituted Arduengo-type carbenes.
- Marchenko, Anatolii P.,Koidan, Heorgii N.,Huryeva, Anastasiya N.,Zarudnitskii, Evgeniy V.,Yurchenko, Aleksandr A.,Kostyuk, Aleksandr N.
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supporting information; experimental part
p. 7141 - 7145
(2010/12/29)
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- Transfer of Alkoxycarbonyl from Alkyl Imidazolium-2-carboxylates to Benzyl Alcohol, a Cyclohexanone Enamine and Diethylamine
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Alkylimidazole-2-carboxylates may be alkylated with methyl triflate to give the corresponding N-methylimidazolium salts.These salts react with benzyl alcohol in the presence of 1,4-diazabicyclooctane, with 1-(pyrrolidin-1-yl)cyclohexene and with diethylamine to give benzyl alkyl carbonates, an enamino ester and a urethane respectively; in one case a tetrahedral intermediate is observed.The corresponding phenyl ester was consumed without attack by benzyl alcohol at the carbonyl group.A 2-cyanoimidazolium salt underwent similar ill-defined consumption whereas a 2-dimethylaminocarbonyl derivative remained unchanged. 2-Methylsulfonylimidazolium salts suffered attack by benzyl alcohol at the ring C-2.
- Bakhtiar, Cuross,Smith, Edward H.
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p. 239 - 244
(2007/10/02)
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