- Ionic liquids - Advanced reaction media for organic synthesis
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The advantages in the application of ionic liquids as reaction media in organic synthesis, i.e., in the preparation of chromane derivatives, substituted pyrazines, 4-aminofuran-2(5H)-ones, or in bromination of Levulinic acid or dehydration of alcohols, saccharides, and polysaccharides, have been demonstrated on several examples. Ionic liquids with Bronsted acidity have been shown to possess catalytic activity and provide access to convenient technologies for the preparation of various useful compounds. Copyright Merck KGaA.
- Ignat'ev, Nikolai V.,Schulte, Michael,Koppe, Karsten,Barthen, Peter,Zlotin, Sergei G.,Makhova, Nina N.,Sheremetev, Aleksei B.,Valente, Anabela A.
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scheme or table
p. 1205 - 1216
(2011/09/16)
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- Variation in the regioselectivity of levulinic acid bromination in ionic liquids
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The reaction of levulinic acid and its esters with bromine in ionic liquids results in the formation of 3-bromo derivatives as the major products and not the 5-bromo substituted isomers, which are typically formed in organic solvents. The bromination of l
- Zavozin, Alexander G.,Kravchenko, Natalya E.,Ignat'ev, Nikolay V.,Zlotin, Sergei G.
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scheme or table
p. 545 - 547
(2010/10/02)
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- Reinvestigation of the sulfuric acid-catalysed cyclisation of brominated 2-alkyllevulinic acids to 3-alkyl-5-methylene-2(5H)-furanones
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A synthesis of ethyl-, butyl-, hexyl- and dodecyl-substituted fimbrolides from alkyl-substituted levulinic acid derivatives through bromination and acid promoted lactonisation is described. The underlying reactions have been investigated using levulinic acid as a model, and the effects of varying the bromination conditions and changing acid concentration on product distribution are discussed. Dibromination proceeds best in CHCl3 and proceeds in EtOH-free CHCl3 without the complication of ester formation. Cyclisation. occurs with concomitant oxidation in 98-100% H2SO4 but gives highest yields of fimbrolides in 100% H2SO4. The formation of related beckerelide substances is also described.
- Manny, Anthony J.,Kjelleberg, Staffan,Kumar, Naresh,De Nys, Rocky,Read, Roger W.,Steinberg, Peter
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p. 15813 - 15826
(2007/10/03)
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