- Thermal rearrangement of an N-hydroxyimidazole thiocarbamoyl derivative as a simple entry into the 4-thioimidazole motif
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A thermal rearrangement of a thio-ester derivative of N-hydroxyimidazole gives rise, in a clean reaction, to the corresponding 4-and 2-thiol ester derivatives in a 1 : 1 ratio.
- Pinto, Luis F. V.,Justino, Goncalo C.,Vieira, Abel J. S. C.,Prabhakar, Sundaresan,Lobo, Ana M.
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experimental part
p. 17 - 23
(2010/08/22)
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- Synthesis and crystal structures of 1-alkoxy-3-alkylimidazolium salts including ionic liquids, 1-alkylimidazole 3-oxides and 1-alkylimidazole perhydrates
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Functionalized quaternary imidazolium salts were prepared with the intention to obtain new ionic liquids (ILs). Thus, more than forty 3-alkoxy-1-alkylimidazolium salts, 3-alkoxy-1-alkyl-2-methylimidazolium salts, 1-methylimidazole 3-oxide and 1,2-dimethylimidazole 3-oxide as well as their salts, 1,3-dihydroxyimidazolium salts and 1,3-dihydroxy-2-methylimidazolium salts were synthesized and characterized by spectroscopy and, to a limited extent, by viscosity and conductivity measurements. Results of fourteen single crystal X-ray structure determinations are reported, among them also the parent compounds 1-hydroxyimidazole 3-oxide and 1-hydroxy-2-methylimidazole 3-oxide. Selective debenzylation of 1-benzyloxy-3-methylimidazolium salts and mono-demethoxylation of 1,3-dimethoxyimidazolium salts were achieved by hydrogenolysis. In addition, a crystalline semiperhydrate of 1,2-dimethylimidazole was characterized. Furthermore, an addition compound of 1-methylimidazole 3-oxide with tris(2-thienyl)borane and a silver carbene complex derived from 1-benzyloxy-3-methylimidazolium hexafluorophosphate was crystallized and characterized.
- Laus, Gerhard,Schwaerzler, Alexander,Bentivoglio, Gino,Hummel, Michael,Kahlenberg, Volker,Wurst, Klaus,Kristeva, Elka,Schuetz, Johannes,Kopacka, Holger,Kreutz, Christoph,Bonn, Guenther,Andriyko, Yuriy,Nauer, Gerhard,Schottenberger, Herwig
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experimental part
p. 447 - 464
(2009/01/31)
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- Synthesis of 2-Substituted 1-Hydroxyhnidazoles through Directed Lithiation
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Benzylation of 3-hydroxyimidazole 1-oxide gave 3-(benzyloxy)imidazole 1-oxide, which was deoxygenated with phosphorous trichloride to produce 1-(benzyloxy)imidazole. 1-(Benzyloxy)imidazole was deprotonated selectively at C-2 by n-butyllithium. The anion formed was reacted with electrophiles to give 1-(benzyloxy)imidazoles with carbon, halogen, silicon, or sulfur substituents at the 2-position. Subsequent debenzylation afforded 2-substituted 1-hydroxyimidazoles which in turn could be deoxygenated to give 2-substituted imidazoles.
- Eriksen, Birgitte Langer,Veds?, Per,Morel, Sandrine,Begtrup, Mikael
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- Preparation of N-Hydroxyazoles by Oxidation of Azoles
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Azoles without N-substituents are oxidized with per-acids or perborate to the corresponding N-hydroxy substituted azoles. 1,2,4-Triazole and tetrazole produce two isomers separated through their O-benzyl derivatives.Imidazole and 1,2,3- and 1,2,4-triazole can be di-oxygenated in low yields.N-Hydroxypyrazole is deoxygenated by per-acid.
- Begtrup, Mikael,Vedso, Per
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p. 243 - 248
(2007/10/02)
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- 1-Hydroxyimidazole Derivatives III. Synthesis of 1-Alkyloxy-, 1-Arylalkyloxy-, and 1-Phenoxy-1H-imidazoles
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1-Hydroxy-1H-imidazole and 2-alkyl-1-hydroxy-1H-imidazoles are prepared by selective hydrogenation of the corresponding 1-hydroxy-1H-imidazole 3-oxides and subsequently transformed to the 1-alkoxy, 1-arylalkyloxy and 1-phenoxy derivatives.
- Laus, Gerhard,Stadlwieser, Josef,Kloetzer, Wilhelm
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p. 773 - 775
(2007/10/02)
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