- Synthesen von 3-Hydroxy-4-methyl-3-cyclobuten-1,2-dion (Methylmoniliformin)
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New routes to 3-hydroxy-4-methyl-3-cyclobutene-1,2-dione (9), the lowest homologue of the mycotoxine moniliformin are described.A common feature of all pathways is the synthesis of methylcyclobutanes having the oxidation level 6.Precursors, which are easily transformed to 9 by acid catalyzed hydrolysis, include -cycloadducts of in situ generated methyl ketene to tetraethoxyethylene and -photocycloadducts of dichlorovinylenecarbonate with 1,1-dichloro-1-propene.The acid hydrolysis of -cycloadducts of chlorotrifluoroethylene to N,N-diethyl-1-propylamine yields the diethylamine of 9 (=22) in 50percent overall yield.In addition, aconvenient one-pot-two-steps synthesis of a new electronich ethylene, 1,1,2-triethoxy-2-trimethylsilyloxy-ethylene (11), is described.
- Bellus, Daniel,Martin, Pierre,Sauter, Hanspeter,Winkler, Tammo
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- Anhydrous proton conductivities of squaric acid derivatives
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In this communication, we introduce squaric acid derivatives as anhydrous proton conductors. We report the synthesis, characterization and proton conductivities of four squaric acid derivatives. The anhydrous proton conductivity of one of the derivatives
- Basak, Dipankar,Versek, Craig,Toscano, Daniel T.,Christensen, Scott,Tuominen, Mark T.,Venkataraman
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experimental part
p. 5922 - 5924
(2012/08/08)
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- Efficient synthesis of a novel 4-hydroxy-2,3-dioxocyclobut-1-enyl group containing amino acids
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matrix presented Syntheses of novel amino acids possessing a squaryl group, 1-3, in an optically active form are described. The syntheses of 1-3 were conducted by a concise route involving (1) an aldol addition of an enolate derived from Gly, L-Asp, or L-Glu to diisopropyl squarate (4) and (2) an efficient decarboxylation of the aldol adducts based on the electron-withdrawing property of the squaryl group. Introducing N-protected group to 2 and 3 and peptide formation reactions are also described.
- Shinada, Tetsuro,Hayashi, Ken-Ichi,Hayashi, Toshihiro,Yoshida, Yasutaka,Horikawa, Manabu,Shimamoto, Keiko,Shigeri, Yasushi,Yumoto, Noboru,Ohfune, Yasufumi
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p. 1663 - 1666
(2008/02/10)
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- An Improved Method for the Synthesis of Substituted Cyclobutenediones
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Practical and high yielding routes to substituted cyclobutenediones are described. 3,4-Bis(1-methylethoxy)cyclobut-3-ene-1,2-dione (diisopropyl squarate), a stable, crystalline derivative of squaric acid, was easily prepared by refluxing squaric acid in 2
- Liebeskind, Lanny S.,Fengl, Richard W.,Wirtz, Kevin R.,Shawe, Thomas T.
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p. 2482 - 2488
(2007/10/02)
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