14289-45-3Relevant articles and documents
Diphenylparabanic acid as a synthon for the synthesis of α-diketones and α-ketocarboxylic acids
Watanabe, Nobuko,Hamano, Mitsutaka,Todaka, Shota,Asaeda, Takahiro,Ijuin, Hisako K.,Matsumoto, Masakatsu
, p. 632 - 639 (2012/03/22)
Diphenylparabanic acid was found to react with >2 equiv of organolithiums at -78 °C to effectively give the corresponding symmetrical α-diketones. However, upon treatment with 1 equiv of organolithium, the parabanic acid gave mainly 5-substituted 5-hydroxyimidazolidine-2,4-diones. On the other hand, Grignard reagents were less reactive toward the parabanic acid at low temperature, and selectively gave the corresponding 5- hydroxyimidazolidine-2,4-diones even if more than 1 equiv of the reagents was used. A tandem process in which the parabanic acid was first reacted with a Grignard reagent and then reacted in one-pot with an organolithium effectively gave the unsymmetrical α-diketone. 5-Substituted 5-hydroxyimidazolidine-2, 4-diones were useful as versatile precursors for preparing α- ketocarboxylic acids as well as unsymmetrical α-diketones.