Synthesis of 3-Methylthio-4-aryl-3-pyrroline-2,5-diones and 3-Arylpyrrolidine-2,5-diones by Reaction of Nitroketene Dithioacetal with Arylacetonitriles
摘要:
The reaction of nitroketene dithioacetal (1a), i.e., 2,2-bis(methylthio)-1-nitroethylene, with arylacetonitriles (2a-I) in the presence of the base like sodium hydroxide gave 4-nitrobut-2-enenitriles (3a-I) which were converted into 5-hydroxyimino-4-methylthio-3-phenyl-3-pyrrolin-2-ones (4a-i) under refluxing in methanol. Title compounds (5a-i) were readily obtained by the treatment of 4a-i with hydrochloric acid and were finally led to N-methylated products (6a-I) with methyl iodide. The reduction of maleimides (4-6) with zinc dust in acetic acid afforded the corresponding 3-arylpyrrolidine-2,5-diones (7a-i) that can be converted to pharmacologycally active compounds like mesembrines.
arenediazonium tetrafluoroborates and maleimides in the presence of TiCl3. The reactions generated 3-arylsuccinimides in satisfactory yields under mild reaction conditions. In addition, 3-arylmaleimides were obtained by the coupling of arenediazonium tetrafluoroborate and maleimides catalyzed by CuCl. This methodology provided the selective and tunable synthesis of two classes of products by simply
Microwave-enhanced rhodium-catalyzed conjugate-addition of aryl boronic acids to unprotected maleimides
作者:Pravin S. Iyer、Meaghan M. O’Malley、Matthew C. Lucas
DOI:10.1016/j.tetlet.2007.04.084
日期:2007.6
Various boronicacids were treated with a rhodium (I) catalyst enabling their 1,4-conjugate addition to unprotected maleimide. The scope of the reaction was explored to include both electron-rich and electron poor boronicacids. These reactions were also performed in the microwave resulting in reduced reaction times and improved efficiencies. Additionally, substrates that were recalcitrant under conventional