反应详情

The above procedure is repeated in all respects, excepting that the strong base reagent is altered. In separate experiments, sodium hydride, potassium hydroxide, barium oxide, diisopropylethylamine, 1,5-diazobicyclo[5.4.0]undicene-5, tetramethylguanidine, tetramethylbenzyl ammonium hydroxide, Amberlite A21 (Rohm & Haas) strongly basic ion exchange resin and p-toluenesulfonic acid, are substituted for sodium hydroxide and yield the desired 3-isopropyl-3-methyl-5H-imidazo[2,1-a]isoindole-2(3H),5-dione. In practice of the above-described method, sodium hydroxide or sodium hydride in refluxing toluene is preferred.