Efficient synthesis of 3-(4,5-dihydro-1H-imidazole-2-yl)-1H-indoles

A simple method for the synthesis of various 3-(4,5-dihydro-1 H -imidazole-2-yl)-1 H -indoles is described. Treatment of different substituted indoles with 1-acetyl-imidazolidin-2-one in the presence of phosphorus oxychloride afforded after hydrolysis in ethanol the corresponding 3-(4,5-dihydro-1 H -imidazole-2-yl)-1 H -indoles in moderate to good yields.