Nitric Acid → 2-Methyl-5-nitroindoline

Participants

Reaction Conditions

Reaction Steps

To a cooled (0-10 C.) mixture of concentrated nitric acid (12 mL) and concentrated sulfuric acid (40 mL) was added 1-acetyl-2-methyl-indoline XII (12.5 g, 0.0713 moles), prepared by an analgous method to that described in Chem.Ber.; 14; 1881; 890, in small portions so that the internal temperature of the reaction remained between 10-20° C. The resulting mixture was allowed to stir at 5-10° C. overnight. The mixture was poured slowly into 300 mL of cold water and the precipitate that formed was collected by filtration, washed with water and redissolved in an ethanol-6N HCl solution and warmed to reflux for 30 minutes. The resulting solution was concentrated, EtOAc was added and the Ph of the solution adjusted to 10. The organic phase was separated and dried over MgSO4. The mixture was filtered, and evaporated and the crude material purified by column chromatography (50% EtOAc-Hexane) to give 3.31 g, 26% of 2-methyl-5-nitro-2,3-dihydro-1H-indole XIII: LRMS for C9H10N2O2 (M+H)+at m/z=179.

Provenance & Evidence