Nitric Acid → 2-Methyl-5-nitroindoline

Temperature

7.5 °C

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.

1. temperatureTo a cooled
2. customprepared by an analgous method to
3. customremained between 10-20° C
4. customthe precipitate that formed
5. filtrationwas collected by filtration
6. washwashed with water
7. dissolutionredissolved in an ethanol-6N HCl solution
8. temperaturewarmed
9. temperatureto reflux for 30 minutes
10. concentrationThe resulting solution was concentrated
11. additionEtOAc was added
12. customThe organic phase was separated
13. dry with materialdried over MgSO4
14. filtrationThe mixture was filtered
15. customevaporated
16. customthe crude material purified by column chromatography (50% EtOAc-Hexane)

ORD record

ord-a2693784af244fe69335e5d908050131

Source dataset

uspto-grants-2007_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07262297B2