Maleic Anhydride → 1H-Pyrrole-2,5-dione, 1-[3-(methylphenylamino)propyl]-

N-(3-Aminopropyl)-N-methylaniline [S. L. Shapiro et al., J. Am. Chem. Soc., 81, 3081 (1958)](8.3 g) was dissolved in dichloromethane (50 ml). Maleic anhydride (6 g) was added portionwise under ice-cooling and the mixture was stirred at room temperature for 1 hour. The solvent was distilled off and then acetic anhydride (20 ml) was added. The resulting mixture was allowed to stand at room temperature for 2 days. The reaction mixture was stirred at 60° C. for 2 hours and further at 100° C. for 2 hours. The mixture was concentrated under reduced pressure and the residue was extracted with ethyl acetate. The organic layer was neutralized with an aqueous sodium bicarbonate, washed with saturated brine and dried over anhydrous sodium sulfate. After concentration, the residue was subjected to column chromatography on silica gel and eluted with hexane/ethyl acetate (4:1). The desired compound thus obtained was recrystallized from the same solvent to obtain the compound as yellow needles (4.1 g).

1. temperaturecooling
2. distillationThe solvent was distilled off
3. additionacetic anhydride (20 ml) was added
4. waitto stand at room temperature for 2 days
5. stirringThe reaction mixture was stirred at 60° C. for 2 hours and further at 100° C. for 2 hours
6. concentrationThe mixture was concentrated under reduced pressure
7. extractionthe residue was extracted with ethyl acetate
8. washwashed with saturated brine
9. dry with materialdried over anhydrous sodium sulfate
10. concentrationAfter concentration
11. washeluted with hexane/ethyl acetate (4:1)

ORD record

ord-d7b6f08d0c3c4e3b8210c27b3e516a7f

Source dataset

uspto-grants-1994_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05344928