Dimethylformamide → 1-Methylindole

Temperature

0 °C

To a solution of the cyclopentanone adduct intermediate 1-3 from step 2 (3.81 g, 14.8 mmol) in anhydrous DMF (150 mL) at 0° C., NaH (60% dispersion in oil, 770 mg, 19.2 mmol) was added slowly. The reaction mixture was stirred at 0° C. for 5 min, then MeI (1.2 mL, 19.2 mmol) was added drop-wise and stirring was continued at 0° C. for 3 h. The mixture was allowed to warm-up to RT and was quenched by the addition of aqueous saturated NH4Cl (200 mL). The mixture was extracted with EtOAc (2×500 mL) and the organic layer was washed with aqueous saturated NH4Cl (2×200 mL) H2O (200 mL) and brine (200 mL). The combined organic layers were dried over anhydrous MgSO4, evaporated to dryness and the residue was purified by flash column chromatography (using 30% EtOAc in hexane as the eluent) to isolate the N-methylindole intermediate 1-4 as a beige solid (3.1 g, 77% yield).

1. stirringstirring
2. waitwas continued at 0° C. for 3 h
3. temperatureto warm-up to RT
4. customwas quenched by the addition of aqueous saturated NH4Cl (200 mL)
5. extractionThe mixture was extracted with EtOAc (2×500 mL)
6. washthe organic layer was washed with aqueous saturated NH4Cl (2×200 mL) H2O (200 mL) and brine (200 mL)
7. dry with materialThe combined organic layers were dried over anhydrous MgSO4
8. customevaporated to dryness
9. customthe residue was purified by flash column chromatography (

ORD record

ord-d32c94cbbbd54f309bb68173045f9b5a

Source dataset

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07879851B2