Sodium Hydroxide → tert-butyl-carbamic acid 2-(2-oxo-2,3-dihydro-1H-indol-4-yl)-ethyl ester

Participants

Reaction Conditions

Reaction Steps

Tert-butyl isocyanate (0.685 mL, 6 mmol) was added dropwise to a stirred mixture of 4-(2-hydroxy-ethyl)-1,3-dihydro-indol-2-one (709 mg, 4 mmol) in tetrahydrofuran (8 mL), dimethylforamide (2 mL) and pyridine (3 drops). The mixture was heated at 70° C. for 15 hours and 80° C. for 39 hours. 0.457 mL of tert-butyl isocyanate was added to the reaction and continued to heat at 90° C. for 24 hours. More tert-butyl isocyanate (0.457 mL) was added and continued to heat at 90° C. for 37 hours. The reaction was cooled, poured into 1 N sodium hydroxide solution (100 mL) and extracted with ethyl acetate (200 mL). The organic layer was washed with 1 N hydrochloric acid (100 mL) and brine, dried over anhydrous sodium sulfate and concentrated. The residue was recrystallized from methanol/ethyl acetate/hexane to give 130 mg (12%) of tert-butyl-carbamic acid 2-(2-oxo-2,3-dihydro-1H-indol-4-yl)-ethyl ester.

Provenance & Evidence