Acetic Acid → 1-Tert-butyl 2-ethyl 7-(cyclopropylamino)-5-(2-methoxyethoxy)indoline-1,2-dicarboxylate

Participants

Reaction Steps

To a mixture of 1-tert-butyl 2-ethyl 7-amino-5-(2-methoxyethoxy)indoline-1,2-dicarboxylate (2.76 g), [(1-ethoxycyclopropyl)oxy](trimethyl)silane (7.29 mL), acetic acid (4.19 mL) and ethanol (70 mL) was added sodium cyanoborohydride (122 mg), and the mixture was refluxed for 3 hr. The reaction mixture was concentrated under reduced pressure, and the residue was diluted with ethyl acetate and water. The organic layer was washed with saturated brine, dried over anhydrous sodium sulfate, and filtered, and the filtrate was concentrated under reduced pressure. The residue was subjected to silica gel column chromatography to give the title compound (2.30 g, yield 75%) as a pale-yellow oil from a fraction eluted with ethyl acetate-hexane (4:1, volume ratio).

Provenance & Evidence