Methyl p-toluenesulfonate → 5-Bromo-3-methoxy-3-prop-1-ynyl-1,3-dihydroindol-2-one

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Reaction Steps

To a solution of 5-bromo-3-hydroxy-3-prop-1-ynyl-1,3-dihydroindol-2-one (1.0 g, 3.75 mmol) in dry DMF (15 cm3) at 0° C., was added potassium tert-butoxide (1M in THF, 4.1 cm3, 4.1 mmol). After 15 min. methyl p-toluenesulfonate (0.85 g, 4.6 mmol) was added and the mixture was allowed to warm up to room temperature. After 16 h the mixture was poured into saturated ammonium chloride, extracted with EtOAc (×3), washed with water, brine, dried (MgSO4) and evaporated. The residue was purified by column chromatography (SiO2, EtOAc:hexane 1:3) to afford 5-bromo-3-methoxy-3-prop-1-ynyl-1,3-dihydroindol-2-one (0.62 g, 2.21 mmol, 59%): (CDCl3) δ inter alia 1.87 (s, 3H), 3.19 (s, 3H), 3.35 (s, 1H), 6.72 (d, 1H, J=8.3 Hz), 7.48 (dd, 1H, J=8.3, 2 Hz), 7.63 (d, 1H, J=2 Hz): MS (EI) m/z 279 (M)+.

Provenance & Evidence