Water → Tropenol 9-fluorofluorene-9-carboxylate

Participants

Reaction Steps

1.66 mL (0.009 mol) of bis-(2-methoxyethyl)aminosulfur trifluoride are placed in 10 mL dichloromethane and within 20 minutes at 15°-20° C., a solution of 2.4 g (0.007 mol) of 4a in 25 mL dichloromethane is added dropwise thereto. The mixture is stirred for 20 hours at ambient temperature, cooled to 0° C., and carefully combined with 80 mL of water with thorough stirring. Then the mixture is carefully adjusted to pH 8 with aqueous NaHCO3 solution, the organic phase is separated off, the aqueous phase is extracted again with dichloromethane, the combined organic phases are washed with water, dried over magnesium sulfate, and evaporated to dryness. The hydrochloride is precipitated and recrystallized from acetonitrile-diethyl ether. Then the free base is liberated again using 10% aqueous sodium carbonate solution. Yield: 1.05 g bright yellow crystals (53% of theoretical yield).

Provenance & Evidence