Hydrochloric Acid → 6-Fluoro-2,3,4,9-tetrahydro-1H-carbazole-3-carboxylic acid

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Reaction Conditions

Reaction Steps

6-Fluoro-2,3,4,9-tetrahydro-1H-carbazole-3-carboxylic acid ethyl ester (80 g, 0.3 mol) was dissolved in 1 L of ethanol solution of KOH (28 g, 0.5 mol). The resulting mixture was stirred under nitrogen at 40-45° C. until completion of hydrolysis (TLC, HPLC) in 3 hrs. To the cooled solution were added 0.5 L of 1N aqueous HCl and 0.5 L of water; the resulting mixture was concentrated under reduced pressure. The target compound crystallized out of the aqueous solution when ethanol boiled out; 71.2 g (99%) of the title compound were obtained after drying.

Provenance & Evidence