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

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Reaction Steps

4-fluorophenyhydrazine (0.90 g, 7.14 mmol) was dissolved in glacial acetic acid (25 mL) under a nitrogen atmosphere and added dropwise to a refluxing solution of 3-cyclohexanonecarboxylic acid ethyl ester (1.73 g, 10 mmol) dissolved in glacial acetic acid (15 mL). After the addition was complete, the solution was heated under reflux for 1 hr, cooled to room temperature and allowed to stir overnight. The orange solution was evaporated under reduced pressure to give a yellow-brown solid. The solid was suspended in 10% sulfuric acid and heated under reflux for 5 hrs, cooled to room temperature and allowed to stir overnight. The brown solid was collected by filtration and recrystallized from acetic acid and water to give the compound I (1.21 g), mp: >200° C. MS [M−H]− m/z 232.

Provenance & Evidence