Sulfuric Acid → 1H,2H,3H,4H-cyclopenta(b)indole-5-carboxylic acid

Participants

Reaction Steps

To a stirred solution of 2-hydrazinobenzoic acid hydrochloride (53 mmol, 10.0 g) and cyclopentanone (58 mmol, 4.9 g) in 1,4-dioxane (100 mL) was added dropwise concentrated H2SO4 (˜18M, 63 mmol, 3.5 mL). The resulting solution was heated to reflux for 2 hours. 1H NMR analysis of a crude aliquot indicated complete reaction. The reaction was allowed to cool to room temperature and then concentrated to dryness to give a red solid which was used without further purification.

Provenance & Evidence