Aluminum(III) Chloride → 9-Fluoro-6-hydroxybenzo[g]isoquinoline-5,10-dione

Participants

Reaction Steps

Aluminum chloride (19.05 g) is added in one portion to a stirred refluxing solution of 6-methoxy-9-fluorobenzo[g]isoquinoline-5,10-dione (7.20 g) in methylene chloride (432 mL). After refluxing for 4 hours the reaction mixture is cooled and poured in water (1,300 mL). Methylene chloride (200 mL) is added and after stirring for 10 min the organic phase is separated. The aqueous solution is saturated with NaCl and further extracted with methylene chloride (3×400 mL). The combined organic solutions are washed with brine (1,000 mL), dried and the solvent removed by roto-evaporation. The brown solid obtained (6.5 g) is recrystallized from ethyl acetate/n-hexane 1/1 (65 mL) to yield a 9/1 mixture (1H-NMR evaluation) of 9-fluoro-6-hydroxybenzo[g]isoquinoline-5,10-dione and 9-chloro-6-hydroxybenzo[g]isoquinoline-5,10-dione respectively (6.00 g).

Provenance & Evidence