Methanesulfonic Acid → 3-Bromo-7,9-dimethoxy-10,11-dihydrodibenz[b,f]oxepin-10-one

Participants

Reaction Conditions

Reaction Steps

To 27.3 g (F.W. 367.195, 74.3 mmol) of carboxylic acid (26) was added 140 mL of methanesulfonic acid to dissolve carboxylic acid (26). This solution was stirred at 40° C. for three days. To the resulting reaction solution was added 300 mL of ice water to deposit a cyclized compound. The cyclized compound was separated by filtration and extracted with ethyl acetate and treated according to the conventional method to obtain a crude product. This crude product was purified by silica gel column chromatography (developing solvent; ethyl acetate:hexane=1:2) and recrystallized from hexane-ethyl acetate to obtain 17.1 g (66%) of cyclized compound (27). (TLC; ethyl acetate:hexane=1:2).

Provenance & Evidence