“…(1 H, d, J 2 Hz, 8-H), 7.13 (1 H, t, J 8 Hz, 3-H), 7.29-7.52 (5 H, 1,4-Dihydrocarbazole-1 ,4-dione (18).-A solution of 1methoxy-9H-carbazole (15a) (17 mg, 0.086 mmol) in dry dichloromethane (0.5 ml) was kept at -78 "C under nitrogen during the dropwise addition of boron tribromide in dichloromethane ( IM; 0.2 ml, 0.2 mmol). The mixture was stirred for 16 h and then poured into ice-water (5 ml) and extracted with ether (20 ml).…”