Bromination of 5-methoxyindane: Synthesis of new benzoindenone derivatives and ready access to 7H-Benzo[c]fluoren-7-one skeleton

The photobromination of 5-methoxyindane and 5-methoxyindanone was studied at both high and low temperatures. 1,2,3-Tribromo-6-methoxyindene was easily synthesized by photolytic bromination of 5-methoxyindane at low temperature. 1,1,2,3-Tetrabromo-6-methoxyindene was obtained from the photobromination of 5-methoxyindan at 77 degrees C, which could then be easily converted to the 2,3-dibromo-6-methoxyindene by silver-supported hydrolysis. Photochemical bromination of 5-methoxy-1-indanone with N-bromosuccinimide (NBS) gave 3-bromo-6-methoxyindene, which upon thermolysis gave a benzo[c]fluorenone derivative