Sulfuric Acid → 2-Bromo-7-iodo-9H-fluorene

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-bromofluorene (compound 19) (25.0 g, 0.1020 mol), glacial acetic acid (250 cm3), concentrated sulphuric acid (3 cm3) and water (20 cm3) became homogeneous on heating to 75° C. Periodic acid dihydrate (H5IO6, 4.56 g, 0.0200 mol) and pulverised 12 (10.2 g, 0.0402 mol) were added. The initial deep-purple colour changed to a brown during 2 h of heating and stirring at 75° C. Upon dilution with sodium hydrogensulphite (2.50 g) in water (25 cm3), the colour changed to yellow. The solution was subsequently diluted with water (500 cm3) and cooled to 0° C. to give a yellow precipitate. The excess liquid was decanted and the solid filtered off, washed repeatedly with cold ethanol (4×50 cm3), aqueous NaOH (5% solution, 4×50 cm3) and with water (4×50 cm3) to leave a yellow powder. The product was recrystallised from a solvent mixture of DCM and ethanol to yield a yellow powder (28.4 g, 74.9%). Melting point/° C.: 185.

Provenance & Evidence