Iodine → 3-Bromo-6-phenylperhydroazepin-2-one

Participants

Reaction Steps

4.4 g of phosphorus pentachloride were added slowly to 60 ml of methylene chloride containing 4.0 g of 6-phenylperhydroazepin-2-one [prepared as described in step (d) above], under a stream of nitrogen, keeping the temperature of the reaction solution at 0° to 5° C. After this addition, the reaction mixture was stirred for 20 minutes, and then 40 mg of iodine, followed by 21.1 ml of a 1M methylene chloride solution of bromine, were dropped into it at 0°-5° C. When this addition was complete, the reaction mixture was stirred for 1 hour. The volume of reaction mixture was reduced by half by evaporation under reduced pressure, to separate the title compound as crystals. After the addition of water, the separated crystals were collected by filtration and washed with ethyl acetate, to give 1.8 g of an isomer of the title compound, melting at 218°-219.5° C.

Provenance & Evidence