4-Methylbenzophenone → 4-(Bromomethyl)benzophenone

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Reaction Steps

4-Methylbenzophenone, 750 g (3.82 moles), is added to a 5 liter Morton flask equipped with an overhead stirrer and dissolved in 2850 ml of benzene. The solution is then heated to reflux, followed by the dropwise addition of 610 g (3.82 moles) of bromine in 330 ml of benzene. The addition rate is approximately 1.5 ml/min and the flask is illuminated with a 90 watt (90 joule/sec) halogen spotlight to initiate the reaction. A timer is used with the lamp to provide a 10% duty cycle (on 5 seconds, off 40 seconds), followed in one hour by a 20% duty cycle (on 10 seconds, off 40 seconds). After cooling, the reaction mixture is washed with 10 g of sodium bisulfite in 100 ml of water, followed by washing with 3×200 ml of water. The product is dried over sodium sulfate and recrystallized twice from toluene/hexane (⅓ by volume). The final compound is stored for use in the preparation of a reagent suitable for derivatization of nucleic acids as described in Example 4(b).

Provenance & Evidence