Synthesis of 3-bromo-4-methylacetophenone

METAL CATALYSED CARBON-CARBON BOND-FORMING REACTIONS 

Anhydrous aluminum chloride (30 g, 225 mmol) and one magnetic stirrer bar were put into a 100-mL two-necked round-bottomed flask equipped with one septum at one neck and a pressure-equalizer dropping funnel at the other neck. Then, the flask was flushed with nitrogen through the septum. 4-Methylaceto-phenone (13.3 mL, 100 mmol) was added slowly from the dropping funnel to the stirred solid over a period of 10 minutes. The flask was stirred continuously for another 30 minutes after completion of the addition. 

Bromine (5.7 mL, 110 mmol) was added, dropwise, to the stirred, molten mass over a period of 5 minutes. The reaction was completed when the stirred mass solidified and no more hydrogen bromide was emitted. 

The solidified mass was dropped, portion wise, into 3M aqueous hydrochloric acid solution (250 mL). The dark oil at the bottom of the solution was extracted by ether (3 x 30 mL). The organic layer was then washed by saturated ammonium chloride aqueous solution (50 mL), dried with magnesium sulfate, and concentrated to get the crude product. 

Lithium aluminium hydride (LAH) (6.45 g, 170 mmol) and one magnetic stirrer bar were added into a 250-mL round-bottomed flask, which was then closed with a septum and dried under vacuum followed by filling with nitrogen. One part of dry ether (50 mL) was first injected into the stirred LAH. The mixture of 3-bromo-4-methylacetophenone (38 g, 180 mmol) in dry ether (50 mL) was injected into the flask dropwise. Stirring was continued after the completion of addition of 3-bromo-4-methylacetophenone until no more gas was generated. 

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