1,4-Dimethoxybenzene → Benzophenone

Participants

Reaction Steps

A mixture of 2-fluorobenzoyl chloride (15.86 g, 0.1 mole) and 1,4-dimethoxybenzene (13.82 g, 0.1 mole) in 1,2-dichloroethane (200 ml) was cooled in an ice bath and treated cautiously with AlCl3 (13.82 g, 0.103 mole) portionwise. The temperature of the reaction mixture was kept at 0-5° during the addition, and then warmed to room temperature over 4 hrs after completion of addition. The resulting deep red reaction mixture was further refluxed for 1.5 hrs, followed by stirring at room temperature overnight. The reaction was quenched by addition of ice and 6N HCl solution in an ice bath with continued stirring at 0° for an hour. The mixture was then extracted three times with CH2Cl2. The combined organic layers were washed with 50% NaCl solution, dried over anhydrous Na2SO4 and filtered through a silica gel plug, yielding the intermediate benzophenone (24.68 g, 100%) as an orange colored oil which was used for cyclization without further purification. IR (neat): 3070, 2998, 2936, 2736, 1605, 1477, 1445, 1328, 1265, 1226, 1212, 1135, 1038, 960, 870, 792, 758 and 646 cm-1.

Provenance & Evidence