3',4',5'-Trimethoxyacetophenone → 2-Bromo-1-(3,4,5-trimethoxyphenyl)ethanone

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Reaction Steps

A mixture of 3.0 g of 3,4,5-trimethoxyacetophenone in 70 ml of dimethyl ether and 30 ml of chloroform is cooled to 0° and then treated with a mixture containing 0.73 ml of bromine in 15 ml of chloroform in a dropwise manner. The reaction mixture is allowed to warm to 20°- 25° and stirred for 1 hr. The reaction mixture is partitioned between chloroform and water. The organic layer is separated, washed with dilute sodium bicarbonate, washed with saline, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The crude product (4.31 g) is recrystallized from ethanol/water. The solid is isolated and dried (18 hours, 0.01 mm, 40°) to give the title compound, mp 61°-62°; IR (mineral oil) 3010, 2995, 2952, 2926, 2868, 2855, 1695, 1687, 1586, 1505, 1466, 1455, 1428, 1417, 1389, 1335, 1255, 1229, 1190, 1151, 1128, 1004, 820, 636, and 602 cm-1 ; NMR (CDCl3, TMS) 7.24, 4.43 and 3.93δ; CMR (CDCl3) 190.2, 153.1, 149.9, 143.3, 128.9, 106.5, 60.9, 56.3 and 30.4δ; MS (m/z) M+ =288, other ions at m/z 259, 228, 195, 181, 167, 152, 137, 122, 109, 77, 66 and 53.

Provenance & Evidence