Benzoyl chloride → 4-Benzoyl-1,2,3,4-tetrahydroquinoxalin-2-one

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Reaction Steps

A mixture of 1,2,3,4-tetrahydroquinoxalin-2-one (IV, EXAMPLE 1, 0.593 g) and triethylamine (0.725 ml) in THF (5 ml) is cooled at 0°. To this is added benzoyl chloride (0.56 ml). After the addition is complete, the ice bath is removed and additional THF (5 ml) is added. The reaction is stirred for 30 min and then partitioned between ethyl acetate, aq. sodium bicarbonate, and saline. The organic phases are separated and the organic phase is dried over magnesium sulfate and concentrated. The crude product is recrystallized from methanol/dichloromethane/hexane to give the title compound, mp 208.0°-208.5°; MS (m/z) at 252; IR (mineral oil) 1684, 1666, 1502, 757 and 1362 cm-1 ; NMR (CDCl3) 4.58, 6.7, 6.79, 6.98, 7.10, 7.34 and 7.40 δ.

Provenance & Evidence