N-bromobutanimide → 7-Bromo-2,3,4,5-tetrahydro-1-benzoxepin-5-ol

Participants

Reaction Conditions

Reaction Steps

104.9 g (0.64 mole) of 2,3-dihydro-1-benzoxepin-5(4H)-one are dissolved at room temperature in 780 ml of glacial acetic acid and then, while stirring vigorously at 10° C., 113.9 g (0.64 mole) of N-bromosuccinimide are introduced in portions so that the temperature does not exceed 18°-20° C. (about 30 min). The reaction is complete after about 4 hours (TLC check) and the mixture is poured into 3 l of vigorously stirred ice-water and then stirred for 30 minutes. The solid produced which is initially oily crystallizes completely after some time. The solid is filtered off with suction and washed with about 5 l of water. It is dried over calcium chloride in vacuo and crystallized in cyclohexane.

Provenance & Evidence