1,3-dibromo-5,5-dimethyl-hydantoin; dibenzoyl peroxide in tetrachloromethane 4 h; Heating;

N-bromosuccinmide; meta-chloroperoxybenzoic acid in tetrachloromethane 10 h; Heating;

1: K2CO3 / acetone / 24 h 2: 93 percent / NBS, dibenzoyl peroxide / CCl4 View Scheme

1: 85 percent / nitrosylsulfuric acid / 1) H2SO4, 5 deg C, 30 min 2) room temp., 3 h, 100 deg C, 2 h 2: 95 percent / K2CO3 / acetone; butan-2-one / 4 h / Heating 3: 93 percent / 1,3-dibromo-5,5-dimethylhydantoin, dibenzoylperoxide / CCl4 / 4 h / Heating View Scheme