1: 65 percent / N-bromosuccinimide / CH2Cl2 / 6 h / Irradiation 2: 1) thiourea, 2) 10percent NaOH / 1) DMSO, r.t., 10 h, 2) DMSO, 2 h View Scheme

(i) thiourea, (ii) aq. NaOH; Multistep reaction;