Bromomethanesulphonylbromide is prepared as followed: to a stirred suspension of sym-trithiane (0.73 mol) in water was added Br2 (7.1 mol)
dropwise to maintain a reaction temperature of 35-40 °C. Cooling by ice bath may be required. After the addition
of Br2 is complete, the reaction is stirred for an additional 15 min. The product is extracted into CH2Cl2, washed
with 5% sodium bisulfite solution, and dried. Concentration and distillation yields bromomethanesulfonyl
bromide in 42-48% yield as a pale yellow liquid.
