2-Chloroethyl (methylsulfonyl)methanesulfonate and related (methylsulfonyl)methanesulfonates. Antineoplastic activity in vivo

2-Haloethyl and ethyl (methylsulfonyl)methanesulfonates were prepared via sulfene intermediates. 2-Chloroethyl (methylsulfonyl)methanesulfonate is highly active against P388 leukemia in vivo; the majority of leukemic mice treated with this compound at 50 mg/kg per day, qd 1-5, survived more than 30 days and about 37% survived for more than 60 days. 2- Fluoroethyl (methylsulfonyl)methanesulfonate is also highly effective against P388 cells in vivo, but it is more toxic. Other (methylsulfonyl)methanesulfonate esters are more active than the analogous methanesulfonates and chloromethanesulfonates .