has role has functional parent independent continuant alkylating agent antifibrotic agent methanesulfonate ester busulfan CHEBI:28901 A methanesulfonate ester that is butane-1,4-diol in which the hydrogens of the hydroxy groups are replaced by methanesulfonyl groups. An alkylating antineoplastic agent, it is used for the treatment of chronic myeloid leukemia (although it has been largely replaced by newer drugs). It is also used as an insect sterilant. sulfonic acid derivative antineoplastic agent butane-1,4-diol anticoagulant carcinogenic agent teratogenic agent anti-HIV agent insect sterilant anti-anaemic agent