Structure of Busulfan (CAS NO.55-98-1):

IUPAC Name: 4-methylsulfonyloxybutyl methanesulfonate
Molecular Formula: C₆H₁₄O₆S₂
Molar mass: 246.30176 g/mol
H bond acceptors: 6
H bond donors: 0
Freely Rotating Bonds: 7
Polar Surface Area: 103.5Ų
Index of Refraction: 1.47
Molar Refractivity: 50.94 cm³
Molar Volume: 182.3 cm³
Surface Tension: 46.6 dyne/cm
Density: 1.35 g/cm³
Flash Point: 234.4 °C
Enthalpy of Vaporization: 69.75 kJ/mol
Boiling Point: 464 °C at 760 mmHg
Vapour Pressure: 2.41E-08 mmHg at 25°C
Appearance: White Crystalline Solid
Melting point: 114-118°C
Solubility: Solubility in acetone at 25 °C for 2.4g/100ml, in ethanol solubility for 0.1g/100ml, almost no smell.
Water solubility:Decomposes

  Busulfan was the mainstay of the chemotherapeutic treatment of Chronic Myeloid Leukemia (CML) until it was displaced by the new gold standard, Imatinib, though it is still in use to a degree as a result of the drug's relative inexpense.

NTP 10th Report on Carcinogens. IARC Cancer Review: Group 1 IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 (1987),p. 137.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 4 (1974),p. 247.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Human Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 4 (1974),p. 247.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . EPA Genetic Toxicology Program.

Confirmed carcinogen producing leukemia, kidney, and uterine tumors. Experimental neoplastigenic and tumorigenic data. Poison by ingestion, subcutaneous, intraperitoneal, intravenous, and possibly other routes. Ingestion by pregnant women can cause cancer of the reproductive system of the fetus including the uterus. Human teratogenic effects by ingestion and possibly other routes include developmental abnormalities of the eye, ear, craniofacial area including the nose and tongue, gastrointestinal system, endocrine system, urogenital system, and other unspecified areas. Other human reproductive effects by ingestion and possibly other routes include: impotence, changes in the uterus, cervix, and vagina, and menstrual-cycle disorders. Experimental reproductive effects. Human systemic effects by ingestion: general arteriolar or venous dilation of the eye, changes in structure or function of salivary glands. When heated to decomposition it emits toxic fumes of SO_x. See also Hazard SULFONATES.
Codes: T+,T
Risk Statements:
23:  Toxic by inhalation
24:  Toxic in contact with skin
25:  Toxic if swallowed
26:  Very Toxic by inhalation
27:  Very Toxic in contact with skin
28:  Very Toxic if swallowed
36:  Irritating to the eyes
37:  Irritating to the respiratory system
38:  Irritating to the skin
45:  May cause cancer
46:  May cause heritable genetic damage
63:  Possible risk of harm to the unborn child
Safety Statements:
28:  After contact with skin, wash immediately with plenty of ... (to be specified by the manufacturer) 
36:  Wear suitable protective clothing 
37:  Wear suitable gloves
39:  Wear eye/face protection
45:  In case of accident or if you feel unwell, seek medical advice immediately (show label where possible)
63:  In case of accident by inhalation, remove casualty to fresh air and keep at rest
RIDADR: UN 2811 6.1/PG 1
WGK Germany: 3
RTECS: EK1750000
HazardClass: 6.1(b)
PackingGroup: III

  Busulfan , with CAS number of 55-98-1, can be called 1,4-Bis(methyl sulfonoxy)butane;busulphan ; 1,4-dimethanesulfonoxybutane ; 1,4-Butanediol dimethyl sulfonate; busulfex ; tetramethylene bis(methanesulfonate) . It is a white crystalline solid, Busulfan (CAS NO.55-98-1) can be used as alkylating agent with antileukemic activity. It can be used for antineoplastic.