DIMETHYL SULFATE(77-78-1) was first discovered in the early 1800s in an impure form. P. Claesson later extensively studied its preparation.

NTP 10th Report on Carcinogens. IARC Cancer Review: Group 2A IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 7 , 1987,p. 200.(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 Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 4 , 1974,p. 271.(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. 271.(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. Community Right-To-Know List. EPA Extremely Hazardous Substances List. Reported in EPA TSCA Inventory.

OSHA PEL: TWA 0.1 ppm (skin)
ACGIH TLV: TWA 0.1 ppm (skin); Animal Carcinogen
DFG MAK: DFG TRK: Production: 0.02 ppm; Use: 0.04 ppm; Animal Carcinogen, Suspected Human Carcinogen
DOT Classification:  3; Label: Poison, Corrosive

For occupational chemical analysis use NIOSH: Dimethyl Sulfate, 2524.

The IUPAC name of this chemical is Dimethyl sulfate. With the CAS registry number 77-78-1 and EINECS registry number 201-058-1, it is also named as Sulfuricacid, dimethyl ester. In addition, the molecular formula is C₂H₆O₄S and the molecular weight is 126.13. It is a kind of colourless liquid and belongs to the class of Pharmaceutical Intermediates.

Physical properties about this chemical are: (1)ACD/LogP: 0.12; (2)ACD/LogD (pH 5.5): 0.121; (3)ACD/LogD (pH 7.4): 0.121; (4)ACD/BCF (pH 5.5): 1; (5)ACD/BCF (pH 7.4): 1; (6)ACD/KOC (pH 5.5): 27.723; (7)ACD/KOC (pH 7.4): 27.723; (8)#H bond acceptors: 4; (9)#Freely Rotating Bonds: 2; (10)Polar Surface Area: 60.98 Å²; (11)Index of Refraction: 1.41; (12)Molar Refractivity: 23.597 cm³; (13)Molar Volume: 95.306 cm³; (14)Polarizability: 9.355 ×10^-24cm³; (15)Surface Tension: 36.492 dyne/cm; (16)Density: 1.323 g/cm³; (17)Flash Point: 83.333 °C; (18)Enthalpy of Vaporization: 40.684 kJ/mol; (19)Boiling Point: 187.999 °C at 760 mmHg; (20)Vapour Pressure: 0.845 mmHg at 25°C.

Preparation of Dimethyl sulfate: it can be prepared by methanol with sulfuric acid. The methanol react with sulfuric acid to give methyl hydrogen sulfate at first. Then the methyl hydrogen sulfate can react with methanol to get dimethyl ether. At last, dimethyl ether react with sulfur trioxide to prepare the product.

Uses of Dimethyl sulfate: it can be used as a reagent for the methylation of phenols, amines, and thiols. And it can effect the base-specific cleavage of guanine in DNA by rupturing the imidazole rings present in guanine. This process can be used to determine base sequencing, cleavage on the DNA chain, and other applications. In addition, it can react with 1H-benzoimidazole to get 1-methyl-1H-benzoimidazole. This reaction will need reagents K₂CO₃ and triethylbenzylammonium chloride and solvent benzene. The reaction time is 0.5 hour at reaction temperature of 20 °C. The yield is about 50%.

When you are using this chemical, please be cautious about it as the following:
This chemical is toxic if swallowed and very toxic by inhalation. And it can cause burns and may cause sensitization by skin contact. Moreover, it may cause cancer and has risk of irreversible effects possibly. You should avoid exposure - obtain special instruction before use. During using it, in case of accident or if you feel unwell, seek medical advice immediately (show label where possible).

You can still convert the following datas into molecular structure:
(1)SMILES: COS(=O)(=O)OC
(2)InChI: InChI=1/C2H6O4S/c1-5-7(3,4)6-2/h1-2H3
(3)InChIKey: VAYGXNSJCAHWJZ-UHFFFAOYAK

The toxicity data is as follows:

Organism	Test Type	Route	Reported Dose (Normalized Dose)	Effect	Source
guinea pig	LC50	inhalation	32ppm/1H (32ppm)		"Prehled Prumyslove Toxikologie; Organicke Latky," Marhold, J., Prague, Czechoslovakia, Avicenum, 1986Vol. -, Pg. 1079, 1986.
human	LCLo	inhalation	97ppm/10M (97ppm)		"Toxicology of Drugs and Chemicals," Deichmann, W.B., New York, Academic Press, Inc., 1969Vol. -, Pg. 226, 1969.
mouse	LC50	inhalation	280mg/m3 (280mg/m3)	SENSE ORGANS AND SPECIAL SENSES: OTHER CHANGES: OLFACTION BEHAVIORAL: SOMNOLENCE (GENERAL DEPRESSED ACTIVITY) LUNGS, THORAX, OR RESPIRATION: RESPIRATORY DEPRESSION	Gigiena Truda i Professional'nye Zabolevaniya. Labor Hygiene and Occupational Diseases. Vol. 23(3), Pg. 28, 1979.
mouse	LD50	oral	140mg/kg (140mg/kg)		Gigiena Truda i Professional'nye Zabolevaniya. Labor Hygiene and Occupational Diseases. Vol. 23(3), Pg. 28, 1979.
rabbit	LDLo	intravenous	50mg/kg (50mg/kg)	BEHAVIORAL: MUSCLE CONTRACTION OR SPASTICITY)	Archiv fuer Experimentelle Pathologie und Pharmakologie. Vol. 47, Pg. 113, 1902.
rabbit	LDLo	oral	45mg/kg (45mg/kg)	BEHAVIORAL: FOOD INTAKE (ANIMAL)	Archiv fuer Experimentelle Pathologie und Pharmakologie. Vol. 47, Pg. 113, 1902.
rabbit	LDLo	subcutaneous	53mg/kg (53mg/kg)	BEHAVIORAL: MUSCLE CONTRACTION OR SPASTICITY) SKIN AND APPENDAGES (SKIN): "DERMATITIS, OTHER: AFTER SYSTEMIC EXPOSURE"	Archiv fuer Experimentelle Pathologie und Pharmakologie. Vol. 47, Pg. 113, 1902.
rat	LC50	inhalation	45mg/m3/4H (45mg/m3)	LUNGS, THORAX, OR RESPIRATION: DYSPNEA LUNGS, THORAX, OR RESPIRATION: CYANOSIS BLOOD: HEMORRHAGE	Gigiena Truda i Professional'nye Zabolevaniya. Labor Hygiene and Occupational Diseases. Vol. 24(11), Pg. 55, 1980.
rat	LD50	oral	205mg/kg (205mg/kg)		Gigiena Truda i Professional'nye Zabolevaniya. Labor Hygiene and Occupational Diseases. Vol. 23(3), Pg. 28, 1979.
rat	LD50	subcutaneous	100mg/kg (100mg/kg)		Zeitschrift fuer Krebsforschung. Vol. 74, Pg. 241, 1970.