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Substance Name: Methylthiouracil [USP:INN]
RN: 56-04-2
UNII: QW24888U5F
InChIKey: HWGBHCRJGXAGEU-UHFFFAOYSA-N

Note

  • A thiourea antithyroid agent that inhibits the synthesis of thyroid hormone. It is used in the treatment of hyperthyroidism.

Molecular Formula

  • C5-H6-N2-O-S

Molecular Weight

  • 142.1814
 

Classification Codes

Classification Codes

  • Antithyroid Agents
  • Drug / Therapeutic Agent
  • Hormone Antagonists
  • Hormones, Hormone Substitutes, and Hormone Antagonists
  • Human Data
  • Mutation Data
  • Reproductive Effect
  • TSCA Flag S (Substance is Identified in a Final Significant New Use Rule)
  • Tumor Data

Superlist Classification Codes

  • Overall Carcinogenic Evaluation: Group 2B
  • Reportable Quantity (RQ) = 10 lb
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Names and Synonyms

Name of Substance

  • Methylthiouracil
  • Methylthiouracil [USP:INN]

MeSH Heading

  • Methylthiouracil

Synonyms

  • 2,3-Dihydro-6-methyl-2-thioxo-4(1H)-pyrimidinone
  • 2-Mercapto-4-hydroxy-6-methylpyrimidine
  • 2-Mercapto-6-methyl-4-pyrimidinol
  • 2-Mercapto-6-methylpyrimid-4-one
  • 2-Thio-4-oxo-6-methyl-1,3-pyrimidine
  • 2-Thio-6-methyl-1,3-pyrimidin-4-one
  • 2-Thio-6-methyluracil
  • 4-Methyl-2-thiouracil
  • 6-Methyl-2-mercaptouracil
  • 6-Methyl-2-thio-2,4-(1H,3H)-pyrimidinedione
  • 6-Methyl-2-thio-2,4-(1H3H)-pyrimidinedione
  • 6-Methyl-2-thiouracil
  • 6-Methyl-2-thiouracyl
  • 6-Methyl-2-thiouracyl [Czech]
  • 6-Methyl-4-oxo-2-thioxo1,2,3,4-tetrahydropyrimidine
  • 6-Methylthiouracil
  • 6-Metil-tiouracile
  • 6-Metil-tiouracile [Italian]
  • 6-Thio-4-methyluracil
  • AI3-25476
  • Alkiron
  • Alkiron (VAN)
  • Antibason
  • Basecil
  • Basethyrin
  • CCRIS 409
  • EINECS 200-252-3
  • HSDB 3366
  • Metacil
  • Metacil (VAN)
  • Methacil
  • Methacil (VAN)
  • Methiacil
  • Methicil
  • Methiocil
  • Methyl thiouracil
  • Methylthiouracil
  • Methylthiouracile
  • Methylthiouracile [INN-French]
  • Methylthiouracilum
  • Methylthiouracilum [INN-Latin]
  • Metiltiouracile
  • Metiltiouracile [DCIT]
  • Metiltiouracilo
  • Metiltiouracilo [INN-Spanish]
  • MTU
  • Muracil
  • NSC 193526
  • Orcanon
  • Prostrumyl
  • RCRA waste number U164
  • Strumacil
  • Thimecil
  • Thiomecil
  • Thiomidil
  • Thioryl
  • Thiothymin
  • Thiuryl
  • Thyreonorm
  • Thyreostat
  • Thyreostat I
  • Thyril
  • Tiomeracil
  • Tiorale M
  • Tiotiron
  • UNII-QW24888U5F
  • Uracil, 6-methyl-2-thio-
  • USAF EK-6454

Systematic Names

  • 4(1H)-Pyrimidinone, 2,3-dihydro-6-methyl-2-thioxo-
  • Methylthiouracil
  • Uracil, 6-methyl-2-thio-

Superlist Names

  • 4(1H)-Pyrimidinone, 2,3-dihydro-6-methyl-2-thioxo-
  • Methylthiouracil
  • RCRA waste no. U164

Registry Numbers

CAS Registry Number

  • 56-04-2

FDA UNII

  • QW24888U5F

Other Registry Numbers

  • 1123-10-0
  • 31909-18-9
  • 91795-77-6

System Generated Number

  • 0000056042

Structure Descriptors

InChI

1S/C5H6N2OS/c1-3-2-4(8)7-5(9)6-3/h2H,1H3,(H2,6,7,8,9)

InChIKey

HWGBHCRJGXAGEU-UHFFFAOYSA-N

Smiles

c1(cc(=O)[nH]c(=S)[nH]1)C

Toxicity

Organism Test Type Route Reported Dose (Normalized Dose) Effect Source
mouse LD50 intraperitoneal 200mg/kg (200mg/kg)   National Technical Information Service. Vol. AD277-689,
mouse LD50 oral 2125mg/kg (2125mg/kg)   Pharmaceutical Chemistry Journal Vol. 30, Pg. 320, 1996.
rabbit LDLo oral 2500mg/kg (2500mg/kg)   "Merck Index; an Encyclopedia of Chemicals, Drugs, and Biologicals", 11th ed., Rahway, NJ 07065, Merck & Co., Inc. 1989Vol. 11, Pg. 963, 1989.
rat LD50 intraperitoneal 920mg/kg (920mg/kg) LUNGS, THORAX, OR RESPIRATION: OTHER CHANGES Farmaco, Edizione Scientifica. Vol. 13, Pg. 882, 1958.
rat LD50 oral 1500mg/kg (1500mg/kg)   Nature. Vol. 157, Pg. 659, 1946.

Physical Properties

Physical Property Value Units Temp (deg C) Source
Melting Point 330 dec deg C   EXP
log P (octanol-water) 1.450 (none)   EST
Water Solubility 533 mg/L 25 EXP
Vapor Pressure 1.08E-03 mm Hg 25 EST
Henry's Law Constant 1.26E-09 atm-m3/mole 25 EST
Atmospheric OH Rate Constant 5.99E-11 cm3/molecule-sec 25 EST

Physical property data is provided to ChemIDplus by SRC, Inc.