C5H6N2OS
142.18 g/mol
APIWarning
Methylthiouracil
CAS56-04-2EC200-252-3
Category
API
Compound Class
Heterocycle
Primary Use
Pharmaceutical Raw Material
Methylthiouracil is an organosulfur compound used as an antithyroid active pharmaceutical ingredient. It is a thioamide structurally related to propylthiouracil, sharing a similar mechanism of action and side effect profile.
antithyroid pharmaceutical raw materialresearch compound for thyroid-related studies
Content scope: Information here supports chemical identification and industrial supply, research, and manufacturing contexts. It is not a therapeutic claim, medical advice, or drug-use instructions.
Restricted or banned substances
Substances on this list are banned or restricted under the named regulation. This page is a compliance reference — verify your obligations under applicable law.
Relevant lists:California Proposition 65
CAS 56-04-2
Related Compounds
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ReferenceSame Category
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Referencesame scaffold
4-Amino-6-hydroxy-2-mercaptopyrimidine monohydrate
CAS65802-56-4
research compound
Referencesame scaffold
4-Hydroxy-5-methyl-2-mercaptopyrimidine
CAS636-26-0
pharmaceutical intermediate
Referencesame scaffold
2-Thiouracil
CAS141-90-2
pharmaceutical raw material
Safety Reference
Warning
H302Harmful if swallowed
H351Suspected of causing cancer
H372Causes damage to organs through prolonged or repeated exposure
Regulatory Compliance1
- California Proposition 65USRegulation
Customs Tariff Classification
The international HS code for Methylthiouracil (CAS 56-04-2) is 2933.59.
HS code (international, 6-digit)
2933.59
EU CN code (8-digit)
2933 59 95
Classification per the EU customs inventory ECICS (2026-07 snapshot, HS 2022). National tariff lines and product form can affect the final classification.
Identifiers
IUPAC Name
6-methyl-2-sulfanylidene-1H-pyrimidin-4-one
InChIKey
HWGBHCRJGXAGEU-UHFFFAOYSA-N
SMILES
CC1=CC(=O)NC(=S)N1
Synonyms (88)
- MTU
- Methylthiouracil (INN)
- Methylthiouracile [INN-French]
- Methylthiouracilum [INN-Latin]
- Metiltiouracilo [INN-Spanish]
- 2-Thio-6-methyluracil
- 2-Thiouracil, 6-methyl-
- 4-Methyl-2-thiouracil
- 6-Methyl-2-mercaptouracil
- 6-Methyl-2-thiouracil
- 6-Methyl-2-thiouracyl
- 6-Methyl-2-thiouracyl [Czech]
- 6-Methylthiouracil
- 6-Metil-tiouracile
- 6-Metil-tiouracile [Italian]
- 6-Thio-4-methyluracil
- Alkiron
- Alkiron (VAN)
- Antibason
- Basecil
- Basethyrin
- METHYLTHIOURACIL [MART.]
- Metacil
- Metacil (VAN)
- Methacil
- Methacil (VAN)
- Methiacil
- Methicil
- Methiocil
- Methylthiouracil (Standard)
- Methylthiouracile
- Methylthiouracilum
- Metiltiouracile
- Metiltiouracilo
- Mizolastine Impurity 10
- Muracil
- Muracin
- Orcanon
- Prostrumyl
- Strumacil
- Thimecil
- Thimecil (TN)
- Thiomecil
- Thiomidil
- Thioryl
- Thiothymin
- Thiothyron
- Thiuryl
- Thyreonorm
- Thyreostat
- Thyreostat I
- Thyril
- Tiomeracil
- Tiorale M
- Tiotiron
- Uracil, 6-methyl-2-thio-
- Usaf ek-6454
- methylthiouracil