Thiouracil

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  • Identifiers

    CAS number
    141-90-2

    Molecular formula
    C4H4N2OS

    SMILES
    C1=CNC(=S)NC1=O

    Safety labels

    Health Hazard
    Health

  • Odor profile

    Fragrance
    Odorless 58.03%
    Burnt 39.88%
    Sulfurous 31.49%
    Pungent 30.2%
    Nutty 24.17%
    Garlic 23.31%
    Cooked 22.66%
    Roasted 20.85%
    Bitter 19.91%
    Meaty 17.47%

     

    Flavor
    Bitter 61.28%
    Odorless 37.09%
    Nutty 25.02%
    Formyl 21.06%
    Nitrile 20.82%
    Rotten 20.48%
    Bread crust 20.42%
    Urine 20.3%
    Sulfur 19.94%
    Mousy 19.66%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    -0.3

    pKa est.
    9.07 (weak base)

    Molecular weight
    128.15 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    428°C

    Melting point expt.

    • NO DEFINITE MP, ABOUT 340 °C WITH DECOMP

    Flash point

    • 166.61 ˚C est.

    Solubility expt.

    • VERY SLIGHTLY SOL IN WATER (1:2000); PRACTICALLY INSOL IN ETHER, ACIDS; READILY SOL IN ALKALINE SOLN
    • SLIGHTLY SOL IN ALC; SOL IN ANHYD HYDROGEN FLUORIDE

  • Synonyms

    • 2-thiouracil
    • Thiouracil
    • 141-90-2
    • 2-Mercaptopyrimidin-4-ol
    • 4-Hydroxy-2-mercaptopyrimidine
    • Deracil
    • 2-thioxo-2,3-dihydropyrimidin-4(1H)-one
    • Antagothyroid
    • 80275-68-9
    • 4(1H)-Pyrimidinone, 2,3-dihydro-2-thioxo-
    • Antagothyroil
    • Nobilen
    • 2-Mercapto-4-hydroxypyrimidine
    • 6-Thiouracil
    • 2-Mercapto-4-pyrimidone
    • 2-Mercapto-4-pyrimidinol
    • 4-Hydroxy-2-pyrimidinethiol
    • Uracil, 2-thio-
    • 2-sulfanylidene-1H-pyrimidin-4-one
    • 4-Pyrimidinol, 2-mercapto-
    • 2-sulfanylpyrimidin-4-ol
    • 6-Hydroxy-2-mercaptopyrimidine
    • Tiouracyl [Polish]
    • 2-Thio-1,3-pyrimidin-4-one
    • MFCD00006039
    • 2,3-Dihydro-2-thioxo-4(1H)-pyrimidinone
    • Tiouracyl
    • 2-Thiouracil (VAN)
    • 2-Thio-6-oxypyrimidine
    • 2-TU
    • 125220-28-2
    • CCRIS 587
    • 126160-72-3
    • 156-82-1
    • 2-Mercapto-4(1H)-pyrimidinone
    • 2-Thio-2,4-(1H,3H)-pyrimidinedione
    • HSDB 2954
    • 2-Mercaptopyrimid-4-one
    • CHEBI:348530
    • 4-Hydroxy-2(1H)-pyrimidinethione
    • 4-hydroxypyrimidine-2(1H)-thione
    • 4(3H)-Pyrimidinone, 2-mercapto- (9CI)
    • 2-Mercapto-pyrimidin-4-ol
    • EINECS 205-508-8
    • NSC 19473
    • 124700-71-6
    • DTXSID4021347
    • 4(1H)-Pyrimidinone, 2-mercapto- (9CI)
    • AI3-25474
    • 2-Thioxo-2,3-dihydro-1H-pyrimidin-4-one
    • 2(1H)-Pyrimidinethione, 4-hydroxy- (9CI)
    • 2(1H)-Pyrimidinethione, 6-hydroxy- (9CI)
    • 4-Pyrimidinol, 2-mercapto- (9CI)
    • NSC-19473
    • THIOURACIL [HSDB]
    • THIOURACIL [IARC]
    • 124700-72-7
    • TU
    • 2-THIOURACIL [MI]
    • THIOURACIL [WHO-DD]
    • 2-thioxo-2,3-dihydro-4(1h)-pyrimidinone
    • 59X161SCYL
    • DTXCID701347
    • NSC19473
    • NCGC00095088-01
    • THIOURACIL (IARC)
    • 2-Thio-4-oxypyrimidine
    • 4-Hydroxypyrimidine-2-thiol
    • CAS-141-90-2
    • 2-Thio-4-oxo-1,3-pyrimidine
    • NCI-C01490
    • Uracil, 2-thio- (VAN)
    • UNII-59X161SCYL
    • 2-thioxo-1H-pyrimidin-4-one
    • 2-sulfanylpyrimidin-4(3H)-one
    • 4(3H)-Pyrimidinone, 2-mercapto-
    • 2-thio-4-pyrimidone
    • Spectrum_001652
    • SpecPlus_000746
    • 4-hydroxypyrimidinethione
    • 2,3-dihydro-2-thioxopyrimidin-4(1h)-one
    • Spectrum3_000979
    • Spectrum4_001104
    • Spectrum5_001378
    • WLN: T6MYMVJ BUS
    • Uracil, 2-thio-(VAN)
    • 2-mercaptopyrimidine-4-one
    • 2-Thiouracil, >=99%
    • SCHEMBL9172
    • 2-Sulfanyl-4-pyrimidinol #
    • 6-hydroxypyrimidine-2-thione
    • BSPBio_002617
    • KBioGR_001548
    • KBioSS_002132
    • DivK1c_000104
    • DivK1c_006842
    • SPECTRUM1503973
    • 2-sulfanylidene-1,2,3,4-tetrahydropyrimidin-4-one
    • CHEMBL345768
    • HMS500F06
    • KBio1_000104
    • KBio1_001786
    • KBio2_002132
    • KBio2_004700
    • KBio2_007268
    • KBio3_001837
    • NINDS_000104
    • HMS1922O08
    • HMS3651F22
    • HMS3885A09
    • Pharmakon1600-01503973
    • pyrimidine, 4-hydroxy-2-mercapto-
    • Uracil, 2-thio-(VAN) (8CI)
    • HY-B0503
    • Tox21_111418
    • Tox21_202418
    • Tox21_302955
    • AB7033
    • BDBM50608607
    • CCG-39926
    • NSC758660
    • s3100
    • STL011919
    • STL134904
    • STL168055
    • STL185506
    • AKOS000119226
    • AKOS002303247

  • Applications

    Thiouracil (CAS 141-90-2) is primarily used as an intermediate in pharmaceutical synthesis, notably as a precursor for thiouracil-derived compounds employed in antithyroid drugs. It also serves as a core scaffold for the synthesis of diverse thiouracil derivatives in medicinal chemistry and chemical biology research. In laboratory settings, thiouracil is used as a reactive building block for nucleobase analogs and related heterocyclic compounds. Additionally, it functions as a general synthetic starting material in organic manufacturing, subject to appropriate safety, purity, and regulatory controls.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 3.2
    methanol 4.97
    isopropanol 2.43
    water 2.29
    ethyl acetate 2.68
    n-propanol 2.92
    acetone 9.83
    n-butanol 2.09
    acetonitrile 3.72
    DMF 104.67
    toluene 0.14
    isobutanol 1.97
    1,4-dioxane 4.38
    methyl acetate 4.72
    THF 11.73
    2-butanone 6.5
    n-pentanol 2.21
    sec-butanol 1.98
    n-hexane 0.02
    ethylene glycol 8.96
    NMP 72.5
    cyclohexane 0.01
    DMSO 128.19
    n-butyl acetate 3.56
    n-octanol 0.87
    chloroform 0.18
    n-propyl acetate 3.72
    acetic acid 11.32
    dichloromethane 0.29
    cyclohexanone 5.46
    propylene glycol 8.34
    isopropyl acetate 2.09
    DMAc 103.27
    2-ethoxyethanol 18.21
    isopentanol 2.35
    n-heptane 0.05
    ethyl formate 4.76
    1,2-dichloroethane 0.43
    n-hexanol 1.36
    2-methoxyethanol 28.52
    isobutyl acetate 2.19
    tetrachloromethane 0.06
    n-pentyl acetate 2.31
    transcutol 30.71
    n-heptanol 1.14
    ethylbenzene 0.17
    MIBK 3.01
    2-propoxyethanol 15.07
    tert-butanol 3.44
    MTBE 1.27
    2-butoxyethanol 8.95
    propionic acid 6.25
    o-xylene 0.27
    formic acid 13.28
    diethyl ether 0.69
    m-xylene 0.27
    p-xylene 0.29
    chlorobenzene 0.23
    dimethyl carbonate 6.12
    n-octane 0.02
    formamide 20.17
    cyclopentanone 11.66
    2-pentanone 3.83
    anisole 1.87
    cyclopentyl methyl ether 1.91
    gamma-butyrolactone 17.52
    1-methoxy-2-propanol 19.85
    pyridine 2.21
    3-pentanone 2.76
    furfural 20.98
    n-dodecane 0.03
    diethylene glycol 23.17
    diisopropyl ether 0.29
    tert-amyl alcohol 2.82
    acetylacetone 8.32
    n-hexadecane 0.03
    acetophenone 4.1
    methyl propionate 5.2
    isopentyl acetate 3.51
    trichloroethylene 0.81
    n-nonanol 0.94
    cyclohexanol 0.94
    benzyl alcohol 3.03
    2-ethylhexanol 1.13
    isooctanol 1.17
    dipropyl ether 1.32
    1,2-dichlorobenzene 0.41
    ethyl lactate 7.41
    propylene carbonate 9.13
    n-methylformamide 22.89
    2-pentanol 1.02
    n-pentane 0.02
    1-propoxy-2-propanol 10.35
    1-methoxy-2-propyl acetate 8.44
    2-(2-methoxypropoxy) propanol 15.74
    mesitylene 0.24
    ε-caprolactone 7.12
    p-cymene 0.42
    epichlorohydrin 9.64
    1,1,1-trichloroethane 0.28
    2-aminoethanol 10.2
    morpholine-4-carbaldehyde 48.33
    sulfolane 35.68
    2,2,4-trimethylpentane 0.03
    2-methyltetrahydrofuran 3.59
    n-hexyl acetate 2.44
    isooctane 0.03
    2-(2-butoxyethoxy)ethanol 15.04
    sec-butyl acetate 2.08
    tert-butyl acetate 2.84
    decalin 0.03
    glycerin 21.55
    diglyme 24.81
    acrylic acid 8.91
    isopropyl myristate 1.3
    n-butyric acid 5.08
    acetyl acetate 2.58
    di(2-ethylhexyl) phthalate 3.74
    ethyl propionate 3.4
    nitromethane 28.43
    1,2-diethoxyethane 3.97
    benzonitrile 2.51
    trioctyl phosphate 2.26
    1-bromopropane 0.18
    gamma-valerolactone 28.8
    n-decanol 0.8
    triethyl phosphate 3.2
    4-methyl-2-pentanol 1.0
    propionitrile 2.41
    vinylene carbonate 7.4
    1,1,2-trichlorotrifluoroethane 14.97
    DMS 4.28
    cumene 0.23
    2-octanol 0.62
    2-hexanone 4.02
    octyl acetate 1.96
    limonene 0.55
    1,2-dimethoxyethane 22.62
    ethyl orthosilicate 2.47
    tributyl phosphate 2.77
    diacetone alcohol 9.58
    N,N-dimethylaniline 2.2
    acrylonitrile 4.62
    aniline 0.97
    1,3-propanediol 9.85
    bromobenzene 0.13
    dibromomethane 0.15
    1,1,2,2-tetrachloroethane 0.86
    2-methyl-cyclohexyl acetate 3.48
    tetrabutyl urea 5.14
    diisobutyl methanol 0.96
    2-phenylethanol 2.78
    styrene 0.18
    dioctyl adipate 3.84
    dimethyl sulfate 18.59
    ethyl butyrate 3.64
    methyl lactate 12.52
    butyl lactate 5.64
    diethyl carbonate 3.15
    propanediol butyl ether 10.19
    triethyl orthoformate 3.32
    p-tert-butyltoluene 0.41
    methyl 4-tert-butylbenzoate 6.91
    morpholine 8.41
    tert-butylamine 0.94
    n-dodecanol 0.64
    dimethoxymethane 18.39
    ethylene carbonate 5.38
    cyrene 19.81
    2-ethoxyethyl acetate 5.41
    2-ethylhexyl acetate 2.47
    1,2,4-trichlorobenzene 0.74
    4-methylpyridine 2.59
    dibutyl ether 0.77
    2,6-dimethyl-4-heptanol 0.96
    DEF 11.06
    dimethyl isosorbide 20.63
    tetrachloroethylene 0.4
    eugenol 9.4
    triacetin 6.63
    span 80 8.7
    1,4-butanediol 6.44
    1,1-dichloroethane 0.24
    2-methyl-1-pentanol 2.26
    methyl formate 14.66
    2-methyl-1-butanol 2.12
    n-decane 0.03
    butyronitrile 2.19
    3,7-dimethyl-1-octanol 1.24
    1-chlorooctane 0.16
    1-chlorotetradecane 0.11
    n-nonane 0.03
    undecane 0.03
    tert-butylcyclohexane 0.04
    cyclooctane 0.01
    cyclopentanol 2.28
    tetrahydropyran 1.12
    tert-amyl methyl ether 1.41
    2,5,8-trioxanonane 22.6
    1-hexene 0.12
    2-isopropoxyethanol 10.16
    2,2,2-trifluoroethanol 7.36
    methyl butyrate 5.15

    Scent© AI

1 4

IFRA standard 51

Recommendation
No restriction
Maximum acceptable concentrations in the finished product (%)
Category 1
Products applied to the lips
 No restriction Category 7A
Rinse-off products applied to the hair with some hand contact
 No restriction
Category 2
Products applied to the axillae
 No restriction Category 7B
Leave-on products applied to the hair with some hand contact
 No restriction
Category 3
Products applied to the face/body using fingertips
 No restriction Category 8
Products with significant anogenital exposure
 No restriction
Category 4
Products related to fine fragrance
 No restriction Category 9
Products with body and hand exposure, primarily rinse off
 No restriction
Category 5A
Body lotion products applied to the body using the hands (palms), primarily leave on
 No restriction Category 10A
Household care products with mostly hand contact
 No restriction
Category 5B
Face moisturizer products applied to the face using the hands (palms), primarily leave on
 No restriction Category 10B
Household care products with mostly hand contact, including aerosol/spray products (with potential leave-on skin contact)
 No restriction
Category 5C
Hand cream products applied to the hands using the hands (palms), primarily leave on
 No restriction Category 11A
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate without UV exposure
 No restriction
Category 5D
Baby Creams, baby Oils and baby talc
 No restriction Category 11B
Products with intended skin contact but minimal transfer of fragrance to skin from inert substrate with potential UV exposure
 No restriction
Category 6
Products with oral and lip exposure
 No restriction Category 12
Products not intended for direct skin contact, minimal or insignificant transfer to skin
 No restriction