Thymine

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  • Identifiers

    CAS number
    65-71-4

    Molecular formula
    C5H6N2O2

    SMILES
    CC1=CNC(=O)NC1=O

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 58.25%
    Burnt 35.56%
    Bitter 29.67%
    Nutty 23.42%
    Roasted 20.91%
    Pungent 20.71%
    Caramellic 18.48%
    Musty 17.6%
    Cooked 16.34%
    Sharp 15.84%

     

    Flavor
    Bitter 65.89%
    Odorless 34.89%
    Nutty 22.76%
    Bread crust 21.08%
    Formyl 20.78%
    Urine 20.67%
    Nitrile 20.59%
    Fragrant 20.43%
    Almond shell 20.38%
    Mild 20.3%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    -0.6

    pKa est.
    9.64 (weak base)

    Molecular weight
    126.11 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    379°C

    Melting point expt.

    • 316 °C
    • 320 °C

    Flash point

    • 192.78 ˚C est.

    Solubility expt.

    • 3820 mg/L (at 25 °C)
    • 3.82 mg/mL

  • Synonyms

    • thymine
    • 65-71-4
    • 5-methyluracil
    • 2,4-Dihydroxy-5-methylpyrimidine
    • Thymin
    • 5-Methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione
    • Thymine anhydrate
    • 2,4(1H,3H)-Pyrimidinedione, 5-methyl-
    • 5-methyl-1H-pyrimidine-2,4-dione
    • 5-methyl-2,4(1H,3H)-pyrimidinedione
    • Thymin (purine base)
    • DTXSID4052342
    • QR26YLT7LT
    • NSC14705
    • CHEBI:17821
    • NSC-14705
    • DTXCID4030914
    • NSC-168663
    • 5 Methyluracil
    • RefChem:6308
    • 200-616-1
    • 5-methylpyrimidine-2,4(1H,3H)-dione
    • 5-Methyl Uracil
    • MFCD00006026
    • CCRIS 5584
    • 5-methylpyrimidine-2,4-diol
    • AI3-25479
    • CHEMBL993
    • THYMINE-13C1
    • 123430-67-1
    • 153445-43-3
    • thymine-d4
    • 5-METHYLPYRIMIDINE-2,4(1H,3H)-DIONE (THYMINE)
    • 2792-47-4
    • 3059-73-2
    • Thy
    • THYMINE,[2-14C]
    • Thymine-t
    • Zidovudine EP Impurity C
    • Thymine (VAN)
    • (3H)Methylthymidine
    • 5-methyl-1,3-dihydropyrimidine-2,4-dione
    • Methyl-3H thymidine
    • Thymine (8CI)
    • 24523-96-4
    • EINECS 200-616-1
    • UNII-QR26YLT7LT
    • NSC 14705
    • 5-methyl-uracil
    • Thymine (Standard)
    • 200496-79-3
    • Thymine, >=99%
    • THYMINE [MI]
    • THYMINE [WHO-DD]
    • Epitope ID:167476
    • SCHEMBL5235
    • 2,4(1H,3H)-Pyrimidinedione, 5-methyl- (9CI)
    • 4(1H)-Pyrimidinone, 2-hydroxy-5-methyl- (9CI)
    • 4(3H)-Pyrimidinone, 2-hydroxy-5-methyl- (9CI)
    • 69497-78-5
    • SCHEMBL143917
    • SCHEMBL439035
    • SCHEMBL537218
    • SCHEMBL546931
    • 5-Methyl-2,4-dioxypyrimidine
    • THYMINE [USP IMPURITY]
    • 2.6-Dioxy-5-methyl-pyrimidin
    • GTPL4581
    • orb1296050
    • SCHEMBL2304446
    • SCHEMBL2322416
    • SCHEMBL4152636
    • SCHEMBL15496760
    • SCHEMBL16356870
    • WLN: T6N CNJ BQ DQ E1
    • 2,4(1H,3H)-Pyrimidinedione, 5-methyl-, labeled with tritium
    • HMS5086D03
    • AIA49679
    • BB_SC-12833
    • HY-W010450R
    • TCA94198
    • 2,3H)-Pyrimidinedione, 5-methyl-
    • Tox21_303929
    • BDBM50134397
    • EBC-04269
    • MSK000951
    • s9382
    • SBB058343
    • STL280241
    • STL477641
    • STAVUINE IMPURITY A [WHO-IP]
    • AKOS000120923
    • AKOS002337369
    • AC-7756
    • CCG-266101
    • CS-W011166
    • DB03462
    • FT06260
    • HY-W010450
    • SB57778
    • ZIDOVUDINE IMPURITY C [WHO-IP]
    • CAS-65-71-4
    • CID 5274265
    • NCGC00357169-01
    • SY014896
    • Thymine, Vetec(TM) reagent grade, 99%
    • 2(1H)-Pyrimidinone, 4-hydroxy-5-methyl-
    • 4(1H)-Pyrimidinone, 2-hydroxy-5-methyl-
    • 4(3H)-Pyrimidinone, 2-hydroxy-5-methyl-
    • DB-016098
    • DB-268941
    • DB-268967
    • DB-272085
    • DB-272203
    • pyrimidine-2,4(1H,3H)-dione, 5-methyl-
    • ZIDOVUDINE IMPURITY C [EP IMPURITY]
    • NS00001295
    • ST51016238
    • T0234
    • EN300-21969
    • C00178
    • Thymine, suitable for cell culture, BioReagent
    • 006T026
    • 2(1H)-PYRIMIDINONE, 6-HYDROXY-5-METHYL-
    • 2,4-Dihydroxy-5-methylpyrimidine; 5-Methyluracil
    • F036430
    • Q171973
    • 65-71-4

  • Applications

    Thymine (CAS 65-71-4) is primarily used as a biochemical reagent and building block in nucleotide and nucleoside synthesis, supporting gene research and DNA/RNA technologies. It serves as a fundamental component in oligonucleotide assembly and in the development of DNA/RNA assays. Thymine is used as an analytical reference material and standard for HPLC/LC-MS methods in life sciences analysis. In pharmaceutical R&D, it may function as a precursor or intermediate in the synthesis of nucleoside analogs for drug discovery. It is also employed as a research reagent in educational and academic laboratory settings.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 1.94
    methanol 4.08
    isopropanol 1.13
    water 3.51
    ethyl acetate 0.25
    n-propanol 1.29
    acetone 0.5
    n-butanol 0.78
    acetonitrile 0.3
    DMF 22.64
    toluene 0.09
    isobutanol 0.89
    1,4-dioxane 1.55
    methyl acetate 0.62
    THF 4.94
    2-butanone 0.42
    n-pentanol 0.82
    sec-butanol 0.89
    n-hexane 0.02
    ethylene glycol 4.04
    NMP 22.72
    cyclohexane 0.01
    DMSO 27.06
    n-butyl acetate 0.91
    n-octanol 0.44
    chloroform 0.64
    n-propyl acetate 0.45
    acetic acid 1.85
    dichloromethane 0.78
    cyclohexanone 1.03
    propylene glycol 3.72
    isopropyl acetate 0.28
    DMAc 24.07
    2-ethoxyethanol 4.79
    isopentanol 1.04
    n-heptane 0.02
    ethyl formate 1.85
    1,2-dichloroethane 0.43
    n-hexanol 0.71
    2-methoxyethanol 10.96
    isobutyl acetate 0.42
    tetrachloromethane 0.23
    n-pentyl acetate 0.67
    transcutol 5.51
    n-heptanol 0.75
    ethylbenzene 0.12
    MIBK 0.61
    2-propoxyethanol 5.77
    tert-butanol 1.87
    MTBE 0.4
    2-butoxyethanol 4.8
    propionic acid 1.52
    o-xylene 0.17
    formic acid 8.27
    diethyl ether 0.14
    m-xylene 0.16
    p-xylene 0.25
    chlorobenzene 0.17
    dimethyl carbonate 1.7
    n-octane 0.01
    formamide 8.89
    cyclopentanone 3.03
    2-pentanone 0.31
    anisole 0.8
    cyclopentyl methyl ether 0.64
    gamma-butyrolactone 5.94
    1-methoxy-2-propanol 6.19
    pyridine 0.92
    3-pentanone 0.2
    furfural 10.75
    n-dodecane 0.02
    diethylene glycol 9.72
    diisopropyl ether 0.07
    tert-amyl alcohol 1.51
    acetylacetone 0.83
    n-hexadecane 0.02
    acetophenone 1.36
    methyl propionate 0.63
    isopentyl acetate 1.37
    trichloroethylene 0.78
    n-nonanol 0.45
    cyclohexanol 0.43
    benzyl alcohol 1.45
    2-ethylhexanol 0.52
    isooctanol 0.75
    dipropyl ether 0.33
    1,2-dichlorobenzene 0.38
    ethyl lactate 1.77
    propylene carbonate 3.83
    n-methylformamide 7.81
    2-pentanol 0.34
    n-pentane 0.01
    1-propoxy-2-propanol 3.55
    1-methoxy-2-propyl acetate 2.11
    2-(2-methoxypropoxy) propanol 5.71
    mesitylene 0.15
    ε-caprolactone 1.75
    p-cymene 0.27
    epichlorohydrin 4.74
    1,1,1-trichloroethane 0.31
    2-aminoethanol 5.29
    morpholine-4-carbaldehyde 14.47
    sulfolane 14.1
    2,2,4-trimethylpentane 0.02
    2-methyltetrahydrofuran 1.35
    n-hexyl acetate 0.74
    isooctane 0.02
    2-(2-butoxyethoxy)ethanol 5.17
    sec-butyl acetate 0.32
    tert-butyl acetate 0.67
    decalin 0.02
    glycerin 10.39
    diglyme 9.63
    acrylic acid 2.13
    isopropyl myristate 0.38
    n-butyric acid 1.29
    acetyl acetate 0.32
    di(2-ethylhexyl) phthalate 1.64
    ethyl propionate 0.52
    nitromethane 3.73
    1,2-diethoxyethane 0.71
    benzonitrile 1.07
    trioctyl phosphate 0.97
    1-bromopropane 0.19
    gamma-valerolactone 7.71
    n-decanol 0.35
    triethyl phosphate 1.43
    4-methyl-2-pentanol 0.45
    propionitrile 0.49
    vinylene carbonate 3.14
    1,1,2-trichlorotrifluoroethane 8.48
    DMS 1.16
    cumene 0.2
    2-octanol 0.36
    2-hexanone 0.52
    octyl acetate 0.55
    limonene 0.24
    1,2-dimethoxyethane 7.39
    ethyl orthosilicate 1.21
    tributyl phosphate 1.12
    diacetone alcohol 2.73
    N,N-dimethylaniline 1.26
    acrylonitrile 1.02
    aniline 0.44
    1,3-propanediol 4.85
    bromobenzene 0.13
    dibromomethane 0.37
    1,1,2,2-tetrachloroethane 0.99
    2-methyl-cyclohexyl acetate 1.24
    tetrabutyl urea 1.97
    diisobutyl methanol 0.5
    2-phenylethanol 1.42
    styrene 0.11
    dioctyl adipate 0.95
    dimethyl sulfate 6.19
    ethyl butyrate 0.82
    methyl lactate 3.7
    butyl lactate 2.14
    diethyl carbonate 1.0
    propanediol butyl ether 4.42
    triethyl orthoformate 1.12
    p-tert-butyltoluene 0.27
    methyl 4-tert-butylbenzoate 3.23
    morpholine 2.64
    tert-butylamine 0.62
    n-dodecanol 0.26
    dimethoxymethane 5.06
    ethylene carbonate 2.08
    cyrene 7.69
    2-ethoxyethyl acetate 1.12
    2-ethylhexyl acetate 0.9
    1,2,4-trichlorobenzene 0.59
    4-methylpyridine 1.09
    dibutyl ether 0.23
    2,6-dimethyl-4-heptanol 0.5
    DEF 1.66
    dimethyl isosorbide 9.48
    tetrachloroethylene 0.64
    eugenol 4.43
    triacetin 1.29
    span 80 3.06
    1,4-butanediol 2.4
    1,1-dichloroethane 0.24
    2-methyl-1-pentanol 1.05
    methyl formate 6.18
    2-methyl-1-butanol 0.95
    n-decane 0.02
    butyronitrile 0.49
    3,7-dimethyl-1-octanol 0.58
    1-chlorooctane 0.09
    1-chlorotetradecane 0.06
    n-nonane 0.02
    undecane 0.02
    tert-butylcyclohexane 0.04
    cyclooctane 0.01
    cyclopentanol 1.17
    tetrahydropyran 0.38
    tert-amyl methyl ether 0.42
    2,5,8-trioxanonane 8.42
    1-hexene 0.08
    2-isopropoxyethanol 2.33
    2,2,2-trifluoroethanol 2.61
    methyl butyrate 1.01

    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