Uracil

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  • Identifiers

    CAS number
    66-22-8

    Molecular formula
    C4H4N2O2

    SMILES
    C1=CNC(=O)NC1=O

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 60.79%
    Burnt 39.85%
    Nutty 29.08%
    Pungent 24.4%
    Bitter 23.23%
    Musty 18.11%
    Roasted 17.79%
    Cooked 17.72%
    Sour 16.88%
    Sulfurous 16.13%

     

    Flavor
    Bitter 58.72%
    Odorless 37.3%
    Nutty 22.49%
    Urine 20.97%
    Formyl 20.83%
    Nitrile 20.5%
    Rotten 20.29%
    Sour 20.13%
    Bread crust 19.99%
    Fragrant 19.52%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    -1.1

    pKa est.
    10.58 (weak base)

    Molecular weight
    112.09 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    398°C

    Melting point expt.

    • 338 °C
    • 330 °C

    Flash point

    • 212.98 ˚C est.

    Solubility expt.

    • 3600 mg/L (at 25 °C)
    • 3.6 mg/mL

  • Synonyms

    • uracil
    • 66-22-8
    • 2,4(1H,3H)-Pyrimidinedione
    • pyrimidine-2,4(1H,3H)-dione
    • Pyrod
    • Hybar X
    • 2,4-Dioxopyrimidine
    • Pirod
    • 2,4-Pyrimidinedione
    • 1H-Pyrimidine-2,4-dione
    • 1,2,3,4-tetrahydropyrimidine-2,4-dione
    • NSC-3970
    • DTXSID4021424
    • SQ-6201
    • SQ-7726
    • SQ-8493
    • CHEBI:17568
    • BMS-205603-01
    • 56HH86ZVCT
    • NSC3970
    • DTXCID101424
    • 2, 4-Dioxopyrimidine
    • RefChem:6338
    • 2-hydroxy-4-(1H)-pyrimidione
    • 2-hydroxy-4-(3H)-pyrimidione
    • 4-hydroxy-2-(1H)-pyrimidione
    • 200-621-9
    • 2,4-Dihydroxypyrimidine
    • pyrimidine-2,4-diol
    • 2,4-Pyrimidinediol
    • 51953-14-1
    • Uracil [USAN]
    • MFCD00006016
    • RU 12709
    • 2-Hydroxy-4(3H)-pyrimidinone
    • Ura
    • NSC 3970
    • 2,4-Pyrimidinediol (9CI)
    • CCRIS 3077
    • Urazil
    • 2-Hydroxy-4(1H)-pyrimidinone
    • SQ 6201
    • SQ 7726
    • SQ 8493
    • BMS 205603-01
    • AI3-25470
    • Lamivudine impurity e
    • 4-Hydroxy-2(1H)-pyrimidinone
    • 66255-05-8
    • Lamivudine impurity e rs
    • 144104-68-7
    • Fluorouracil specified compound c
    • NCGC00181030-01
    • 4-Hydroxyuracil
    • CAS-66-22-8
    • CID 5274267
    • Pyrimidine-2,4(1H,3H)-dione (Uracil)
    • Uracil (8CI)
    • Uracil [USAN:JAN]
    • 2(1H)-Pyrimidinone, 4-hydroxy-
    • 2(1H)-Pyrimidinone, 6-hydroxy-
    • 4(3H)-Pyrimidinone, 2-hydroxy-
    • EINECS 200-621-9
    • UNII-56HH86ZVCT
    • Uracyl
    • 66224-60-0
    • 8h-uracil
    • hydroxypyrimidinone
    • Uracil (Standard)
    • 2,6-Dioxypyrimidin
    • 2,4-Dioxypyrimidine
    • 2,4(1H,3H)-Pyrimidinedione (9CI)
    • Uracil, 99%
    • 1ui0
    • Uracil (JAN/USAN)
    • 2,3H)-Pyrimidinedione
    • 2,6-Dihydroxypyrimidine
    • URACIL [JAN]
    • URACIL [USP-RS]
    • URACIL [WHO-DD]
    • Lamivudine EP Impurity F
    • URACIL [MI]
    • URACIL [MART.]
    • bmse000187
    • bmse000940
    • CHEMBL566
    • Epitope ID:120356
    • NCIMech_000782
    • SCHEMBL8235
    • Fluorouracil impurity C CRS
    • Uracil, >=99.0%
    • pyrimidine, 2,4-dihydroxy-
    • SCHEMBL29730
    • SCHEMBL80962
    • SCHEMBL94310
    • 51953-19-6
    • MLS001304993
    • SCHEMBL144010
    • SCHEMBL151239
    • SCHEMBL537174
    • SCHEMBL877869
    • SCHEMBL925137
    • GTPL4560
    • orb1310972
    • SCHEMBL1050479
    • SCHEMBL5089507
    • SCHEMBL6286831
    • SCHEMBL6434097
    • SCHEMBL6434098
    • SCHEMBL7267501
    • SCHEMBL7335265
    • SCHEMBL9734266
    • SCHEMBL9779787
    • 2,4-(1h,3h)-pyrimidinedione
    • SCHEMBL10580164
    • SCHEMBL11607890
    • SCHEMBL13276278
    • SCHEMBL29525634
    • SCHEMBL31434533
    • HY-I0960R
    • Uracil, >=99.0% (T)
    • 1,3-dihydropyrimidine-2,4-dione
    • HMS2234E19
    • HMS3264C13
    • HMS3373E18
    • HMS3652N05
    • HMS5082D06
    • 66-22-8

  • Applications

    Uracil (CAS 66-22-8) is a pyrimidine base used primarily as a building block in nucleotide and nucleoside synthesis, supporting pharmaceutical production and bioscience R&D. It is processed to give uridine and pyrimidine derivatives for pharmaceutical and biotechnological applications. In the laboratory, uracil serves as a reagent for nucleic acid synthesis and related enzymatic or biochemical labeling applications. In biotech research, it underpins uridine derivatives and nucleotide analogs under development for antiviral and anticancer research. In organic synthesis, it is a core starting material for preparing functional pyrimidine compounds. Additionally, it is commonly used as an educational reagent and a basis for method development in research laboratories.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 0.23
    methanol 0.59
    isopropanol 0.17
    water 2.57
    ethyl acetate 0.12
    n-propanol 0.21
    acetone 0.34
    n-butanol 0.16
    acetonitrile 0.26
    DMF 23.77
    toluene 0.01
    isobutanol 0.15
    1,4-dioxane 0.29
    methyl acetate 0.29
    THF 0.84
    2-butanone 0.28
    n-pentanol 0.18
    sec-butanol 0.14
    n-hexane 0.01
    ethylene glycol 2.82
    NMP 26.66
    cyclohexane 0.0
    DMSO 20.85
    n-butyl acetate 0.3
    n-octanol 0.09
    chloroform 0.02
    n-propyl acetate 0.28
    acetic acid 1.92
    dichloromethane 0.03
    cyclohexanone 0.43
    propylene glycol 2.51
    isopropyl acetate 0.12
    DMAc 21.7
    2-ethoxyethanol 2.39
    isopentanol 0.2
    n-heptane 0.01
    ethyl formate 0.49
    1,2-dichloroethane 0.03
    n-hexanol 0.12
    2-methoxyethanol 4.64
    isobutyl acetate 0.19
    tetrachloromethane 0.01
    n-pentyl acetate 0.19
    transcutol 4.79
    n-heptanol 0.12
    ethylbenzene 0.02
    MIBK 0.23
    2-propoxyethanol 2.2
    tert-butanol 0.26
    MTBE 0.06
    2-butoxyethanol 1.58
    propionic acid 1.03
    o-xylene 0.03
    formic acid 5.08
    diethyl ether 0.04
    m-xylene 0.03
    p-xylene 0.03
    chlorobenzene 0.01
    dimethyl carbonate 0.9
    n-octane 0.0
    formamide 5.72
    cyclopentanone 1.01
    2-pentanone 0.19
    anisole 0.14
    cyclopentyl methyl ether 0.18
    gamma-butyrolactone 2.68
    1-methoxy-2-propanol 3.29
    pyridine 0.2
    3-pentanone 0.15
    furfural 4.19
    n-dodecane 0.0
    diethylene glycol 5.46
    diisopropyl ether 0.02
    tert-amyl alcohol 0.22
    acetylacetone 0.51
    n-hexadecane 0.0
    acetophenone 0.42
    methyl propionate 0.38
    isopentyl acetate 0.34
    trichloroethylene 0.05
    n-nonanol 0.1
    cyclohexanol 0.11
    benzyl alcohol 0.3
    2-ethylhexanol 0.11
    isooctanol 0.12
    dipropyl ether 0.14
    1,2-dichlorobenzene 0.03
    ethyl lactate 1.62
    propylene carbonate 1.55
    n-methylformamide 4.81
    2-pentanol 0.09
    n-pentane 0.0
    1-propoxy-2-propanol 1.63
    1-methoxy-2-propyl acetate 1.03
    2-(2-methoxypropoxy) propanol 3.91
    mesitylene 0.03
    ε-caprolactone 0.74
    p-cymene 0.05
    epichlorohydrin 0.69
    1,1,1-trichloroethane 0.02
    2-aminoethanol 2.47
    morpholine-4-carbaldehyde 14.21
    sulfolane 9.96
    2,2,4-trimethylpentane 0.0
    2-methyltetrahydrofuran 0.23
    n-hexyl acetate 0.22
    isooctane 0.0
    2-(2-butoxyethoxy)ethanol 3.19
    sec-butyl acetate 0.15
    tert-butyl acetate 0.24
    decalin 0.0
    glycerin 10.55
    diglyme 5.53
    acrylic acid 2.08
    isopropyl myristate 0.13
    n-butyric acid 0.6
    acetyl acetate 0.16
    di(2-ethylhexyl) phthalate 0.63
    ethyl propionate 0.3
    nitromethane 4.11
    1,2-diethoxyethane 0.28
    benzonitrile 0.22
    trioctyl phosphate 0.33
    1-bromopropane 0.01
    gamma-valerolactone 4.51
    n-decanol 0.08
    triethyl phosphate 0.63
    4-methyl-2-pentanol 0.1
    propionitrile 0.2
    vinylene carbonate 1.41
    1,1,2-trichlorotrifluoroethane 3.44
    DMS 0.54
    cumene 0.03
    2-octanol 0.07
    2-hexanone 0.27
    octyl acetate 0.18
    limonene 0.05
    1,2-dimethoxyethane 2.86
    ethyl orthosilicate 0.45
    tributyl phosphate 0.46
    diacetone alcohol 1.31
    N,N-dimethylaniline 0.28
    acrylonitrile 0.5
    aniline 0.09
    1,3-propanediol 1.61
    bromobenzene 0.01
    dibromomethane 0.01
    1,1,2,2-tetrachloroethane 0.07
    2-methyl-cyclohexyl acetate 0.41
    tetrabutyl urea 0.91
    diisobutyl methanol 0.12
    2-phenylethanol 0.24
    styrene 0.01
    dioctyl adipate 0.48
    dimethyl sulfate 4.44
    ethyl butyrate 0.39
    methyl lactate 3.37
    butyl lactate 1.1
    diethyl carbonate 0.45
    propanediol butyl ether 2.64
    triethyl orthoformate 0.5
    p-tert-butyltoluene 0.05
    methyl 4-tert-butylbenzoate 1.23
    morpholine 0.7
    tert-butylamine 0.08
    n-dodecanol 0.07
    dimethoxymethane 2.07
    ethylene carbonate 0.81
    cyrene 6.47
    2-ethoxyethyl acetate 0.45
    2-ethylhexyl acetate 0.24
    1,2,4-trichlorobenzene 0.07
    4-methylpyridine 0.22
    dibutyl ether 0.08
    2,6-dimethyl-4-heptanol 0.12
    DEF 1.19
    dimethyl isosorbide 5.22
    tetrachloroethylene 0.04
    eugenol 2.06
    triacetin 0.92
    span 80 1.96
    1,4-butanediol 1.09
    1,1-dichloroethane 0.01
    2-methyl-1-pentanol 0.2
    methyl formate 2.6
    2-methyl-1-butanol 0.19
    n-decane 0.0
    butyronitrile 0.17
    3,7-dimethyl-1-octanol 0.12
    1-chlorooctane 0.01
    1-chlorotetradecane 0.01
    n-nonane 0.0
    undecane 0.0
    tert-butylcyclohexane 0.01
    cyclooctane 0.0
    cyclopentanol 0.25
    tetrahydropyran 0.07
    tert-amyl methyl ether 0.1
    2,5,8-trioxanonane 5.55
    1-hexene 0.02
    2-isopropoxyethanol 1.16
    2,2,2-trifluoroethanol 2.03
    methyl butyrate 0.52

    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