4-Hydroxy-2-cyclopentenone

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  • Identifiers

    CAS number
    59995-49-2

    Molecular formula
    C5H6O2

    SMILES
    C1[C@@H](C=CC1=O)O

    Safety labels

  • Odor profile

    Fragrance
    Caramellic 57.77%
    Sweet 52.85%
    Nutty 46.51%
    Burnt 44.27%
    Roasted 35.24%
    Spicy 32.72%
    Buttery 29.97%
    Coumarinic 27.75%
    Coconut 25.15%
    Odorless 24.25%

     

    Flavor
    Bitter 42.46%
    Fenugreek 21.46%
    Maple 21.07%
    Odorless 20.79%
    Cotton candy 20.68%
    Seedy 20.6%
    Extremely sweet 20.5%
    Maple syrup 20.48%
    Leaves 19.74%
    Basil 19.58%

     

    Odor impact est.
    High

  • Properties

    XLogP3-AA
    -0.6

    pKa est.
    7.73 (neutral)

    Molecular weight
    98.1 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Moderately slow

    Boiling point est.
    237°C

    Flash point

    • 94.09 ˚C est.

  • Synonyms

    • 59995-49-2
    • RefChem:99151
    • 4-Hydroxy-2-cyclopentenone
    • (S)-4-HYDROXYCYCLOPENT-2-ENONE
    • (4S)-4-hydroxycyclopent-2-en-1-one
    • 2-Cyclopenten-1-one, 4-hydroxy-, (4S)-
    • (s)-4-hydroxycyclopentenone
    • SCHEMBL727480
    • DTXSID50975411
    • MFCD27926141
    • (S)-4-Hydroxycyclopent-2-en-1-one
    • (4S)-4-Hydroxy-2-cyclopenten-1-one
    • 2-Cyclopenten-1-one, 4-hydroxy-, (S)-
    • 59995-49-2

  • Applications

    4-Hydroxy-2-cyclopentenone (CAS 59995-49-2) is an enone-containing cyclopentenone compound that is primarily used as a synthetic intermediate with potential applications across several industries; in fragrance and cosmetics, it is commonly used as an odorant or as an intermediate in the synthesis of fragrance materials; in household and personal care products, it may serve as a fragrance component or fragrance-vehicle in formulations; in pharmaceutical development, it is evaluated as a building block for the synthesis of functional compounds; in industrial manufacturing and polymer-related chemistry, it can be considered as a precursor or building block for specialized chemical syntheses; however, all applications are subject to local regulations and formulation limits, and suitability depends on the specific formulation and quality standards.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 134.42
    methanol 292.78
    isopropanol 93.69
    water 331.36
    ethyl acetate 20.64
    n-propanol 85.9
    acetone 91.43
    n-butanol 57.68
    acetonitrile 65.61
    DMF 399.67
    toluene 1.72
    isobutanol 61.89
    1,4-dioxane 62.82
    methyl acetate 37.22
    THF 85.25
    2-butanone 45.39
    n-pentanol 48.85
    sec-butanol 61.08
    n-hexane 1.26
    ethylene glycol 248.94
    NMP 226.02
    cyclohexane 0.88
    DMSO 216.59
    n-butyl acetate 15.0
    n-octanol 29.65
    chloroform 10.59
    n-propyl acetate 22.42
    acetic acid 283.05
    dichloromethane 9.26
    cyclohexanone 38.76
    propylene glycol 253.73
    isopropyl acetate 14.47
    DMAc 273.52
    2-ethoxyethanol 150.76
    isopentanol 45.58
    n-heptane 1.79
    ethyl formate 26.57
    1,2-dichloroethane 6.9
    n-hexanol 32.46
    2-methoxyethanol 245.06
    isobutyl acetate 16.25
    tetrachloromethane 3.46
    n-pentyl acetate 14.39
    transcutol 310.47
    n-heptanol 25.21
    ethylbenzene 2.44
    MIBK 25.28
    2-propoxyethanol 104.89
    tert-butanol 93.3
    MTBE 20.49
    2-butoxyethanol 70.22
    propionic acid 112.04
    o-xylene 3.77
    formic acid 334.79
    diethyl ether 13.43
    m-xylene 3.72
    p-xylene 4.46
    chlorobenzene 3.6
    dimethyl carbonate 32.13
    n-octane 0.82
    formamide 297.38
    cyclopentanone 68.73
    2-pentanone 29.48
    anisole 19.78
    cyclopentyl methyl ether 24.07
    gamma-butyrolactone 84.82
    1-methoxy-2-propanol 167.84
    pyridine 18.9
    3-pentanone 22.06
    furfural 82.51
    n-dodecane 1.11
    diethylene glycol 183.59
    diisopropyl ether 5.73
    tert-amyl alcohol 66.1
    acetylacetone 40.74
    n-hexadecane 1.15
    acetophenone 27.8
    methyl propionate 32.45
    isopentyl acetate 14.73
    trichloroethylene 15.06
    n-nonanol 25.57
    cyclohexanol 29.81
    benzyl alcohol 30.39
    2-ethylhexanol 16.8
    isooctanol 21.14
    dipropyl ether 13.57
    1,2-dichlorobenzene 6.02
    ethyl lactate 42.07
    propylene carbonate 42.65
    n-methylformamide 184.73
    2-pentanol 31.77
    n-pentane 1.18
    1-propoxy-2-propanol 64.95
    1-methoxy-2-propyl acetate 29.96
    2-(2-methoxypropoxy) propanol 91.23
    mesitylene 3.83
    ε-caprolactone 39.49
    p-cymene 4.88
    epichlorohydrin 51.17
    1,1,1-trichloroethane 7.62
    2-aminoethanol 279.51
    morpholine-4-carbaldehyde 185.53
    sulfolane 116.45
    2,2,4-trimethylpentane 1.61
    2-methyltetrahydrofuran 38.12
    n-hexyl acetate 28.37
    isooctane 1.42
    2-(2-butoxyethoxy)ethanol 115.16
    sec-butyl acetate 14.02
    tert-butyl acetate 20.87
    decalin 1.34
    glycerin 380.57
    diglyme 154.91
    acrylic acid 138.83
    isopropyl myristate 11.99
    n-butyric acid 64.53
    acetyl acetate 18.55
    di(2-ethylhexyl) phthalate 21.88
    ethyl propionate 21.49
    nitromethane 235.02
    1,2-diethoxyethane 27.34
    benzonitrile 18.06
    trioctyl phosphate 15.73
    1-bromopropane 2.83
    gamma-valerolactone 109.36
    n-decanol 18.64
    triethyl phosphate 14.32
    4-methyl-2-pentanol 22.75
    propionitrile 33.63
    vinylene carbonate 40.38
    1,1,2-trichlorotrifluoroethane 115.48
    DMS 25.03
    cumene 4.18
    2-octanol 15.62
    2-hexanone 28.64
    octyl acetate 17.66
    limonene 6.88
    1,2-dimethoxyethane 113.38
    ethyl orthosilicate 13.13
    tributyl phosphate 17.71
    diacetone alcohol 63.53
    N,N-dimethylaniline 21.97
    acrylonitrile 51.21
    aniline 11.82
    1,3-propanediol 176.22
    bromobenzene 2.02
    dibromomethane 4.4
    1,1,2,2-tetrachloroethane 15.34
    2-methyl-cyclohexyl acetate 18.88
    tetrabutyl urea 26.64
    diisobutyl methanol 11.43
    2-phenylethanol 24.35
    styrene 2.56
    dioctyl adipate 23.62
    dimethyl sulfate 60.28
    ethyl butyrate 15.9
    methyl lactate 72.3
    butyl lactate 30.39
    diethyl carbonate 13.76
    propanediol butyl ether 110.98
    triethyl orthoformate 15.22
    p-tert-butyltoluene 4.98
    methyl 4-tert-butylbenzoate 39.94
    morpholine 92.02
    tert-butylamine 37.17
    n-dodecanol 13.56
    dimethoxymethane 90.18
    ethylene carbonate 28.51
    cyrene 92.62
    2-ethoxyethyl acetate 25.78
    2-ethylhexyl acetate 11.02
    1,2,4-trichlorobenzene 10.02
    4-methylpyridine 16.0
    dibutyl ether 12.32
    2,6-dimethyl-4-heptanol 11.43
    DEF 60.14
    dimethyl isosorbide 84.32
    tetrachloroethylene 11.06
    eugenol 54.08
    triacetin 45.31
    span 80 69.07
    1,4-butanediol 108.98
    1,1-dichloroethane 6.1
    2-methyl-1-pentanol 38.98
    methyl formate 100.4
    2-methyl-1-butanol 48.95
    n-decane 1.58
    butyronitrile 22.41
    3,7-dimethyl-1-octanol 24.11
    1-chlorooctane 5.83
    1-chlorotetradecane 2.86
    n-nonane 1.34
    undecane 1.28
    tert-butylcyclohexane 1.68
    cyclooctane 0.53
    cyclopentanol 52.06
    tetrahydropyran 23.46
    tert-amyl methyl ether 18.96
    2,5,8-trioxanonane 128.19
    1-hexene 3.83
    2-isopropoxyethanol 86.49
    2,2,2-trifluoroethanol 139.17
    methyl butyrate 28.92

    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