Methyl isobutanethioate

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  • Identifiers

    CAS number
    42075-42-3

    Molecular formula
    C5H10OS

    SMILES
    CC(C)C(=O)SC

  • Odor profile

    Fragrance
    Fruity 87.53%
    Sulfurous 69.35%
    Cheesy 65.67%
    Tropical 63.39%
    Vegetable 46.58%
    Dairy 39.85%
    Cabbage 36.37%
    Ripe 36.1%
    Sweet 35.55%
    Creamy 34.06%

     

    Flavor
    Sulfurous 46.95%
    Onion 41.18%
    Garlic 32.25%
    Cheese 32.03%
    Sulfury 30.27%
    Cabbage 30.14%
    Cooked 29.77%
    Alliaceous 26.96%
    Mustard 24.14%
    Roasted 23.35%

     

    Odor impact est.
    High

  • Properties

    XLogP3-AA
    1.7

    pKa est.
    8.13 (weak base)

    Molecular weight
    118.2 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Very fast

    Boiling point est.
    161°C

    Flash point

    • 39.09 ˚C est.

    Solubility expt.

    • Practically insoluble or insoluble in water
    • Soluble (in ethanol)

  • Synonyms

    • S-Methyl 2-methylpropanethioate
    • 42075-42-3
    • Methyl isobutanethioate
    • FEMA No. 4586
    • UNII-C49X23N7M7
    • C49X23N7M7
    • Propanethioic acid, 2-methyl-, S-methyl ester
    • DTXSID20194915
    • S-methyl thioisobutyrate
    • Methyl thioisobutyric acid
    • SCHEMBL8581184
    • DTXCID60117406
    • MFCD22377272
    • AKOS025396852
    • Q27275169

  • Applications

    Methyl isobutanethioate (CAS 42075-42-3) is a thioester used primarily as an organic-synthesis intermediate and acyl-transfer reagent, enabling the introduction of the isobutyryl–S–CH3 fragment into target molecules via thioester chemistry; it also serves as a building block for sulfur-containing esters in fragrance chemistry and related formulations. In cosmetics and personal care, it may function as an odor precursor or fragrance ingredient within formulations, subject to regulatory and formulation limits. In the polymers and coatings sector, it can be used as a building block for specialized thioesters and derivatives that support tailored polymer or coating systems. Additionally, it is commonly employed in research and development as a thioester reagent for acylation-type reactions, with use governed by local regulations.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 822.96
    methanol 1267.81
    isopropanol 516.19
    water 10.91
    ethyl acetate 604.37
    n-propanol 557.49
    acetone 865.95
    n-butanol 548.41
    acetonitrile 808.73
    DMF 830.52
    toluene 348.43
    isobutanol 410.62
    1,4-dioxane 1016.91
    methyl acetate 635.8
    THF 1119.29
    2-butanone 687.48
    n-pentanol 455.62
    sec-butanol 475.55
    n-hexane 153.8
    ethylene glycol 191.51
    NMP 1110.36
    cyclohexane 178.53
    DMSO 806.76
    n-butyl acetate 743.54
    n-octanol 336.74
    chloroform 2041.53
    n-propyl acetate 526.92
    acetic acid 973.98
    dichloromethane 1669.47
    cyclohexanone 1068.21
    propylene glycol 166.96
    isopropyl acetate 386.84
    DMAc 677.91
    2-ethoxyethanol 632.57
    isopentanol 486.23
    n-heptane 118.81
    ethyl formate 521.33
    1,2-dichloroethane 908.79
    n-hexanol 497.56
    2-methoxyethanol 834.34
    isobutyl acetate 317.45
    tetrachloromethane 634.55
    n-pentyl acetate 605.52
    transcutol 1846.56
    n-heptanol 317.14
    ethylbenzene 259.09
    MIBK 379.94
    2-propoxyethanol 736.87
    tert-butanol 591.77
    MTBE 581.87
    2-butoxyethanol 558.16
    propionic acid 549.87
    o-xylene 286.33
    formic acid 484.4
    diethyl ether 607.56
    m-xylene 271.18
    p-xylene 361.05
    chlorobenzene 637.51
    dimethyl carbonate 183.38
    n-octane 59.63
    formamide 599.62
    cyclopentanone 1126.21
    2-pentanone 585.57
    anisole 501.0
    cyclopentyl methyl ether 612.12
    gamma-butyrolactone 1231.81
    1-methoxy-2-propanol 531.65
    pyridine 876.07
    3-pentanone 460.56
    furfural 1309.91
    n-dodecane 40.69
    diethylene glycol 499.62
    diisopropyl ether 236.04
    tert-amyl alcohol 545.51
    acetylacetone 636.75
    n-hexadecane 46.0
    acetophenone 518.81
    methyl propionate 419.13
    isopentyl acetate 614.01
    trichloroethylene 1866.38
    n-nonanol 285.65
    cyclohexanol 530.38
    benzyl alcohol 408.37
    2-ethylhexanol 363.22
    isooctanol 265.75
    dipropyl ether 402.57
    1,2-dichlorobenzene 679.19
    ethyl lactate 204.94
    propylene carbonate 693.5
    n-methylformamide 588.61
    2-pentanol 383.14
    n-pentane 128.81
    1-propoxy-2-propanol 559.52
    1-methoxy-2-propyl acetate 529.91
    2-(2-methoxypropoxy) propanol 431.57
    mesitylene 195.76
    ε-caprolactone 957.79
    p-cymene 234.61
    epichlorohydrin 1147.31
    1,1,1-trichloroethane 1094.13
    2-aminoethanol 336.18
    morpholine-4-carbaldehyde 1070.06
    sulfolane 1274.61
    2,2,4-trimethylpentane 78.46
    2-methyltetrahydrofuran 1020.61
    n-hexyl acetate 731.62
    isooctane 59.28
    2-(2-butoxyethoxy)ethanol 604.0
    sec-butyl acetate 352.55
    tert-butyl acetate 468.59
    decalin 108.04
    glycerin 248.95
    diglyme 1176.84
    acrylic acid 511.24
    isopropyl myristate 237.8
    n-butyric acid 746.14
    acetyl acetate 422.35
    di(2-ethylhexyl) phthalate 216.04
    ethyl propionate 394.76
    nitromethane 1282.45
    1,2-diethoxyethane 799.46
    benzonitrile 750.32
    trioctyl phosphate 167.94
    1-bromopropane 582.48
    gamma-valerolactone 1335.99
    n-decanol 198.53
    triethyl phosphate 233.72
    4-methyl-2-pentanol 236.32
    propionitrile 561.96
    vinylene carbonate 680.17
    1,1,2-trichlorotrifluoroethane 844.76
    DMS 436.59
    cumene 202.78
    2-octanol 251.28
    2-hexanone 571.6
    octyl acetate 298.88
    limonene 334.54
    1,2-dimethoxyethane 960.17
    ethyl orthosilicate 241.67
    tributyl phosphate 228.91
    diacetone alcohol 463.8
    N,N-dimethylaniline 347.44
    acrylonitrile 712.98
    aniline 424.48
    1,3-propanediol 500.75
    bromobenzene 656.2
    dibromomethane 1152.54
    1,1,2,2-tetrachloroethane 1332.79
    2-methyl-cyclohexyl acetate 392.7
    tetrabutyl urea 270.18
    diisobutyl methanol 226.9
    2-phenylethanol 450.52
    styrene 345.06
    dioctyl adipate 324.8
    dimethyl sulfate 293.71
    ethyl butyrate 483.94
    methyl lactate 211.45
    butyl lactate 388.62
    diethyl carbonate 325.91
    propanediol butyl ether 439.56
    triethyl orthoformate 351.5
    p-tert-butyltoluene 218.44
    methyl 4-tert-butylbenzoate 429.28
    morpholine 963.75
    tert-butylamine 440.85
    n-dodecanol 147.46
    dimethoxymethane 502.97
    ethylene carbonate 547.42
    cyrene 400.6
    2-ethoxyethyl acetate 712.35
    2-ethylhexyl acetate 518.71
    1,2,4-trichlorobenzene 754.8
    4-methylpyridine 942.3
    dibutyl ether 425.24
    2,6-dimethyl-4-heptanol 226.9
    DEF 641.86
    dimethyl isosorbide 742.92
    tetrachloroethylene 1128.46
    eugenol 438.49
    triacetin 502.47
    span 80 402.45
    1,4-butanediol 260.65
    1,1-dichloroethane 962.12
    2-methyl-1-pentanol 414.32
    methyl formate 472.49
    2-methyl-1-butanol 447.38
    n-decane 72.83
    butyronitrile 660.51
    3,7-dimethyl-1-octanol 316.44
    1-chlorooctane 270.28
    1-chlorotetradecane 96.53
    n-nonane 76.49
    undecane 51.34
    tert-butylcyclohexane 115.59
    cyclooctane 71.49
    cyclopentanol 534.12
    tetrahydropyran 826.04
    tert-amyl methyl ether 469.16
    2,5,8-trioxanonane 686.75
    1-hexene 362.15
    2-isopropoxyethanol 461.9
    2,2,2-trifluoroethanol 359.0
    methyl butyrate 559.3

    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