S-Isopropyl 3-methylthiocrotonate

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  • Identifiers

    CAS number
    34365-79-2

    Molecular formula
    C8H14OS

    SMILES
    CC(C)SC(=O)C=C(C)C

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Sulfurous 86.2%
    Green 80.91%
    Tropical 74.42%
    Vegetable 62.76%
    Fruity 53.26%
    Meaty 52.37%
    Herbal 51.2%
    Onion 50.7%
    Alliaceous 43.47%
    Spicy 40.25%

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  • Properties

    XLogP3-AA
    2.9

    Molecular weight
    158.26 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Moderately fast

    Boiling point

    • 236.00 °C. @ 760.00 mm Hg

    Flash point est.
    75.97 ˚C

    Solubility expt.

    • very slightly
    • Practically insoluble to insoluble in water
    • Soluble (in ethanol)

  • Synonyms

    • 34365-79-2
    • S-Isopropyl 3-methylbut-2-enethioate
    • S-Isopropyl 3-methylthiocrotonate
    • s-isopropyl thiosenecioate
    • S-propan-2-yl 3-methylbut-2-enethioate
    • 2-Butenethioic acid, 3-methyl-, S-(1-methylethyl) ester
    • NZT1CT5W8U
    • S-1-Methylethyl 3-methylbut-2-enethioate
    • EINECS 251-966-7
    • DTXSID1067837
    • FEMA NO. 4260
    • Crotonic acid, 3-methylthio-, S-isopropyl ester
    • S-ISOPROPYL 3-METHYL-2-BUTENETHIOATE
    • 3-methyl-1-(propan-2-ylsulfanyl)but-2-en-1-one
    • S-ISOPROPYL 3-METHYLBUT-2-ENETHIOATE [FHFI]
    • UNII-NZT1CT5W8U
    • ISOPROPYL 3-METHYLTHIO-2-BUTENOATE
    • isopropyl 3-methyl thiocrotonate
    • SCHEMBL3505568
    • DTXCID6038829
    • CHEBI:230802
    • IZVXTRDVESJRTA-UHFFFAOYSA-N
    • AKOS006288005
    • DB-221872
    • NS00012762
    • Q27285131
    • 251-966-7

  • Applications

    S-Isopropyl-3-methylbut-2-enethioate (CAS 34365-79-2) is a thio-ester prized by flavor, fragrance and cosmetic formulators for its ability to recreate authentic onion, leek and delicate sulfide notes in savory flavors, instant soups, liquid seasonings, sauces and plant-based meat products; it is also used in tobacco to enhance the full “sweet” body of smoke, in fishing baits where its sulfurous odor attracts aquatic species, and in sensory chemistry research to probe olfactory mechanisms of volatile sulfur compounds; typical inclusion rates are very low (ppm or ppb) owing to its powerful odor threshold, and it should be stored tightly closed at low temperature while complying with REACH, FEMA and IFRA safety regulations.

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 488.39
    methanol 449.45
    isopropanol 479.44
    water 2.85
    ethyl acetate 327.25
    n-propanol 446.44
    acetone 534.52
    n-butanol 476.79
    acetonitrile 400.09
    DMF 601.17
    toluene 345.14
    isobutanol 380.63
    1,4-dioxane 704.43
    methyl acetate 322.64
    THF 1335.73
    2-butanone 448.26
    n-pentanol 335.82
    sec-butanol 479.39
    n-hexane 226.52
    ethylene glycol 116.64
    NMP 846.16
    cyclohexane 374.32
    DMSO 407.07
    n-butyl acetate 441.91
    n-octanol 417.39
    chloroform 1432.79
    n-propyl acetate 276.1
    acetic acid 541.11
    dichloromethane 826.87
    cyclohexanone 931.57
    propylene glycol 260.09
    isopropyl acetate 229.7
    DMAc 440.34
    2-ethoxyethanol 255.23
    isopentanol 375.45
    n-heptane 231.4
    ethyl formate 316.85
    1,2-dichloroethane 444.19
    n-hexanol 655.6
    2-methoxyethanol 449.55
    isobutyl acetate 222.73
    tetrachloromethane 272.53
    n-pentyl acetate 288.4
    transcutol 677.89
    n-heptanol 316.33
    ethylbenzene 253.28
    MIBK 281.93
    2-propoxyethanol 558.32
    tert-butanol 560.5
    MTBE 371.02
    2-butoxyethanol 318.76
    propionic acid 381.15
    o-xylene 243.45
    formic acid 133.03
    diethyl ether 341.06
    m-xylene 280.16
    p-xylene 311.6
    chlorobenzene 441.36
    dimethyl carbonate 145.81
    n-octane 91.74
    formamide 139.53
    cyclopentanone 981.48
    2-pentanone 425.39
    anisole 364.9
    cyclopentyl methyl ether 630.22
    gamma-butyrolactone 870.55
    1-methoxy-2-propanol 430.27
    pyridine 643.71
    3-pentanone 298.73
    furfural 790.79
    n-dodecane 71.03
    diethylene glycol 353.27
    diisopropyl ether 150.55
    tert-amyl alcohol 496.47
    acetylacetone 408.04
    n-hexadecane 81.32
    acetophenone 350.0
    methyl propionate 271.49
    isopentyl acetate 408.5
    trichloroethylene 969.97
    n-nonanol 348.64
    cyclohexanol 655.26
    benzyl alcohol 330.19
    2-ethylhexanol 418.16
    isooctanol 247.92
    dipropyl ether 361.83
    1,2-dichlorobenzene 391.84
    ethyl lactate 195.88
    propylene carbonate 659.12
    n-methylformamide 300.51
    2-pentanol 372.63
    n-pentane 189.42
    1-propoxy-2-propanol 480.51
    1-methoxy-2-propyl acetate 364.49
    2-(2-methoxypropoxy) propanol 365.03
    mesitylene 197.13
    ε-caprolactone 704.57
    p-cymene 236.69
    epichlorohydrin 747.6
    1,1,1-trichloroethane 639.95
    2-aminoethanol 249.54
    morpholine-4-carbaldehyde 664.64
    sulfolane 947.59
    2,2,4-trimethylpentane 88.97
    2-methyltetrahydrofuran 878.95
    n-hexyl acetate 506.04
    isooctane 71.43
    2-(2-butoxyethoxy)ethanol 468.3
    sec-butyl acetate 202.98
    tert-butyl acetate 301.3
    decalin 155.01
    glycerin 255.08
    diglyme 584.39
    acrylic acid 349.71
    isopropyl myristate 239.92
    n-butyric acid 549.25
    acetyl acetate 245.99
    di(2-ethylhexyl) phthalate 235.29
    ethyl propionate 235.88
    nitromethane 537.17
    1,2-diethoxyethane 315.11
    benzonitrile 483.64
    trioctyl phosphate 186.55
    1-bromopropane 418.62
    gamma-valerolactone 1000.11
    n-decanol 274.08
    triethyl phosphate 193.91
    4-methyl-2-pentanol 218.24
    propionitrile 370.2
    vinylene carbonate 536.86
    1,1,2-trichlorotrifluoroethane 577.57
    DMS 278.93
    cumene 193.53
    2-octanol 280.36
    2-hexanone 368.08
    octyl acetate 309.1
    limonene 361.83
    1,2-dimethoxyethane 486.71
    ethyl orthosilicate 193.34
    tributyl phosphate 215.63
    diacetone alcohol 387.02
    N,N-dimethylaniline 272.27
    acrylonitrile 387.05
    aniline 383.14
    1,3-propanediol 328.45
    bromobenzene 456.96
    dibromomethane 685.57
    1,1,2,2-tetrachloroethane 856.69
    2-methyl-cyclohexyl acetate 392.87
    tetrabutyl urea 281.64
    diisobutyl methanol 247.86
    2-phenylethanol 420.01
    styrene 286.01
    dioctyl adipate 321.62
    dimethyl sulfate 202.13
    ethyl butyrate 327.4
    methyl lactate 220.89
    butyl lactate 291.11
    diethyl carbonate 239.7
    propanediol butyl ether 429.05
    triethyl orthoformate 259.81
    p-tert-butyltoluene 244.68
    methyl 4-tert-butylbenzoate 374.2
    morpholine 805.86
    tert-butylamine 427.63
    n-dodecanol 217.85
    dimethoxymethane 341.83
    ethylene carbonate 423.3
    cyrene 395.65
    2-ethoxyethyl acetate 280.59
    2-ethylhexyl acetate 334.79
    1,2,4-trichlorobenzene 498.44
    4-methylpyridine 658.14
    dibutyl ether 339.21
    2,6-dimethyl-4-heptanol 247.86
    DEF 378.81
    dimethyl isosorbide 618.28
    tetrachloroethylene 506.76
    eugenol 352.78
    triacetin 349.99
    span 80 462.1
    1,4-butanediol 170.28
    1,1-dichloroethane 571.72
    2-methyl-1-pentanol 309.05
    methyl formate 266.8
    2-methyl-1-butanol 378.88
    n-decane 117.88
    butyronitrile 499.96
    3,7-dimethyl-1-octanol 345.98
    1-chlorooctane 299.85
    1-chlorotetradecane 138.05
    n-nonane 126.08
    undecane 89.59
    tert-butylcyclohexane 136.29
    cyclooctane 140.58
    cyclopentanol 662.92
    tetrahydropyran 902.4
    tert-amyl methyl ether 311.23
    2,5,8-trioxanonane 471.4
    1-hexene 391.55
    2-isopropoxyethanol 224.99
    2,2,2-trifluoroethanol 186.49
    methyl butyrate 337.26

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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

Botanical

Name CAS Botanical Proportion
Galbanum 4 9000-24-2 Ferula galbaniflua Boiss. et Buhse, fam. Apiaceae (Umbelliferae) 0.01%