Indole-2-carboxylic acid

Overview IFRA Request a quote

  • Identifiers

    CAS number
    1477-50-5

    Molecular formula
    C9H7NO2

    SMILES
    C1=CC=C2C(=C1)C=C(N2)C(=O)O

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 48.86%
    Grape 32.05%
    Fruity 30.08%
    Burnt 29.22%
    Phenolic 27.84%
    Bitter 27.31%
    Honey 26.27%
    Balsamic 26.13%
    Animal 25.73%
    Neroli 25.41%

     

    Flavor
    Odorless 50.97%
    Bitter 50.87%
    Mild 37.16%
    Nutty 35.75%
    Faint 29.88%
    Sour 29.81%
    Balsam 25.11%
    Urine 24.61%
    Honey 24.46%
    Phenolic 23.91%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    2.3

    pKa est.
    7.08 (neutral)

    Molecular weight
    161.16 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    365°C

    Flash point

    • 212.33 ˚C est.

  • Synonyms

    • Indole-2-carboxylic acid
    • 1H-Indole-2-carboxylic acid
    • 1477-50-5
    • DTXSID20163782
    • RefChem:790959
    • DTXCID9086273
    • 216-030-4
    • 2-Carboxyindole
    • 2-Indolecarboxylic acid
    • MFCD00005611
    • Indol-2-Carboxylic Acid
    • 2-INDOLYLFORMIC ACID
    • 1H-indole-2-carboxylicacid
    • CHEMBL278390
    • 137497-03-1
    • N-[4-(2-Pyridinyl)-2-thiazolyl]-2-pyridinamine
    • Indole-2-carboxylicAcid-13C
    • 1H-Indolecarboxylic acid
    • EINECS 216-030-4
    • NSC 16598
    • carboxyindole
    • 2-Indolecarboxylate
    • ICB
    • indolecarboxylic acid
    • indole carboxylic acid
    • 2-carboxy-1H-indole
    • 2-indolcarboxylic acid
    • Spectrum_001485
    • 2-indol carboxylic acid
    • SpecPlus_000676
    • indole_2_carboxylic_acid
    • Spectrum2_000021
    • Spectrum3_000943
    • Spectrum4_001042
    • Spectrum5_001735
    • 1H-2-indolecarboxylic acid
    • SCHEMBL1935
    • 1H-indol-2-carboxylic acid
    • Oprea1_557882
    • KBioGR_001304
    • KBioSS_001965
    • MLS002207203
    • DivK1c_006772
    • SPECTRUM1502082
    • SPBio_000081
    • SCHEMBL1151122
    • SCHEMBL3483057
    • SCHEMBL3483232
    • SCHEMBL4259995
    • SCHEMBL4491530
    • SCHEMBL6358504
    • SCHEMBL8078900
    • 1H-indole-2-carbonsäure
    • 2-INDOLE CARBOXYLIC ACID
    • SCHEMBL29395165
    • HCUARRIEZVDMPT-UHFFFAOYSA-
    • Indole-2-carboxylic acid, 98%
    • KBio1_001716
    • KBio2_001965
    • KBio2_004533
    • KBio2_007101
    • KBio3_002006
    • CHEBI:169990
    • HMS1921H22
    • BB_NC-02789
    • CS-M1850
    • HY-I0096
    • NSC16598
    • STR02479
    • BDBM50004955
    • CCG-39889
    • EBC-03263
    • NSC-16598
    • s6228
    • SBB003953
    • STK001808
    • AKOS000121595
    • AB00454
    • AC-3062
    • CG-0515
    • FI02860
    • SDCCGMLS-0065971.P001
    • NCGC00094957-01
    • NCGC00094957-02
    • NCGC00094957-03
    • SMR000112260
    • SY003715
    • DB-011564
    • I0332
    • NS00015137
    • ST45028103
    • EN300-16592
    • 77I505
    • I-2300
    • AQ-776/40177767
    • F043684
    • SR-01000392684
    • SR-01000392684-1
    • Q27461367
    • Z56347139
    • F0451-0610
    • InChI=1/C9H7NO2/c11-9(12)8-5-6-3-1-2-4-7(6)10-8/h1-5,10H,(H,11,12)
    • 1477-50-5

  • Applications

    Indole-2-carboxylic acid (CAS 1477-50-5) is a versatile building block in organic synthesis, commonly used as an intermediate in the preparation of indole-containing pharmaceuticals; it also serves as a precursor for indole-containing agrochemicals and as a starting point for the synthesis of diverse heterocycles. In perfumery and fragrance chemistry, it can function as an indole-derived fragment for note development, while in dyes and pigments it provides a scaffold for indole-based colorants. Additionally, it is used as a precursor for functionalized derivatives and specialty polymers that incorporate indole moieties, enabling applications in materials science and related fields.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 253.76
    methanol 433.12
    isopropanol 156.52
    water 0.55
    ethyl acetate 132.45
    n-propanol 160.86
    acetone 109.05
    n-butanol 120.09
    acetonitrile 35.65
    DMF 379.65
    toluene 1.11
    isobutanol 67.62
    1,4-dioxane 8.49
    methyl acetate 57.19
    THF 79.97
    2-butanone 105.54
    n-pentanol 53.2
    sec-butanol 101.78
    n-hexane 0.25
    ethylene glycol 47.33
    NMP 75.64
    cyclohexane 0.15
    DMSO 143.12
    n-butyl acetate 17.91
    n-octanol 12.67
    chloroform 1.09
    n-propyl acetate 18.47
    acetic acid 37.35
    dichloromethane 3.93
    cyclohexanone 23.03
    propylene glycol 54.34
    isopropyl acetate 38.14
    DMAc 244.69
    2-ethoxyethanol 128.87
    isopentanol 64.94
    n-heptane 0.76
    ethyl formate 40.09
    1,2-dichloroethane 5.11
    n-hexanol 27.58
    2-methoxyethanol 299.65
    isobutyl acetate 5.91
    tetrachloromethane 0.38
    n-pentyl acetate 14.97
    transcutol 90.99
    n-heptanol 16.18
    ethylbenzene 1.96
    MIBK 27.64
    2-propoxyethanol 74.72
    tert-butanol 80.48
    MTBE 20.32
    2-butoxyethanol 44.76
    propionic acid 40.99
    o-xylene 2.0
    formic acid 46.34
    diethyl ether 28.25
    m-xylene 2.06
    p-xylene 2.37
    chlorobenzene 1.27
    dimethyl carbonate 26.8
    n-octane 0.48
    formamide 140.87
    cyclopentanone 55.82
    2-pentanone 100.04
    anisole 9.15
    cyclopentyl methyl ether 15.77
    gamma-butyrolactone 58.49
    1-methoxy-2-propanol 216.66
    pyridine 13.78
    3-pentanone 41.02
    furfural 31.0
    n-dodecane 0.56
    diethylene glycol 73.03
    diisopropyl ether 5.03
    tert-amyl alcohol 61.68
    acetylacetone 55.8
    n-hexadecane 0.6
    acetophenone 13.99
    methyl propionate 100.74
    isopentyl acetate 14.82
    trichloroethylene 5.24
    n-nonanol 12.64
    cyclohexanol 13.84
    benzyl alcohol 17.09
    2-ethylhexanol 11.25
    isooctanol 12.55
    dipropyl ether 11.33
    1,2-dichlorobenzene 1.87
    ethyl lactate 19.05
    propylene carbonate 20.05
    n-methylformamide 208.09
    2-pentanol 60.79
    n-pentane 0.41
    1-propoxy-2-propanol 46.38
    1-methoxy-2-propyl acetate 32.57
    2-(2-methoxypropoxy) propanol 37.51
    mesitylene 1.68
    ε-caprolactone 27.26
    p-cymene 3.17
    epichlorohydrin 46.59
    1,1,1-trichloroethane 1.7
    2-aminoethanol 99.15
    morpholine-4-carbaldehyde 56.81
    sulfolane 42.57
    2,2,4-trimethylpentane 0.38
    2-methyltetrahydrofuran 33.67
    n-hexyl acetate 15.76
    isooctane 0.33
    2-(2-butoxyethoxy)ethanol 57.3
    sec-butyl acetate 11.76
    tert-butyl acetate 21.9
    decalin 0.27
    glycerin 68.73
    diglyme 67.8
    acrylic acid 27.06
    isopropyl myristate 7.1
    n-butyric acid 66.38
    acetyl acetate 17.52
    di(2-ethylhexyl) phthalate 9.45
    ethyl propionate 25.74
    nitromethane 91.1
    1,2-diethoxyethane 23.42
    benzonitrile 7.5
    trioctyl phosphate 8.23
    1-bromopropane 3.49
    gamma-valerolactone 50.07
    n-decanol 10.64
    triethyl phosphate 6.34
    4-methyl-2-pentanol 20.48
    propionitrile 30.75
    vinylene carbonate 12.58
    1,1,2-trichlorotrifluoroethane 25.6
    DMS 11.31
    cumene 2.13
    2-octanol 11.04
    2-hexanone 23.11
    octyl acetate 11.06
    limonene 4.05
    1,2-dimethoxyethane 70.64
    ethyl orthosilicate 6.34
    tributyl phosphate 7.48
    diacetone alcohol 61.64
    N,N-dimethylaniline 9.63
    acrylonitrile 37.11
    aniline 5.62
    1,3-propanediol 154.89
    bromobenzene 0.81
    dibromomethane 1.65
    1,1,2,2-tetrachloroethane 4.35
    2-methyl-cyclohexyl acetate 8.11
    tetrabutyl urea 16.32
    diisobutyl methanol 7.69
    2-phenylethanol 14.87
    styrene 1.69
    dioctyl adipate 11.01
    dimethyl sulfate 27.09
    ethyl butyrate 14.97
    methyl lactate 48.45
    butyl lactate 17.8
    diethyl carbonate 8.08
    propanediol butyl ether 37.98
    triethyl orthoformate 8.71
    p-tert-butyltoluene 2.95
    methyl 4-tert-butylbenzoate 19.54
    morpholine 28.75
    tert-butylamine 20.7
    n-dodecanol 8.03
    dimethoxymethane 147.91
    ethylene carbonate 11.05
    cyrene 31.46
    2-ethoxyethyl acetate 24.92
    2-ethylhexyl acetate 9.28
    1,2,4-trichlorobenzene 2.62
    4-methylpyridine 12.01
    dibutyl ether 8.05
    2,6-dimethyl-4-heptanol 7.69
    DEF 101.03
    dimethyl isosorbide 35.82
    tetrachloroethylene 3.09
    eugenol 23.68
    triacetin 14.13
    span 80 24.53
    1,4-butanediol 53.39
    1,1-dichloroethane 3.54
    2-methyl-1-pentanol 33.32
    methyl formate 80.39
    2-methyl-1-butanol 60.0
    n-decane 0.7
    butyronitrile 33.68
    3,7-dimethyl-1-octanol 11.38
    1-chlorooctane 2.51
    1-chlorotetradecane 1.48
    n-nonane 0.56
    undecane 0.64
    tert-butylcyclohexane 0.33
    cyclooctane 0.13
    cyclopentanol 27.44
    tetrahydropyran 11.06
    tert-amyl methyl ether 19.14
    2,5,8-trioxanonane 60.03
    1-hexene 2.09
    2-isopropoxyethanol 58.03
    2,2,2-trifluoroethanol 15.05
    methyl butyrate 30.12

    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