Indole-3-Carboxylic Acid

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  • Identifiers

    CAS number
    771-50-6

    Molecular formula
    C9H7NO2

    SMILES
    C1=CC=C2C(=C1)C(=CN2)C(=O)O

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 42.76%
    Grape 38.6%
    Floral 36.36%
    Phenolic 36.22%
    Animal 33.56%
    Balsamic 32.99%
    Neroli 31.92%
    Fruity 31.23%
    Honey 30.99%
    Burnt 27.66%

     

    Flavor
    Odorless 49.78%
    Bitter 49.62%
    Mild 39.03%
    Nutty 36.92%
    Faint 32.03%
    Sour 31.02%
    Balsam 29.65%
    Honey 28.32%
    Phenolic 28.01%
    Urine 25.32%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    2.0

    pKa est.
    6.98 (neutral)

    Molecular weight
    161.16 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    388°C

    Melting point expt.

    • 206.5 °C

    Flash point

    • 208.6 ˚C est.

  • Synonyms

    • Indole-3-carboxylic acid
    • 1H-Indole-3-carboxylic acid
    • 771-50-6
    • 3-Carboxyindole
    • CHEBI:24809
    • 59711R38B0
    • DTXSID50227886
    • RefChem:923413
    • DTXCID00150377
    • 212-231-6
    • 3-Indoleformic acid
    • 3-Indolecarboxylic acid
    • MFCD00005624
    • Indole-3-carboxylicacid
    • 3-Indolylcarboxylic acid
    • beta-Indolylcarboxylic acid
    • 3-Indolecarboxylate
    • .beta.-Indolylcarboxylic acid
    • ICO
    • EINECS 212-231-6
    • Indole - 3 Carboxylic acid
    • 3-Indoleformate
    • Indole-3-carboxylic acid, 99%
    • 4ahu
    • 3-indolecarboxylic
    • 3-carboxyl-indole
    • UNII-59711R38B0
    • Tropisetron Hydrochloride Imp. B (EP); Tropisetron Imp. B (EP); 1H-Indole-3-carboxylic Acid; Tropisetron Hydrochloride Impurity B; Tropisetron Impurity B
    • 3-Indolylcarboxylate
    • 3-Indolecarboxylicacid
    • Tropisetron impurity B
    • Indole - 3 Carboxylate
    • Indole 3-carboxylic acid
    • Indole-3 carboxylic acid
    • 3-Indole Carboxylic acid
    • indolyl-3-carboxylic acid
    • Tropisetron impurity B CRS
    • Oprea1_560034
    • SCHEMBL64182
    • CHEMBL387527
    • orb1301369
    • SCHEMBL1642680
    • SCHEMBL2125950
    • SCHEMBL8078829
    • SCHEMBL11791103
    • SCHEMBL20562057
    • BDBM93015
    • HMS5083H16
    • ALBB-007628
    • BB_NC-02788
    • CS-D0682
    • EBC-04079
    • HY-40161R
    • Indole-3-carboxylic acid (Standard)
    • s4860
    • SBB003952
    • STK500561
    • INDOLE-.BETA.-CARBOXYLIC ACID
    • AKOS001071938
    • AC-2264
    • CCG-266287
    • FI02425
    • FS-1053
    • SB14951
    • SDCCGMLS-0065969.P001
    • Tropisetron Hydrochloride EP Impurity B
    • NCGC00323250-01
    • HY-40161
    • ST066880
    • SY004104
    • DB-011569
    • I0028
    • NS00015706
    • EN300-13123
    • 71I506
    • C19837
    • I-2320
    • AB00443727-03
    • Indole-3-carboxylic acid, ReagentPlus(R), 99%
    • AQ-776/40182782
    • F003408
    • Indole-3-carboxylic acid, purum, >=98.0% (T)
    • Q27103090
    • Z89283908
    • Indole-3-carboxylic acid, Vetec(TM) reagent grade, 98%
    • TROPISETRON HYDROCHLORIDE IMPURITY B [EP IMPURITY]
    • Tropisetron impurity B, European Pharmacopoeia (EP) Reference Standard
    • InChI=1/C9H7NO2/c11-9(12)7-5-10-8-4-2-1-3-6(7)8/h1-5,10H,(H,11,12
    • 771-50-6

  • Applications

    Indole-3-Carboxylic Acid (CAS 771-50-6) is a versatile building block in organic synthesis and finds use across several industrial segments. In pharmaceutical development, it is an intermediate to construct indole cores and tryptophan-like derivatives for lead compounds. In agrochemical chemistry, it serves as a starting material for synthesizing heterocyclic scaffolds used in herbicides and insecticides. In fragrance and flavor chemistry, indole derivatives contribute characteristic notes and I3CA can be elaborated to generate fragrance precursors. In dye and pigment chemistry, it functions as a precursor for indole-based dyes and colors. In research and development, it is a substrate for cross-coupling and other functionalization strategies to access diverse 3-substituted indoles. Subject to local regulations and formulation limits.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 28.99
    methanol 42.48
    isopropanol 27.33
    water 0.34
    ethyl acetate 20.2
    n-propanol 24.68
    acetone 29.4
    n-butanol 22.86
    acetonitrile 8.54
    DMF 180.14
    toluene 0.56
    isobutanol 17.01
    1,4-dioxane 7.49
    methyl acetate 16.47
    THF 55.17
    2-butanone 27.61
    n-pentanol 19.85
    sec-butanol 20.93
    n-hexane 0.17
    ethylene glycol 20.89
    NMP 72.1
    cyclohexane 0.05
    DMSO 122.88
    n-butyl acetate 10.24
    n-octanol 10.06
    chloroform 0.83
    n-propyl acetate 9.85
    acetic acid 13.97
    dichloromethane 1.9
    cyclohexanone 17.14
    propylene glycol 23.29
    isopropyl acetate 11.51
    DMAc 111.57
    2-ethoxyethanol 54.72
    isopentanol 20.21
    n-heptane 0.42
    ethyl formate 13.01
    1,2-dichloroethane 2.56
    n-hexanol 15.16
    2-methoxyethanol 103.77
    isobutyl acetate 4.63
    tetrachloromethane 0.4
    n-pentyl acetate 11.29
    transcutol 52.87
    n-heptanol 12.09
    ethylbenzene 1.17
    MIBK 16.12
    2-propoxyethanol 49.35
    tert-butanol 27.05
    MTBE 6.18
    2-butoxyethanol 32.16
    propionic acid 15.6
    o-xylene 1.14
    formic acid 15.88
    diethyl ether 5.54
    m-xylene 1.46
    p-xylene 1.65
    chlorobenzene 1.15
    dimethyl carbonate 14.0
    n-octane 0.27
    formamide 40.94
    cyclopentanone 40.93
    2-pentanone 29.13
    anisole 5.67
    cyclopentyl methyl ether 10.01
    gamma-butyrolactone 45.64
    1-methoxy-2-propanol 86.89
    pyridine 5.53
    3-pentanone 12.89
    furfural 26.61
    n-dodecane 0.41
    diethylene glycol 53.61
    diisopropyl ether 1.96
    tert-amyl alcohol 19.22
    acetylacetone 26.85
    n-hexadecane 0.45
    acetophenone 10.42
    methyl propionate 26.11
    isopentyl acetate 9.22
    trichloroethylene 3.65
    n-nonanol 10.22
    cyclohexanol 7.32
    benzyl alcohol 10.6
    2-ethylhexanol 8.43
    isooctanol 10.42
    dipropyl ether 6.22
    1,2-dichlorobenzene 1.86
    ethyl lactate 15.05
    propylene carbonate 17.19
    n-methylformamide 68.05
    2-pentanol 15.06
    n-pentane 0.12
    1-propoxy-2-propanol 31.32
    1-methoxy-2-propyl acetate 19.96
    2-(2-methoxypropoxy) propanol 28.44
    mesitylene 1.28
    ε-caprolactone 17.91
    p-cymene 2.33
    epichlorohydrin 35.17
    1,1,1-trichloroethane 1.52
    2-aminoethanol 35.4
    morpholine-4-carbaldehyde 46.49
    sulfolane 66.1
    2,2,4-trimethylpentane 0.21
    2-methyltetrahydrofuran 18.29
    n-hexyl acetate 13.34
    isooctane 0.25
    2-(2-butoxyethoxy)ethanol 40.07
    sec-butyl acetate 6.44
    tert-butyl acetate 11.2
    decalin 0.23
    glycerin 41.94
    diglyme 50.19
    acrylic acid 12.89
    isopropyl myristate 6.71
    n-butyric acid 21.59
    acetyl acetate 7.09
    di(2-ethylhexyl) phthalate 9.18
    ethyl propionate 11.79
    nitromethane 33.5
    1,2-diethoxyethane 12.96
    benzonitrile 6.12
    trioctyl phosphate 8.82
    1-bromopropane 1.4
    gamma-valerolactone 41.0
    n-decanol 8.78
    triethyl phosphate 6.35
    4-methyl-2-pentanol 9.69
    propionitrile 9.97
    vinylene carbonate 11.27
    1,1,2-trichlorotrifluoroethane 23.54
    DMS 9.95
    cumene 1.59
    2-octanol 8.38
    2-hexanone 13.89
    octyl acetate 10.06
    limonene 3.0
    1,2-dimethoxyethane 43.2
    ethyl orthosilicate 5.73
    tributyl phosphate 7.65
    diacetone alcohol 35.55
    N,N-dimethylaniline 6.81
    acrylonitrile 14.58
    aniline 2.99
    1,3-propanediol 46.97
    bromobenzene 0.74
    dibromomethane 0.92
    1,1,2,2-tetrachloroethane 3.46
    2-methyl-cyclohexyl acetate 7.69
    tetrabutyl urea 15.61
    diisobutyl methanol 5.8
    2-phenylethanol 11.97
    styrene 0.92
    dioctyl adipate 10.31
    dimethyl sulfate 25.37
    ethyl butyrate 9.18
    methyl lactate 29.59
    butyl lactate 15.89
    diethyl carbonate 5.78
    propanediol butyl ether 28.68
    triethyl orthoformate 7.03
    p-tert-butyltoluene 2.18
    methyl 4-tert-butylbenzoate 17.81
    morpholine 16.24
    tert-butylamine 7.23
    n-dodecanol 6.69
    dimethoxymethane 59.65
    ethylene carbonate 9.58
    cyrene 31.2
    2-ethoxyethyl acetate 16.41
    2-ethylhexyl acetate 6.56
    1,2,4-trichlorobenzene 2.66
    4-methylpyridine 6.54
    dibutyl ether 5.62
    2,6-dimethyl-4-heptanol 5.8
    DEF 34.16
    dimethyl isosorbide 34.66
    tetrachloroethylene 2.19
    eugenol 22.62
    triacetin 13.46
    span 80 21.12
    1,4-butanediol 26.88
    1,1-dichloroethane 1.76
    2-methyl-1-pentanol 15.76
    methyl formate 32.82
    2-methyl-1-butanol 17.66
    n-decane 0.5
    butyronitrile 10.8
    3,7-dimethyl-1-octanol 8.15
    1-chlorooctane 2.34
    1-chlorotetradecane 1.37
    n-nonane 0.39
    undecane 0.46
    tert-butylcyclohexane 0.3
    cyclooctane 0.05
    cyclopentanol 15.4
    tetrahydropyran 5.02
    tert-amyl methyl ether 6.63
    2,5,8-trioxanonane 44.72
    1-hexene 1.06
    2-isopropoxyethanol 31.99
    2,2,2-trifluoroethanol 9.54
    methyl butyrate 14.26

    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