4-Hydroxypyridine

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  • Identifiers

    CAS number
    626-64-2

    Molecular formula
    C5H5NO

    SMILES
    C1=CNC=CC1=O

    Safety labels

    Corrosive
    Corrosive

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Nutty 69.6%
    Burnt 59.37%
    Sweet 49.68%
    Almond 39.21%
    Roasted 37.94%
    Caramellic 37.86%
    Phenolic 37.62%
    Musty 37.57%
    Tobacco 36.46%
    Coumarinic 34.83%

     

    Flavor
    Bitter 51.23%
    Sweet 51.06%
    Almond 41.23%
    Balsam 31.78%
    Nutty 30.57%
    Tonka 29.6%
    Medical 29.49%
    Green 28.32%
    Burnt sugar 24.71%
    Balsamic 24.06%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    -1.3

    pKa est.
    7.9 (neutral)

    Molecular weight
    95.1 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Very slow

    Boiling point est.
    273°C

    Flash point

    • 110.78 ˚C est.

  • Synonyms

    • 4-HYDROXYPYRIDINE
    • 626-64-2
    • 4-Pyridinol
    • DTXSID2052310
    • DTXCID9030882
    • CHEBI:87614
    • RefChem:1070836
    • pyridin-4-ol
    • pyridin-4(1H)-one
    • 108-96-3
    • 4(1H)-Pyridinone
    • 4-Pyridone
    • 1H-pyridin-4-one
    • 4-Pyridinone
    • 4-Oxopyridine
    • 4-Pyridol
    • gamma-Hydroxypyridine
    • gamma-Pyridone
    • 4(1H)-Pyridone
    • .gamma.-Pyridone
    • MFCD00006419
    • .gamma.-Hydroxypyridine
    • 1,4-Dihydro-4-pyridinone
    • NSC5080
    • 3P2MV07G53
    • NSC-5080
    • NSC-146174
    • NSC-26021
    • NSC 5080
    • EINECS 210-958-3
    • 1,4-dihydropyridin-4-one
    • BRN 0105800
    • UNII-3P2MV07G53
    • AI3-61970
    • 4-hydroxypridine
    • p-Hydroxypyridine
    • Pyridin-4-one
    • 4-hydroxy-pyridine
    • hydropyridin-4-one
    • CQG
    • EINECS 203-633-2
    • MFCD00040458
    • NSC 146174
    • pyridine, 4-hydroxy-
    • 4-Hydroxypyridine, 95%
    • SCHEMBL3107
    • HYDROXYPYRIDINE, 4-
    • SCHEMBL13353
    • 5-21-07-00152 (Beilstein Handbook Reference)
    • MLS004491722
    • SCHEMBL130113
    • SCHEMBL200660
    • SCHEMBL301997
    • SCHEMBL332060
    • SCHEMBL788891
    • 4-hydroxypyridine, AldrichCPR
    • CHEMBL237459
    • orb2802576
    • SCHEMBL1384665
    • SCHEMBL6013078
    • SR-1C7
    • CHEBI:133125
    • STR01041
    • EINECS 222-380-9
    • Tox21_303817
    • BBL022970
    • c1201
    • NSC146174
    • SBB005800
    • STL363251
    • AKOS000121024
    • AKOS022377006
    • AC-2927
    • BS-3730
    • CS-W007690
    • EBC-656496
    • FH02024
    • HY-W007690
    • MSK170682-100M
    • PB17041
    • SB52275
    • NCGC00357095-01
    • CAS-626-64-2
    • SMR003288679
    • ST044793
    • SY003367
    • SY112252
    • DB-014976
    • DB-040853
    • CS-0166783
    • H0332
    • NS00022560
    • EN300-21574
    • D82355
    • 382H161
    • 4-Hydroxypyridine Solution in Methanol, 100ug/mL
    • AC-907/34116018
    • F045193
    • Q230024
    • Butanoic acid,heptafluoro-,1,10-decanediyl ester(9ci)
    • 4-Pyridinol; 4-Pyridol; NSC 5080; gamma-Hydroxypyridine;
    • A1E9A648-09AC-4FC9-A7AF-37534D102469
    • InChI=1/C5H5NO/c7-5-1-3-6-4-2-5/h1-4H,(H,6,7
    • 626-64-2

  • Applications

    4-Hydroxypyridine is primarily used as an organic synthesis intermediate and a building block for more complex heterocyclic compounds. It serves as a ligand precursor in coordination chemistry and for metal-catalyzed systems. In pharmaceutical and agrochemical R&D, it is used as a starting material to prepare heterocyclic cores and drug-like scaffolds. It may also be used as a precursor to other functionalized pyridine derivatives in the development of specialty chemicals.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 38.12
    methanol 57.07
    isopropanol 21.64
    water 19.15
    ethyl acetate 6.69
    n-propanol 28.05
    acetone 15.73
    n-butanol 18.5
    acetonitrile 13.9
    DMF 140.88
    toluene 0.78
    isobutanol 17.72
    1,4-dioxane 11.57
    methyl acetate 11.39
    THF 26.65
    2-butanone 15.1
    n-pentanol 14.45
    sec-butanol 16.72
    n-hexane 0.48
    ethylene glycol 24.98
    NMP 114.37
    cyclohexane 0.27
    DMSO 120.49
    n-butyl acetate 7.25
    n-octanol 4.35
    chloroform 8.57
    n-propyl acetate 6.6
    acetic acid 75.51
    dichloromethane 7.34
    cyclohexanone 21.0
    propylene glycol 25.05
    isopropyl acetate 3.95
    DMAc 114.49
    2-ethoxyethanol 26.62
    isopentanol 14.44
    n-heptane 0.63
    ethyl formate 10.3
    1,2-dichloroethane 5.03
    n-hexanol 8.67
    2-methoxyethanol 52.92
    isobutyl acetate 4.16
    tetrachloromethane 1.94
    n-pentyl acetate 5.96
    transcutol 87.97
    n-heptanol 5.77
    ethylbenzene 0.83
    MIBK 6.16
    2-propoxyethanol 21.96
    tert-butanol 18.28
    MTBE 4.5
    2-butoxyethanol 18.06
    propionic acid 42.73
    o-xylene 1.59
    formic acid 65.19
    diethyl ether 3.3
    m-xylene 1.39
    p-xylene 1.8
    chlorobenzene 2.53
    dimethyl carbonate 7.02
    n-octane 0.22
    formamide 83.08
    cyclopentanone 36.02
    2-pentanone 8.52
    anisole 4.38
    cyclopentyl methyl ether 7.62
    gamma-butyrolactone 50.28
    1-methoxy-2-propanol 33.68
    pyridine 13.75
    3-pentanone 7.56
    furfural 45.18
    n-dodecane 0.22
    diethylene glycol 28.57
    diisopropyl ether 1.18
    tert-amyl alcohol 15.15
    acetylacetone 9.95
    n-hexadecane 0.23
    acetophenone 8.46
    methyl propionate 11.32
    isopentyl acetate 6.58
    trichloroethylene 12.2
    n-nonanol 4.26
    cyclohexanol 9.18
    benzyl alcohol 8.51
    2-ethylhexanol 5.25
    isooctanol 5.17
    dipropyl ether 4.02
    1,2-dichlorobenzene 3.69
    ethyl lactate 9.21
    propylene carbonate 21.7
    n-methylformamide 65.58
    2-pentanol 8.06
    n-pentane 0.43
    1-propoxy-2-propanol 15.71
    1-methoxy-2-propyl acetate 9.76
    2-(2-methoxypropoxy) propanol 21.22
    mesitylene 1.18
    ε-caprolactone 20.33
    p-cymene 1.9
    epichlorohydrin 24.45
    1,1,1-trichloroethane 4.16
    2-aminoethanol 45.37
    morpholine-4-carbaldehyde 59.51
    sulfolane 69.94
    2,2,4-trimethylpentane 0.44
    2-methyltetrahydrofuran 14.27
    n-hexyl acetate 7.1
    isooctane 0.29
    2-(2-butoxyethoxy)ethanol 28.12
    sec-butyl acetate 3.84
    tert-butyl acetate 4.99
    decalin 0.35
    glycerin 42.11
    diglyme 43.53
    acrylic acid 44.82
    isopropyl myristate 2.91
    n-butyric acid 28.5
    acetyl acetate 5.8
    di(2-ethylhexyl) phthalate 6.33
    ethyl propionate 5.58
    nitromethane 79.11
    1,2-diethoxyethane 8.74
    benzonitrile 8.62
    trioctyl phosphate 4.2
    1-bromopropane 2.35
    gamma-valerolactone 44.44
    n-decanol 3.23
    triethyl phosphate 5.21
    4-methyl-2-pentanol 5.02
    propionitrile 12.54
    vinylene carbonate 18.85
    1,1,2-trichlorotrifluoroethane 41.46
    DMS 7.76
    cumene 1.39
    2-octanol 3.03
    2-hexanone 8.02
    octyl acetate 4.39
    limonene 2.49
    1,2-dimethoxyethane 23.66
    ethyl orthosilicate 4.68
    tributyl phosphate 5.27
    diacetone alcohol 15.31
    N,N-dimethylaniline 5.53
    acrylonitrile 20.85
    aniline 6.12
    1,3-propanediol 37.48
    bromobenzene 1.54
    dibromomethane 4.02
    1,1,2,2-tetrachloroethane 11.43
    2-methyl-cyclohexyl acetate 6.18
    tetrabutyl urea 8.52
    diisobutyl methanol 3.34
    2-phenylethanol 7.26
    styrene 0.98
    dioctyl adipate 6.25
    dimethyl sulfate 20.82
    ethyl butyrate 6.01
    methyl lactate 17.28
    butyl lactate 10.31
    diethyl carbonate 5.1
    propanediol butyl ether 21.82
    triethyl orthoformate 5.59
    p-tert-butyltoluene 1.78
    methyl 4-tert-butylbenzoate 11.55
    morpholine 23.11
    tert-butylamine 8.1
    n-dodecanol 2.51
    dimethoxymethane 17.51
    ethylene carbonate 13.1
    cyrene 22.47
    2-ethoxyethyl acetate 9.23
    2-ethylhexyl acetate 5.21
    1,2,4-trichlorobenzene 5.5
    4-methylpyridine 10.34
    dibutyl ether 3.2
    2,6-dimethyl-4-heptanol 3.34
    DEF 23.21
    dimethyl isosorbide 24.61
    tetrachloroethylene 8.01
    eugenol 14.2
    triacetin 11.23
    span 80 16.44
    1,4-butanediol 17.1
    1,1-dichloroethane 3.9
    2-methyl-1-pentanol 11.97
    methyl formate 26.91
    2-methyl-1-butanol 14.55
    n-decane 0.31
    butyronitrile 10.04
    3,7-dimethyl-1-octanol 5.1
    1-chlorooctane 1.27
    1-chlorotetradecane 0.64
    n-nonane 0.27
    undecane 0.25
    tert-butylcyclohexane 0.42
    cyclooctane 0.12
    cyclopentanol 18.12
    tetrahydropyran 7.09
    tert-amyl methyl ether 4.51
    2,5,8-trioxanonane 33.83
    1-hexene 1.74
    2-isopropoxyethanol 15.33
    2,2,2-trifluoroethanol 31.75
    methyl butyrate 9.12

    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