Chlorzoxazone

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  • Identifiers

    CAS number
    95-25-0

    Molecular formula
    C7H4ClNO2

    SMILES
    C1=CC2=C(C=C1Cl)NC(=O)O2

    Safety labels

    Irritant
    Irritant

  • Odor profile

    Fragrance
    Odorless 38.47%
    Burnt 31.61%
    Animal 29.66%
    Fruity 27.14%
    Phenolic 25.36%
    Bitter 24.61%
    Floral 24.15%
    Roasted 23.09%
    Powdery 23.01%
    Nutty 22.08%

     

    Flavor
    Bitter 80.9%
    Odorless 29.04%
    Mild 23.57%
    Very strong 20.74%
    Nitrile 20.7%
    Bread crust 20.49%
    Indole 20.08%
    Roasted peanuts 19.92%
    Scallion 19.86%
    Formyl 19.64%

     

    Odor impact est.
    Low

  • Properties

    XLogP3-AA
    1.8

    pKa est.
    7.84 (neutral)

    Molecular weight
    169.56 g/mol

    Vapor pressure est.

    • hPa @ 20°C
    • hPa @ 25°C

    Evaporation rate
    Ultra slow

    Boiling point est.
    342°C

    Melting point expt.

    • 191-191.5
    • 191.5 °C

    Flash point

    • 167.06 ˚C est.

    Solubility expt.

    • 1000 mg/L
    • 2.96e+00 g/L
    • >25.4 [ug/mL] (The mean of the results at pH 7.4)

  • Synonyms

    • chlorzoxazone
    • 95-25-0
    • Paraflex
    • 5-Chloro-2(3H)-benzoxazolone
    • 5-Chloro-2-benzoxazolone
    • 2(3H)-Benzoxazolone, 5-chloro-
    • 5-Chloro-2-benzoxazolinone
    • 5-Chloro-2-hydroxybenzoxazole
    • 5-Chloro-2-benzoxazolol
    • Parafon Forte DSC
    • 5-Chlorobenzoxazolidone
    • 5-chloro-3H-1,3-benzoxazol-2-one
    • Chlorzoxane
    • Parafon
    • Strifon Forte Dsc
    • 2-Hydroxy-5-chlorobenzoxazole
    • Chlorzoxazonum
    • Clorzoxazona
    • Strifon
    • 5-chlorobenzoxazolin-2-one
    • DTXSID9022813
    • 5-chloro-2,3-dihydro-1,3-benzoxazol-2-one
    • H0DE420U8G
    • CHEBI:3655
    • DTXCID302813
    • NSC26189
    • chlorozoxazone
    • Clorzoxazone
    • Parafon-Forte
    • Parafon Dsc
    • RefChem:5678
    • M03BB03
    • 202-403-9
    • Chloroxazone
    • Chlorzoxazon
    • Biomioran
    • Myoflexine
    • Escoflex
    • Miotran
    • Neoflex
    • Solaxin
    • Mioran
    • 5-Chlorobenzo[d]oxazol-2(3H)-one
    • Myoflexin
    • Pathorysin
    • Usaf ma-10
    • 5-Chloro-1,3-benzoxazol-2(3H)-one
    • 5-Chlorobenzoxazol-2-one
    • 5-Chlorobenzoxazolone
    • 5-Chlorbenzoxazolin-2-on
    • 5-Chloro-3(H)-2-benzoxazolone
    • 5-chlorobenzo[d]oxazol-2-ol
    • 5-Chlorobenzoksazolon-2
    • MFCD00005717
    • 5-Chlorobenzoksazolinon-2
    • NSC 26189
    • 2-BENZOXAZOLINONE, 5-CHLORO-
    • 5-chloro-3H-benzooxazol-2-one
    • 5-chloro-1,3-benzoxazol-2-ol
    • CHEMBL1371
    • MLS000069380
    • Chlorsoxazone
    • Klorzoxazon
    • Nyoflex
    • Remofleks
    • Parafon Forte
    • NSC-26189
    • s4155
    • CAS-95-25-0
    • NCGC00015238-02
    • SMR000058269
    • CLW
    • Chlorzoxazonum [INN-Latin]
    • Clorzoxazona [INN-Spanish]
    • chlorzoxazona
    • 5-chloro-3-hydrobenzoxazol-2-one
    • Lorzone
    • 5-Chlorobenzoksazolon-2 [Polish]
    • 5-Chlorobenzoksazolinon-2 [Polish]
    • Paraflex (TN)
    • SR-01000075207
    • EINECS 202-403-9
    • component of Parafon Forte
    • UNII-H0DE420U8G
    • AI3-63119
    • Chlorzoxazone (JAN/USP/INN)
    • Prestwick_62
    • Chlorzoxazone [USP:INN:BAN:JAN]
    • 5-Chlorobenzoxazolinone
    • Spectrum_000148
    • Chlorzoxazone (Standard)
    • Opera_ID_1659
    • Prestwick0_000163
    • Prestwick1_000163
    • Prestwick2_000163
    • Prestwick3_000163
    • Spectrum2_001149
    • Spectrum3_000350
    • Spectrum4_000287
    • Spectrum5_000745
    • Lopac-C-4397
    • CHLORZOXAZONE [MI]
    • C 4397
    • CHLORZOXAZONE [INN]
    • CHLORZOXAZONE [JAN]
    • 5-Chloro-benzooxazol-2-ol
    • 5-chloro-2-benzoxazolinoone
    • 5-chloro-benzoxazolin-2-one
    • Lopac0_000253
    • SCHEMBL35177
    • SCHEMBL35178
    • BSPBio_000025
    • BSPBio_002019
    • CHLORZOXAZONE [VANDF]
    • KBioGR_000814
    • KBioSS_000628
    • WLN: T56 BMVOJ HG
    • CHLORZOXAZONE [MART.]
    • DivK1c_000895
    • SPECTRUM1500188
    • SPBio_001077
    • SPBio_001946
    • CHLORZOXAZONE [USP-RS]
    • CHLORZOXAZONE [WHO-DD]
    • BPBio1_000029
    • GTPL2322
    • orb1307897
    • 95-25-0

  • Applications

    Chlorzoxazone (CAS 95-25-0) is primarily used as an active pharmaceutical ingredient (API) in prescription muscle-relaxant medications to provide short-term relief from acute musculoskeletal pain and muscle spasm; it is commonly formulated in fixed-dose combinations with analgesics, and its action is central nervous system mediated skeletal muscle relaxation. Its use is governed by local regulations and manufacturing controls; it is frequently considered in formulation development and pharmacology research, and outside the pharmaceutical field its applications are limited.

    gpt-5-nano

  • Solubility @25˚C

    Solvent Solubility (g/L)
    ethanol 67.32
    methanol 92.97
    isopropanol 55.49
    water 1.43
    ethyl acetate 52.5
    n-propanol 57.0
    acetone 126.38
    n-butanol 45.55
    acetonitrile 27.82
    DMF 516.64
    toluene 2.07
    isobutanol 40.91
    1,4-dioxane 81.8
    methyl acetate 70.82
    THF 200.25
    2-butanone 101.27
    n-pentanol 43.51
    sec-butanol 54.42
    n-hexane 0.37
    ethylene glycol 55.27
    NMP 200.75
    cyclohexane 0.11
    DMSO 364.49
    n-butyl acetate 33.48
    n-octanol 25.87
    chloroform 3.94
    n-propyl acetate 45.37
    acetic acid 36.89
    dichloromethane 6.81
    cyclohexanone 51.65
    propylene glycol 46.1
    isopropyl acetate 34.03
    DMAc 330.74
    2-ethoxyethanol 186.51
    isopentanol 45.35
    n-heptane 0.81
    ethyl formate 43.03
    1,2-dichloroethane 9.57
    n-hexanol 27.57
    2-methoxyethanol 283.32
    isobutyl acetate 22.58
    tetrachloromethane 0.62
    n-pentyl acetate 31.19
    transcutol 324.84
    n-heptanol 20.22
    ethylbenzene 3.53
    MIBK 45.27
    2-propoxyethanol 140.49
    tert-butanol 65.06
    MTBE 35.73
    2-butoxyethanol 68.76
    propionic acid 38.72
    o-xylene 3.48
    formic acid 41.09
    diethyl ether 29.71
    m-xylene 3.13
    p-xylene 5.17
    chlorobenzene 3.91
    dimethyl carbonate 63.98
    n-octane 0.49
    formamide 99.64
    cyclopentanone 105.02
    2-pentanone 76.62
    anisole 36.72
    cyclopentyl methyl ether 38.82
    gamma-butyrolactone 114.65
    1-methoxy-2-propanol 231.52
    pyridine 28.72
    3-pentanone 48.32
    furfural 91.17
    n-dodecane 1.05
    diethylene glycol 155.96
    diisopropyl ether 8.1
    tert-amyl alcohol 58.17
    acetylacetone 86.26
    n-hexadecane 1.17
    acetophenone 38.24
    methyl propionate 72.43
    isopentyl acetate 30.82
    trichloroethylene 14.9
    n-nonanol 26.12
    cyclohexanol 19.22
    benzyl alcohol 33.65
    2-ethylhexanol 17.97
    isooctanol 17.84
    dipropyl ether 23.53
    1,2-dichlorobenzene 5.8
    ethyl lactate 52.46
    propylene carbonate 48.83
    n-methylformamide 160.34
    2-pentanol 34.59
    n-pentane 0.26
    1-propoxy-2-propanol 89.71
    1-methoxy-2-propyl acetate 65.55
    2-(2-methoxypropoxy) propanol 98.57
    mesitylene 2.68
    ε-caprolactone 53.85
    p-cymene 5.65
    epichlorohydrin 104.09
    1,1,1-trichloroethane 4.53
    2-aminoethanol 69.98
    morpholine-4-carbaldehyde 196.68
    sulfolane 141.75
    2,2,4-trimethylpentane 0.59
    2-methyltetrahydrofuran 71.58
    n-hexyl acetate 42.37
    isooctane 0.45
    2-(2-butoxyethoxy)ethanol 124.18
    sec-butyl acetate 28.32
    tert-butyl acetate 38.45
    decalin 0.56
    glycerin 85.55
    diglyme 180.48
    acrylic acid 37.55
    isopropyl myristate 24.41
    n-butyric acid 38.34
    acetyl acetate 21.71
    di(2-ethylhexyl) phthalate 24.07
    ethyl propionate 48.29
    nitromethane 124.8
    1,2-diethoxyethane 74.32
    benzonitrile 20.73
    trioctyl phosphate 20.38
    1-bromopropane 5.17
    gamma-valerolactone 141.15
    n-decanol 22.46
    triethyl phosphate 21.88
    4-methyl-2-pentanol 22.15
    propionitrile 29.08
    vinylene carbonate 38.31
    1,1,2-trichlorotrifluoroethane 68.84
    DMS 45.41
    cumene 4.03
    2-octanol 16.78
    2-hexanone 57.45
    octyl acetate 30.99
    limonene 7.43
    1,2-dimethoxyethane 238.77
    ethyl orthosilicate 19.6
    tributyl phosphate 24.71
    diacetone alcohol 90.07
    N,N-dimethylaniline 30.54
    acrylonitrile 42.86
    aniline 11.98
    1,3-propanediol 92.55
    bromobenzene 2.48
    dibromomethane 3.21
    1,1,2,2-tetrachloroethane 15.06
    2-methyl-cyclohexyl acetate 26.9
    tetrabutyl urea 42.96
    diisobutyl methanol 13.69
    2-phenylethanol 28.31
    styrene 4.11
    dioctyl adipate 34.01
    dimethyl sulfate 105.0
    ethyl butyrate 32.94
    methyl lactate 85.64
    butyl lactate 42.52
    diethyl carbonate 25.2
    propanediol butyl ether 88.09
    triethyl orthoformate 27.87
    p-tert-butyltoluene 5.62
    methyl 4-tert-butylbenzoate 46.92
    morpholine 101.82
    tert-butylamine 21.44
    n-dodecanol 18.02
    dimethoxymethane 267.42
    ethylene carbonate 32.72
    cyrene 79.57
    2-ethoxyethyl acetate 55.22
    2-ethylhexyl acetate 22.79
    1,2,4-trichlorobenzene 9.25
    4-methylpyridine 28.65
    dibutyl ether 25.02
    2,6-dimethyl-4-heptanol 13.69
    DEF 100.96
    dimethyl isosorbide 117.19
    tetrachloroethylene 6.97
    eugenol 62.78
    triacetin 50.12
    span 80 54.99
    1,4-butanediol 53.23
    1,1-dichloroethane 5.8
    2-methyl-1-pentanol 35.95
    methyl formate 120.4
    2-methyl-1-butanol 42.14
    n-decane 1.25
    butyronitrile 26.8
    3,7-dimethyl-1-octanol 25.84
    1-chlorooctane 6.18
    1-chlorotetradecane 4.07
    n-nonane 0.92
    undecane 1.15
    tert-butylcyclohexane 0.69
    cyclooctane 0.1
    cyclopentanol 35.68
    tetrahydropyran 31.63
    tert-amyl methyl ether 35.43
    2,5,8-trioxanonane 148.43
    1-hexene 3.36
    2-isopropoxyethanol 108.49
    2,2,2-trifluoroethanol 25.91
    methyl butyrate 60.51

    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