Ibuprofen
Athanor · official
C13H18O2 · 206.28 g/mol
IUPAC name: 2-[4-(2-methylpropyl)phenyl]propanoic acid
Also called Advil, Nurofen, Motrin, Brufen, NSAID
WarningHarmful if swallowed · Causes serious eye irritation · May cause respiratory irritation · Suspected of damaging fertility or the unborn childNames and identifiers
- IUPAC name
- 2-[4-(2-methylpropyl)phenyl]propanoic acid
- Synonyms
- Advil, Nurofen, Motrin
+ 35 more
Brufen, NSAID, IBUPROFEN, (+-)-, RefChem:6648, 2-(4-Isobutylphenyl)propanoic acid, 2-[4-(2-methylpropyl)phenyl]propanoic acid, Medipren, Liptan, Nuprin, Anflagen, Buburone, Butylenin, Ibuprocin, Andran, Dolgit, Ebufac, Lamidon, Mynosedin, Epobron, Haltran, Ibumetin, Roidenin, Trendar, Adran, Nobfen, Nobgen, Brufanic, Ibuprohm, Nobfelon, Apsifen, Bluton, Burana, Pantrop, Rebugen, PediaProfen
- Molecular formula
- C13H18O2
- Empirical formula
- C13H18O2
- Molecular weight
- 206.28 g/mol
- Exact mass
- 206.13068
- CAS number
- 15687-27-1
- PubChem CID
- 3672
- Canonical SMILES
- CC(C)CC1=CC=C(C=C1)C(C)C(=O)O
- Isomeric SMILES
- CC(C)CC1=CC=C(C=C1)C(C)C(=O)O
- InChI
- InChI=1S/C13H18O2/c1-9(2)8-11-4-6-12(7-5-11)10(3)13(14)15/h4-7,9-10H,8H2,1-3H3,(H,14,15)
- InChIKey
- HEFNNWSXXWATRW-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
- Appearance
- Other Solid[1]
- Odor
- Characteristic odor[2]
- Solubility in water
- In water, 21 mg/l @ 25 °C[2]
2 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source – VERY SOLUBLE IN ALCOHOL [2] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1057 –shown In water, 21 mg/l @ 25 °C [2] Hazardous Substances Data Bank (HSDB)cites Yalkowsky SH, Dannenfelser RM; The AQUASOL dATAbASE of Aqueous Solubility. Ver 5. Tucson, AZ: Univ AZ, College of Pharmacy (1992) - log P
- log Kow= 3.97[2]
- pKa
- pKa = 4.91[2]
2 values
Only one source reports it.
Value As written Source – pKa= 5.2 [2] Hazardous Substances Data Bank (HSDB)cites McEvoy, G.K. (ed.). AHFS Drug Information 90. Bethesda, MD: American Society of Hospital Pharmacists, Inc., 1990 (Plus Supplements 1990)., p. 1020 –shown pKa = 4.91 [2] Hazardous Substances Data Bank (HSDB)cites Sangster J; LOGKOW Databank. Sangster Res. Lab., Montreal Quebec, Canada (1994) - Vapor pressure
- 4.74 × 10⁻⁵ mmHg @ 25 °C[2]
Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.
Calculated
- Heavy atoms
- 15
- Rings
- 1
- Aromatic rings
- 1
- Fraction sp³ carbons (Fsp3)
- 0.46
- H-bond donors
- 1
- H-bond acceptors
- 1 computed here · PubChem 2
- Rotatable bonds
- 4
- TPSA (Ų)
- 37.3
- Formal charge
- 0
- XLogP3
- 3.5 PubChem
- Complexity
- 203 PubChem
- Stereocenters
- 0 defined, 1 undefinedCIP: C11: undefined
- Double-bond geometry
- None specified
- Point group
- C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C75.69%
- H8.80%
- O15.51%
Isotope pattern
Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.
Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.
Predicted
- log P
- 3.07 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -3.09 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 2.19 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 206.28
- log P ≤ 5 (Crippen): 3.07
- H-bond donors ≤ 5: 1
- H-bond acceptors ≤ 10: 1
Passes all four rules.
¹³C NMR shifts, predicted
Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.
Safety
Warning
Most widely reported: 511 company reports to ECHA. Source [3].
- Harmful or irritant
- Health hazard
- H302Harmful if swallowed
- H319Causes serious eye irritation (72% of reports)
- H335May cause respiratory irritation (70.8% of reports)
- H361Suspected of damaging fertility or the unborn child (17.8% of reports)
Precautionary statements: P203, P261, P264, P264+P265, P270, P271, P280, P301+P317, P304+P340, P305+P351+P338, P318, P319, P330, P337+P317, P403+P233, P405, P501
Storage
- Preparations containing ibuprofen tablets should be stored in well closed, light resistant containers at 15-30 °C.[2]
Safety data sheets on the supplier’s page: Moldb, BLD Pharm, Alfa Chemistry.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRNMRShiftDB
- 1H NMRHuman Metabolome Database (HMDB) (Varian · 500 MHz · CDCl3) · Human Metabolome Database (HMDB) (JEOL · 400 MHz · CDCl3) · SpectraBase (BRUKER AC-300)
- 13C NMRHuman Metabolome Database (HMDB) (50.32 MHz · CDCl3) · SpectraBase
- 1H-13C NMRHuman Metabolome Database (HMDB) (Bruker · 600 MHz · CDCl3)
- GC-MSHuman Metabolome Database (HMDB) (EI-B · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF · positive) · Human Metabolome Database (HMDB) (GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) · Positive) · Human Metabolome Database (HMDB) (GC-EI-TOF (Pegasus III TOF-MS system, Leco; GC 6890, Agilent Technologies) · Positive)
- MS-MSHuman Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Quattro_QQQ · N/A) · Human Metabolome Database (HMDB) (Quattro_QQQ · N/A)
- LC-MSMassBank Europe (QExactive Orbitrap HF-X (Thermo Scientific) · LC-ESI-QFT · NEGATIVE) · MassBank Europe (Bruker maXis Impact · LC-ESI-QTOF · NEGATIVE) · MassBank Europe (TripleTOF 5600 SCIEX · LC-ESI-QTOF · NEGATIVE) · MassBank Europe (Q Exactive Orbitrap (Thermo Scientific) · LC-ESI-QFT · NEGATIVE) · MassBank Europe (Q Exactive Orbitrap (Thermo Scientific) · LC-ESI-QFT · NEGATIVE) · MassBank Europe (LCMS-8040 coupled to Nexera XR (Shimadzu, Kyoto, Japan). · LC-ESI-QQ · POSITIVE)
- Other MSMassBank Europe (HITACHI RMU-6E · EI-B · POSITIVE) · MassBank of North America (MoNA) (TQD, Waters · Flow-injection QqQ/MS · ESI) · MassBank of North America (MoNA) (TQD, Waters · Flow-injection QqQ/MS · ESI)
- FTIRSpectraBase (Bruker IFS 85 · KBr-Pellet)
- ATR-IRSpectraBase (Bio-Rad FTS · ATR-Neat (DuraSamplIR II))
- RamanSpectraBase (FT-Raman)
Experimental spectra held by these sources; each link opens the source's own record.
Literature
Reading PubChem, OpenAlex and GSRS…
Bioactivity
Reading ChEMBL…
References
- [1]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
- [2]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
- [3]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [4]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [5]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
- [6]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [7]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
- [8]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [9]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
- ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
- ·Literature on PubChem
Data last updated 2026-10-14.