HEPES
Athanor · official
C8H18N2O4S · 238.31 g/mol
IUPAC name: 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid
Also called buffer, Good buffer
Names and identifiers
- IUPAC name
- 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid
- Synonyms
- buffer, Good buffer, 4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid
+ 37 more
1-Piperazineethanesulfonic acid, 4-(2-hydroxyethyl)-, HEPES solution, 4-(2-Hydroxyethyl)-1-piperazineethane sulfonic acid, RWW266YE9I, CHEBI:42334, hydroxyethylpiperazine ethane sulfonic acid, NSC-166663, NSC166663, Monosodium Salt, HEPES, Salt, HEPES Monosodium, N 2 Hydroxyethylpiperazine N' 2' ethanesulfonic Acid, N-2-Hydroxyethylpiperazine-N'-2'-ethanesulfonic Acid, RefChem:783545, CHEBI:46756, Hydroxyethyl Piperazine Ethanesulfonic Acid Solution, 230-907-9, 2-(4-(2-Hydroxyethyl)piperazin-1-yl)ethanesulfonic acid, 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid, 4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID, 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid, MFCD00006158, N-2-Hydroxyethylpiperazine-N'-ethanesulfonate, N-2-Hydroxyethylpiperazine-N'-ethanesulfonic acid, N-2-Hydroxyethylpiperazine-N-ethane sulfonic acid, NSC 166663, N-2-Hydroxyethylpiperazine N',2'-ethanesulfonic acid, 2-[4-(2-Hydroxyethyl)-1-piperazinyl]ethanesulfonic acid, 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethane-1-sulfonic acid, 4-(2-Hydroxyethyl)piperazin-1-ylethanesulphonic acid, 2-(4-(2-Hydroxyethyl)piperazin-1-yl)ethane-1-sulfonic acid, TVZ 7;WAS 13;NSC 166663, BRN 0883043, N-(2-Hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid), 2-[4-(2-hydroxyethyl)piperazinyl]ethanesulfonic acid, UNII-RWW266YE9I, DTXSID5040382, HeBES
- Molecular formula
- C8H18N2O4S
- Empirical formula
- C8H18N2O4S
- Molecular weight
- 238.31 g/mol
- Exact mass
- 238.09873
- CAS number
- 7365-45-9
- PubChem CID
- 23831
- Canonical SMILES
- C1CN(CCN1CCO)CCS(=O)(=O)O
- Isomeric SMILES
- C1CN(CCN1CCO)CCS(=O)(=O)O
- InChI
- InChI=1S/C8H18N2O4S/c11-7-5-9-1-3-10(4-2-9)6-8-15(12,13)14/h11H,1-8H2,(H,12,13,14)
- InChIKey
- JKMHFZQWWAIEOD-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
- Appearance
- Dry Powder; Liquid[1]
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
- 0
- Fraction sp³ carbons (Fsp3)
- 1
- H-bond donors
- 2
- H-bond acceptors
- 5 computed here · PubChem 6
- Rotatable bonds
- 5
- TPSA (Ų)
- 81.1 computed here · PubChem 89.5
- Formal charge
- 0
- XLogP3
- -4 PubChem
- Complexity
- 267 PubChem
- Stereocenters
- None
- 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
- C40.32%
- H7.61%
- N11.76%
- O26.85%
- S13.46%
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
- -1.52 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- -0.03 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 2.14 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 238.31
- log P ≤ 5 (Crippen): -1.52
- H-bond donors ≤ 5: 2
- H-bond acceptors ≤ 10: 5
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
This chemical does not meet GHS hazard criteria for 95.6% (194 of 203) of all reports.[2]
Safety data sheets on the supplier’s page: AKos Consulting & Solutions, 001Chemical, Sigma-Aldrich.
Always read the supplier’s safety data sheet before working with it.
Spectra
- 1H NMRSpectraBase
- 13C NMRSpectraBase
- GC-MSNIST Mass Spectrometry Data Center
- MS-MSHuman Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · Human Metabolome Database (HMDB) (Negative) · NIST Mass Spectrometry Data Center (IT/ion trap)
- LC-MSMassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · ESI) · MassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · ESI) · MassBank of North America (MoNA) (Agilent 6550 iFunnel · LC-ESI-QTOF · ESI)
- Other MSMassBank Europe (ESI-QTOF · NEGATIVE · ESI) · MassBank Europe (ESI-QTOF · POSITIVE · ESI) · MassBank Europe (ESI-QTOF · NEGATIVE · ESI) · MassBank Europe (ESI-QTOF · POSITIVE · ESI) · MassBank Europe (ESI-QTOF · POSITIVE · ESI) · MassBank Europe (ESI-QTOF · NEGATIVE · ESI)
- FTIRSpectraBase (KBr WAFER)
- ATR-IRSpectraBase (Bio-Rad FTS · ATR-Neat (DuraSamplIR II))
- RamanSpectraBase (Thermo Nicolet FT-Raman 960 · 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]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [3]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
- [4]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
- [5]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
- [6]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
- [7]MassBank Europe · 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.