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Hypoxanthine

Athanor · official

C5H4N4O · 136.11 g/mol

IUPAC name: 1,7-dihydropurin-6-one

Also called 6-hydroxypurine, sarcine, inosine base

RingsNucleic acid parts
Open in Athanor
The structure of Hypoxanthine
Drawn from its SMILES with RDKit
Harmful or irritantWarningCauses skin irritation · Causes serious eye irritation · May cause respiratory irritation

Names and identifiers

IUPAC name
1,7-dihydropurin-6-one
Synonyms
6-hydroxypurine, sarcine, inosine base
+ 33 more

6-Hydroxypurine, 9H-Purin-6-ol, 7H-Purin-6-ol, Sarkin, 3H-Purin-6-ol, Sarcine, 1,7-Dihydro-6H-purin-6-one, 6-Oxopurine, Sarkine, Hypoxanthine enol, Purin-6(1H)-one, 6-Hydroxy-1H-purine, Purin-6-ol, 9H-Purin-6(1H)-one, 6(1H)-Purinone, Purin-6(3H)-one, 6H-Purin-6-one, 1,7-dihydro-, Purine-6-ol, 6,7-dihydro-3H-purin-6-one, DTXSID8045983, CHEBI:17368, 2TN51YD919, NSC-14665, DTXCID6025983, NSC14665, RefChem:789621, 200-697-3, 1h-purin-6-ol, 1,9-dihydro-6H-purin-6-one, 1,7-Dihydro-6H-purine-6-one, 3,7-dihydropurin-6-one, 1H-Purin-6-ol (9CI), 6H-Purin-6-one, 1,9-dihydro-

Molecular formula
C5H4N4O
Empirical formula
C5H4N4O
Molecular weight
136.11 g/mol
Exact mass
136.03851
CAS number
68-94-0
PubChem CID
135398638
Canonical SMILES
C1=NC2=C(N1)C(=O)NC=N2
Isomeric SMILES
C1=NC2=C(N1)C(=O)NC=N2
InChI
InChI=1S/C5H4N4O/c10-5-3-4(7-1-6-3)8-2-9-5/h1-2H,(H2,6,7,8,9,10)
InChIKey
FDGQSTZJBFJUBT-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Calculated

Heavy atoms
10
Rings
2
Aromatic rings
2
Fraction sp³ carbons (Fsp3)
0
H-bond donors
2
H-bond acceptors
3
Rotatable bonds
0
TPSA (Ų)
74.4 computed here · PubChem 70.1
Formal charge
0
XLogP3
-0.5 PubChem
Complexity
190 PubChem
Stereocenters
None
Double-bond geometry
None specified
Point group
Cs of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

  • C44.12%
  • H2.96%
  • N41.16%
  • O11.75%

Isotope pattern

100%136.0387.0%137.041138.043

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
-0.35 Crippen (Wildman and Crippen 1999)
log S (water solubility)
-1.13 ESOL (Delaney 2004), log mol/L
Synthetic accessibility
3.1 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

  • Molecular weight ≤ 500: 136.11
  • log P ≤ 5 (Crippen): -0.35
  • H-bond donors ≤ 5: 2
  • H-bond acceptors ≤ 10: 3

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: 10 company reports to ECHA. Source [1].

  • Harmful or irritant
  • H315Causes skin irritation (40% of reports)
  • H319Causes serious eye irritation (40% of reports)
  • H335May cause respiratory irritation (40% of reports)

Precautionary statements: P261, P264, P264+P265, P271, P280, P302+P352, P304+P340, P305+P351+P338, P319, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501

View all classifications (2)
  • [1] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 60% (6 of 10) of all reports.
  • [1] European Chemicals Agency (ECHA) · 10 reports · WarningH315, H319, H335

Safety data sheets on the supplier’s page: AKos Consulting & Solutions, Alfa Chemistry, Enamine.

Always read the supplier’s safety data sheet before working with it.

Spectra

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. [1]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
  2. [2]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
  3. [3]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
  4. [4]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
  5. [5]MassBank Europe · Linked only · via PubChem · retrieved 2026-10-14
  6. [6]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
  7. [7]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
  8. ·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
  9. ·Literature on PubChem

Data last updated 2026-10-14.