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Guanine

Athanor · official

C5H5N5O · 151.13 g/mol

IUPAC name: 2-amino-1,7-dihydropurin-6-one

Also called 2-amino-6-oxypurine, G, purine base

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

Names and identifiers

IUPAC name
2-amino-1,7-dihydropurin-6-one
Synonyms
2-amino-6-oxypurine, G, purine base
+ 38 more

2-Amino-6-hydroxypurine, 2-Aminohypoxanthine, Guanin, Mearlmaid, Guanine enol, Pearl essence, Stella Polaris, Dew Pearl, Naturon, Natural white 1, Natural pearl essence, 6H-Purin-6-one, 2-amino-1,7-dihydro-, 2-Amino-1,7-dihydro-6H-purin-6-one, CI Natural white 1, C.I. Natural White 1, Hypoxanthine, 2-amino-, 6-Hydroxy-2-aminopurine, 2-amino-1,7-dihydropurin-6-one, CI 75170, 2-amino-3,7-dihydropurin-6-one, C.I. 75170, DTXSID9052476, CHEBI:16235, 5Z93L87A1R, C.i. no. 75170 (guanine), 2-amino-6,9-dihydro-1H-purin-6-one, 2-amino-6,7-dihydro-3H-purin-6-one, RefChem:5874, DTXCID6031049, 200-799-8, 2-amino-1H-purin-6(7H)-one, 2-Amino-6-purinol, 2-amino-1,9-dihydro-6H-purin-6-one, 2-amino-9H-purin-6-ol, 6H-Purin-6-one, 2-amino-1,9-dihydro-, HSDB 2127, Mearlmaid AA, AI3-24393

Molecular formula
C5H5N5O
Empirical formula
C5H5N5O
Molecular weight
151.13 g/mol
Exact mass
151.04941
CAS number
73-40-5
PubChem CID
135398634
Canonical SMILES
C1=NC2=C(N1)C(=O)NC(=N2)N
Isomeric SMILES
C1=NC2=C(N1)C(=O)NC(=N2)N
InChI
InChI=1S/C5H5N5O/c6-5-9-3-2(4(11)10-5)7-1-8-3/h1H,(H4,6,7,8,9,10,11)
InChIKey
UYTPUPDQBNUYGX-UHFFFAOYSA-N
Molfile

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

Calculated

Heavy atoms
11
Rings
2
Aromatic rings
2
Fraction sp³ carbons (Fsp3)
0
H-bond donors
3
H-bond acceptors
4 computed here · PubChem 3
Rotatable bonds
0
TPSA (Ų)
100.4 computed here · PubChem 96.2
Formal charge
0
XLogP3
-1.1 PubChem
Complexity
225 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

  • C39.74%
  • H3.33%
  • N46.34%
  • O10.59%

Isotope pattern

100%151.0497.3%152.051153.053

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
-0.77 Crippen (Wildman and Crippen 1999)
log S (water solubility)
-0.9 ESOL (Delaney 2004), log mol/L
Synthetic accessibility
3.15 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

  • Molecular weight ≤ 500: 151.13
  • log P ≤ 5 (Crippen): -0.77
  • H-bond donors ≤ 5: 3
  • H-bond acceptors ≤ 10: 4

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: 115 company reports to ECHA. Source [2].

  • Harmful or irritant
  • H315Causes skin irritation (98.3% of reports)
  • H319Causes serious eye irritation (98.3% of reports)
  • H335May cause respiratory irritation (93% 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)
  • [2] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for 0.9% (1 of 115) of reports.
  • [2] European Chemicals Agency (ECHA) · 115 reports · WarningH315, H319, H335

Safety data sheets on the supplier’s page: Matrix Scientific, AbMole Bioscience, MuseChem.

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

Data last updated 2026-10-14.