Barbituric acid
Athanor · official
C4H4N2O3 · 128.09 g/mol
IUPAC name: 1,3-diazinane-2,4,6-trione
Also called malonylurea, pyrimidinetrione, barbiturate core
WarningCauses skin irritation · Causes serious eye irritation · May cause respiratory irritationNames and identifiers
- IUPAC name
- 1,3-diazinane-2,4,6-trione
- Synonyms
- malonylurea, pyrimidinetrione, barbiturate core
+ 38 more
Malonylurea, Pyrimidinetrione, 2,4,6(1H,3H,5H)-Pyrimidinetrione, pyrimidine-2,4,6(1H,3H,5H)-trione, Pyrimidinetriol, 2,4,6-Trioxohexahydropyrimidine, Barbiturate, DTXSID8020129, CHEBI:16294, WQ92Y2793G, NSC-7889, DTXCID20129, 4,6-dihydroxy-2,5-dihydropyrimidin-2-one, CHEBI:29745, RefChem:116475, CHEBI:22693, 200-658-0, 6-Hydroxyuracil, 1,3-diazinane-2,4,6-trione, 2,4,6-Trihydroxypyrimidine, 2,4,6-Pyrimidinetrione, Hexahydropyrimidine-2,4,6-trione, Malonylharnstoff, Barbitursaeure, Fluorouracil EP Impurity A, Barbituric acid (VAN), Hydrouracil, 6-hydroxy-, 2,4,6-Pyrimidinetrione(1H,3H,5H), Urea, N,N'-(1,3-dioxo-1,3-propanediyl)-, MFCD00006666, 1,2,3,4,5,6-Hexahydro-2,4,6-pyrimidinetrione, NSC 7889, 1,3,5-trihydropyrimidine-2,4,6-trione, EINECS 200-658-0, barbituric, Barbitursaure, UNII-WQ92Y2793G, AI3-02724
- Molecular formula
- C4H4N2O3
- Empirical formula
- C4H4N2O3
- Molecular weight
- 128.09 g/mol
- Exact mass
- 128.02219
- CAS number
- 67-52-7
- PubChem CID
- 6211
- Canonical SMILES
- C1C(=O)NC(=O)NC1=O
- Isomeric SMILES
- C1C(=O)NC(=O)NC1=O
- InChI
- InChI=1S/C4H4N2O3/c7-2-1-3(8)6-4(9)5-2/h1H2,(H2,5,6,7,8,9)
- InChIKey
- HNYOPLTXPVRDBG-UHFFFAOYSA-N
- Molfile
Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.
Physical properties
- Appearance
- Dry Powder[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
- 9
- Rings
- 1
- Aromatic rings
- 0
- Fraction sp³ carbons (Fsp3)
- 0.25
- H-bond donors
- 2
- H-bond acceptors
- 3
- Rotatable bonds
- 0
- TPSA (Ų)
- 75.3
- Formal charge
- 0
- XLogP3
- -1.5 PubChem
- Complexity
- 168 PubChem
- Stereocenters
- None
- Double-bond geometry
- None specified
- Point group
- C2v of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)
Elemental analysis
- C37.51%
- H3.15%
- N21.87%
- O37.47%
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
- -1.26 Crippen (Wildman and Crippen 1999)
- log S (water solubility)
- 0.16 ESOL (Delaney 2004), log mol/L
- Synthetic accessibility
- 2.63 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)
Drug-likeness: Lipinski’s rule of five
- Molecular weight ≤ 500: 128.09
- log P ≤ 5 (Crippen): -1.26
- 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: 168 company reports to ECHA. Source [2].
- Harmful or irritant
- H315Causes skin irritation (63.1% of reports)
- H319Causes serious eye irritation (63.7% of reports)
- H335May cause respiratory irritation (61.9% 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 35.7% (60 of 168) of reports.
- [2] European Chemicals Agency (ECHA) · 168 reports · WarningH315, H319, H335
Safety data sheets on the supplier’s page: CAPOT, ChemDiv, Clearsynth.
Always read the supplier’s safety data sheet before working with it.
Spectra
- NMRNMRShiftDB
- 1H NMRSpectraBase (BRUKER AC-300)
- 13C NMRSpectraBase
- 15N NMRSpectraBase
- GC-MSHuman Metabolome Database (HMDB) (EI-B · positive) · Human Metabolome Database (HMDB) (GC-MS) · MassBank of North America (MoNA) (HITACHI M-80 · EI-B · positive) · MassBank of North America (MoNA) (GC-MS) · NIST Mass Spectrometry Data Center · NIST Mass Spectrometry Data Center
- LC-MSMassBank Europe (Thermo Scientific Q-Exactive Focus · LC-ESI-ITFT · NEGATIVE) · MassBank Europe (Thermo Scientific Q-Exactive Focus · LC-ESI-ITFT · NEGATIVE) · MassBank Europe (Thermo Scientific Q-Exactive Focus · LC-ESI-ITFT · NEGATIVE) · MassBank Europe (Thermo Scientific Q-Exactive Focus · LC-ESI-ITFT · NEGATIVE) · MassBank Europe (Thermo Scientific Q-Exactive Focus · LC-ESI-ITFT · NEGATIVE) · MassBank Europe (Thermo Scientific Q-Exactive Focus · LC-ESI-ITFT · NEGATIVE)
- Other MSMassBank Europe (HITACHI M-80 · EI-B · POSITIVE)
- 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]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
- [3]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
- [4]SpectraBase · 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]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
- [8]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.