moleculefinder

Phenobarbital

C12H12N2O3232.23 g/mol Calculated

Also called phenylethylbarbiturate, luminal, phenobarbituric acid and phenobarbitone.

The oldest anticonvulsant still in wide use, more than a century old, and still on the WHO essential medicines list for seizures.

Sources and notes
  • The introductionfrom sourceMoleculeFinder curated
  • Other namesfrom sourceWikidataIts English label and aliases on Wikidata.
  • Formula and weightcomputedPubChem
  • 2D drawingcomputedPubChem structure, drawn by RDKit
  • 3D modelfrom sourcePubChem 3D conformerLoaded after the page has painted, and on a phone only when you ask for it; the 2D drawing shows until it arrives.

Where you encounter it

Dispensed on prescription, not sold on a shelf.

Sources and notes
  • The line abovefrom sourceMoleculeFinder curatedFrom the group the molecule belongs to.

Explore its structure

Choose a part to light it up.

A ring of four carbons and two nitrogens carrying three C=O groups, the ring every barbiturate is built on. The two groups on its one carbon with no oxygen are what tell one barbiturate from another.

From: standard chemistry (pyrimidine-2,4,6-trione, barbituric acid's ring).

Sources and notes
  • The drawingcomputedPubChem structure, drawn by RDKitThe page's one shipped drawing, with the chosen part lit in amber under it.
  • The partscomputedFound by ruleEach part is found by a chemical pattern, never picked by hand atom by atom; its words say where they come from.

Properties and sources

Calculated by PubChem

Molecular formula
C12H12N2O3
Molecular weight
232.23 g/mol
XLogP3octanol/water, log units
1.5
Polar surface areatopological
75.3 Ų
H-bond donors
2
H-bond acceptors
3
Rotatable bonds
2
Complexity
339

Measured LD50, HSDB via PubChem

660 mg/kg pure phenobarbital, rat, oral

An LD50 is an animal study measurement, not a dose for a person.

Reported Hazard label (GHS), ECHA via PubChem

Danger Toxic pictogram (GHS06), Irritant pictogram (GHS07) and Health hazard pictogram (GHS08); hazard statements H301, H317, H351, H360

Reported Licence

The US Food and Drug Administration licenses Phenobarbital for human use (NDA 215910, authorized November 17, 2022), as Sezaby. Drugs@FDA

Groups it belongs to

Category
Prescription medicine
Family
Barbiturates
Chemical groups
Aromatics, Amides
Elements
Nitrogen
Hazard classes
Acutely toxic, Irritant, Health hazard, GHS Danger
SMILESCCC1(C(=O)NC(=O)NC1=O)C2=CC=CC=C2

PubChem CID 4763 · Wikidata Q407241 · InChIKey DDBREPKUVSBGFI-UHFFFAOYSA-N · Data refreshed

How MoleculeFinder sources and labels its data

Questions
What is Phenobarbital?
The oldest anticonvulsant still in wide use, more than a century old, and still on the WHO essential medicines list for seizures.
How toxic is Phenobarbital?
The reported LD50 of Phenobarbital is 660 mg/kg (rat, oral). An LD50 is an animal study measurement, not a dose for a person. Its GHS hazard label carries the signal word Danger and the hazard pictograms Toxic, Irritant and Health hazard. from sourcefrom source
What kind of molecule is Phenobarbital?
Phenobarbital has the formula C12H12N2O3 and a molecular weight of 232.23 g/mol. MoleculeFinder files it under barbiturates, in the prescription medicine group. from sourcefrom sourcefrom sourcefrom source
What else is Phenobarbital called?
Phenobarbital is also called phenylethylbarbiturate, luminal, phenobarbituric acid and phenobarbitone. from source
Who licenses Phenobarbital as a medicine?
The US Food and Drug Administration licenses Phenobarbital for human use (NDA 215910, authorized November 17, 2022), as Sezaby. from source
Sources and notes
  • Calculated valuescomputedPubChemComputed from the structure, so no laboratory conditions apply; complexity is PubChem's own structural score.
  • LD50from sourceHSDB via PubChemOther values the sources report: rat, another route, 151 mg/kg; rat, another route, 200 mg/kg. The page shows the one LD50 the site uses everywhere.
  • Hazard labelfrom sourceECHA via PubChemThe label combines these classifications.
  • ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
  • Licencefrom sourceDrugs@FDARead 2026-10-21.
  • Data refreshedfrom sourceMoleculeFinder2026-11-09

Keep exploring

Also a barbituratePentobarbitalC11H18N2O3Also a barbiturateAmobarbitalC11H18N2O3Both carry an amide group.PhenytoinC15H12N2O2
Sources and notes
  • The same kind of moleculefrom sourceMoleculeFinder curated groupsA structural neighbour in the same family or type group; the line names the group in its own words.
  • Similar in shapecomputedRDKit Morgan/TanimotoNeighbours by structural fingerprint; the sentence names the chemical groups the two share.
  • The drawingscomputedPubChem structures, drawn by RDKit