MolDraw › Chemistry tools › Structure to IUPAC Name

Structure to IUPAC Name Generator

Draw a molecule in the editor (or paste SMILES) and get its systematic IUPAC name, molecular formula and PubChem record. Stereochemistry you draw (wedges, E/Z) is included in the name.

Quick answer: draw the structure, then click Get IUPAC name. For example, the structure of aspirin returns 2-acetyloxybenzoic acid.

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Draw a structure or paste SMILES, then click Get IUPAC name.
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How to use the structure to iupac name

  1. Draw the molecule in the editor using the bond and atom tools, or type a SMILES string into the box.
  2. The SMILES updates as you draw, and after a short pause the name is looked up automatically. You can also click Get IUPAC name.
  3. Read the IUPAC name, molecular formula and molecular weight. Follow the PubChem link for properties, synonyms and safety data.
  4. Click Open in MolDraw editor to keep working on the structure, add it to a reaction scheme or export an image.

Worked examples

Aspirin

CC(=O)Oc1ccccc1C(=O)O

2-acetyloxybenzoic acid

(E)-crotonic acid

C/C=C/C(=O)O

(E)-but-2-enoic acid

The E descriptor comes from the double-bond geometry you draw.

Ibuprofen

CC(C)Cc1ccc(cc1)C(C)C(=O)O

2-[4-(2-methylpropyl)phenyl]propanoic acid

How the IUPAC name is generated

The editor converts your drawing to a SMILES string. That string is sent to PubChem, which standardises the structure and returns the IUPAC name it has computed for that compound (PubChem holds over 100 million compounds). Stereochemistry in the drawing is preserved. If the exact stereoisomer is not in PubChem, the tool retries without stereo and tells you, so you can add R/S or E/Z yourself.

Limitation: automatic naming works for compounds that exist in PubChem. Brand-new structures from your own synthesis may return no name; then use the rules below, or name a close analogue and adapt it.

Naming an organic compound by hand (short version)

  1. Find the principal functional group (carboxylic acid > ester > amide > nitrile > aldehyde > ketone > alcohol > amine). It sets the suffix: -oic acid, -al, -one, -ol…
  2. Choose the parent chain or ring that contains that group and is longest: meth-, eth-, prop-, but-, pent-, hex-…
  3. Number the chain so the principal group, then multiple bonds, then substituents get the lowest locants.
  4. Name substituents in alphabetical order with locants (2-methyl, 4-chloro), using di-, tri- for repeats.
  5. Add stereodescriptors (R/S, E/Z) in front.

Already have a SMILES string? Use the SMILES to IUPAC name converter. For the reverse direction use IUPAC name to SMILES.

Need publication-quality structures? MolDraw is a free online ChemDraw alternative with templates, reactions and image export.

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Frequently asked questions

How do I get the IUPAC name from a structure?

Draw the structure in the editor on this page or paste its SMILES. The tool looks up the systematic IUPAC name from PubChem and shows it with the formula and molecular weight.

Is this IUPAC name generator free?

Yes. It runs in your browser with the free MolDraw editor and public PubChem data. No sign-up is needed.

Does it include stereochemistry?

Yes. Wedge bonds and double-bond geometry are encoded in the SMILES and returned as R/S and E/Z in the name when PubChem has that stereoisomer.

Why do I get 'No IUPAC name found'?

PubChem can only name structures in its database. Check for drawing errors such as wrong valences or missing charges. A genuinely new compound has to be named by hand.

Can I get a name from a picture of a structure?

Not directly. Redraw the structure in the editor (it takes seconds for most molecules) or convert the image to SMILES first.

What is the difference between an IUPAC name and a common name?

An IUPAC name is systematic and describes the structure (2-acetyloxybenzoic acid). A common or trade name such as aspirin is shorter but carries no structural information.

Related chemistry tools

Build a MoleculeRelated toolSMILES to IUPAC nameConvert SMILES to a systematic nameIUPAC name to SMILESName to SMILES and structureStructure to SMILESDraw and copy SMILESSMILES to structureDraw a structure from SMILESMolecular weight calculatorFormula to g/mol with % compositionLewis structure generatorLewis dot structures and VSEPR shapeChemical reaction drawerDraw reaction schemes onlineExact mass calculatorMonoisotopic mass for MS

Need to sketch molecules for a report? Draw chemical structures online with MolDraw, a free online ChemDraw alternative (see the ChemDraw vs MolDraw comparison).