What the tool does
SMILES → IUPAC name
- Checks the SMILES string and draws the 2D structure, in your browser.
- Gives the molecular formula, molar mass, canonical SMILES and InChI.
- Looks the structure up in PubChem and shows its IUPAC name and common name, with a link to the PubChem record.
Name → structure
- Converts systematic names with OPSIN, and common or trade names with PubChem.
- Draws the structure and gives the same details as above.
How names are found, and why
Naming a structure correctly is a hard problem. The IUPAC recommendations run to well over a thousand pages, covering parent chains and rings, the priority of functional groups, numbering, and stereochemistry. A simplified naming routine would give confident, wrong answers for many molecules, which is worse than no answer.
This tool therefore uses established sources instead of generating names itself.
| Step | Source |
|---|---|
| Validate and draw the structure | RDKit, running in your browser |
| Name a structure | PubChem, which computes names with OpenEye Lexichem TK |
| Read a systematic name | OPSIN, developed at the University of Cambridge and hosted by EMBL-EBI |
| Read a common name | PubChem’s name index |
As an extra check, a PubChem name is only shown if PubChem’s molecular formula matches the structure you entered.
Worked example: aspirin
Enter the SMILES CC(=O)Oc1ccccc1C(=O)O.
- Validation. RDKit reads it as a valid structure: a benzene ring bearing a carboxylic acid group and an ester group.
- Formula. C₉H₈O₄, molar mass 180.16 g/mol.
- Name. PubChem compound 2244: 2-acetyloxybenzoic acid, common name aspirin.
Common mistakes
- Unclosed rings. Every ring-opening digit needs a matching closing digit.
- Mixing aromatic and non-aromatic notation, such as writing c1ccCcc1.
- Spaces. A SMILES string cannot contain spaces.
- Expecting a name for a new structure. If a compound has never been registered in PubChem, there is no verified name to show.
Practical applications
- Checking homework and reports. Confirm a structure and its accepted name.
- Literature searches. Canonical SMILES and InChI identify a compound unambiguously across databases.
- Laboratory records. Formula and molar mass from a drawn structure.
Requirements and limitations
Drawing and analysing structures works offline once the page has loaded the structure toolkit (about 2.4 MB, downloaded the first time you use the tool). Name lookups need an internet connection and depend on PubChem and OPSIN being available; if they are not, the tool says so and still shows the structure. Names are given only for compounds in PubChem. Stereochemistry is shown when it is in the SMILES you enter.