Identifier Resolution

ChemAudit's universal identifier resolver converts any chemical identifier into a canonical SMILES structure with cross-database linking. It supports 10+ identifier types with automatic detection.

Supported Identifier Types

Type	Example	Detection Pattern
SMILES	CCO, C[C@H](N)C(=O)O	Valid SMILES characters
InChI	InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3	Starts with InChI=
InChIKey	LFQSCWFLJHTTHZ-UHFFFAOYSA-N	27-character pattern with hyphens
PubChem CID	702	Numeric, resolved via PubChem
ChEMBL ID	CHEMBL545	Starts with CHEMBL
CAS Number	64-17-5	Digit-digit-digit pattern
DrugBank ID	DB00898	Starts with DB
ChEBI ID	CHEBI:16236	Starts with CHEBI:
UNII	3K9958V90M	10-character alphanumeric
Wikipedia URL	https://en.wikipedia.org/wiki/Ethanol	Wikipedia URL pattern
Compound name	aspirin, caffeine	Fallback — resolved via PubChem/OPSIN

How It Works

1. Auto-detection: The identifier type is automatically detected from the input pattern
2. Resolution chain: The resolver follows a chain of lookups to convert the identifier to SMILES
3. Cross-references: After resolution, UniChem and database APIs are queried to populate cross-references (PubChem CID, ChEMBL ID, DrugBank ID, ChEBI ID, KEGG ID)

Resolution Sources

Different identifier types use different resolution sources:

• SMILES/InChI/InChIKey: Direct RDKit conversion or UniChem lookup
• PubChem CID: PubChem PUG REST API
• ChEMBL ID: ChEMBL API
• CAS/DrugBank/ChEBI/UNII: UniChem cross-reference service
• Wikipedia URL: Wikidata SPARQL query
• Compound names: PubChem name resolution, then OPSIN as fallback

Using the Web Interface

The Identifier Resolver card appears on the Database Lookup tab of Single Validation:

1. Enter any supported identifier in the resolver input field
2. The identifier type is auto-detected and shown
3. Click Resolve (or it resolves automatically)
4. View results:
   • Resolved canonical SMILES
   • InChI and InChIKey
   • Molecular formula and weight
   • IUPAC name
   • Resolution source and chain
   • Cross-references with links to external databases

The resolved SMILES can be used directly for validation by clicking Validate This Structure.

API Reference

Resolve Identifier

curl -X POST http://localhost:8001/api/v1/integrations/resolve \
  -H "Content-Type: application/json" \
  -d '{
    "identifier": "CHEMBL25",
    "identifier_type": "auto"
  }'

Field	Type	Required	Description
identifier	string	Yes	The identifier to resolve
identifier_type	string	No	auto (default), or specify: smiles, inchi, inchikey, pubchem_cid, chembl_id, cas, drugbank_id, chebi_id, unii, wikipedia, name

Response:

{
  "resolved": true,
  "identifier_type_detected": "chembl_id",
  "canonical_smiles": "CC(=O)Oc1ccccc1C(=O)O",
  "inchi": "InChI=1S/C9H8O4/c1-6(10)13-8-5-3-2-4-7(8)9(11)12/h2-5H,1H3,(H,11,12)",
  "inchikey": "BSYNRYMUTXBXSQ-UHFFFAOYSA-N",
  "molecular_formula": "C9H8O4",
  "molecular_weight": 180.16,
  "iupac_name": "aspirin",
  "resolution_source": "chembl",
  "resolution_chain": ["chembl_id → ChEMBL API → SMILES"],
  "cross_references": {
    "pubchem_cid": 2244,
    "chembl_id": "CHEMBL25",
    "drugbank_id": "DB00945",
    "chebi_id": "CHEBI:15365",
    "kegg_id": "D00109"
  }
}

If the identifier cannot be resolved:

{
  "resolved": false,
  "identifier_type_detected": "unknown",
  "canonical_smiles": null,
  "resolution_source": null,
  "resolution_chain": ["Unable to detect identifier type"]
}

import requests

# Resolve a ChEMBL ID
response = requests.post(
    "http://localhost:8001/api/v1/integrations/resolve",
    json={"identifier": "CHEMBL25"}
)
result = response.json()
if result["resolved"]:
    print(f"SMILES: {result['canonical_smiles']}")
    print(f"Source: {result['resolution_source']}")
    print(f"Cross-refs: {result['cross_references']}")

# Resolve a CAS number
response = requests.post(
    "http://localhost:8001/api/v1/integrations/resolve",
    json={"identifier": "50-78-2"}
)

# Resolve a compound name
response = requests.post(
    "http://localhost:8001/api/v1/integrations/resolve",
    json={"identifier": "ibuprofen"}
)

Rate Limits

Endpoint	Limit
POST /integrations/resolve	30 req/min

Next Steps

• Database Integrations — Full database lookup and comparison
• Single Validation — Validate resolved structures
• IUPAC Conversion — Name-to-SMILES conversion