chem-similarity-search

To find structurally similar compounds, provide a SMILES string or PubChem CID to query the PubChem fastsimilarity_2d engine. The search ranks chemical analogs by 2D molecular fingerprint similarity and returns matched compounds with metadata like canonical SMILES and IUPAC names.

Yes, you can configure a custom similarity threshold and maximum record count for PubChem chemical similarity searches. This allows you to control the stringency of the 2D fingerprint matching and limit the number of ranked analogs returned for your lead optimization workflow.

PubChem similarity search results export as JSON files containing compound metadata for downstream screening. Each record includes the PubChem CID, canonical and absolute SMILES, IUPAC name, molecular formula, molecular weight, and PubChem URLs.

Yes, PubChem PUG-REST supports 2D similarity searches via the fastsimilarity_2d endpoint for lead optimization workflows. It requires HTTP access to PubChem and accepts either a SMILES string or an exact PubChem CID to generate ranked candidate analog lists.

The best way to identify chemical analogs from a known PubChem CID is to query the PubChem fastsimilarity_2d engine. It ranks related compounds by 2D molecular fingerprint similarity and outputs structured JSON with compound metadata for hypothesis generation and candidate replacement.

A limitation of PubChem 2D fast similarity for candidate search is that it requires HTTP access to the PUG-REST API. It also relies entirely on 2D molecular fingerprint matching, which may not capture full 3D pharmacological properties, and returns results bounded by your configured maximum record limit.