Chemical Identifier Resolver

Getting started ...

This service works as a resolver for different chemical structure identifiers and allows one to convert a given structure identifier into another representation or structure identifier. It can help you identify and find the chemical structure if you have an identifier such as an InChIKey. You can either use the resolver web form above or use the following simple URL API scheme:

https://cactus.nci.nih.gov/chemical/structure/"structure identifier"/"representation"

Example: Chemical name to Standard InChIKey:

https://cactus.nci.nih.gov/chemical/structure/aspirin/stdinchikey

The service returns the requested new structure representation with a corresponding MIME-Type specification (in most cases MIME-Type: "text/plain"). If a requested URL is not resolvable for the service an HTML 404 status message is returned. In the (unlikely) case of an error, an HTML 500 status message is generated. Note: Triple bonds in SMILES strings represented by '#' have to be URL-escaped as '%23' (e.g. the SMILES string of ethyne has to be specified as 'C%23C' instead of 'C#C' if encoded as part of a URL). Similarly, question marks, which can occur in InChI, need to be URL-escaped as %3F.