USPTO Complex Work Units

The United States Patent and Trademark Office provides additional metadata with patent grants and applications from 2001 to the present. Known as Complex Work Units (CWU), they include chemical structure .mol files as well as mathematical formulae, three-dimensional protein crystalline structure data and some table information. 

SureChEMBL adds CWU chemical structure data to its database, making it possible to retrieve US grants and applications containing these compounds. However, the quality of this data varies considerably, and includes many invalid structures. As a result, we have filtered out a considerable amount of data. For example, as of September 2012 the USPTO had issued more than 6 million .mol files as part of the CWU's, of which 4.7 million were deposited into the SureChEMBL database following filtering.