Search on STN for Substances with Zero References

To learn more about a substance in CAS REGISTRYSM that does not have any literature or patent references in an STN® database, consult the following fields:

  • Source of Registrations (SR)

    For CAS Registry Numbers® 97314-93-7 and higher, the SR field indicates the reason for first registering the substance. You can EXPAND or SEARCH the content of the SR field.

  • Class Identifier (CI)

    For substances registered to support CAS registration policies, the CI field may provide additional insights as to why the substance was registered.

 

Examples of substances in REGISTRY without any literature or patent references in an STN database.

The substance was initially registered

And the SR (and CI) field contains

Then the substance is

To find additional information

To support CAS registration policies

SR:  CA
CI: COM








SR: CA Index GuideTM or Ring Systems Handbook *

CI: RPS
SR: GENBANK®

A component of a multicomponent substance such as a copolymer, salt, or mixture






A ring parent, i.e., the main ring system excluding substituents

A translated protein from GenBank

Search the CAS Registry Number in the Component Registry Number (/CRN) field to retrieve the multicomponent substances containing this component. Many of these multicomponent substances will have references.

Display the Ring System Data information, i.e., D RSD, to obtain the Ring Identifier (RID) for the ring system, e.g., 7086.54.2.  Search the first two parts of the RID in the /RID field to obtain substance(s) containing the ring system.  Many of the compounds containing ring systems will have references.

Use the SEQLINK EXACT command to locate the CAS Registry Numbers for all sequences with the same backbone.  Use the CAS Registry Numbers for comprehensive retrieval of associated references.

From chemical libraries in CHEMCATS®

SR: Chemical Library

An individual  member of a chemical library

Most of these substances are either new registrations not yet linked to CHEMCATS or substances that were removed from CHEMCATS at the suppliers request.  See the name of the supplier in the SR field.

From chemical catalogs in CHEMCATS

SR: Chemical Catalog

From a chemical catalog

Most of these substances are either new registrations not yet linked to CHEMCATS or substances that were removed from CHEMCATS at the suppliers request.  See the name of the supplier in the SR field.

From web sources

SR: Other Sources

From a web source

Contact the database supplier listed under SR.

From a reaction database

SR: Reaction Database

From processing of a reaction database

Check the LC field.

From data collections that are not represented in STN databases

SR: American Society of Hospital Pharmacists

SR: Environment Canada

SR: European Union

SR: U.S. Adopted Names Council (USAN)

SR: U.S. Environmental Protection Agency (US EPA)

SR: U.S. National Library of Medicine (NLM)

SR: World Health Organization (WHO)

Included at the request of one of these agencies

Consult the original source for any additional known information.

By CAS Client ServicesSM

SR: CAS Client  Services

Included as a request submitted to CAS Client Services

Additional information is not available.

*The CA Index Guide and Ring Systems Handbook have been discontinued.


Substances that become referenced due to REGISTRY updates

The content of the SR field reflects the reason a substance was initially registered. However, because REGISTRY is updated daily, reference information may be added for a substance that was initially registered without a reference. Here are two examples of substances initially registered from other sources. The first example does not have any associated references, while the second example is associated with a CASM/CAplusSM reference.

References not available:

Zero References

References available:

References available