Beilstein Preferred (BPR)



The Beilstein Preferred RN is the single CAS Registry Number that has been selected as the best choice for a compound from the one or more RNs that may be present in the database. The BPR is, however, not always present and is selected according to the following criteria:


1.    If there is only one RN available from all sources, this will also be BPR.

2.    Some compounds have one or more Registry Numbers that have been assigned by CAS in Columbus. If Beilstein has one of these Registry Numbers on record in its file, this RN will be the BPR. If, however, Beilstein has different Registry Numbers in its file, the compound will not be given a BPR and only the CAS supplied numbers will appear in the RN field.

3.    If a compound has not received a Registry Number from CAS and Beilstein has several RNs in its file, these RNs will appear in the compound record, but no BPR will be given.


Type of Indexing:

string (phrase)


Tips and Hints:

When searching for CAS Registry Numbers, it is recommended to first use the BPR field, which contains unique Registry Numbers. If the search results in no hits, then one should search in the RN field.