Storage and retrieval of generic chemical structure representations

Abstract

An information retrieval system for storing and searching Markush formulations is described. All implicit specific structures (ISSRs) of the Markush formulation are stored as a specific multiple-connectivity node representation (SpMCN) by allowing the appropriate atoms to expand beyond their normal valance and accommodate all substituents of the Markush structure. The SpMCN is simplified by using a generic group hierarchy to reduce common structural features to an associated generic multi-connectivity node representation (GnMCN) that contains within it implicit generic structures (IGSRs) corresponding to each ISSR. Attributes such as ring size and hetero atom identification are also associated with each generic feature whenever possible. The SpMCN and GnMCN are further simplified by storing their associated structural characteristics as bit strings. To search the stored Markush formulations, a query structure is reduced to its generic structure, attributes, and associated structural characteristic bits strings. The bits strings are compared with the bit strings of the stored structures to eliminate stored structures without the requisite structural features. The generic structure and attributes of the query and remaining stored structures are then compared on a group by group basis and additional structures are thereby eliminated from the search. Finally the specific structure of the query is compared with the specific structures of the remaining stored structures to determine more precisely if there is a match. Reference data, such as patent numbers, are then retrieved for the matched structures.