Dialog substructure searching

Structure searching and display software are host-specific. The Softon Substructure Search System (S4) was developed by the Beilstein Institute and Softon of Graefelfing Germany (50). It is a full structure and substructure searching module. The S4 is used in-house by the Beilstein Institute and is operated by DIALOG. STN uses CAS ONLINE s messenger software for on-line structure searching of the Beilstein on-line database (51). 

The HTSS system has been previously used for substructure searches of the Beilstein database on the Orbit online system, but this service was withdrawn in 1992 and replaced by the Dialog online system [28], which allows one to perform substructure searches of the Beilstein database using another substructure search system called S4. 

The systems analysis showed that it was important for Dialog to adopt a fully integrated subsystem that would effectively perform structure and substructure searches. Such a subsystem would permit the Dialog program to remain in control of all the communications functions to the user s terminal, but would use searching techniques that were different from those of Dialog and more appropriately suited to the handling of structure information. 

When the QS command is incorporated in a SearchSave or ALERT strategy, DIALOG changes it to QC (Query Command). QC is displayed when you RECALL or EXECUTE a saved strategy that contains a structure or substructure search. 

Four chapters on other operational substructure search systems follow. Jean Marcah and co-workers describe the Du Pont global technical information system Steve Welford and Clemens Jochum report on chemical structure registration for Beilstein Online Peter Rusch also covers Beilstein Onhne in a paper about substructure searching on Dialog and the DARC Toolkit which was described by Pascal Huguet is summarised in a chapter written by Bill Town with some suggestions from myself and Pierre Buffet of Questel. 

We would stress that CrossFire is an excellent example of this sort of interactive involvement of the end user, with practically immediate response times, but is by no means the only system attempting to provide this. However, the example is particularly relevant because of the fact that the Beilstein file under traditional access at the online hosts STN and DIALOG displays no possibility of such fluent combination of document, substance, property, and reaction views, and substructure searching can be at least an order of magnitude slower. That this is not due to an inherent deficit of online files as opposed to inhouse files is shown by the fact that many subscribers to CrossFire do use this client/server system via remote access (i.e., by the telephone system, online). Rather, it is an indication of the flexibility, immediacy, and integration... 

A number of systems now offer graphics-based substructure search capabilities for online access to a variety of chemical structure data bases. From December 1988 the first subset of the Beilstein Online data bank (organic heterocyclic compounds reported in the literature prior to 1960) goes online on STN International. Other hosts, which at present offer only name-based structure and substructure search capabilities are also likely to provide online access to the Beilstein files in the near future these include Dialog, Pergamon Orbit Infoline and Datastar. 

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