Questel DARC

Description, Acquisition, Retrieval, and Correlation File. This is the only other pubhc substmcture search system, apart from CAS Online, that provides full access to the CAS Chemical Registry File. The DARC file, commercially available on-line from Telesystems-Questel, offered the first pubhc on-line implementation of substmctural searching of the CAS Chemical Registry System. The advantages and disadvantages of the CAS Online and DARC systems have been discussed (49). 

PharmSearch. Institut National de Propriete Industrielle, Paris. Pharmaceutical patents indexed by INPI, the French Patent Office, with chemical structures searchable in the Mar-kush DARC system on Questel-Orbit. Abstracts, bibliographic information, and proprietary indexing from one patent per family. PharmSearch shares the topological chemical structure... 

DARC - Chemical information system for online and in-house use, available from Telesystemes Questel, 83-85, bd Vincent-Auriol, 75013 Paris, France. 

A number of commercial systems that were available at the time were evaluated. Several failed to meet all criteria, due to a lack of U.S. installations and/or U.S.-based system support groups. Those that failed were DARC/Questel, Telesystemes, Paris, France the NIH-EPA Chemical Information System CHEMPIX, developed by Moreaux of Roussel-Uclaf and marketed by Chemical Information Management Inc. and SYNLIB, marketed by Smith Kline Beckman. The Upjohn COUSIN system, developed by Dr J Howe, was not commercially available. Chemical Abstracts Service (CAS) private file support was considered too expensive. Security with the CAS file was also a concern of MSDRL since it could not be brought in-house. 

The structures of the Beilstein compounds are stored in connection tables (CT s) to allow a very flexible structure and substructure search. Since most commercially available structure/substructure handling programs such as MACCS (MDL) or DARC (Telesystemes/Questel) work on the basis of CT s, the Beilstein Registry Connection Table (BRCT) can be easily adapted for in-house systems. 

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. 

Markush DARC (MDARC) is commercially available on the Questel online system, and contains two databases World Patents Index Markush (WPIM), produced by Derwent Information, Ltd. and Markush Pharmsearch (MPHARM), produced by Institut National de la Ptopriete Industrielle (INPI, the French patent office). The initial development of MDARC was a collaboration between Questel and INPI. This development was later Joined by Derwent with commercial implementation in 1987. 

Schmuff has published a comparison of MARPAT and Markush DARC software. To generalize, at this stage both commercially available systems have similar capabilities in terms of retrieval and overall functionality. Both systems have the ability to represent in their databases and queries generic nodes typical of Markush structures in patents. Both systems have translation capabilities between generic node.s and specific nodes in database records and queries, and both systems have the ability to highlight elements in the database record that caused the retrieval. The similarities no doubt reflects the Sheffield connection, which both Questel and STN supported, but also the demands the patent searching community, which the developers of both systems consulted with extensively. 

Apart from MARPAT there is another database describing Markush structures, it is the Markush system of Derwent in combination with the database PHARMPAT of the Institut National de la Propriete, which is offered exclusively by the host QUESTEL, where it is searchable using the Markush-Darc system. Markush-Darc is a joint venture by Derwent Publications Ltd., the Institut National de la Propriete Industrielle and QUESTEL. It has been available since 1989 online and contains two files ... 

QUESTEL and STN are the only hosts providing the graphic structure search using the Generic DARC System. Under the same command mode Derwent s Markush Dare file, containing the Markush structures is available. Regrettably, there is no nomenclature file text on QUESTEL which would allow searches for substance names und molecular formulae. 

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