Structures Systems Derwent

Whatever the search software offered, however, the database was of utmost importance. The DARC system not only offered a means to search generic structures in the short term, it also offered a way to record all of the information about structures found in patents, through a new and flexible input system. This capability was of incredible import to Derwent we could build a database that would not only serve the users today, but in future could be of more utility as search software was further developed. As opposed to the fragmentation code, there should never be a question of time-ranging. Moreover, though we assume that Markush DARC is a system not only of today but of tomorrow, we are building a database that can be converted and adapted to other search systems that may be offered by other organisations. 

A module of the CHEM-X modelling system (see modelling section). Storage and retrieval of two- and three-dimensional structures with substructure-search capability. Available databases include Chapman Hall Dictionary of Drugs (15,000 compounds). Chapman Hall Dictionary of Fine Chemicals (120,000 small organics). Chapman Hall Dictionary of Natural Products (54,000), Derwent Standard Drug File (31,000 biologically active compounds), ChemReact (370,000 reaction types) and others. 

Recently, a series of chemical substances called functional dyes have attracted considerable attention. Because such dyes have long conjugated pi-electron systems and in many cases possess intramolecular charge transfer structures, functional dyes are expected to show interesting optical and electronic properties. Among functional dyes, phthalocyanine compounds have been extensively investigated because of their excellent physical, chemical and coloristic properties, as mentioned above. For example, about 1000 related US patents, published from 1990 onwards, are retrievable from the World Patent Index data base of Derwent, and more than 30 % of these are classified in such non-colorant applications as electrophotography, catalysis, and infrared radiation absorption. 

Secondly, chemical IR may be thought of as a specialized index into the scientific and patent literature, with the chemical structure representing an extremely condensed abstract of the journal article or patent document. In this sense, the structures are not stored for their intrinsic interest, but as pointers to other documents, some of which, for example, may be related to their synthesis, physicochemical properties and numeric data, or applications. This is the sense in which a few data vendors supply chemical and reaction databases (Derwent and Institute for Scientific Information), and the alternate sense in which the CAS databases may be used. The use of CIR systems in synthesis design - providing access, for example, to databases of reagents or starting materials, or of name reactions - provides a crucial tool for the contemporary chemical and pharmaceutical industry. 

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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