Derwent Chemical Reactions

We are evaluating the Derwent Chemical Reactions Documentation Service as the basis of a reaction retrieval system. If Derwent succeeds in their objective of coding ca, 20,000 reactions from Theilheimer, Organic Syntheses, etc, - plus coding 4000 new reactions per year - they will create a data base which we could not hope to duplicate ourselves. 

In considering the limitions of disk storage we must further consider the data base of chemical reactions which must be available to the program We have mentioned the number 25,000 as the number of synthetic reactions now existing. This is the present size of the file of Derwent.(2) Naturally, of these 25,000 the most popular 2000 are used more than all of the rest put together. Nonetheless, many molecules of interest have something special about them so that their synthesis may require an unusual reaction. Finally we observe that there is an enormous store of literature observations about reactions which show us that such and such a reaction is inappropriate when such and such a substructure is present because the desired reaction proceeds at a slower rate than that of a side reaction. These must in principle and sooner or later in fact be incorporated into any useful reaction data base. 

Chemical Reactions Documentation Service which also includes abstracts from patents and provides the data coded on magnetic tape and punched cards as additional retrieval tools. All the abstracts in Vol. 1-30, Synthetic Methods, have been coded according to the same system, and the respective tapes or punched cards are also available from Derwent Publications. 

Science Citation Index , ISI ProceedingsSM, Reaction Citation Index, and the Derwent Innovations IndexSM. Science Citation Index is available on STN , where it is called SciSearch. We wiU begin with the older print-versions for chemical searches. 

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. 

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. 

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