System reaction indexing

ORAC - Reaction indexing system, hardware supported DEC VAX, available from Wolfson CADOS Unit, Department of Organic Chemistry, University of Leeds, Leeds LS2 9JT, U.K. 

REACCS - Reaction indexing system for in-house use, hardware supported, DEC VAX, IBM mainframe, Prime, available from Molecular Design Limited, 2132 Farallon Drive, San Leandro, CA 94577, U.S.A. 

Program Operations. This facility performs operations necessary to start-up, command processing, and exiting MACCS-II, as weU as allowing adjustment of some of the terminal characteristics. AdditionaUy, a command is provided to invoke external processes such as MDL s reaction indexing system, REACCS or BBN Software Products Corporation s statistics program, RS/1. 

The same canonical name matching used for chemical structure retrieval systems works very well also in reaction indexing systems and provides rapid retrieval. 

With a full-featured reaction indexing system such as the Reaction Access System (REACCS), there exists a wide variety of criteria for creating such a review. Table 1... 

Research into the methods to be used in reaction indexing and their adaptation to meet user needs has led to the development of a potentially useful reaction indexing system. It uses techniques commonly available in compound-oriented chemical infoimation systems, with slight modifications, and yet presents data in a foim readily understandable by the chemists themselves. 

The results of the study indicate that the best method of searching explicit schemes in REACCS is by exhaustive enumeration and prior registration of all possible subschemes, analogous to the method adopted by the developers of CASREACT. The same conclusion may not be made for all reaction indexing systems, however both CASREACT and REACCS maintain a separate molecule registry, which hmits the growth of the database when prior registration is used. 

Chapter 5 deals with integration and standards both for a reaction indexing systems (ORAC) and for structure management software (OSAC). 

However, it emerged dining the compilation phase that most two component reaction hazard systems of this type involve a fairly obvious oxidant material as one of the reactants. Where this situation was recognised, the oxidant has normally been selected as primary (indexing) reactant, with the other as secondary reactant, following the colon. 

The major commercially available reaction indexing programs are REACCS (Molecular Design Limited), SYNLIB (started by Clark Still, developed by Smith, Kline and French and now sold by Dan Chodosh), ORAC (developed at the University of Leeds) and DARC-RMS (Telelsystemes). Pfizer s in-house system CONTRAST is noteworthy but is not available outside Pfizer. The release of CASREACT by Chemical Abstracts is awaited with interest. 

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