Reactions Systems REACCS

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. 

At present REACCS, as well as most other in-house reaction systems, treat reaction schemes by manually identifying and registering overall steps, after each of the component steps have been registered. This method has several disadvantages ... 

FIZ Chemie = Fachinformation.szentrum Cheniie ISl = institute for Scientific Information IRDAS = ISIS reaction database access system ISIS = integrated scientific information system JSM = Journal of Synthetic Methods MACCS = molecule access system MOS = Metlwd.s in Organic Synthesis, ORAC = Organic Reaction Acce.ss by Computer REACCS = Reaction Access System SMD = standard molecular data SPORE = Solid Phase Organic Reactions, STN = Scientific and Technical Information Network SYNLIB = Synthesis Library. 

MDL Information Systems, Inc. MDL provides modular software systems for managing chemical information, as weU as related molecular and reaction databases for use with the software. MDL s database management programs, MACCS-II and REACCS, provide access to compound and reaction databases and also have the capabiHty to manage user-created databases (37). Although MDL is not considered to be an on-line database vendor, it is mentioned here because of the value of its information products and services to the chemical industry. 

Eastman Kodak has many laboratories worldwide, all with their own information departments, but the Information and Computer Technology Division in Rochester, and in particular the Application and Data Resources Unit, is responsible for the 555,000 compounds in the Chemical Registry System (under both MACCS and CAS Registry System software). There are also on file 17000 reactions under REACCS, 190,000 reports and 65,000 patents in a photographic patents index. The Chemical Information Centre holds 1,100,000 index cards, half of them in accession number order and half in molecular formula sequence. 

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 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. 

THE IMPLEMENTATION OF ATOM-ATOM MAPPING AND RELATED FEATURES IN THE REACTION ACCESS SYSTEM (REACCS)... 

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... 

REACCS, the reaction management system developed by Molecular Design Limited, effectively handles information on reactions as well as on molecules. The use of this program in environments as different as laboratories in basic research or process... 

This technique can be used to search the public literature, to retrieve the "hesV literature precedents for a desired reaction. The search question can be generally formulated as Which possibilities are available to convert starting material P into target material T Systems to answer this question are SYNLIB, ORAC and REACCS. 

Reaction-oriented searching can also be used as an in-house tool to store and retrieve company reactions. The DARC-RMS and MACCS/REACCS systems are typical examples of this usage, although SYNLIB and ORAC could alsobe used for this purpose. 

On the other hand, the data in the base file may be converted into an SMD file (Standardised Molecular Data) which is used by the companies of the CASP pool in Europe for interchanging substance and reaction data. Interfaces to commercially available reaction retrieval systems, using the SMD data structure, exist or are being developed. In this way, in-house versions of the database to be used with REACCS, ORAC, SYNLIB, etc., will be made available. 

This account of the LHASA and CAMEO programs has been necessarily very limited readers interested in further details should contact the suppliers of the software as listed in the Software appendix. Another approach to the problem of synthesis planning is to provide literature references to model reactions, thus allowing the chemist user to make his or her own assessment of feasibility, using his or her own expert system A number of reaction database systems are in common use (e.g., REACCS,... 

Similarity searching in reaction databases has gained widespread interest since it became available (in REACCS and ORAC) about two years ago. The definition of similarity of reactions in these reaction retrieval systems is based on common substructural features in the reaction centres and in the reactants. Without doubt, these definitions of reaction similarity are of great usefulness. However, we wanted to broaden the discussion of reaction similarity and search for additional helpful ideas. To achieve this we took a totally different approach to specify the similarity of reactions. Our approach is based on the idea that chemists often want to know the exact conditions for running a reaction. We assumed that similar reactions should be those that proceed under similar reaction conditions. 

This paper describes a feasibility and prototyping study of multi-step reaction sequence representation and searching, using REACCS as a starting point. The results of this study will show the benefits and costs of a few alternatives, and the utility of such a system in the hands of practising synthetic chemists. Detailed studies were carried out on probable architectures of systems which support Explicit- and First-Order Implicit schemes options for the support of Second-order Implicit schemes are described in theoretical terms only. 

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. 

Moock, T.E. Nourse, J.G. Grier, D. Hounshell, W.D. The Implementation of Atom-Atom Mapping and Related Features in the Reaction Access System (REACCS) . In Chemical Structures The International Language of Chemistry) Warr, W. A., Ed. Springer-Verlag Heidelberg, 1988 pp. 303-314. 

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