Reactions CASREACT

CASREACT The CASREACT Eile (The Chemical Absiracts Reaction Search Service) is a chemical reaction database with reaction inlormatioii derived from journal documients from 1974 to the present and from patent documeiiis from 1982 to date. Thie document-based file conlains both 3 million single-step and 3.0 million multi-step reactions (Pcbiniaiy, 2003). 

CASREACT (Chemical Abstracts Reaction Search Service) is a reaction database started in 1985 with more than 6.7 million reactions (3 million single-step and 3.7 million multi-step reactions) (March, 2003) derived from 400 000 documents (journals, patents, etc.). The records contain the following information ... 

CASREACT Chemical Abstracts Service chemical reactions biblio., reaction, struc- ture >400 000 documents >6.6 mio reactions journals, patents STN commercial CD-ROM, online weekly WUW.CflS.OTg... 

Compounds are stored as connection tables (CT) in structure and reaction databases, e.g., Beilstein, Cmelin, CAS Registry, and CASREACT. 

CASREACT Database of abstracts related to reaction chemistry, including hazard/safety information American Chemical Society (Chemical Abstract Service)... 

CASREACT is a structure and text-searchable organic chemical reaction database containing more than 17 million single- and multistep reactions with more than six hundred thousand records from journal articles and patents with reaction information. Coverage is from 1840 to the present. 

CASREACT Reaction information for single- and multiple-step reactions from 1840 to the present. 

CASREACT . 1840-. Columbus, OH Chemical Abstracts Service. Weekly. Contains single-step and multistep reaction information from journals and patent documents. Information consists of structure diagrams for reactants and products, CAS Registry numbers for all compounds listed, textual reaction information. Available online. 

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. 

CASREACT is in a different league - 170,000 reactions are being abstracted every year. It is an interesting question how many reactions a user needs in a selective database. The critical question is whether there are redundant examples. The only way of pruning a database is to remove similar extraneous examples. 

Chemical Abstracts Service (CAS) has created a protocol for machine generation of multi-step reactions within a document from the single-step reactions which are input. This protocol is being used in the CASREACT database for both explicit and imphed multi-step reactions. Both the input data and the output are described. Special features of this tool include ... 

It is planned to produce an online version of the database, which will be implemented on STN International. For this purpose, a data file in standard format that can be used under Messenger software will be derived from the base file. (Stereochemical information will be kept in this file, even though Messenger cannot handle this information at present). The enhancements to Messenger developed at CAS for CASREACT, the online reaction retrieval system developed by CAS, will also be used for this database. The display capability of Messenger will, in this configuration, also allow for the display of the whole (multi-step) reaction schemes. 

Bob Dana and colleagues at Chemical Abstracts Service presented a poster on the machine generation of multi-step reactions for the CASREACT system on STN International. The online version of FIZ s Cheminform database will be available on STN International also. Alex Parlow gave a poster presentation on the creation of Cheminform both as an electronic database (for onhne and in-house use) and as a printed product. 

Blake JE, Dana RC (1990) CASREACT more than a million reactions. J Chem Inf Comput Sci 30 394-399 Cheminform (2010)41(01)... 

Other useful databases available from STN include Beilstein and CASREACTS. As described in Section 29.10, Beilstein is very useful to organic chemists. Currently, there are more than 3.5 million compounds listed in the database. You can use the CAS Numbers to help in a search that has the potential of going back to 1830. CASREACTS is a chemical reactions database derived from over 100 journals covered by Chemical Abstracts, starting in 1985. With this database, you can specify a starting material and a product using the CAS Numbers. Further information on CA Online, Beilstein, CASREACTS, and other databases can be obtained from the following references ... 

SciFinder. SciFinder is an interface to the Chemical Abstracts family of databases. The CAPLUS file is the equivalent to the printed Chemical Abstracts from 1907 to the present. The Registry file of chemical substances is described above. CASREACT is a file of single- and multistep organic reactions drawn from selected organic journals. SciFinder provides a user-friendly, graphical interface that permits searching by topic, author, chemical structure, and substructure. Search results can be refined, analyzed, and displayed in a number of ways. SciFinder also provides links to the electronic full text of many papers. 

The first commercial computer system to store, search and retrieve reaction schemes was ChemBase (see Figure 1). ChemBase could represent and display linear schemes, but was limited in its ability to perform scheme-oriented structure searches (see below). The Chemical Abstracts Service (CAS) has announced the availability of their reaction file (CASREACT)," organised with reaction schemes in mind. Although at present the scheme searching capabilities available at the user interface are limited, CASREACT appears to represent schemes in a more rigorous manner internally, allowing further user interface refinements in the future. 

The developers of CASREACT have pubhshed methods of assigning and searching both reaction centres and explicit reaction schemes. At the time of writing its user interface does not allow the assignment of atom mappings or reaction centres. CASREACT also can retrieve false hits where the direction of the arrow is reversed, similar to the limitation in ChemBase. Improvements in its user interface may resolve some of these limitations. 

The developers of CASREACT chose the former method. For a given sequence of reactions, the challenge is to register each single step, then enumerate and register all possible transformations between each pair of components. Figure 6 illustrates this process and how it was accomplished in this study. 

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. 

CASREACT includes single-step and multi-step reactions from journals and patents indexed in the Organic Sections of CA (Sections 21-34). Organometallic and Organometal-loidal Compounds, Section 29, is included. Physical Organic Chemistry, Section 22, is included from Volume 113 to the present. The reaction information is from journals covered for CA from 1985 to the present and patents covered for CA from January, 1991 to the present. There are more than 156 800 documents (2/97), more than 1.36 million single-step reactions (2/97), more than 1.98 million multistep reactions (2/97) in the database which is updated weekly with 600-1300 new reactions in 250-10(X) new records. 

Functional groups are a precise, well established way of describing the important components involved in a reaction. CAS has analyzed all single step reactions on the CASREACT reaction database in terms of functional group transformations (see Reaction Databases). 

This analysis is both an exhaustive index to the database and a highly descriptive summary of the reaction classes in the CASREACT database. This can be equally useful as a learning tool, helping the chemist to discover unexpected relationships. As an index, the analysis offers an alternative and complementary approach to traditional substructure-based reaction... 

Famous examples of reaction databa.ses are CASREACT, Chemreact, and ChemInformRX, all online on STN. None of the reaction databases covers the whole chemical literature, and furthermore there arc time periods that are not included in any of the available databases. ... 

The CrossFire file is by far the world s largest collection of synthetic information, containing details of ca. 10 million reactions. Other large or medium-sized files include Casreact (CAS), Cheminform (FIZ-Chemie), Chemreact (Springer/Info-Chem), and various data compilations from Derwent. 

Casreact has over 140000 document records with more than 1 million reactions. It contains information on reactions of organic substances, including organometallics and biomolecules, and single- and multi-step reaction information for reactants, products, reagents, solvents, and catalysts. 

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