Registry File - Structure Search

The following sections deal with structure searches in the Registry File. The commands are the same as for other structure databases. Particularities can be retrieved from the manual Building and Searching Structures on STN. 

There are two ways for building up a command sequence for a structure search  

The structures are drawn by means of special graphic programs and automatically converted into alphanumeric commands. Software programs which convert graphic into alphanumeric commands should be regarded critically, although they are able to facilitate structure searches especially for non-professional chemists. 

An alternative is the direct entering of alphanumeric commands and this is what experienced searchers prefer. Alphanumeric commands present a vocabulary to be learnt and which differs completely from other retrieval commands discussed here previously. 

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Retrieval of Polymer Structures, it is axiomatic that to conduct an efficient search, searchers need to know the rules of the database or file being searched. Although this article is not intended to be a teaching manual on how to search polymer files or databases, some basic differences between searching the CAS Registry File and searching an MDL database by means of the ISIS program merit discussion. 

Registry File with searching text and structures,... 

ChemIDplus. Published by the U.S. National Library of Medicine, ChemIDplus [62] is a web-based search system, http //chem.sis.nlm.nih.gov/ chemidplus/, that provides free access to structure and nomenclature authority files used for the identification of chemical substances cited in National Library of Medicine (NLM) databases. ChemIDplus also provides structure searching and direct links to biomedical resources at NLM and on the Internet. The database contains over 349,000 chemical records, over 56,000 of which include chemical structures, and is searchable by name, synonym, CAS registry number, molecular formula, classification code, locator code, and structure. 

It is not necessary to build structures to use the Registry File. Compounds can also be searched for by using names, combinations of name fragments. Registry Numbers, molecular formulas, and in other ways. The display methods are the same. 

Databases include the Beilstein File, the Gmeliu File, the Registry File, the Description. Acquisition. Retrieval, and Correlation File, and Ihc Structure and Nomenclature Search System. 

Answers from all of these searches contain CAS Registry Numbers. Answer sets may be combined, using the Boolean operators AND, OR, or NOT, with other answer sets or with text terms, such as names or molecular formulas. Any answer set also may be used to define subsets of the file for subsequent structure searching. Answer sets of up to 10,000 Registry Numbers from any type of search in this file may also be used as search terms in other files, such as the CA or CAOLD files (53). 

A number of files under the generic tide CAS ONLINE are available on-line on STN International. The system software, MESSENGER, includes chemical substructure, text, and numeric data searching facilities. Chemical structures and Registry Numbers are contained in the CA Registry file. The four ways to search the structures are EXA, FAM, SSS, and CSS. 

Structure building, manipulation, comparison. SYBYL energy minimization of organic and biomolecules. Stick, space-filling, or cylinder (thick bonds) display. Interface to Chemical Abstracts Service registry files. Molfile transfer to SYBYL and Lab Vision. ChemPrint (under Windows) for 2D chemical structure drawing. PowerSearch for systematic and Monte Carlo conformational searching under Windows environment. Macintosh and PCs (DOS and Windows). 

CAS ONLINE is Chemical Abstracts Service s computerized system that provides access to substance information from the CAS registry file. CAS ONLINE allows users to search for substances on the basis of structural units, registry number, chemical name, or molecular formula. Portions of the CAS information base are licensed by several information vendors. 

An extension of SOCRATES to handle chemical reactions, called CONTRAST, has also been developed at Sandwich, again with some collaboration from Peter Willett at Sheffield. In SOCRATES the precursors of our company compounds are stored in the compound registry file, and so application of a reaction site detection algorithm to the starting material and product generates a set of modified connection tables and fragment screens, and a set ofreaction bit-screens. The substructure search graphical structure input menu was modified to enable the chemist to identify the atoms involved in the reaction, but otherwise is essentially the same interface as in SOCRATES. 

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