Chemical Abstracts Service system

The systematic lUPAC nomenclature of compounds tries to characterize compounds by a unique name. The names are quite often not as compact as the trivial names, which are short and simple to memorize. In fact, the lUPAC name can be quite long and cumbersome. This is one reason why trivial names are still heavily used today. The basic aim of the lUPAC nomenclature is to describe particular parts of the structure (fi agments) in a systematic manner, with special expressions from a vocabulary of terms. Therefore, the systematic nomenclature can be, and is, used in database systems such as the Chemical Abstracts Service (see Section 5.4) as index for chemical structures. However, this notation does not directly allow the extraction of additional information about the molecule, such as bond orders or molecular weight. 

The WLN was applied to indexing the Chemical Structure Index (CSI) at the Institute for Scientific Information (ISI) [13] and the Ituiex Chemicus Registry System (ICRS) as well as the Crossbow System of Imperial Chemical Industries (ICl). With the introduction of connection tables in the Chemical Abstracts Service (CAS) in 1965 and the advent of molecular editors in the 1970s, which directly produced connection tables, the WLN lost its importance. 

More than 10 000 databases exist that provide a small or large amount of data on various topics (including chemistry). The contents in databases are supplied by approximately 3500 database developers (e.g., the Chemical Abstracts Service, MDL Information Systems, etc.). Since there is a variety of topics from economics to science, as well as a variety of structures of the database, only some of the vendors (-2000) offer one or more databases as either local or as online databases (Figure 5-4) [4]. Usually, databases are provided by hosts that permit direct access to more than one database. The search occurs primarily through different individual soft-... 

The lUPAC rules are not the only nomenclature system in use today Chemical Abstracts Service sur veys all the worlds leading scientific journals that publish papers relating to chemistry and publishes brief abstracts of those papers The publication Chemical Abstracts and its indexes are absolutely es sential to the practice of chemistry For many years Chemical Abstracts nomenclature was very similar to lUPAC nomenclature but the tremendous explosion of chemical knowledge has required Chemical Abstracts to modify Its nomenclature so that its indexes are better adapted to computerized searching This means that whenever feasible a compound has a sin gle Chemical Abstracts name Unfortunately this Chemical Abstracts name may be different from any of the several lUPAC names In general it is easier to make the mental connection between a chemical structure and its lUPAC name than its Chemical Abstracts name... 

When compounds of complex structure are considered, the number of name possibilities grows rapidly. To avoid having index entries for all possible names. Chemical Abstracts Service has developed what might be called the principle of inversion. The indexing system employs inverted... 

Quite naturally there is a certain amount of arbitrariness in this system, although the lUPAC nomenclature is followed. The preferred Chemical Abstracts index names for chemical substances have been, with very few exceptions, continued unchanged (since 1972) as set forth in the Ninth Collective Index Guide and in a journal article. Any revisions appear in the updated Index Guide new editions appear at 18-month intervals. Appendix VI is of particular interest to chemists. Reprints of the Appendix may be purchased from Chemical Abstracts Service, Marketing Division, P.O. Box 3012, Columbus, Ohio 43210. 

GORE. The CORE Electronic Chemistry Library is a joint project of Cornell University, OCLC (On-line Computer Library Center), Bell Communications Research (Bellcore), and the American Chemical Society. The CORE database will contain the full text of American Chemical Society Journals from 1980, associated information from Chemical Abstracts Service, and selected reference texts. It will provide machine-readable text that can be searched and displayed, graphical representations of equations and figures, and full-page document images. The project will examine the performance obtained by the use of a traditional printed index as compared with a hypertext system (SUPERBOOK) and a document retrieval system (Pixlook) (6,116). 

Parent Compound Handbook, Chemical Abstracts Service, Columbus, Ohio, 1976, and supplements. Ring Systems Handbook, Chemical Abstracts Service, Columbus, Ohio, 1988 and supplements 1993 and supplements. 

Rang Systems Handbook, Chemical Abstracts Service, Columbus, Ohio, 1993, and supplements. 

CA Search Data-Star, DIALOG, ORBIT, Questel, etc Chemical Abstracts Service international, chemistry limited bibhographic data deep indexing of chemical concepts compound registry searchable by stmcture on Questel and by name and molecular features on other systems... 

The nomenclature of boron hydride derivatives has been somewhat confusing and many inconsistencies exist in the Hterature. The stmctures of some reported boron hydride clusters are so compHcated that only a stmctural drawing or graph, often accompanied by explanatory text, is used to describe them. Traditional nomenclature systems often can be used to describe compounds unambiguously, but the resulting descriptions may be so long and unwieldy that they are of Htde use. The lUPAC (7) and the Chemical Abstract Service (8) have made recommendations, and nomenclature methods have now been developed that can adequately handle nearly all clusters compounds however, these methods have yet to be widely adopted. Eor the most part, nomenclature used in the original Hterature is retained herein. 

J. B. Casey, W. J. Evans, W. H. PoweU, and T. E. Sloan, "A Stmctural Definitive Descriptor and Numbering System for Cluster Compound Nomenclature," Chemical Abstract Service, presented at the 198th National Meeting of the American Chemical Society, Miami Beach, FI., Sept. 1989. 

The Chemical Abstracts Service has institutionalized the use of graphic representations for identification of and retrieval of information about chemical compounds through their Graphical Data Stmcture (GDS) and connection table (CT). Two information packages. Messenger and STN Express, are the basis for this on-line retrieval system (42). 

CAS = Chemical Abstracts Services DOT/UN/NA/IMCO = Department of Transportation/United Nations/North America/International Maritime Dangerous Goods Code EPA = Environmental Protection Agency HSDB = Hazardous Substance Data Bank NCI = National Cancer Institute NIOSH = National Institute for Occupational Safety and Health OHM/TADS = Oil and Hazardous Materials/Technical Assistance Data System RTECS = Registry of Toxic Effects of Chemical Substances... 

Weisgerber DW. Chemical Abstracts Service Chemical Registry System history, scope, and impacts. J Am Soc Inf Sci 1997 48 349-60. 

Fisanick W, Amaral NJ, Metanomski WV, Shively ER, Soukop KM, Stobaugh RE. Chemical Abstracts Service Information System. In Schleyer P von R, Allinger NL, Clark T, Gasteiger J, Kollman PA, Schaefer HP and Schriener PR, editors. Encyclopedia of computational chemistry. Vol. 1. New York John Wiley Sons, 1998. p. 277-315. 

For each selected PFC, a profile was edited including the name of the compound, its CAS (Chemical Abstracts Service) number and the SMILES (Simplified Molecular Input Line Entry System) formula. 

CAS registry number An identifying numberi ng system for chemicals called the Chemical Abstract Service (CAS) with individual numbers assigned by the American Chemical Society. CAS numbers identify specific chemicals and are assigned sequentially. Such a number is a concise and unique means of material identification. 

The 8(b) inventory accumulation was the next major activity. For a decentralized company like Monsanto or, for that matter, most major chemical companies, the experience of centralized information gathering was a new experience. However, we believe that the experience not only was novel, but proved to be beneficial from several points of view. First of all, it enabled us to evolve a network of expertise. Second it gave us a central data-base on which to build other information important from a corporate point of view, and permit a one-time expense for developing a system. Third, it revealed that we needed to improve our data files in some areas. And, fourth, it gave our central staff departments some surprises as to substance locations. We used the Chemical Abstract Service Registry Profile capabilities to gather all the known synonyms and added our internal numeric and common identifiers to access the file via dozens of possible names or numbers. 

It becomes difficult to decide whether, for example 1 is cis or trans isomer No. two groups are the same and the same is true for the compound II. The Chemical Abstracts Service has proposed an unambiguous system that has been adopted by IUPAC and is based on the preferences of groups. It is also called the E-Z system and applies to alkene diastereomers of all types. 

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