Structures Chemical Abstracts Service

Sadtler offer nearly 200 000 digital infrared reference spectra in over fifty different collections and also publish handbooks and guides which cover the areas mentioned above. The Sadtler computer-based search system" and the other systems available from manufacturers such as Nicolet, Perkin Elmer, Bio Rad, etc., are all relatively easy to use. Sadtler also offer a computer-based system which contains both IR and NMR data, etc. Library search software packages, such as the Sadtler IR SearchMaster Software, the Spectrafile IR Search Software or the Spectra Calc Search Software, are frequently offered by FT-IR manufacturers in addition to specific search software formatted to operate with their particular data-stations/instruments/computer systems. Some of these search facilities may also cover a number of libraries not only of different suppliers but also of other techniques such as UV, NMR, MS etc. Obviously, such search software packages are dependent not only on the instrument but also on the user s interests. It should be home in mind that the information retrieved from some search software may not cover certain aspects which may normally be available from the particular Sadtler library being searched, such as physical properties, molecular structure. Chemical Abstracts Service (CAS) Registry Number, common impurities, etc. 

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. 

In the ancient times" the 1950s), data were transferred to computers by using punched cards. But already in 1959 Ascher Opier from Dow Chemical Company reported the use of a light pen for graphical entiy of chemical structures into a computer. Light pens were also used in the Chemical Abstracts Service in the 1970s. 

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-... 

MARPAT Chemical Abstracts Service (CAS), USA Markush structures in patents struc- ture, Mar- kush, biblio. 180000 records, 505 000 Markush struct. patent ofBces STN commercial CD-ROM, online weekly www.cas.org/ ONLINE/ DBSS/mar- patss.html... 

B and W J Howe 1991. Computer Design of Bioactive Molecules - A Method for Receptor-Based Novo Ligand Design. Proteins Structure, Function and Genetics 11 314-328. i H L 1965. The Generation of a Unique Machine Description for Chemical Structures - A hnique Developed at Chemical Abstracts Service. Journal of Chemical Documentation 5 107-113. J 1995. Computer-aided Estimation of Symthetic Accessibility. PhD thesis. University of Leeds, itan R, N Bauman, J S Dixon and R Venkataraghavan 1987. Topological Torsion A New )lecular Descriptor for SAR Applications. Comparison with Other Descriptors. Journal of emical Information and Computer Science 27 82-85. 

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... 

With more than 30 million organic compounds now known and thousands more being created daily, naming them all is a real problem. Part of the problem is due to the sheer complexity of organic structures, but part is also due to the fact that chemical names have more than one purpose. For Chemical Abstracts Service (CAS), which catalogs and indexes the worldwide chemical literature, each compound must have only one correct name. It would be chaos if half the entries for CH3B1 were indexed under "M" for methyl bromide and half under "B" for bromomethane. Furthermore, a CAS name must be strictly systematic so that it can be assigned and interpreted by computers common names are not allowed. 

Morgan HL. The generation of a unique machine description for chemical structures a technique developed at Chemical Abstracts Service. / Chem Docum 1965 5 107-13. 

Several of the software tools used most frequently today include Beilstein Crossfire (information at www.mdli.com) and SciFinder from the Chemical Abstracts Service (www.cas.org/scifinder/) for structure-based reaction searches. Reagent availability information is often searched with MDL s ACD and CAS s SciFinder. Special compound collections and contract services offered by new companies such as ChemNavigator (www.chemnavigator.com)... 

Correct chemical identity including molecular formula, Chemical Abstracts Service (CAS) Registry number, common synonyms, trade names, and a structural diagram. Gosselin et al. (1984) and Ash and Ash (1994, 1995) are excellent sources of information on existing commercial products, their components and uses ... 

Users can easily search the CD-ROM by employing the Aldrich catalog number, Chemical Abstracts Service (CAS) number, chemical name, or molecular formula. One can also export the chemical structures to some supported software for subsequent inclusion into word processing programs. The product is available from Aldrich Chemical Company, Inc., 940 West St. Paul Ave., Milwaukee, WI 54233. 

Figure 16.1 illustrates the process we recommend for obtaining chemical property data [5]. Assessors usually start with a chemical name or synonym, Chemical Abstracts Service (CAS) Registry Number, and/or the chemical structure. The first task is to confirm the identification and structure of the chemical of interest. The largest (over 30 million chemicals) and most authoritative, but a relatively expensive source of chemical identification information is the Chemical Registry file of the American Chemical Society. However, there are several... 

Chemicals are omnipresent in our world today. Chemical risk is a permanent issue in our everyday environment, obviously on work premises, and may also be caused by different circumstances of chemical assaults. Among all chemical accidents, eye projections are a specific issue because of the vulnerability of ocular structures and also because of the risk of major functional after-effects. Chemical Abstracts Service (CAS) is a division of the American Chemical Society. This International database of the American Chemical Society is a worldwide reference registering... 

The nomenclature of boron hydride derivatives has been somewhat confusing and many inconsistencies exist in the literature. The structures of some reported boron hydride clusters are so complicated that only a structural 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 litde use. The IUPAC (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. For the most part, nomenclature used in the original literature is retained herein. 

J. B. Casey, W. J. Evans, W. H. PoweU, and T. E. Sloan, "A Structural 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. 

Morgan, H. L., "The Generation of a Unique Machine Description for Chemical Structures — A Technique Developed at Chemical Abstracts Service," Journal of Chemical Documentation,. 5.(2), 107-113 (1965). 

Zamora, Antonio, and David L. Dayton, "The Chemical Abstracts Service Chemical Registry System. V. Structure Input and Editing," to be published in the August 1976 issue of Journal of Chemical Information and Computer Sciences. 

The systematic nomenclature for the cycloproparenes is confused because the fusion rule (IUPAC Rule A 21.3) requires that at least two rings of five or more members be present before the prefix cyclopropa may be used. Thus while l//-cyclopropa[a]- and -[/ naphthalene are correct for 10 and 11, respectively, 1 //-cyclopropabenzene is incorrect for 1. The Chemical Abstracts service and IUPAC are unanimous in naming 1 as bicyclo-[4.1. Ojhepta-1,3,5-triene la. Thus if the parent member is strictly named, not only does it differ from that of its higher homologues, but also it could be taken to imply a bond localized structure. Throughout this chapter parent 1 and its derivatives 5-9 are referred to as cyclopropabenzenes and numbered as shown for structure 1. 

CAST-3D The Chemical Abstracts Service 3-D Structure DB Chemical Abstracts Service... 

CAS/STN International. CAS/STN offers structure searchable files such as Registry, Beilstein, MARPAT, CASREACT, and Gmelin a variety of learning files, eg, LRegistry, LBeilstein, LMARPAT, and LCASREACT and software products such as STN Express for on-line structure and substructure searching. Chemical Abstracts Service, a division of the American Chemical Society, has published Chemical Abstracts since 1907 and joindy operates STN International with FIZ Kadsruhe and the Japan Information Center of Science and Technology. 

MARPATy produced by Chemical Abstracts Service, contains the generic structure records for patent publications since 1988, which are included in the CA file. Sources include patents from 26 countries plus EPO and PCT publications. Bibliographic records for retrieved references can be directly accessed in this database (101). 

Number of CAS registered structures listed as of March 1997, Chemical Abstracts Service, American Chemical Society NW Washington DC. 

CAS CHEMICAL REGISTRY 8,000,000 compounds CHEMICAL ABSTRACTS SERVICE The world s largest file of substance information, including coordination compounds, polymers, incompletely defined substances, alloys, mixtures, and minerals. In each record, the registry number is linked to molecular structure diagram, molecular formula, CA index name, synonyms, and the ten most recent references in Chemical Abstracts. Easy crossover to the bibliographic file... 

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