CHEM 370_ Chemical Literature by ert554898


									CHEM 370, Chemical Literature

     Chemical Abstracts in Print
         Chemical Abstracts Service
• Founded in 1907 as a division of the American
  Chemical Society
• 1st volume contained 15,000 abstracts and was
  distributed free of charge to ACS members
• About 700,000 abstracts per year, total of 22.5
  million documents indexed
• Annual subscription is ~$27,000
• Website located at:
                           What CAS does
• Comprehensively index the chemical
  – 9,000 journals
  – patents from 38 national patent offices and 2
    international organizations
  – technical reports, conference papers, books, and
  – electronic journals and preprint servers
  – meeting abstracts from ACS national meetings
                       Other CAS Services
• Chemical Industry Notes (CIN)
  – began in 1974, over 1.5 million records
  – indexes the literature of chemical business (80
    journals, newspapers, etc…)
     • C&EN
     • Chemical Week
  – covers production, pricing, sales, facilities,
    products and processes, corporate activities,
    government activities, and people
                    Other CAS Services

• CAS Registry Service
  – originally began to track chemical substances
    for internal CAS files
  – now is the standard method for uniquely
    identifying chemicals
  – all substances indexed by CAS get registry
    numbers, plus substances submitted by outside
    firms or agencies
                       Other CAS Services
• CAS Registry Service
  – every chemically distinct substance gets its own
    registry number, including stereoisomers,
    isotopically labeled substances, mixtures,
    polynucleotides, etc…
  – registry numbers are of the form: xxxxxx-xx-x
     • number of digits in the first group may vary but the
       second and third groups do not
  – registry number has no chemical meaning
                           Other CAS Services
• CAS Document Detective Service
• Located at:
   – provides copies of documents indexed by CA or CIN,
     generally from 1975-present
      • exceptions: indirectly indexed documents, like technical
        reports or dissertations
   – if copyright issues are a problem, they will lend the
   – if they don’t have it themselves, they will forward the
     request to the British Library Document Supply Centre
                    Other CAS Services

• Chemical Abstracts Service Source Index
  – lists all periodicals ever indexed by CAS
  – lists many pre-1907 sources, such as those
    appearing in Beilstein or Gmelin
  – available in print at our library
                           Other CAS Services
• Chemical Abstracts Service Source Index
  – periodicals are listed in alphabetical order by their
     • the name appears in full with the abbreviated portion in
  – listings include language information, starting dates,
    current volume numbers, cross-references to changed
    titles or translations, and holdings information
                        Other CAS Services
• Why CASSI?
  – help you locate the document when you only
     • abbreviation of the publication title
     • non-English journal title
     • variation of a publication title
  – allow you to find who has that particular
     • lists the major resource libraries which contain that
          Other CAS Services

               Importance of Chemical

• Scope
  – CA attempts to cover chemistry in the broad
  – chemistry as the “central science”
     • high overlap
  – CA focuses on “new chemistry”
     • older versions did not index all chemical patents
             Importance of Chemical

• Comprehensiveness
  – CA attempts to cover the literature of chemistry
    worldwide, in any language
  – CA attempts to cover all forms of primary
  – covers technical reports and dissertations
                Importance of Chemical
• Chronological Coverage
  – print CA began in 1907; electronic CA in 1967
     • abstracts, with author and patent indexing have been converted
       to electronic form for 1907-1966
     • subject and substance indexing have not
  – abstracts are added to the print sections weekly, daily in
    the online form
  – print abstracts get keyword indexing when published
     • detailed indexing when a volume is completed
         – every ten volumes
               Importance of Chemical
• Access Points
  – weekly issues index by author, keyword, and
    patent number
  – volume indexes by author, subject heading,
    systematic chemical name, molecular formula,
    and patent number
  – electronic forms combine keyword and subject
    heading approaches and add structure searching
     • links to the registry file add enhanced searching of
             Importance of Chemical

• Constant Enhancements
  – the top company for computerization of
    indexing records
  – always refining its search tools
         Arrangement of Abstracts in
                          Print CA

• Abstracts are grouped by subject area
  – 80 subject sections in five broad groups
     •   Biochemistry
     •   Organic Chemistry
     •   Macromolecular Chemistry
     •   Applied Chemistry and Chemical Engineering
     •   Physical, Inorganic, and Analytical Chemistry
  – abstracts are added in all sections each week
       Arrangement of Abstracts in
                        Print CA
• Cross-references are used where a given
  abstract might appear in more than one
• Subject sections change with time to reflect
  current research
• “Subject Coverage Manual” gives a detailed
  definition of each section and a table of
  changes over the years
       Arrangement of Abstracts in
                        Print CA

• One volume per year published from 1907-
• 1962-present two volumes published per
• Indexed every 10 years from 1907-1957
  – every 5 years 1957-present
      Arrangements of Abstracts in
                        Print CA

• 1907-1932, pages were numbered and
  indexes would refer to a page number, with
  a superscript denoting the order of the
  abstract on the page

               Example: 3216
      Arrangements of Abstracts in
                        Print CA

• 1933-1966, two columns of abstracts were
  placed on each page with letters identifying
  where the abstract fell on the page

              Example: 1733h
      Arrangements of Abstracts in
                        Print CA

• 1967-present, abstracts are numbered in
  consecutive order, the letter is meaningless

             Example: 223717w
  Contents of the Abstract Record

• All records contain:
  – Title of the document
  – Author(s) or inventor(s) for patents
     • author’s name as given in the original
  – Corporate source or patent assignee information
  – Source information
     • journal title, volume, issue, pages, etc…
  Contents of the Abstract Record

• All records contain:
  – Language
  – Abstracts
     • journal abstracts are those written by the author
     • the indexer will normally write the patent abstract
     • dissertations and some technical reports have no
     • earlier abstracts were much more detailed
• Journal names are listed using CASSI
• Corporate names are heavily abbreviated
• All abstracts use abbreviations for common
  chemical terms

        Example: Hb (hemoglobin)
          carboxyHb or oxyHb
                         Indexing in Print CA
• Types of indexing available reflects the constraints
  of print
   – weekly indexing is arranged by that which can be done
     most quickly
      • Author
      • Keyword
      • Patent
   – collective indexing is more systematic
      •   Author
      •   Chemical Substance
      •   General Subject
      •   Molecular Formula
      •   Patent
                           Author Indexing

• Weekly issues
  – All authors are listed by last names and initials
    only and gives only the abstract number
            Example: Little R D 152780u
  – Patents have entries for both inventor and
    assignee, abstracts have P before the number
            Example: Genentech, Inc. P146735s
                          Leong S R P146735s
                        Author Indexing

• Weekly issues
  – corporate authors, such as societies and
    government agencies are also indexed
      Example: United States Food and Drug
          Administration 150996v 150997w
                          Author Indexing
• Volume and Collective Indexes
  – first authors get both the abstract number and
    title of the paper listed under their names
  – author name is not necessarily the form used in
    the article, but may be a standardized form of
    the name
           Example: Ford, Peter Campbell
       Quantitative mechanistic studies of the
               photoreactions of… 148754a
                               Author Indexing
• Volume and Collective Indexes
  – other authors are cross-referenced to the first author of
    the document

  Example: Lange, Frederick Fouse
                  see Miller, Kelly T.; Sudre,
           ---; Lam, D.C.C.; Sudre, O.
           Powder processing and densification of
           ceramics 144196x
                              Author Indexing
• Volume and Collective Indexes
  – alphabetization is by last name and initials even when
    the names are spelled out
  Example:           Ellis, A.
                     Ellis, Arthur Baron
                     Ellis, A.D.
                     Ellis, Anthony Ewart
                     Ellis, Avery K.
                     Ellis, Andrew Michael
                     Ellis, Albert T.
                               Author Indexing

• Volume and Collective Indexes
  – Spelling of author names
     • “Mc”, umlauted letters (ä, ö, ü), or transliteration
       from non-Roman alphabets can be tricky

         Example: Mössbauer is listed as Moessbauer
                          Patent Indexing

• Arranged by country code and patent
• CA only indexes the first version of each
  patent it receives
  – cross-references to the same invention patented
    in many different countries
                         Keyword Indexing
• Keywords are assigned by the indexer based
  on the body of the document
  – not just the abstract and title
• Terms are often abbreviated
  – CA abbreviations
• A keyword is not assigned if it is part of the
  section heading
  – e.g. steroids
                      Keyword Indexing

• Additional keywords are listed beneath the
  main keyword heading for concept analysis
• Chemical names are listed along with
  concept terms in the issue indexes
  – not systematic, author’s nomenclature
                                   Keyword Indexing
• Example
  – article title:“Facile Preparations of 4-fluororesorcinol”
     •   Acetophenone, methoxy fluorination regiochem
     •   Benzene, fluoro dihydroxy
     •   Deacetylation, fluorodimethoxyacetophenone
     •   Demethylation, fluorodimethoxybenzene
     •   Methoxybenzene, methoxyacetophenone fluorination regiochem
     •   Fluorodihydroxybenzene
     •   Fluororesorcinol
     •   Resorcinol, fluoro
                 General Subject Index

• Volume and collective indexes
  – uses standard subject headings
  – standard headings get modified and expanded
    to reflect new areas of research
  – major changes occur at the beginning of a
    collective index period
  – headings are chosen to draw related topics into
    physical proximity with each other
                  General Subject Index
• Contains:
  –   classes of chemical substances
  –   physical and chemical phenomena
  –   types of reactions
  –   chemical technology
  –   industrial processes and equipment
  –   scientific names for living organisms
  –   biological and medical terminology
                     General Subject Index
• Qualifiers are added as part of the main subject
   – e.g.: blood, analysis
• Classes of substances have derivative categories
   – e.g.: carboxylic acids, esters
• Classes of compounds also have qualifiers
   – e.g.:    sulfonic acids, miscellaneous
              sulfonic acids, uses
                      General Subject Index
• Substance categories
   – Ketones, aldehydes
      • acetals, hydrazones, mercaptals, oximes
   – Acids
      • anhydrides, anhydrosulfides, esters, lactones
   – Alcohols
      • ethers
   – Amines
      • oxides
   – General
      • compounds, derivatives, polymers
                      General Subject Index
• Heading qualifiers
   –   analysis
   –   biological studies
   –   occurrence
   –   preparations
   –   reactions
   –   formation
   –   processes
   –   uses
   –   miscellaneous
                  General Subject Index

• Organs and tissues qualifiers
  –   composition
  –   disease or disorder
  –   metabolism
  –   neoplasm
  –   toxic chemical or physical damage
                           CA Index Guide

• key printed tool for identifying the correct
  subject heading
  – each guide lists the approved headings in use
    for its period of coverage
  – published at the beginning of each collective
    index period with updates every 18 months
  – the final is published with the collective index
                              CA Index Guide
• Contents
  – alphabetical listing of the approved subject headings,
    with cross-references to related headings and
    descriptive notes
  – many common terms not used as headings are listed
    with “see references” to the correct heading
  – many common and/or trade names for chemical
    substances, giving the correct CA systematic name and
  – appendices on the organization and use of the subject
    indexes, how CA selects headings, CA nomenclature,
    and a hierarchical list of the headings
                 The Rule of Specificity

• CA indexers will assign the most specific
  subject heading that applies to the document
  – e.g.: cancer of the lungs is listed as “lung,
    neoplasm” not “lung, disease”
                           Substance Indexing
• The challenge of nomenclature
  – CA has their own system of nomenclature (not
    IUPAC!) for arrangement in the Chemical Substance
  – can be very complex (changed over time)
     • dodecahedrane (C20H20) used to be listed as dodecahedrane
     • systematic name: 5,2,1,6,3,4-
     • now is treated as a fullerene: [5]fullerene-C20-Ih
                      Basic Rules of CAS

• Indexers select the “main” part of the
  compound to act as the heading parent
• Substituents to the parent are listed after it
   – inverted order
• What constitutes a parent compound and
  how it would be named are not always
  obvious, even to a chemist
                         Basic Rules of CAS

• Examples                     CH3

  – toluene
     • benzene, methyl               CH3

  – ortho-xylene                           CH3

     • benzene, 1,2-dimethyl
  – benzyl alcohol                               HO
     • benzenemethanol
                       Basic Rules of CAS

• Multiple substituents are listed in
  alphabetical order, including prefixes
  – carbon tetrachloride, CCl4
     • Methane, tetrachloro
  – dichlorodifluoromethane, CCl2F2
     • methane, dichlorodifluoro
  – trichlorofluoromethane, CCl3F
     • methane, fluorotrichloro
                       Basic Rules of CAS

• Polymers are listed by the monomer or
  repeating unit with polymer or
  homopolymer appended
  – Teflon
     • ethene, tetrafluoro-, homopolymer
    Alphabetization of Compounds
• Compounds are listed first by parent compound,
  then qualifiers and categories, then substituted
  forms in alphabetical order
   – Benzene
      •   Benzene
      •   Benzene, analysis
      •   Benzene, uses and miscellaneous
      •   Benzene, compounds
      •   Benzene, polymers
      •   Benzene, azido
      •   Benzene, chloro-
      •   Benzene, 1,2-dibutyl-
                                         Special Cases

• Salts
  – salts of organic acids or inorganic oxyacids are
    named as derivatives of the parent acid
     • potassium chloride, KCl
          – potassium chloride
     • potassium sulfate, K2SO4
          – sulfuric acid, potassium salt (2:1)
  Help for Finding CAS Chemical

• In general, it is very tricky to look at the
  structure of a complex compound and
  decide what the CA name will be
• You can use a variety of resources to find
  the name
  – Merck Index
  – CRC Handbook of Chemistry and Physics
          Using the Index Guide for
                  Chemical Names

• If the compound has a common or trade
  name, check the Index Guide
• The Index Guide is especially good for
  drugs, natural products, dyes, etc…
• For other common chemicals, you may be
  able to find a similar one to get a clue
         Registry Number Handbook
• CAS publishes a handbook which lists registry
  numbers and gives the CA systematic name for the
• Use a number of sources to find the registry
   – different sources may give different registry numbers
     for what appears to be the same substance
      • parent compounds with salts, stereoisomers, polymers
           Molecular Formula Index

• There may be a large number of possible
  compounds for each possible molecular
  – it is easier to look at a possible name and see if
    it applies
• Molecular formula index gives just a list of
  abstract numbers, not a breakdown by
               Molecular Formula Index

•   Organization
    –   molecular formulas are listed in “Hill Order”
        1. If carbon is present, it comes first, followed by
           hydrogen, then all other elements in alphabetical
        2. If not, then all (including H) in alphabetical order
              Molecular Formula Index

•   Examples
    –   Benzene          Teflon
        •   C6H6         (C2F4)x
    –   Ferrocene        Hydrochloric acid
        •   C10H10Fe     ClH
    –   Benzoic acid     Sodium benzoate
        •   C7H6O2       C7H6O2, sodium salt
                         NOT C7H6NaO2
Using the Ring System Handbook

• Most compounds with a polycyclic ring
  system use the name of the ring system as
  the parent compound
• The handbook lists ring systems in order of
  – increasing number of rings
  – increasing number of atoms in the ring
  – increasing Hill order formula of the ring
Using the Ring System Handbook
• Step 1
  – count the number of rings
     • 2
• Step 2                                            CO2H

  – count the number of atoms in each ring
     • 4 and 5
• Step 3
  – note the “molecular formula” of each ring
     • C3N and C4N
Using the Ring System Handbook

• Step 4
  – arrange the formulas in order of increasing size
    and Hill order
     • C3N, C4N                            N

• Step 5                             O

  – look up the ring systems that fit the formula and
    pick the correct one by inspection
     • 1-azabicyclo[3.2.0]heptane

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