Ninth Collective

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. 

In eadier Hterature carbonochloridic esters are referred to as chloroformates or chlorocarbonates because of the stmctural parallel with formic acid [64-18-6]., chloroformic acid, and carbonic acid. Before 1972, chloroformates were indexed in Chemicaly4bstracts, Eighth Collective Index, under formic acid, chloroesters whereas, in the Ninth Collective Index (Dec. 1990), they are referred to as carbonochloridic acid esters. Table 1 fists the common names of carbonochloridates or chloroformates, the CAS Registry Numbers, and the formulas. 

Chemical Abstracts Ninth Collective Index, Index Guide, Appendix IV F. Specialized Substances, par. 215, pp. 2021—2051 (1972—1976). In the Tenth and Eleventh Collective Indexes, the corresponding page numbers are 1921—1951 and 1931—1971, respectively. 

Chemical Abstracts Ei th Collective Index, pp. 7004F and 12481S (1967—1971) Ninth Collective Index, p. 9668F (1972—1976). 

MI10200 Index Guides, Chem. Abstr., Ninth Collective Index, 1972-1976 and 1977. 9... 

There have been many developments in the chemistry of the 1,3,5-triazines since the comprehensive reviews of Smolin and Rapoport (59HC(13)1) and Modest (B-61MI22000, p.627). It is impossible to include all the vast range of 1,3,5-triazines reported in the literature 138 pages of the Compound Index in the Ninth Collective Index of Chemical Abstracts are dedicated to this system. This review will concentrate on the more important recent developments of 1,3,5-triazine chemistry, and reference will be made to previous reviews, or typical papers, to illustrate the better-known aspects of the subject. 

Fisanick, W., L. D. Mitchell, J. A. Scott, and G. G. Vander Stouw, "Substructure Searching of Computer-Readable Chemical Abstracts Service Ninth Collective Index Nomenclature Files," Journal of Chemical Information and Computer Sciences, lj>(2), 73-84 (1975). 

Although this procedure for replacement names is recommended in the Chemical Abstracts Ninth Collective Index Nomenclature Manual, the Index Guide now employs a more complicated system. 

Although all alkaloids can be named by the principles already outlined in this article, the cumbersome nature of such names for complex ring systems makes it desirable to use trivial parent names for some large heterocyclic skeletons. It is preferable for such trivial names to refer to skeletons with no substituents (or very few), and it is often convenient for them to carry inherent stereochemical implications. The most extensive source of these names is the Chemical Abstracts Index Guide (or the Ninth Collective Index Nomenclature Manual), but the names given here do not correspond, in many cases, to those in common use, and IUPAC recommendations, when they appear, may well differ in some respects. Some of the principal skeletons listed by Chemical Abstracts are illustrated (122-130). 

The Chemical Substance Index was initiated during the ninth Collective Index period (1972 to 1976) before 1972, chemical substances and general subjects were in a single Subject Index. 

This index consists of an alphabetical listing of CA Index Names, each of which identifies a specific chemical substance linked to the appropriate CA abstract number. Chemical Substance Indexes (and the earlier Subject Indexes) reflect changes in chemical nomenclature, and in particular the revision of nomenclature implemented for the ninth Collective Index period. (See Section 3.2 and Chapter 7 for a description of the changes to CA Index Names and stereochemical descriptors.)... 

The Subject Index was subdivided into the General Subject and Chemical Substance Indexes beginning with the ninth Collective Index period. 

Major changes in CAS nomenclature were made at the beginning of the ninth Collective Index period (1972), giving what became widely known as 9C1 nomenclature. This is described in the publication Naming and Indexing of Chemical Substances for Chemical Abstracts (Appendix IV to the CAS 1992 Index Guide, but also available separately). 

At the changeover from the eighth to the ninth Collective Index periods (1972), the use of many older stem names was discontinued. These are all found in the older literature, and some can still be found in the literature today. The list in Table 3.3 equates many 9CI name fragments with those used in the SCI and earlier. An asterisk indicates that the name was used in SCI for the unsubstituted substance only substituted derivatives were indexed elsewhere. 

STN Scientific and Technical Information Network SCI CA Eighth Collective Index 9CI CA Ninth Collective Index 12CI CA Twelfth Collective Index... 

Blackwood, J.E. Giles, P.M. Jr. Chemical Abstracts Stereochemical Nomenclature of Organic Substances in the Ninth Collective Period (1972-1976) . J. Chem. Inf. Comput. Sci. 1975,15, 67-72. 

The unique identification of stereoisomers in the Registry System was originally accomplished via a controlled vocabulary field called the stereochemical descriptor which was introduced with the CA Ninth Collective Period in 1972. This descriptor was used in both the Registry structural record and in the substance index heading in printed CA indexes, with slight differences in punctuation. The CAS stereochemical descriptors used standard stereochemical terms such as alpha, beta, cis, trans, endo, exo, syn, anti, R, S, E, and Z R and S being used for relative stereochemistry. The... 

International Union of Pure and Applied Chemistry MDL = MDL Information Systems, Inc, RN = Registry Number SRU = structural repeating unit SSS = substructure search STN = Scientific and Technical Information Network SCI = CA Eighth Collective Index 9CI = CA Ninth Collective Index 12CI = CA Twelfth Collective Index. 

Once again the Index Guide is indispensable for this purpose, and in this case in two ways either the user finds the trivial or trade names in the alphabetic section of cross-references with the appropriate reference to the CA Index Name, or he attempts - and this is much more difficult - to derive the systematic Index Name based on the nomenclature rules in Appendix IV himself. These rules of nomenclature also appear as a separate small publication for each collective period under the title Naming and Indexing of Chemical Substances for Chemical Abstracts. The most marked changes in the systematic CAS nomenclature were made at the start of the ninth collective period, i.e. at the beginning of 1972. Thus, completely different CA Index Names may be encountered when searching for literature which appeared before 1972. 

From the First to the Seventh Collective Periods there was only one Subject Index, containing all the information available about subject terms and substances as well as cross-references to alternative substance names. Since 1967, the Eighth Collective Period, the Index Guide has been issued. It provides cross-references and indicates relationships between the various substance names and subject terms. In 1972, the Ninth Collective Period, the Subject Index was divided into the General Subject Index and the Chemical Substance Index. From that time, it has been necessary to determine precisely whether a search should be subject- or substance-oriented. 

During the 85 years existence of Chemical Abstracts nomenclature has also undergone further development. A major revision of the CAS nomenclature system was undertaken at the beginning of the Ninth Collective Period. If literature published before 1972 is sought, it is essential to determine the proper CA Index Name used at that time. The Index Guide is helpful for this purpose. Before its existence the appropriate information could be found in the Subject Index. 

Consulting the Index Guides from the twelfth to the ninth collective period it is found that the systematic substance name, the Index Name, did not change. 

The systematic CA Index Name used in the current Chemical Substance Index. The symbol 9CI after the substance name indicates that this name is valid from the ninth collective period (i.e. from 1972) to the present day. 

The systematic CA Index Name for this substance is unknown and it is time-consuming to derive it using the rules of nomenclature. The fastest method of solving this problem is to look up the molecular formula C25H25N3O4S2 in the Ninth Collective Formula Index (1972 to 1976) (Fig. 68). Although it is a ben-zenesulfonamide - which the structure diagram clearly shows - the mentioned names do not refer to the requested compound. As this molecular formula is not included, nothing about the substance itself was published in the years from 1972 to 1976. However, the problem also addressed its derivatives. 

In the Index of Ring Systems for the ninth collective period there are various substance names mentioned under this ring analysis (Fig. 69). Every chemist should recognize that this ring system is a spiro substance with a cyclohexane ring. Thus, the choice of alternative names to be consulted in the Chemical Substance Index is reduced to three. 

In the Ninth Collective Chemical Substance Index, which covers the period from 1972 to 1976, the structure of the substance in the problem can be easily identified using the substance name and the CAS Registry Number. The structure diagram and numerical locants of every substance included in the Ring Systems Handbook is illustrated in the Chemical Substance Index to Chemical Abstracts. 

Due to the fact that Chemical Abstracts Service has made changes to its rules for indexing over the years, it may happen, that a substance may show different parent compounds for the eighth and ninth collective index periods. 

The last thorough changes have been described in section IV of the Index Guide of the Ninth Collective Period (1972-1976). Americal Chemical Society, Chem. Abstr. Service, Columbus, Ohio. In the following Index Guides up to the 13. Coll. Period (1992-1996) further changes have been reported only sporadically. 

N1 is the Chemical Abstracts (CA) preferred index name, l.e., the systematic names used in the Chemical Substance and Formula Indexes of CA. The SCI and 9CI designations following the two N1 niunes for this record indicate that the name comes from the Eighth Collective Index Period (1967-71) and the Ninth Collective Index Period (1972-76) of CA. One can see from this example that the 9CI nomenclature is chemically more standardized than the SCI nomenclature. 

Flsanlck, W., Mitchell, L. D., Scott, J.A., and Vanderstouw, G. G., "Substructure Searching of Computer-Readable Chonlcal Abstracts Service Ninth Collective Index Nomenclature Files", J. Chem. Inf. Comput. Sci., 13 (2)... 

Substructure Searching of Computer-Readable CAS 9CI Chemical Nomenclature Files (Based on Nomenclature in the Ninth Collective Index of Chemical Abstracts) (1972-1976)",... 

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