Registration, by Chemical Abstracts Service

The potential of molecular structures to populate structural chemical space is diverse and the challenge is to make new discoveries that add to the accumulated knowledge base. An important milestone was achieved during the assembly of this volume and it involves the registration, in 2008 by Chemical Abstracts Service (CAS), of the 40 millionth chemical substance. However, a rather surprising outcome was deduced by a CAS team lead by Lipkus his team analyzed these frameworks and concluded that half of the compounds can be described by only 143 framework shapes . The rigorous study of natural products provides an optimal way to expand such understanding and such a prospect is amply illustrated by the 19 chapters in this volume. 

All the substances in ECOIN and all the substances reported by industry have been registered by Chemical Abstracts Service. This registration was finished in the autumn of 1986. The official publication of the EINECS Inventory is awaiting a translation of the inventory into all the official languages of the EC, but a provisional version is being published in the English language only. 

Industrial use of a Grignard reagent in the United States requires that it be included on the Environmental Protection Agency (EPA) list of Chemical Substances in Commerce. A corresponding registration exists for the European Community and for Japan. Table 1 gives the Chemical Abstracts Service (CAS) numbers of those listed by the EPA as of 1994. 

CAS Registration Number—number assigned by the Chemical Abstracts Service to identify a chemical... 

Octanol/water partition coefficients (log P) were taken from the compilation by Hansch and Leo (1979). Where no experimental values were recorded, log P was calculated from pi or fragment values and related compounds, if neither was available, log P was estimated on the basis of similar compounds or groups partition coefficients. TABLE 1 gives a complete list of the investigated compounds, including their Chemical Abstracts Service registration numbers (CAS), log P, - [eV], and the substituents molar refractivity contributions (AMR), the latter also taken from Hansch and Leo (1979) or calculated or estimated, as indicated. 

The unique registration number of a chemical compound or substance assigned by the Chemical Abstract Service, a division of the American Chemical Society. The intention is to make database searches more convenient, as chemicals often have many names. Almost all molecule databases today allow searching by CAS number. The CAS no. usually is given in the substance entries of many library mass spectra. 

By means of this CAS Registry File it is possible to ascertain whether or not a substance with a certain name has already been mentioned under another name. In the course of registration for Chemical Abstracts about 6000 substances are checked daily. If not yet registered, the structural formula of the new substance is first stored. The substance is then awarded a systematic CA Index Name based on lUPAC rules, and the rules of the Chemical Abstracts Service, by a nomenclature expert (Sect. 2.1.3.2). Weekly about 13,000 structures are registered, 690,000 new substances each year (1992). 

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