Search on-line substructure

Reviews on 1 H-imidazoles (1), have mentioned only isolated examples of the iso compounds 2 and 3, although a later treatise has covered the latter two classes in more detail. The present review seeks to cover all known 2//-imidazoles, whereas the following one will deal with the 4H compounds. Chemical Abstracts have been covered up to and including issue 4 of Volume 97, using a comprehensive CAS on line substructure search a few additional references are included from the more common international journals. The search excluded structures with exocyclic double bonds, and hence those fused to a benzene ring. 

The present review is comprehensive Chemical Abstracts has been searched by indexes up to mid 1981 and by a computer on-line substructure search up to Issue 26 of Volume 96. A few more recent references are included directly from the commoner international journals. This review covers 3//-pyrazoles that have been isolated or characterized spectroscopically, although some examples that are only transient intermediates in rearrangement reactions are also mentioned. Compounds having exocyclic double bonds and the benz-fused derivatives, the 3//-indazoles, are considered to be outside its scope. 

Although the 4//-pyrazoles have not previously been reviewed, some aspects of their synthesis and chemistry have been discussed in reviews and treatises2-5 dealing with the 1H compounds. For the present review, the literature has been covered using Chemical Abstracts, by indexes up until mid 1981, and by computer on-line substructure search up to Issue 26 of Volume 96. Some more recent references have been taken directly from the commoner international journals. 

The selection of keys is of prime importance in designing a screening system. In the early 1970s, Lynch et al. studied the statistical occurrence of substructures in large databases of compounds, and concluded that keys that occur often may provide little discrimination, while keys that occur infrequently may similarly be of little use if they do not occur in typical queries. These results led to the creation of the BASIS fragment dictionarywhich was later adopted by STN International for its on-line substructure search system. ... 

The 4f/-imidazoles have not previously been reviewed comprehensively. In earlier reviews on the H compounds " isolated examples are discussed, although in a later work a more thorough treatment has been given. An attempt has been made in the present article to include all known AH-imidazoles using a CAS on line substructure computer search. Chemical Abstracts have been covered up to and including Issue 4 of Volume 97, and a few additional references have been included directly from the more common international journals. Structures having exocyclic double bonds have been excluded benz-fused systems cannot be drawn in this series. 

Structure searching and display software are host-specific. The Softon Substructure Search System (S4) was developed by the Beilstein Institute and Softon of Graefelfing Germany (50). It is a full structure and substructure searching module. The S4 is used in-house by the Beilstein Institute and is operated by DIALOG. STN uses CAS ONLINE s messenger software for on-line structure searching of the Beilstein on-line database (51). 

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. 

A number of files under the generic tide CAS ONLINE are available on-line on STN International. The system software, MESSENGER, includes chemical substructure, text, and numeric data searching facilities. Chemical structures and Registry Numbers are contained in the CA Registry file. The four ways to search the structures are EXA, FAM, SSS, and CSS. 

Description> Acquisition> Retrieval, and Correlation File. This is the only other public substructure search system, apart from CAS Online, that provides full access to the CAS Chemical Registry File. The DARC file, commercially available on-line from Telesystems-Questel, offered the first public on-line implementation of substructural searching of the CAS Chemical Registry System. The advantages and disadvantages of the CAS Online and DARC systems have been discussed (49). 

The first major graphics application for an ACS publication automated the input and composition of structures in CA. Later, this structure input method was modified and added to the Messenger software for use in STN International as the basis for the STRUCTURE command that builds queries for substructure searching. After a search, structure images can be displayed on certain graphics terminals. Chemical structures are also produced by Messenger batch software on STN International off-line prints. 

Eakin, D.R. and Ifyde, E. - "Evaluation of On-Line Techniques in a Substructure Search Syston" in "tonputer Representation and Manipulation of Chemical Iitfoniiation", ed. Wipke, W.T., Ifeller, S.R., Feldman, R.J. and Hyde, E. Wiley. 

CHEMLINE (CHEMical dictionary on-LINE) is a file of chemical descriptors created by NLM s Toxicology Information Program in collaboration with Chemical Abstracts Service (CAS). This file contains nearly 500,000 chemical substance names representing over 246,000 unique substances. Because of CHEMLINE s unique file design, it has capabilities which support both full structure and substructure searching. 

The National Library of Medicine s (NIH) on-line chemical dictionary file (CHEMLINE) is primarily used to enhance the retrieval of bibliographic Information associated with chemical substances. This discussion demonstrates the utility of CHEMLINE as a mechanism to link chemical substructures to biological data. Search techniques are developed to Integrate classes of structurally related chemicals with toxicity data and information contained in on-line retrieval files such as the Registry of Toxic Effects of Chemical Substances (RTECS) and TOXLINE. 

This paper will focus on a project which has been under way at the Upjohn Company to develop a comprehensive chemical and biological Information system to be used by research scientists and research support personnel. Capabilities of the system will eventually Include on-line structure registry, structure and substructure searching, the retrieval and manipulation of pharmacological test data, and the retrieval of spectroscopic, patent, and other types of structure-associated data. 

The usefulness to the WRAIR Staff of searching for substructures on-line has yet to be determined. Since the chemistry retrieval system uses the screen and connection teible generated by the query to search to screen index file for either a whole or a sub-structure no more information (disk-drives) is needed on-line for sub-structure searching than for identity matches, so one is no more costly than the other, in terms of disk resources. But the elapsed time needed for such sub-structure searches varies greatly and may be large. The time needed may be kept small if the query is specific and many screen bits are set. 

CAS Transaction Editor DCRT (NIH) On Line Structure Input System for query formulation (1 ) General processing utilities and a macro processor from Dupont U.S. Army CIDS Substructure Ring Screens and Interactive Search (0) CAS Algorithmic Structure Display (ASD) ( ) and CAS On Line... 

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