Index Chemicus Registry System: Pragmatic Approach to Substructure Chemical Retrieval

Abstract

The Index Chemicus Registry System (ICRS), launched in 1968 with the support of a dozen industrial and government organizations, is now a current operational monthly service. Subscribers receive magnetic tapes and printouts, in which the weekly issues of Index Chemicus (IC) have been encoded in Wiswesser Line Notations (WLN). Over 13,000 compounds per month are provided in machine language. The canonical WLN is also provided in alphabetized printouts. Encoding of over 400,000 new chemical compounds from IC has already been completed, including all those reported in 1967, 1968, and 1969. Since the tapes also include title and other bibliographic information, this paper describes the use of supporting software provided for SOI search systems employing "word" and other searching terms, in addition to the WLN fragments. Use of the monthly and annual printouts are illustrated for those searches which do not require computer manipulation.

The Status of Chemical Information

“…Services based on the ICRS are available, including programs for selective dissemination, files for retrospective manipulation, and printed indexes. 34 Bit screens have been developed to improve the economics of retrospective substructure searching of the ICRS tapes. 35 Another by-product is the preparation of a permuted monthly index with WLN called the Chemical Substructure Index.…”

Organization and Efficient Manual Searching of the Major Chemical Title and Abstract Publications

“…The subject and author index need no further explanation, but the so-called "Chemical Substructure Index," produced since 1967 and available in print since 1971, is unique in permitting manual searching for partial chemical structures. 8 The Wiswesser Line Notation (WLN), an unambiguous linear description of chemical structures developed by Wiswesser,9 forms the basis of this index. The "Chemical Substructure Index" lists the WLN descriptions of all new compounds reported in the corresponding abstract issues in permuted alphabetical order of all significant structure elements thus allowing rapid retrieval of information on all substances with common functional groups.…”

Zombie cheminformatics: extraction and conversion of Wiswesser Line Notation (WLN) from chemical documents

“…Wiswesser Line Notation (WLN) [ 14 ] is one such line notation that predated SMILES, and saw widespread use amongst chemists and early cheminformatics software during its active years. Early look up systems such as the Index Chemicus Registry System (ICRS) [ 15 ] and the CROSSBOW software package [ 16 ] gave access to large chemical queries, and algorithms using WLN allowed for early substructure searching [ 17 ]. While the notation adheres to strict mathematical principles, the WLN language is conveyed through a set of verbose written English rules.…”