Chemical Substructure Index (CSI) A New Research Tool

lndeIxes of permuted notations constitute one application of the WWswesser Line Notation (WLN) in industrial organizations. The Institute for Scientific Information (ISI) has introduced an index of this type for new compounds being reported in the journal literature-more than 150,000 per year. This new tool, called the C#rwrrica/ Substructure /ndex (CSI), was created solely for substructure searches. The creation, advantages, and limitations of the CSI are discussed along with criteria used for selecting the more than 1,000,000 entries for the 1970 Annual. Also discussed are design features of the CSI that enable chemists unfamiliar with WLN to conduct substructure search~, In recent years, the extremely limited value of traditional indexes for substructure searching has become well recognized, As a result, considerable research effort has been financed for substructure search systems. However, with few exceptions, this research effort has been aimed at developing computer systems, even though most chemists do not have immediate access to computers. Manual substructure searches remain laborious or impossible to perform. The development of “desk-top” manually searchable indexes by permuting line notations was first reported