SIMILARITY SEARCHING ON CAS REGISTRY SUBSTANCES .1. GLOBAL MOLECULAR PROPERTY AND GENERIC ATOM TRIANGLE GEOMETRIC SEARCHING

Chemical Abstracts Service (CAS) is exploring approaches for searching on 3D and related molecular property data for CAS Registry substances. This searching includes ''fuzzy-match'' similarity searching. As the first part of this effort, sample files have been created which contain 2D and 3D structure data and molecular property data. The 3D structure data are derived from the 3D coordinates that have been generated by the CONCORD program. The molecular property data such as partial atom charges, ionization potentials, and van der Waals volumes have been derived from the corresponding 2D and/or 3D data via computational chemistry programs. Experimental software is being developed to identify, analyze, and search various characteristics of 2D, 3D, and molecular property data for portions of the substance and/or the entire substance. This paper will discuss the general design of the test system and the analysis and searching of several data characteristics. Preliminary results indicate that fuzzy-match searching on global molecular property features appears to detect chemical or isosteric similarity and that fuzzy-match searching on generic atom triangle geometric features provides a significant amount of shape and size similarity.