||Further Evaluation and Development of Charge Similarity Indices for Choosing Molecular Analogues (Journal Version).
Richard, A. M. ;
Rabinowitz, J. R. ;
||Health Effects Research Lab., Research Triangle Park, NC.
Molecular structure ;
Electron density(Concentration) ;
Charge similarity index ;
Acetic acid/methoxy ;
Intermediate neglect of differential overlap ;
CNDO method ;
Ab initio analysis
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Two molecular charge similarity index (CSI) methods are further evaluated for practical application - one method based on a simple CNDO-type approximation to the electron density function and the other based on an ab-initio pseudo total charge density function. The test system consists of isosteric analogues of dimethyl ether and methoxy acetic acid. The effects of differences in skeletal structure on the CSI measure of electron density similarity about corresponding atoms is estimated and two new developments are presented for application of the ab-initio based methods: (1) an INDO-type approximation which improves the efficiency of the CSI calculation; and (2) a FOCUS feature which enables comparisons of local molecule regions.