Decomposition of the Wiener topological index. Application to drug–receptor interactions

Abstract

The Wiener index W is the sum of topological distances between carbon atoms in a hydrocarbon molecule. It was shown that W is made up of terms related to different substructures of the molecule and terms related to the interactions between these substructures. The contributions of substituents and the interaction terms are the substituent indices. Linear regression equations were derived relating the pharmacological potencies of compounds and the sum of the substituent indices, and linear regression equations were derived between these potencies and the various substituent indices. These regression equations were compared. The comparison allowed a decision on whether variations in the experimental pharmacological potencies were due to global effects linked with the bulk of the molecules or due to substituent effects attributable to various sites of the interacting molecules.