Correlation of Log P with Calculated Quantum Chemical Parameters

1 Correlation of Log P with Calculated Quantum Chemical Parameters 

Two models of practical interest using quantum chemical parameters were developed by Clark et al. [26, 27]. Both studies were based on 1085 molecules and 36 descriptors calculated with the AMI method following structure optimization and electron density calculation. An initial set of descriptors was selected with a multiple linear regression model and further optimized by trial-and-error variation. The second study calculated a standard error of 0.56 for 1085 compounds and it also estimated the reliability of neural network prediction by analysis of the standard deviation error for an ensemble of 11 networks trained on different randomly selected subsets of the initial training set [27]. 

The importance of molecular size for log P prediction was demonstrated by Buch-wald and Bodor [28]. Molecular size determines the AG , term in Eq. (1), i.e. the 

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