Two-dimensional H-bond descriptor

Two-dimensional H-bond descriptors are included in Table 6.1. Considering information content, they may be classified as indirect descriptors (no direct link with the H-bonding process), H-bond indicators (atoms having potential H-bond capability) and thermodynamic factors (calculated on the basis of experimental thermodynamic data of H-bonding). 

I 6 H-bonding Parameterization in Quantitative Structure-Activity Relationships di Drug Design Tab. 6.1 Two-dimensional H-bond descriptors. 

A more profound visual difference of the chemical space covered by natural products and synthetic drugs was presented by Derek Tan, in which he applied a similar PCA analysis of 20 synthetic drugs (including ten best sellers of 2004) and 20 natural products.7 For this analysis, Tan used nine molecular descriptors—molecular weight, clog P, H-bond donors, H-bond acceptors, rotatable bonds, polar surface area (PSA), chiral centres, N and O atoms—and then applied PCA to reduce nine-dimensional vectors to two-dimensional vectors before re-plotting the data. 

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