Drug Design, substituent constants

Regression analysis is currently the most widely used correlative method in drug design. This is because it simplifies problems within a set of compounds by using a limited number of descriptors, notably the Hansch hydrophobic constant n, Hammet constants, or other electronic characteristics of substituents, and the Taft steric constant Eg. 

Table 4.5 Examples of the different electronic substitution constants used in QSAR studies. Inductive substituent constants (crO are the contribution the inductive effect makes to Hammett constants and can be used for aliphatic compounds. Taft substitution constants (cr ) refer to aliphatic substituents but use propanoic acid (the 2-methyl derivative of ethanoic acid) as the reference point. The Swain-Lupton constants represent the contributions due to the inductive (.F) and mesomeric or resonance (R) components of Hammett constants. Adapted from An Introduction to the Principles of Drug Design and Action by Smith and Williams 3rd Ed. (1998) Ed. H.J.Smith. Reproduced by permission of Harwood Academic Publishers.

Foster, R., Hyde, R.M. and Livingstone, DJ. (1978). Substituent Constant for Drug Design Studies Based on Properties of Organic Electron Donor-Acceptor Complexes. J.Pharm.ScL, 67, 1310-1313. 

Chapter 34. The Use of Substituent Constants In Drug Design Corwin Hansch, Pomona College, Claremont, California... 

In the space of about 25 years, computer-aided drug design (CADD) advanced from relying almost exclusively on look-up tables of substituent constants to calculating himdreds, if not thousands, of molecular descriptors, including experimental properties such as solubility and log The... 

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