Hansch analysis 50 years on

The invention of quantitative structure–activity relationships (QSAR) launched the use of computers to understand the multiple factors that contribute to the relationship between the chemical and biological properties of molecules. The original Hansch–Fujita QSAR continues to be performed to this day, fifty years since its inception. In addition, it has inspired vigorous research that has inspired many related methods: for example, methods that use descriptors such as substructures or three-dimensional features or methods that are based on mathematical models such as partial least squares or recursive partitioning. The influence of QSAR is felt in the recognition of the value of predictions from such models by regulatory agencies and by the widespread use of octanol–water log P in agricultural, environmental, and medicinal chemistry.