Structure-activity methods substructural analysis

Some versions of the PRT used in the QSAR problems are based on the description of molecules by more physically grounded elements. These include methods of substructural analysis and logical-structural analysis. The former assumes that the activity under consideration is due to the presence of certain substructures in the molecule their relative contribution is estimated to be proportional to the number of active compounds containing the corresponding substructure. Some versions of this method are given in the literature, where statistical calculations of the substructure contributions and different classification procedures are given. 

The similarity methods described above are currently being tested on ten small data-sets from the medicinal chemistry literature that have been used previously by Ormerod et aL in studies of fragment weighting schemes for substructural analysis. Each of the data-sets contains between one hundred and two hundred compounds for which both 3-D structural and biological activity data are available. 

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