Molecular modeling studies on substituted aminopyrimidines derivatives as potential antimalarial compounds.

We report combined study of k- nearest neighbor, pharmacophore and 2D QSAR was performed on a series of 2,4-diaminopyrimidines dihydrofolate reductase from pyrimethamine-resistant Plasmodium falciparum as antimalarial agents to gain insights into the structural determinants and their structure-activity relationship. The QSAR models for the prediction of activity of antiplasmodial activities against P. falciparum clones with wild-type TM/8.2 and KCB strains have been developed by the SA-PLS and SW-PLS methods, and the proposed models gain satisfactory results. The statistically significant best 2D QSAR model having correlation coefficient r = 0.8569, 0.7853 and cross-validated squared correlation coefficient q = 0.7104, 0.7216 with external predictive ability of pred_ r = 0.7995, 0.7064 was developed by wild-type TM/8.2 and KCB strains with SA-PLS. 3D QSAR studies using k-nearest neighbor molecular field analysis (kNN-MFA) method, identifies two models obtained by SA-PLS and SW-PLS methods leading to antimalarial activity prediction. The obtained pharmacophore model with lowest RMSD value (0.1548 Å), consisting of one hydrogen donor, two hydrogen acceptors and one aromatic region was developed. These models were found to yield reliable clues for further optimization of 2,4-diaminopyrimidines derivatives in the data set. We hope that these results will give new insights into chemical modifications that can be realized with the aim of designing new inhibitors with improved pharmacological properties. [ABSTRACT FROM AUTHOR]