A systematic study of three dimensional quantitative structure activity relationship (3D-QSAR) on 30 compounds of 2-alkyl (alkythio)- 5-pyrazoyl-1,3,4=oxadiazoles (thiodiazoles and triazoles) was performed with respect to their fungicidal activities against rice sheath blight through comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). For CoMFA, the influence of different grid spaces on structure activity relationship was investigated. For CoMSIA, the influence of variations of grid space, combinations of all kinds of field types and attenuation factor α was studied. It was found that the most satisfactory 3D-QSAR models could be constructed by taking into account of the components of steric, hydrophobic and HB acceptor. The resulting 3D contour maps provided useful guidance for more potent compounds discovery.

Key words: PYRAZOLE P, NSECTICIDES, QUANTITATIVE STRUCTURE ACTIVITY RELATIONSHIP, RICE-CROP PEST-INSECTS