Abstract
The tyrosine kinase inhibitory action of the derivatives of N-Phenyl-N′-{4-(4-quinolyloxy)phenyl}urea is quantitatively analyzed using multiple regression analysis. The analysis has helped to ascertain the role of different substituents in explaining the observed inhibitory actions of these compounds for two receptors, namely vascular endothelial growth factor receptor 2 (VEGFR-2) and platelet-derived growth factor receptor α (PDGFRα). From a derived significant correlation equation for inhibition of VEGFR-2, it was concluded that a less hydrophobic molecule with ortho-substituent(s), exerting less steric hindrance and para-substituent devoid of hydrogen-bond acceptor property augment the inhibition action. Besides, a 3-substituent transmitting a higher negative field effect is advantageous to improve the pIC50 value of a compound. The correlation equation, derived for the inhibition of PDGFRα, has revealed that a less hydrophobic molecule, having a 3-substituent which transmits a more negative resonance effect, is helpful in raising its activity. Likewise, in the middle phenyl ring, absence of a fluoro substituent augments the inhibitory activity. Based on derived QSAR equations pertaining to VEGF-2 and PDGFα receptors, the drawn guidelines for selection of substituents, may be used to synthesize potent compounds in future.
Acknowledgements
We are grateful to the Department of Chemistry, S K Government College and Department of Engineering Chemistry, Sobhasaria Engineering College for providing the necessary facilities to complete this work.