Comprehensive QSAR studies reveal structural insights into the NR2B subtype selective benzazepine derivatives as N-Methyl-D-Aspartate receptor antagonists

NMDA receptors are considered as high profile therapeutic target in the treatment of pain and neurodegenerative diseases such as Alzheimer's, Huntington's and Parkinson's disease. NR2 subunit of NMDA receptor divided into four subunits i.e. NR2A, NR2B, NR2C and NR2D. Restricted distribution of NR2B subunit in the brain makes it potential target. In the present study, new structural insights into benzazepine derivatives as NR2B selective NMDA receptor antagonists have been reported using QSAR modelling. Total five QSAR models were developed using various statistical methods. 2D-QSAR models showed that chi3 and SsssNE-index descriptors are crucial for NMDA receptor antagonistic activity. Chi3 descriptor relates with non-hydrogen heteroatom connected with two or three bonds and SsssNE-index descriptor deals with Electrotopological state indices for number of nitrogen atom connected with three single bonds. Both the descriptors were negatively correlated with all the developed 2D-QSAR models. Significance of these descriptors is extensively studied in present work. In 3D-QSAR studies, steric and electrostatic fields were found to be important for antagonistic effect on NMDA receptors. 3D-QSAR studies clarify the substitution pattern of R group on nitrogen atom of benzazepine core. The substitutions with high electropositive with less or medium steric character are favourable for the activity. All developed models were critically validated to establish their reliability and accuracy for prediction of binding affinity of benzazepine derivatives towards NR2B subunit of NMDA receptor. The present study offered not only highly predictive and reliable QSAR models for benzazepine derivatives but also revealed some of the vital structural observations required for their higher binding affinity towards NR2B subunit of NMDA receptors. (C) 2019 Elsevier B.V. All rights reserved.