Novel 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazolines: Synthesis, selectively analgesic action, and QSAR analysis

作者:Zhao, Ming; Li, Zheng; Peng, Li; Tang, Yu-Rong; Wang, Chao; Zhang, Ziding*; Peng, Shiqi
来源:Bioorganic & Medicinal Chemistry, 2007, 15(8): 2815-2826.
DOI:10.1016/j.bmc.2007.02.023

摘要

Based on the knowledge that imidazoline can result in analgesic action due to its selective binding with the prostacyclin receptor, 20 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazolines (3a-t) were prepared in moderate yields. At 0.13 mmol/kg dose, their in vivo analgesic activities were evaluated after the mice were administered at 30, 60, 90, and 150 min. Compared with the pain threshold (12.27 +/- 9.56-17.71 +/- 7.00%) of normal saline (NS) receiving mice, the pain threshold (23.42 +/- 8.14% to 102.58 +/- 10.66%) of 3a-t receiving mice increases significantly. Considering a prostacyclin receptor targeting analgesic agent usually had bleeding action and to appraise the bleeding risk, the in vivo tail bleeding time of 1.30 mmol/kg 3a-t receiving mice was found to be ranged from 116.3 +/- 8.2 s to 120.3 +/- 9.2 s, which was substantially equal to that (117.8 +/- 8.4 s to 119.0 +/- 8.6 s) of NS receiving mice. Based on the possibility of imidazoline acting as vasodilator, the in vitro vasorelaxations of 3a-t were tested using the rat aortic strip model. When the aortic strip contracted by noradrenaline (NE, final concentration 10(-7) mol/l) was treated with 3a-t (final concentration 5 x 10(-4) mol/l), only lower percentage inhibitions (6.55 +/- 5.70-37.40 +/- 4.07%) were recorded, implying that the vasorelaxation of 3a-t was neglectable. By selecting appropriate molecular descriptors generated from e-dragon server, the QSAR model of the analgesic activities of 3a-t was constructed using the multiple linear regression method. The established QSAR model showed reasonable accuracy and thus it is promising to be used for screening new 1-oxyl-2-substitutedphenyl-4,4,5,5-tetramethylimidazoline derivatives as analgesic agents.