Synthesis and in vitro antiplatelet aggregation screening of novel fluorinated diethyl-2-(benzylthio)-2,3-dihydro-1H-imidazole-4,5-dicarboxylate derivatives

Abstract

Seven fluorinated derivatives of diethyl-2-(benzylthio)-2,3-dihydro-1H-imidazole-4,5-dicarboxylate (a–g) as well as a nitro and chloro derivative (h–i) were prepared in five steps from glycine, ethyl formate, diethyl oxalate, potassium thiocyanate and substituted benzyl bromides. The structures of the synthesised compounds were elucidated and verified using 1H, 13C and 2D NMR spectroscopy where appropriate. The synthesised compounds exhibited concentration dependent antiplatelet aggregation activity on both the thrombin and ADP-induced platelet aggregation. The 4-nitro and 4-fluoro compounds exhibited the highest activity from the compounds tested, with IC50 values of 1.06 and 1.20 mM for the thrombin-induced assay and 18.57 and 12.91 mM in the ADP-induced platelet aggregation assay respectively. Three of the compounds, the 3′′,4′′-difluoro (6c), 4′′-nitro (6h) and 3′′-chloro (6i) derivatives, have reasonable activity in both of the assays and could have potential as broad spectrum antiplatelet inhibitors. With the exception of 6c, the fluoro derivatives were not as active as the nitro and chloro compounds.