Structure-activity relationships in platelet-activating factor (PAF) .7. Tetrahydrofuran derivatives as dual PAF antagonists and acetylcholinesterase inhibitors. Synthesis and PAF-antagonistic activity

2,5-Disubstituted tetrahydrofuran derivatives present a dual activity: they are effective PAF antagonists and acetylcholinesterase inhibitors. In this paper their synthesis and in vitro PAF-antagonistic effect are described. Introduction in position 2 of a long aliphatic chain bearing a carbamate group and a pyridinium moiety appears to be required for potent platelet aggregation inhibition, Substitution in position 5, or cis-trans isomerism do not induce any increase in activity. No correlation can be established between global lipophilicity and the anti-aggregant activity. Structural requirements for a potent activity are discussed and are consistent with the hypothesis we have proposed for the PAF receptor considered as a multipolarized structure with alternants of electropositive, electronegative and hydrophobic areas.