1,3-Bispyridinium-dimethylether mono- and dioximes: synthesis, reactivating potency and therapeutic effect in experimental poisoning by organophosphorus compounds

Abstract

Nine bispyridinium oximes containing two pyridinium rings linked by dimethylether were synthesised. Each compound had on one of the pyridinium rings a hydroxyiminomethyl group in position 2 or 4, while the other ring was unsubstituted or had a methyl or a hydroxyiminomethyl group in position 2 or 4. The reactivating potency and therapeutic effect of the oximes were tested on two organophosphates: O,O-dimethyl-2,2-dichlorovinylphosphate (DDVP) and O-ethyl-S-(2-diisopropylaminoethyl)-methylphosphonothioate (VX). The reactivation was measured on human erythrocyte acetylcholinesterase and the therapeutic effect was evaluated on male albino rats. The oximes with a hydroxyiminomethyl group in position 4 in the pyridinium ring were good reactivators of both phosphorylated and phosphonylated acetylcholinesterase. They were also very effective given together with atropine against VX and DDVP poisoning. The compounds are almost as effective as PAM-2, but PAM-2 is less toxic.