SYNTHESIS OF CONFORMATIONALLY RESTRICTED ANALOGS OF KAINIC ACID - IS THE CONFORMATION OF THE C4-SUBSTITUENT OF KAINOID IMPORTANT TO ITS NEUROEXCITATORY ACTIVITY

Conformationally restricted analogs of kainic acid, which have an azab icycto[3.3.0]octane system, were synthesized through the intramolecula r addition reaction of trimethylenemethane to the alpha,beta-unsaturat ed ester. Every synthesized isomer showed very weak depolarizing activ ity. These results indicate that the plane of the isopropenyl group of kainic acid should be diagonal to the pyrrolidine ring to show potent activity.