Abstract
For the development of new antiepileptics the kainate receptors, GluR6 and GluR5, are important targets. Based on the anticonvulsant effects of chinazolines and thieno[2,3-d]pyrimidines that are known from the literature, thieno[2,3-d][1.3]oxazines were synthesized and studied for their inhibitory properties at GluR6 and GluR5 receptors. The strongest inhibitor activity was observed with 5-methyl-6-phenyl-thieno[2,3-d][1.3]oxazines with C1 or C3-substituents in position 2 (3b-f). The 2-trihalide-methyl-substituted compounds 3c and 3d were the most active inhibitors at the GluR5- receptor (IC50=23.4 μmol, 16 μl). The 2-isopropyl-substituted compound 3f displayed the strongest activity at the GluR6- receptor (IC50=8.7 μmol). A number of thieno[2,3-d][1.3]thiazines and thieno[2,3-d]pyrimidines that were synthesized from the thieno[2,3][1.3]oxazines did not show any activity.
Keywords: Glutamate receptor antagonists, kainate receptor antagonists, anticonvulsives, thieno[2,3-d][1.3]oxazines, thieno[2,3-d][1.3]thiazines, thieno[2,3-d]-pyrimidines