Synthesis and inhibitory activities at mGluRs of 3-alkylated and N-alkylated cyclopentyl-glutamate analogues

The conformationally restricted glutamate analogues, 3-alkyl-1-amino-2-cyclopentene-1,3-dicarboxylates and N-alkylated analogues have been prepared in a regioselective and diastereoselective manner. From the biological studies of the 3-alkylated analogues, compound 13b was found to be the most potent antagonist (IC50 7.7 μM) at mGluR2. Amongst the N-alkylated analogues, compound 20 was found to be a partial agonist (EC50 9.5 μM) and as well as an antagonist (IC50 47 μM) at mGluR2.