Synthesis of agonists and antagonists for central glutamate receptors by a novel ‘ring switching’ strategy 1

A novel and versatile ring switching strategy has been developed for the synthesis of compounds with structural features consistent with activity at glutamate receptors. A variety of homochiral L-alanine derivatives substituted at the β-carbon atom with planar five and six-membered heteroaromatic rings have been prepared in a one- or two-pot reaction using this strategy and some of the products have been shown to have biological activity at central glutamate receptors.