Our ring switching strategy for synthesis of compounds with structural
features consistent with activity at glutamate receptors has been mod
ified to prepare L-alanine derivatives substituted at the beta-carbon
atom with six-membered heteroaromatic rings. The pyrimidinone (11, R =
R(1) = R(2) = H) has been shown to be a glutamate agonist and the com
pound (13) to be an antagonist.