The~-isoxazo~ ol amino acid (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid (AMPA, 2) and the isomeric compound (RS)-2-amino-3-(3-hydroxy-4-methylisoxazol-5- yl) propionic acid (4-methylhomoibotenic acid, 4a) are potent agonists at the AMPA subtype of central excitatory amino acid receptors. Using 4a as a lead structure, the amino acids 4c- e, in which the 4-methyl group of 4a is replaced by substituents of different size and ...
