Novel AMPA Receptor Antagonists: Synthesis and Structure−Activity Relationships of 1-Hydroxy-7-(1<i>H</i>-imidazol-1-yl)-6-nitro-2,3(1<i>H</i>,4<i>H</i>)- quinoxalinedione and Related Compounds
AMPA receptoraffinity over unsubstituted derivatives. Among the compounds, 1-hydroxy-7-(1H-imidazol-1-yl)-6-nitro-2,3(1H,4H)-quinoxalinedione (11a) showed highaffinity for AMPA receptor with a Ki value of 0.021 microM, which is severalfold greater than that of 1 and NBQX (2) (1,Ki = 0.084 microM; 2,Ki = 0.060 microM). Compound 11a also showed over 100-fold selectivity for the AMPA receptor than for