Synthesis and potent anticonvulsant activities of 4-oxo-imidazo[1,2-a]indeno[1,2-e]pyrazin-8- and -9-carboxylic (acetic) acid AMPA antagonists

The over-stimulation of excitatory amino acid receptors such as the glutamate AMPA receptor has been suggested to be associated with neurodegenerative disorders. Here we describe an original series of readily water soluble 4-oxo-imidazo1,2-a]indeno1,2-e]pyrazin-8- and -9-carboxylic (acetic) acid derivatives. One of these compounds, 4f, exhibited nanomolar binding affinity, potent competitive antagonism at the ionotropic AMPA receptor and a long duration of anticonvulsant activity after administration by parenteral route in vivo.