Synthesis and preliminary evaluation of trans-3,4-conformationally-restricted glutamate and pyroglutamate analogues as novel EAAT2 inhibitors

Select trans-4,5-bi]cyclohexenylglutamic and pyroglutamic acids (3,4-substituted glutamates) were synthesized in three steps and were screened as potential inhibitors of the sodium dependent excitatory amino acid transporters 2 (EAAT2) and 3 (EAAT3), the chloride dependent glial cystine/glutamate exchanger system x(c)(-), and the glutamate vesicular transport system (VGLUT). Two glutamate analogues and one pyroglutamate analogue were found to inhibit EAAT2 with activity comparable to dihydrokainate.