Synthesis and photoreactivity of caged blockers for glutamate transporters

l-TBOA ( l- threo-β-benzyloxyaspartate) is, so far, the most potent non-transportable blocker for glutamate transporters. We synthesized α-CMCM- l-TBOA ( 1a) possessing [7-(carboxymethoxy)coumarin-4-yl]methyl ester as a caging group. α-CMCM- l-TBOA ( 1a) is biologically inactive until UV irradiation and the photolysis of 1a immediately released l-TBOA to show glutamate uptake inhibition. The photoreactivity of the coumarin-type caging group was superior to that of the o-nitrobenzyl-type caging group. The photolysis of α-CMCM- l-TBOA, a caged blocker for glutamate transporters, immediately released l-TBOA to show glutamate uptake inhibition.