Synthesis and pharmacological activity of O-(5-isoxazolyl)-L-serine

A novel isoxazole derivative, O-(5-isoxazolyl)-L-serine (OIS, 1), was synth esized by a Mitsunobu reaction of isoxazolin-5-one (4) with N-Boc-L-serine tert-butyl ester (5) and subsequent deprotection of the coupling product. I ts structure was elucidated by spectroscopic analyses. The pharmacological activity of I was also examined with cloned glutamate receptors and transpo rters using a Xenopus oocyte-expressing system showing substrate activity o n an excitatory amino acid carrier 1 (EAAC 1) as a glutamate transporter.