The Improved Syntheses of dl-Ibotenic Acid and Muscimol

Abstract

dl-Ibotenic acid (I) was synthesized in a better yield than the known methods, starting from diethyl 3-chloroglutaconate (VII). Reaction of VII with hydroxylamine in the presence of sodium hydroxide followed by esterification afforded ethyl 3-hydroxy-5-isoxazoleacetate (IV), which was, after benzenesulfonylation, brominated with NBS to ethyl α-bromo-3-benzenesulfonyloxy-5-isoxazoleacetate (X). Hydrolysis and treatment with ammonia of X gave I. Synthesis of muscimol (II) from IV was also described.