89] γ-aminobutyric acid

Abstract

Publisher Summary This chapter explains the chemical synthesis and properties of γ-aminobutyric acid (GABA). GABA is widely distributed in plants and bacteria. Work in a number of laboratories has shown that GABA has inhibitory effects in tests with invertebrate and vertebrate nervous systems and has indicated that GABA might play an important role in regulation of activity in the nervous system. GABA is a white crystalline solid, and is highly soluble in water and aqueous solutions without showing any characteristic spectral properties in the ultraviolet. The simplest and cheapest method of preparing GABA is by hydrolysis of 2-pyrrolidone (butyrolactam). The pyrrolidone is refluxed with two to three times its weight of barium hydroxide in approximately 10 volumes of water for 2 hours. After cooling, the barium is precipitated by passing in carbon dioxide. The barium carbonate is removed by filtration or centrifugation, and the precipitate is washed. The combined filtrate and washing is treated with a slight excess of sulfuric acid to liberate the amino acid from its barium salt. The complete procedure for the synthesis is described in the chapter. The synthesis of GABA from potassium phthalimide and γ-chlorobutyronitrile is also discussed.