Total synthesis of poststatin was achieved by both liquid phase and solid phase methods. In both methods, the (2R, 3S)-3-amino-2-hydroxyvaleric acid moiety was incorporated into protected pentapeptides, and was oxidized to (S)-3-amino-2-oxovaleric acid (postine). Deprotection of the oxidized pentapeptides gave a specimen identical with natural poststatin in physico-chemical properties and prolyl endopeptidase inhibitory activity.
Poststatin, a New Inhibitor of Prolyl Endopeptidase. III. Optical Resolution of 3-Amino-2-hydroxyvaleric Acid and Absolute Configuration of Poststatin.
3-Amino-2-hydroxyvaleric acid was prepared, and separated into its diastereomers. The relative stereochemistry was determined by 1H NMR in their oxazolidone derivatives. The threo-isomer was resolved by (S)-1-(1-naphthyl) ethylamine in the N-(p-methoxybenzyloxycarbonyl) derivative. The absolute configuration of (--)-threo-3-(p-methoxybenzyloxycarbonyl)amino-2-hydroxyvaleric acid was confirmed to be 2R