Poststatin, a new inhibitor of prolyl endopeptidase. IV. The chemical synthesis of poststain.

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.