Z)-OMe. The (N-Me)-β-HThr-(N-Me)-β-HPhe analog was also prepd. C- and N-terminal deprotection and cyclization through the pentafluorophenyl ester gave the insol. beta-tetrapeptide with protected Thr and Lys side chains. Solubilization and debenzylation could only be effected in LiCl-contg. THF (ca. 10% yield; with ca. 55% recovery). HPLC Purifn. provided a sample of the title compd., the structure