The Boc protected phenylalanine (Boc-Phe-OH) reacted with phenylalanine amide to give the first dipeptide Boc-Phe-Phe-NH_2 in 86% yield.

• 以叔丁氧羰酰基(Boc)作为苯丙氨酸的氨基保护基，先制备苯丙氨酸酰胺三氟乙酸盐，再用叔丁氧羰酰基(Boc)保护的苯丙氨酸与其缩合得二肽片段Boc-Phe-Phe-NH_2，产率86%25。