Boc-Gly-Ala-Ala(CH3)   、                                                                                      (S)-2-{(S)-2-[(S)-2-((S)-2-Amino-propionylamino)-4-methyl-pentanoylamino]-3-methyl-pentanoylamino}-4-methyl-pentanoic acid benzyl ester                                                                                                                                                              在
                                                                                                                                                                                 
1-羟基苯并三唑   、                                                                                                  
N,N'-二环己基碳二亚胺                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
二氯甲烷                                                                                  为溶剂,
                                                                                                                                                                                        以94%的产率得到(S)-2-{(S)-2-[(S)-2-((S)-2-{2-[(S)-2-(2-tert-Butoxycarbonylamino-acetylamino)-propionylamino]-2-methyl-propionylamino}-propionylamino)-4-methyl-pentanoylamino]-3-methyl-pentanoylamino}-4-methyl-pentanoic acid benzyl ester