Under an argon atmosphere, 321 mg (0.60 mmol) of 1-[4-(thiazol-2-yl)-phenyl]-4(S)-hydroxy-2-amino-5(S)-N-(N-methoxycarbonyl-(L)-iso-leucyl)amino-6-phenyl-2-azahexane (Example 21b) and 182 mg (1.8 mmol) of NMM in 5.8 ml of DMF are added to 136 mg (0.72 mmol) of N-ethoxycarbonyl-(L)-valine and 178 mg (0.60 mmol) of TPTU in 3 ml of DMF and the mixture is stirred at room temperature for 15 hours. The reaction mixture is poured into ice-water, stirred for 30 min and filtered. Crystallisation from THF with DIPE and hexane yields the title compound: m.p.: 209-211° C.; HPLC20-100: tRet=15.2; FAB MS (M+H)+=711.
