(2R,3S)-2-[(S)-2-((R)-2-{2-[((R)-4-tert-Butoxycarbonylamino-4-methoxycarbonyl-butyryl)-methyl-amino]-acryloylamino}-propionylamino)-4-methyl-pentanoylamino]-3-[(S)-1-(2,2,2-trichloro-ethoxycarbonyl)-ethylcarbamoyl]-butyric acid methyl ester

Boc-D-iso-Glu(OMe)-N-(Me)-Gly-D-Ala-L-Leu-OH

Boc-Gly-D-Ala-L-Leu-OtBu

(S)-2-((R)-2-{2-[((R)-4-tert-Butoxycarbonylamino-4-methoxycarbonyl-butyryl)-methyl-amino]-acryloylamino}-propionylamino)-4-methyl-pentanoic acid