2,5-anhydro-3,4-di-O-benzyl-D-idaric acid 、 (S)-2-((S)-2-Amino-3-phenyl-propionylamino)-3-methyl-N-pyridin-2-ylmethyl-butyramide 以55%的产率得到(2R,3S,4S,5R)-3,4-Bis-benzyloxy-tetrahydro-furan-2,5-dicarboxylic acid bis-[((S)-1-{(S)-2-methyl-1-[(pyridin-2-ylmethyl)-carbamoyl]-propylcarbamoyl}-2-phenyl-ethyl)-amide]