(S)-2-(isobutoxycarbonylamino)-3-methylbutanoic acid 、 (2S,4S)-4-Cyclohexyl-pyrrolidine-2-carboxylic acid ((S)-1-{2-[2,6-difluoro-4-(2H-tetrazol-5-yl)-phenyl]-ethylcarbamoyl}-3,3-difluoro-propyl)-amide 在
2,6-二甲基吡啶 、 N-[(dimethylamino)-3-oxo-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl-methylene]-N-methylmethanaminium hexafluorophosphate 作用下,
以
N,N-二甲基甲酰胺 为溶剂,
生成
{(S)-1-[(2S,4S)-4-Cyclohexyl-2-((S)-1-{2-[2,6-difluoro-4-(2H-tetrazol-5-yl)-phenyl]-ethylcarbamoyl}-3,3-difluoro-propylcarbamoyl)-pyrrolidine-1-carbonyl]-2-methyl-propyl}-carbamic acid isobutyl ester