反应详情

(2S,4S)-4-(2-Benzoxazolyl)amino-1-tert-butoxycarbonylpyrrolidine-2-carboxylic acid (title compound of Reference Example 5, 1.04 g) and (S)-2-cyanopyrrolidine hydrochloride (0.40 g) were dissolved in DMF (5 mL), and triethylamine (0.84 mL), HOBT (0.51 g) and EDC hydrochloride (0.63 g) were successively added thereto. The mixture was stirred at room temperature for 15 hr. Water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The extract was dried and evaporated under reduced pressure. The residue was purified by silica gel chromatography to give (S)-1-[(2S,4S)-4-(2-benzoxazolyl)amino-1-tert-butoxycarbonyl-2-pyrrolidinylcarbonyl]-2-cyanopyrrolidine (0.86 g) as amorphous.