反应详情

To a pre-cooled (−45° C.) solution of (2R,3R)-2-(4-cyanonaphthalen-1-ylamino)-3-hydroxybutanoic acid (1.50 g, 5.55 mmol) and benzohydrazide (756 mg, 5.55 mmol) in anhydrous THF (80 mL) was added 1-hydroxybenzotriazole monohydrate (850 mg, 5.55 mmol) and N-(3-Dimethylaminopropyl)-N′-ethylcarbodimide-HCl (2.13 g, 11.1 mmol) at −45° C. followed by triethylamine (1.55 mL, 11.1 mmol). The reaction mixture warmed to room temperature and stirred for 24 h, then quenched with 5% aq. citric acid (300 mL). The solution was extracted with EtOAc (300 mL). The organic extract was washed with 5% aq. citric acid (2×150 mL), sat. aq. NaHCO3 (3×150 mL), H2O (2×150 mL), dried (Na2SO4), filtered and concentrated under reduced pressure to provide the title compound as a off white solid (1.80 g, 83%): 1H NMR (400 MHz, CDCl3, δ in ppm) 10.58 (br s, 1H), 10.34 (br s, 1H), 8.48 (d, J=9.0 Hz, 1H), 7.98 (d, J=8.0 Hz, 1H), 7.91 (d, J=8.4 Hz, 1H), 7.88 (d, J=7.2 Hz, 1H), 7.74 (t, J=7.4 Hz, 1H), 7.62 (t, J=8.0 Hz, 1H), 7.57 (t, J=8.6 Hz, 1H), 7.48 (t, J=8.0 Hz, 2H), 6.93 (d, J=8.6 Hz, 1H), 6.74 (d, J=8.4 Hz, 1H), 5.26 (d, J=4.9 Hz, 1H), 4.32-4.22 (m, 1H), 4.16 (t, J=7.8 Hz, 1H), 1.33 (d, J=6.3 Hz, 3H).

1. customquenched with 5% aq. citric acid (300 mL)
2. extractionThe solution was extracted with EtOAc (300 mL)
3. extractionThe organic extract
4. washwas washed with 5% aq. citric acid (2×150 mL), sat. aq. NaHCO3 (3×150 mL), H2O (2×150 mL)
5. dry with materialdried (Na2SO4)
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure