反应详情

温度

-20 °C

(2R,3S)-2-(3-chloro-4-cyano-2-methylphenylamino)-3-hydroxybutanoic acid (5.0 g, 18.6 mmol), 4-bromobenzhydrazide (CAS 5933-32-4, 4.0 g, 18.6 mmol) and 1-Hydroxybenzotriazole hydrate (2.52 g, 18.6 mmol) were placed in a 250 mL round bottomed flask. Anhydrous THF (120 mL) was added and the mixture was cooled to −20° C. N-(3-Dimethylaminopropyl)-N′-ethylcarbodimide HCl (5.35 g, 27.9 mmol) was added, followed by Et3N (3.9 mL, 28.0 mmol). The reaction mixture was stirred at −20° C. for 1 h and room temperature for overnight. The reaction was quenched by adding water and extracted with EtOAc, which was washed with 5% aqueous NaOH, water, brine and dried over Na2SO4. The extracts were filtered and the filtrate was concentrated to provide a brown solid, which was purified by flash chromatography washed with 80% EtOAc in hexanes to afford the title compound (6.6 g, 76%). 1H NMR (400 MHz, acetone-d6, δ in ppm) 7.87 (d, J=8.6 Hz, 2H), 7.71 (d, J=8.6 Hz, 2H), 7.54 (d, J=8.6 Hz, 1H), 6.67 (d, J=8.6 Hz, 1H), 5.55 (d, J=7.4 Hz, 1H), 4.39 (m, 1H), 4.10 (dd, J=3.3, 7.4 Hz, 1H), 2.36 (s, 3H), 1.35 (d, J=6.4 Hz, 3H).

1. customThe reaction was quenched
2. additionby adding water
3. extractionextracted with EtOAc, which
4. washwas washed with 5% aqueous NaOH, water, brine
5. dry with materialdried over Na2SO4
6. filtrationThe extracts were filtered
7. concentrationthe filtrate was concentrated
8. customto provide a brown solid, which
9. customwas purified by flash chromatography
10. washwashed with 80% EtOAc in hexanes