反应详情

(2R,3S)-2-(3-chloro-4-cyano-2-methylphenylamino)-3-hydroxybutanoic acid (intermediate 1a) (534 mg, 1.9 mmol) and 4-hydroxy-benzohydrazide (304 mg, 2.0 mmol) were coupled similarly to the procedure described for the preparation of intermediate 1b. After column chromatography (3% methanol/EtOAc) the title compound was isolated as a white solid (490 mg, 61%). 1H NMR (500 MHz, acetone-d6, δ in ppm) 9.76 (br s, 1H), 9.49 (br s, 1H), 9.15 (br s, 1H), 7.83 (AA′XX′, =8.8 Hz, 2H), 7.46 (d, J=8.6 Hz, 1H), 6.89 (AA′XX′, J=8.8 Hz, 2H), 6.64 (d, J=8.7 Hz, 1H), 5.53 (d, J=7.2 Hz, 1H), 5.01 (br s, 1H), 4.39 (m, 1H), 4.11 (dd, J=3.0, 6.4 Hz, 1H), 2.33 (s, 3H), 1.33 (d, J=6.5 Hz, 3H).