反应详情

(2R,3R)-2-(3-chloro-4-cyano-2-methylphenylamino)-3-hydroxybutanoic acid (intermediate 3a) (503 mg, 1.9 mmol) was coupled with 4-hydroxy-benzohydrazide (285 mg, 1.9 mmol) similarly to the procedure described for the preparation of intermediate 1b. Trituration with hot methylene chloride provided the title compound as a white solid (380 mg, 62%). 1H NMR (500 MHz, acetone-d6, δ in ppm) 9.68 (br s, 1H), 9.30 (br s, 1H), 7.85 (AA′XX′, J=8.7 Hz, 2H), 7.52 (d, J=8.7 Hz, 1H), 6.91 (AA′XX′, J=8.8 Hz, 2H), 6.71 (d, J=8.6 Hz, 1H), 5.59 (d, J=7.1 Hz, 1H), 4.84 (br s, 1H), 4.20 (m, 1H), 4.09 (m, 1H), 2.34 (s, 3H), 1.37 (d, J=6.3 Hz, 3H).