反应详情

4-Chloro-N′(2R,3R)-2-(3-chloro-4-cyano-2-methylphenylamino)-3-hydroxybutanoyl)benzohydrazide was prepared using 4-chlorobenzoic hydrazide (4.42 mmol, 1.1 equiv.) and (2R,3R)-2-(3-chloro-4-cyano-2-methylphenylamino)-3-hydroxybutanoic acid (4.02 mmol, 1.0 equiv.) according to the procedure as described for intermediate 5a. The crude off-white solid was recrystallized using hot methylene chloride to provide the desired product as a white solid (1.57 g, 93% yield). Other data: 1H NMR (400 MHz, acetone-d6, δ in ppm) 9.94 (br. s, 1H), 9.48 (br. s, 1H), 7.95 (d, J=8.5 Hz, 2H), 7.55 (m, 3H), 6.73 (d, J=8.5 Hz, 1H), 5.59 (br. d., J=7.1 Hz, 1H), 4.25 (m, 1H), 4.13 (m, 1H), 2.35 (s, 3H), 1.37 (d, J=6.4 Hz, 3H); LRMS (ESI+) exact mass calcd for C19H18Cl2N4O3 [M]+ 421.28, found 421.3; TLC Rf=0.32, 100% EtOAc, vanillin stain.

1. customThe crude off-white solid was recrystallized