Triethylamine → 3,4-dichloro-N'-((2R,3S)-2-(3-chloro-4-cyano-2-methylphenyl-amino)-3-hydroxybutanoyl)benzohydrazide

Participants

Reaction Conditions

Reaction Steps

(2R,3S)-2-(3-chloro-4-cyano-2-methylphenylamino)-3-hydroxybutanoic acid (1.0 g, 3.7 mmol), 3,4-dichlorobenzohydrazide (CAS 28036-91-1, 763 mg, 3.7 mmol) and anhydrous THF (100 mL) were placed in a 500 mL round bottomed flask and the mixture was cooled to −15° C. 1-Hydroxybenzotriazole hydrate (502.8 mg, 3.7 mmol) was added to the mixture together with N-(3-Dimethylaminopropyl)-N′-ethylcarbodimide HCl (1.4 g, 7.4 mmol) and triethylamine (1.03 mL, 7.4 mmol) at −15° C. The reaction mixture was maintained at −15° C. and stirred for 1 h after which stirring continued overnight while the mixture slowly warmed to room temperature. After 18 h, the mixture was filtered under vacuum and the residue washed with THF (50 mL). The THF solution was concentrated to ca. 10 mL, whereupon ethyl acetate (200 mL) was added followed by water (100 mL). The phases were partitioned and the organic phase washed with water (50 mL), brine (50 mL), dried (Na2SO4), filtered and concentrated to furnish a light brown solid. 1H NMR (500 MHz, acetone-d6, δ in ppm) 8.10 (d, J=2.1 Hz, 1H), 7.90 (dd, J=2.2 Hz, 8.3 Hz, 1H), 7.74 (d, J=8.3 Hz, 1H), 7.55 (d, J=8.5 Hz, 1H), 6.71 (d, J=8.5 Hz, 1H), 5.57 (d, J=6.8 Hz, 1H), 4.44-4.36 (m, 1H), 4.16-4.10 (m, 1H), 2.88-2.80 (m, 1H), 2.37 (s, 3H), 1.37 (d, J=6.3 Hz, 3H).

Provenance & Evidence