Imidazole → N'-((2R,3S)-3-(tert-Butyldimethylsilyloxy)-2-(3-chloro-4-cyanophenylamino)butanoyl)-4-(methylsulfonyl)benzohydrazide

Participants

Reaction Steps

Imidazole (3.77 g, 55.44 mol) and TBDMS-Cl (5.01 g, 33.24 mmol) were added sequentially to a pre-cooled (0° C.) solution of N′-((2R,3S)-2-(3-chloro-4-cyanophenylamino)-3-hydroxybutanoyl)-4-(methylsulfonyl)benzohydrazide (5 g, 11.08 mmol) in DMF (350 mL). The reaction mixture was allowed to warm to room temperature and stirred for 17 h, whereupon the solution was poured into H2O (90 mL). The white precipitate was filtered, washed with H2O (30 mL) and taken up in CH2Cl2 (170 mL). This organic layer was washed with brine (1×50 mL), dried (Na2SO4), filtered and concentrated to provide the title compound (4.3 g, 69%). 1H NMR (400 MHz, acetone-d6, δ in ppm) 9.8 (br s, 1H), 8.08 (d, J=8.0 Hz, 2H), 8.04 (d, J=9 Hz, 2 H), 7.53 (d, J=8 Hz, 1H), 6.99 (s, 1H), 6.85 (d, J=8 Hz, 1H), 6.22 (d, J=8 Hz, 1H), 4.43-4.38 (m, 1H), 4.27-4.22 (m, 1H), 1.37 (d, J=7 Hz, 3H), 0.86 (s, 9H), 0.11 (s, 3H) and 0.05 (s, 3H).

Provenance & Evidence