Imidazole → N'-((2R,3S)-3-(tert-Butyldimethylsilyloxy)-2-(3-chloro-4-cyano-2-methylphenylamino)butanoyl)-4-((tert-butyldimethylsilyloxy)methyl)benzohydrazide

Participants

Reaction Steps

Imidazole (3.99 g, 58.55 mol) and TBDMS-Cl (5.29 g, 35 mmol) were added sequentially to a pre-cooled (0° C.) solution of 4-((tert-butyldimethylsilyloxy)methyl)-N′-((2R,3S)-2-(3-chloro-4-cyano-2-methylphenylamino)-3-hydroxybutanoyl)benzohydrazide (6.22 g, 11.71 mmol) in DMF (300 mL). The reaction mixture was allowed to warm to room temperature and stirred for 18 h, whereupon the solution was poured into H2O (120 mL). The white precipitate was filtered, washed with H2O (30 mL) and taken up in CH2Cl2 (200 mL). This organic layer was washed with brine (1×100 mL), dried (Na2SO4), filtered and concentrated to provide the title compound (10.2 g). This crude product was used directly in the next step.

Provenance & Evidence