Trifluoroacetic acid → HCID 71237033, compound

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Reaction Steps

Add trifluoroacetic acid (124.0 mL, 1.64 mol) in several portions to a solution of 5-[2-(tert-butyl(dimethyl)silyl)oxyethyl]-7-hydroxyimino-pyrido[2,3-d][3]benzazepin-6-one (155.0 g, 389.9 mmol) in a mixture of dichloromethane (620 mL) and methanol (310 mL) in an ambient temperature water bath. Add zinc (76.5 g, 1.2 mol) in several portions so that internal temperature was maintained at 33-38° C. Stir for 15 hours at ambient temperature. Filter mixture through Celite®, wash with 10% methanol/dichloromethane (100 mL) and concentrate the filtrate. Add dichloromethane (0.5 L) and ice (500 g), stir and basify with a 50% aqueous solution of NaOH. Filter out solids, separate filtrate layers. Extract from aqueous with dichloromethane (2×100 mL), and concentrate combined organics. Slurry solids in hexane, and then filter and dry under high vacuum to obtain the racemate of the title compound as a light yellow solid (74.0 g, 274.8 mmol, 71%). Purify the material on a Chiralpak® AD column eluting with ethanol (0.2% dimethethylamine): acetonitrile (0:100 to 100:0) to obtain the title compound (35.0 g, 130 mmol, 33.3%) as a white solid. MS (m/z): 270 (M+1); [α]Na25=+187.83° (c=6.9, methanol).

Provenance & Evidence