tert-Butyl 2-(4-(pyridin-2-yl)benzyl)hydrazinecarboxylate → N'-(3-tert-Butoxycarbonylamino-2-hydroxy-4-phenyl-butyl)-N'-(4-pyridin-2-yl-benzyl)-hydrazinecarboxylic acid tert-butyl ester

Participants

Reaction Steps

Into a 100 mL flask was placed (5) (1.0 g, 3.34 mmol), (6) (2S,3S)-1,2-epoxy-3-(Boc-amino)-4-phenylbutane (2.78 g, 10.5 mmol, 3.16 equivalents), and 2-propanol (15 mL). The reaction was heated to reflux. After approximately 61 hours of refluxing, the heat was removed, and the mixture cooled to room temperature. To the cooled mixture was added water/ice (50 mL). To the aqueous mixture was added dichloromethane (50 mL) and then transferred to a separatory funnel. The aqueous layer was extracted with dichloromethane (3×50 mL). The combined organics were washed with water, then saturated sodium chloride, and then dried over sodium sulfate. The dried organic solution was filtered, and the filtrate was concentrated under reduced pressure, and then dried under high vacuum overnight. The yellow foam was purified by Biotage chromatography (40+M cartridge; 0 to 5% methanol/dichloromethane over 25 CV) to give 1.24 g (66%) of (7) as a white solid. TLC Rf (hexane/ethyl acetate, 1:2)=0.45; 1H NMR (CD3OD) δ 8.60 (d, 1H), 7.88 (m 4H), 7.50 (d, 2H), 7.36 (m, 1H), 7.25 (m, 4H), 7.18 (m, 1H), 3.93 (m, 2H), 3.70 (m, 2H), 3.0-2.6 (m, 4H), 1.33 (s, 9H), 1.30 (s, 9H); MS (M)+=563; HPLC tR 9.6 minutes.

Provenance & Evidence