Ethanol → HCID 86629020, compound

Participants

Reaction Steps

Adapting procedures or variations thereof according to Duncan et al., J. Org. Chem. 2001, 66, 5237-5240; Shue et al., Bioorg. Med. Chem. Lett. 1996, 6, 1709-1714; and Khan, J. Org. Chem. 1995, 60, 4536-4541, a 100 mL round-bottomed flask was charged with ethyl (2R)-4-{[3-(1,3-dioxobenzo[c]azolin-2-yl)propyl]sulfonyloxy}-3,3-dimethyl-2-(phenylmethoxy)butanoate (22a) (1.4 g, 2.7 mmol) and 20 mL of a mixture of ethanol (EtOH)/ethyl acetate (EtOAc) (1:1 v/v). Hydrazine (N2H4) (ca. 0.17 mL, 0.17 g, 5.4 mmol) was added at room temperature. The reaction was monitored by LC/MS. Upon completion of the reaction, acetic anhydride (Ac2O) (1.02 mL, 1.1 g, 10.8 mmol) was added to the mixture. The solution was diluted with ethyl acetate and washed with a saturated aqueous solution of sodium hydrogencarbonate (NaHCO3). The organic layer was washed with brine, dried over anhydrous magnesium sulfate (MgSO4), filtered, and the solvents removed under reduced pressure using a rotary evaporator. The crude product was purified by silica gel column chromatography using a mixture of ethyl acetate (EtOAc) and methanol (MeOH) (EtOAc/MeOH=19:1) as eluent to provide 0.8 g (69% yield) of the title compound (22b) as a colorless oil. Rf=0.50 (EtOAc/MeOH=19:1). 1H NMR (400 MHz, CDCl3): δ=1.06 (s, 3H), 1.07 (s, 3H), 1.32 (t, J=6.8 Hz, 3H), 2.00-2.06 (m, 2H), 2.05 (s, 3H), 3.08-3.12 (m, 2H), 3.35 (q, J=6.4 Hz, 2H), 3.83 (s, 1H), 3.97 (d, J=9.2 Hz, 1H), 4.17 (d, J=9.2 Hz, 1H), 4.21-4.27 (m, 2H), 4.36 (d, J=11.2 Hz, 1H), 4.62 (d, J=11.2 Hz, 1H), 5.82-5.86 (br. m, 1H), 7.26-7.35 (m, 5H), ppm. MS (ESI) m/z 430.02 (M+H)+. The analytical data was consistent with the proposed structure.

Provenance & Evidence