Acetic Acid → Methyl 2-[(tert-butoxycarbonyl)(3-chloro-2-propen-1-yl)amino]-1-bromo-6-naphthoate

Beteiligte Stoffe

Reaktionsschritte

A stirred solution of bromide 148 (1.05 g, 2.76 mmol) in dry DMF (8 mL) was treated at 0° C. with NaH (132 mg, 60% in oil, 3.30 mmol). The resulting suspension was warmed to room temperature for 30 min, then cooled to 0° C. and treated with 1,3-dichloropropene (0.80 mL, 8.7 mmol, mixed isomers). The mixture was stirred at room temperature for a further 4 h then poured into dilute aqueous AcOH and exacted with EtOAc (×2). The combined organic layers were washed with dilute aqueous NaHCO3 and water (×2), dried, and concentrated to dryness under reduced pressure at 100° C. The residue was chromatographed on silica gel, eluting with CH2Cl2/EtOAc (19:1) to give methyl 2-[(tert-butoxycarbonyl)(3-chloro-2-propen-1-yl)amino]-1-bromo-6-naphthoate (149) (1.19 g, 95%) as a gum; 1H NMR [(CD3)2SO] (mixture of rotamers and E and Z forms) δ 8.73 (s, 1H), 8.34 (d, J=8.9 z, 1H), 8.16 (d, J=8.9 Hz, 1H), 7.63, 7.58 (2 d, J=8.7 Hz, 1H), 8.25, 8.24 (2 d, J=8.6 Hz, 1H), 6.45-6.31 (m, 1H), 6.20-6.00 (m, 1H), 4.58-4.48, 4.43-4.21, 4.16-4.00 (3 m, 2H), 3.95 (s, 3H), 1.50, 1.27 (2 s, 9H). HRMS (FAB) calcd. for C20H2279Br35ClNO4 (MH+) m/z 454.0421, found 454.0410.

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