Acetic Acid → Benzoic acid, 2-bromo-5-chloro-3-[(tetrahydro-2H-pyran-4-yl)amino]-, methyl ester

Participants

Reaction Steps

To a solution of methyl 3-amino-2-bromo-5-chlorobenzoate (1.0 g, 3.8 mmol) in 1,2-dichloroethane (15 ml) at room temperature under nitrogen was added oxan-4-one (0.7 ml, 7.6 mmol) followed by acetic acid (1.3 ml, 23 mmol). This solution was stirred for 5 minutes before the addition of sodium triacetoxyborohydride (2.4 g, 11 mmol) at room temperature. After 21 h, additional oxan-4-one (0.7 ml, 7.6 mmol) was added to the reaction mixture, with stirring for 10 minutes before adding sodium triacetoxyborohydride (2.4 g, 11 mmol). After stirring for 20 h, deionized water (30 ml) was added and the mixture was neutralised with solid NaHCO3. The phases were separated and the aqueous layer was extracted with EtOAc (2×30 ml). The combined organic extracts were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by FCC (25 g silica, Isolute cartridge, gradient of eluents; 9:1 Heptane:EtOAc to 8:2 Heptane:EtOAc) to give 903 mg (68%) of the title compound as a white solid. LC-MS 92%, 2.11 min (3 minute LC-MS method), m/z=348.2/350.2/351.9, 1H NMR (500 MHz, Chloroform-d) δ 6.94-7.07 (1H, m), 6.70 (1H, d, J=2.36 Hz), 4.72 (1H, d, J=7.57 Hz), 3.96-4.15 (2H, m), 3.87-3.96 (3H, m), 3.40-3.67 (3H, m), 2.05 (2H, d, J=13.08 Hz), 1.49-1.69 (2H, m).

Provenance & Evidence