反应详情

温度

50 °C

A solution of N-(4-bromo-2-fluoro-benzyl)-2-hydroxy-5-nitro-benzamide (0.95 g, 2.6 mmol) in acetone (15 mL, 0.2 M) was treated with aq K2CO3 (2 M, 1.9 mL, 3.8 mmol) and t-butyl bromoacetate (2.2 mL, 8.4 mmol). After heating to 50° C. for 30 h, the reaction was acidified to pH 1–2 with 2 N HCl and extracted with ethyl acetate (3×). The combined organic extracts were washed With saturated aq NaCl, dried over Na2SO4, filtered and concentrated. The crude oil was crystallized from heptane and ethyl acetate to give [2-(4-bromo-2-fluoro-benzylcarbamoyl)-4-nitro-phenoxy]-acetic acid tert-butyl ester as a white crystalline solid (1.21 g, 97%): 1H NMR (DMSO-d6, 300 MHz) δ 9.01 (br t, J=5.7 Hz, 1 H), 8.58 (d, J=3.0 Hz, 1 H), 8.33 (dd, J1=9.0 Hz, J2=3.0 Hz, 1 H), 7.51 (br d, J=9.6 Hz, 1 H), 7.42–7.34 (m, 2 H)., 7.32 (d, J=9.3 Hz, 1 H), 4.99 (s, 2 H), 4.52 (d, J=5.7 Hz, 2 H), 1.40 (s, 9 H).

1. extractionextracted with ethyl acetate (3×)
2. washThe combined organic extracts were washed With saturated aq NaCl
3. dry with materialdried over Na2SO4
4. filtrationfiltered
5. concentrationconcentrated
6. customThe crude oil was crystallized from heptane and ethyl acetate