反应详情

Propan-2-yl 4-amino-6-chloro-5-fluoropicolinate (1.191 g, 5.12 mmol) was almost completely dissolved in CH2Cl2 (40 mL). Water (40 mL) was added. Chlorine was bubbled through the solution for 5 min. After 30 min, an aliquot of the reaction mixture was analyzed by GC, showing desired product and only 1.7% starting material. The aqueous layer was separated and extracted with CH2Cl2 (50 mL). The combined organic extracts were washed with satd aq NaHCO3 solution and then brine. The extracts were dried (MgSO4) and concentrated under reduced pressure to yield an orange oil. Flash chromatography (120 g silica column; 0-50% EtOAc-hexane gradient) afforded a bright yellow crystalline solid (394 mg, 28%): 1H NMR (400 MHz, CDCl3) δ 5.29 (septet, J=6.3 Hz, 1H, CHMe2), 5.19 (br s, 2H, NH2), 1.40 (d, J=6.3 Hz, 6H, CHMe2); 13C{1H} NMR (101 MHz, CDCl3) δ 163.2 (CO2R), 143.3 (d, JF-C=5 Hz, C2), 142.8 (d, JF-C=270 Hz, C5), 141.0 (d, JF-C=26 Hz, C4), 135.3 (d, JF-C=17 Hz, C6), 114.9 (s, C3), 70.6 (CHMe2), 21.6 (s, Me); 19F NMR (376 MHz, CDCl3) δ −136.5.

1. customChlorine was bubbled through the solution for 5 min
2. customThe aqueous layer was separated
3. extractionextracted with CH2Cl2 (50 mL)
4. washThe combined organic extracts were washed with satd aq NaHCO3 solution
5. dry with materialThe extracts were dried (MgSO4)
6. concentrationconcentrated under reduced pressure
7. customto yield an orange oil