反应详情

At 0° C., a solution of tin chloride dihydrate (25.9 g) in concentrate aqueous HCl (76 mL) was added dropwise over 40 minutes to a solution of 6-chloro-4-ethylamino-3-nitro-pyridine-2-carbonitrile (2.9 g) in DMF (70 mL). The mixture was stirred for 2.5 hours, then poured to a mixture of ice (400 g) and 50% potassium hydroxide (400 mL), extracted with ethyl acetate (3×100 ml). The combined organic layers were washed with 2N sodium hydroxide (700 mL), then brine (3×100 mL), dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was chromatographed over silica gel (eluent: dichloromethane/ethyl acetate 9/1) to afford the title compound (2.0 g) as white crystals (mp=150° C.). 1H NMR (DMSO-d6) δ: 6.46 (s, 1H); 6.42 (br.s, 1H); 6.02 (br.s, 2H); 3.20 (q, J=8 Hz, 2H); 1.26 (t, J=8 Hz, 3H). MS m/z: 197/199 (M+1).

1. extractionextracted with ethyl acetate (3×100 ml)
2. washThe combined organic layers were washed with 2N sodium hydroxide (700 mL)
3. dry with materialbrine (3×100 mL), dried over sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated under reduced pressure
6. customThe residue was chromatographed over silica gel (eluent: dichloromethane/ethyl acetate 9/1)