反应详情

To an ice-cooled solution of 5-amino-3-methoxy-[1,2,4]thiadiazole (1.31 g, 10 mmol) in THF (25 mL) was added triethylamine (2.22 g, 11 mmol) followed by dropwise addition of bromoacetyl bromide (1.52 g, 15 mmol). The resulting mixture was stirred at room temperature for 16 h. The mixture was diluted with water (25 mL) and ethyl acetate (50 mL). The aqueous layer was extracted with ethyl acetate (3×50 mL). The combined organic layers was dried (sodium sulfate), filtered and concentrated in vacuo. Purification by column chromatography on silica gel using a solvent gradient of a mixture of dichloromethane and methanol (98/2, 97/3 and 96/4) afforded 3-methoxy-5-bromoacetamido-[1,2,4]thiadiazole as a white solid (1.26 g, 50%). M.p. 198-199° C.; 1H-NMR (CDCl3) δ 13.10 (br. s, 1H, NH), 4.28 (s, 2H, CH2), 4.11 (s, 3H, OMe); 13C-NMR (CDCl3) δ 176.8 (C3), 166.9 (C5), 166.6 (C═O), 56.9 (OMe), 25.9 (CH2).

1. extractionThe aqueous layer was extracted with ethyl acetate (3×50 mL)
2. dry with materialThe combined organic layers was dried (sodium sulfate)
3. filtrationfiltered
4. concentrationconcentrated in vacuo
5. customPurification by column chromatography on silica gel using
6. additiona solvent gradient of a mixture of dichloromethane and methanol (98/2, 97/3 and 96/4)