反应详情

To a solution of 3-[dibromo(2-pyridyl)methyl]-1,2,4-thiadiazolo[4,5-a]benzimidazole (2.02 g, 4.76 mmol) in 75 mL tetrahydrofuran was added a solution of silver nitrate (0.890 g, 5.24 mmol) in 75 mL water. The suspension was stirred for 2 days and then basified to pH 6 with aqueous sodium bicarbonate. After the addition of 1 mL saturated aqueous sodium chloride, the mixture was filtered on celite and the celite was washed with ethyl acetate. After extraction with water, the ethyl acetate was dried and evaporated to give a crude residue which was purified by flash chromatography using a mixture of chloroform/methanol 10:0.1 as the eluent. 1.05 g (78%) of the title compound was obtained as a yellow solid: mp 182-186° C. (dec); 1H NMR (CDCl3)δ 8.85 (m, 1H), 8.31 (dt, 1H), 8.19 (d, 1H), 8.01 (td, 1H), 7.83 (d, 1H), 7.63 (ddd, 1H), 7.50 (ddd, 1H), 7.35 (ddd, 1H) ppm; IR (film) 1673, 1511, 1444, 1235, 1057, 879, 733 cm-1 ; MS m/z 280 (M+), 148 (M+ -(2-pyridyl)C(O)CN).

1. filtrationthe mixture was filtered on celite
2. washthe celite was washed with ethyl acetate
3. extractionAfter extraction with water
4. dry with materialthe ethyl acetate was dried
5. customevaporated
6. customto give a crude residue which
7. customwas purified by flash chromatography
8. additiona mixture of chloroform/methanol 10:0.1 as the eluent