反应详情

3-(2-Amino-benzoylamino)-furo[3,2-c]pyrazole-5-carboxylic acid (11.6 g, 0.03668 mol) was dissolved in anhydrous dimethyl formamide (DMF, 70 mL). Diisopropylethylamine (DIEA, 31.4 mL, 0.1834 mol), cumylamine (7.43 mL, 0.055 mol) and 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate (TBTU, 15.31 g, 0.0476 mol) were added respectively added. The solution was stirred at room temperature overnight. Then it was poured in a saturated solution of sodium bicarbonate (700 mL) and extracted with dichloromethane (2×250 ml). The organic layer was washed with water and dried over Na2SO4. The solution was then evaporated to dryness, taken up with toluene and evaporated to dryness, taken up with ethyl ether and filtered off. The solid was then purified by flash column chromatography on silica gel eluting with dichloromethane-methanol 46/4. The title compound was so obtained (3.87 g, 24.4% yield).

1. additionadded
2. extractionextracted with dichloromethane (2×250 ml)
3. washThe organic layer was washed with water
4. dry with materialdried over Na2SO4
5. customThe solution was then evaporated to dryness
6. customevaporated to dryness
7. filtrationfiltered off
8. customThe solid was then purified by flash column chromatography on silica gel eluting with dichloromethane-methanol 46/4