反应详情

A mixture of 3-amino-5-(pyridin-4-yl)thiophene-2-carboxamide (0.044 g, 0.20 mmol) in methyl 2,2-dimethoxypropanoate (0.3 mL) and trifluoroacetic acid (0.5 mL) was stirred at room temperature for 1 h. Then, the reaction mixture was concentrated, and the obtained residue was dissolved in methanol (10 mL), and the solution was concentrated with NaHCO3 (0.5 g) and silica gel (2 mL), and the residue was purified by flash chromatography (Combiflash, silica gel, dichloromethane to 90:10 dichloromethane/methanol) to give a crude product. Trituration with hexanes/ethyl acetate gave the title compound (0.026 g, 42%) as a yellow solid:

1. concentrationThen, the reaction mixture was concentrated
2. dissolutionthe obtained residue was dissolved in methanol (10 mL)
3. concentrationthe solution was concentrated with NaHCO3 (0.5 g) and silica gel (2 mL)
4. customthe residue was purified by flash chromatography (Combiflash, silica gel, dichloromethane to 90:10 dichloromethane/methanol)
5. customto give a crude product