反应详情

To a solution of the compound 16 (1.93 g), 1H-imidazole-2-carboxylic acid (773 mg) and diisopropylethylamine (2.97 g) in dichloromethane (15 mL), O-(7-azabenzotriazol-1-yl)N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU) (2.62 g) was added under ice cooling. The reaction mixture was stirred at room temperature for 4 hours. To the reaction mixture, an aqueous 1N sodium hydroxide solution (30 mL) was added. The aqueous layer was extracted twice with dichloromethane (50 mL). The combined organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and then concentrated. The residue was purified by silica gel chromatography (ethyl acetate:methanol=1:0→10:1) to obtain the title compound (977 mg) having the following physical properties.

1. extractionThe aqueous layer was extracted twice with dichloromethane (50 mL)
2. washThe combined organic layer was washed with saturated brine
3. dry with materialdried over anhydrous magnesium sulfate
4. concentrationconcentrated
5. customThe residue was purified by silica gel chromatography (ethyl acetate:methanol=1:0→10:1)