反应详情

5-(Cyclopropyl-hydroxy-methyl)-3-methyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester 60a (323 mg, 1 mmol) was dissolved in 4 ml of ethanol under stirring, and added with hydrobromic acid (2.8 ml, 40%) to the solution and stirred for 30 minutes at room temperature. After thin lay chromatography showed the disappearance of starting materials, the reaction mixture was extracted with ethyl acetate (10 ml×5). The combined organic extracts were washed with saturated brine (15 ml), dried over anhydrous magnesium sulfate, filtered to remove the drying agent and concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain the title compound 5-(4-bromo-but-1-enyl)-3-methyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester 60b (345 mg, yield 89.5%) as a white solid.

1. stirringstirred for 30 minutes at room temperature
2. extractionthe reaction mixture was extracted with ethyl acetate (10 ml×5)
3. washThe combined organic extracts were washed with saturated brine (15 ml)
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationfiltered
6. customto remove the drying agent
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by silica gel column chromatography