反应详情

3,5-dimethyl-1H-pyrrole-2,4-dicarboxylic acid 4-ethyl ester 6c (3.65 g, 17.3 mmol) was dissolved in the solvent mixture of 100 mL of dichloromethane and 10 mL of water followed by addition of potassium iodide (11.5 g, 69.2 mmol) and iodine (4.39 g, 17.3 mmol). Upon completion of the addition, the reaction mixture was heated to reflux for 2 hours. The reaction was monitored by TLC until the disappearance of the starting materials. The mixture was cooled to room temperature and then 20 mL of water and 10 mL of sodium thiosulfate (2 M) were added. The mixture was extracted with dichloromethane (30 mL×3). The combined organic extracts were washed with saturated brine, dried over anhydrous magnesium sulfate, filtered to remove the drying agent and concentrated under reduced pressure to obtain the title compound 5-iodo-2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester 6d (4.1 g, yield 80.8%) as an orange solid.

1. additionUpon completion of the addition
2. temperaturethe reaction mixture was heated
3. temperatureto reflux for 2 hours
4. extractionThe mixture was extracted with dichloromethane (30 mL×3)
5. washThe combined organic extracts were washed with saturated brine
6. dry with materialdried over anhydrous magnesium sulfate
7. filtrationfiltered
8. customto remove the drying agent
9. concentrationconcentrated under reduced pressure