反应详情

POCl3 (4 mL, 1.1 eq) added to 9 mL (3 eq) of DMF cooled in an ice bath. After 15 mins, a solution of the 4-methyl-1H-pyrrole-3-carboxylic acid ethyl ester (6 g, 39.2 mmol) in DMF (2M, 20 mL) was added to the reaction and stirring continued at rt. After 2 hr, the reaction mixture was diluted with water (100 mL) and basified to pH=11 with 1N NaOH. The aqueous layer was extracted into DCM (2×250 mL), washing the combined organic layers with water (2×400 mL), dried (MgSO4), filtered through a plug of silica and concentrated to afford a pinkish solid. Trituration with hexanes afforded 3.3 g (46%) of 5-formyl-4-methyl-1H-pyrrole-3-carboxylic acid ethyl ester as a tan solid

1. temperaturecooled in an ice bath
2. customcontinued at rt
3. waitAfter 2 hr
4. extractionThe aqueous layer was extracted into DCM (2×250 mL)
5. washwashing the combined organic layers with water (2×400 mL)
6. dry with materialdried (MgSO4)
7. filtrationfiltered through a plug of silica
8. concentrationconcentrated
9. customto afford a pinkish solid