反应详情

5-Iodo-2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester 6d (4.1 g, 13.99 mmol) was dissolved in 80 mL of tetrahydrofuran followed by addition of 4-methyl-benzenesulfonic acid methyl ester (2.73 g, 14.69 mmol) and sodium tert-butoxide (2.02 g, 20.99 mmol). Upon completion of the addition, the reaction mixture was stirred for 0.5 hours and monitored by TLC until the disappearance of the starting materials. The mixture was filtered and the filter cake was washed with tetrahydrofuran. The filtrate was concentrated under reduced pressure to obtain the title compound 5-iodo-1,2,4-trimethyl-1H-pyrrole-3-carboxylic acid ethyl ester 6e (3.8 g, yield 88.6%) as a grey solid.

1. additionUpon completion of the addition
2. filtrationThe mixture was filtered
3. washthe filter cake was washed with tetrahydrofuran
4. concentrationThe filtrate was concentrated under reduced pressure