Реакция #317218

Уравнение реакции

ammonium chloride

2-bromo-7-(pyridin-3-yl)triethylsilyloxymethylimidazo[5,1-b]thiazole

ethylmagnesium bromide

N-Methyl-N-methoxypropionamide

→

2-propionyl-7-(pyridin-3-yl)triethylsilyloxymethylimidazo[5,1-b]thiazole

Выход 79.8%

Растворители

tetrahydrofuran

tetrahydrofuran

Условия реакции

Обработка

1. 1
   workup.STIRRINGat −30° C., and the mixture was stirred at room temperature for 12 hr
2. 2
   Другоеthe reaction
3. 3
   Экстракцияthe reaction mixture was extracted with ethyl acetate
4. 4
   ПромывкаThe extract was washed with a saturated aqueous sodium bicarbonate solution and saturated brine in that order
5. 5
   Сушкаwas then dried over anhydrous magnesium sulfate
6. 6
   ДругоеThe solvent was removed by evaporation
7. 7
   Другоеthe residue was purified by column chromatography on silica gel (3 to 6% methanol/methylene chloride)

Методика

A solution of 5.14 g of 2-bromo-7-(pyridin-3-yl)triethylsilyloxymethylimidazo[5,1-b]thiazole in 36 ml of tetrahydrofuran under an argon atmosphere was cooled to −60° C., 13.3 ml of a 0.89 M tetrahydrofuran solution of ethylmagnesium bromide was added thereto, and the mixture was stirred for one hr. N-Methyl-N-methoxypropionamide (1.71 g) was added thereto at −30° C., and the mixture was stirred at room temperature for 12 hr. A 20% aqueous ammonium chloride solution was added to stop the reaction, and the reaction mixture was extracted with ethyl acetate. The extract was washed with a saturated aqueous sodium bicarbonate solution and saturated brine in that order and was then dried over anhydrous magnesium sulfate. The solvent was removed by evaporation, and the residue was purified by column chromatography on silica gel (3 to 6% methanol/methylene chloride) to give 3.88 g of 2-propionyl-7-(pyridin-3-yl)triethylsilyloxymethylimidazo[5,1-b]thiazole.

Источник