反应详情

A solution of 3,5-dichloro-4-methyl-pyridine (2.06 g, 12.7 mmol) in dry tetrahydrofuran (30 ml) was cooled down to −78° C., then a 1.8 M solution of lithium diisopropylamide in tetrahydrofuran (7.4 ml, 13.3 mmol) was added dropwise under stirring, keeping the temperature below −70° C. The resulting solution was stirred for 30 min., then a solution of 3,4-dimethoxy-benzoyl chloride (2.55 g, 12.7 mmol) in dry tetrahydrofuran (20 ml) was added dropwise, maintaining the temperature below −70° C. After stirring for 15 minutes, ice (20 g) was added, followed by further 500 ml of water. The mixture was extracted with ethyl acetate (2×50 ml), the combined organic layers were dried over sodium sulphate and evaporated under reduced pressure to give an oil that was purified by flash chromatography (Eluent:ethyl acetate/petroleum ether from 10/90 to 30/70 v:v). 2.1 grams (6.4 mmol, 52% yield) of the title compound were obtained as a white solid.

1. customthe temperature below −70° C
2. stirringThe resulting solution was stirred for 30 min.
3. temperaturemaintaining the temperature below −70° C
4. stirringAfter stirring for 15 minutes
5. extractionThe mixture was extracted with ethyl acetate (2×50 ml)
6. dry with materialthe combined organic layers were dried over sodium sulphate
7. customevaporated under reduced pressure
8. customto give an oil that
9. customwas purified by flash chromatography (Eluent:ethyl acetate/petroleum ether from 10/90 to 30/70 v:v)