反应详情

27.0 g of 5-bromo-2,3-dichloropyridine was dissolved in 450 ml of anhydrous tetrahydrofuran and 7.33 g of acetonitrile was added at ambient temperature under argon. 262 ml of lithium hexamethyldisilazide (1N solution in tetrahydrofuran) was added dropwise over a period of 45 min, during which the temperature rose to 35° C. Subsequently, the reaction mixture was stirred at ambient temperature for 1 h, then the reaction mixture was poured into 800 ml of cold water and was extracted with two 1 L portions of diethyl ether. The combined organic phases were washed with brine, dried over sodium sulfate, filtered and concentrated. 29.4 g of crude material was obtained as a brown oil. It was purified by chromatography on silica gel, using heptane/ethyl acetate (9:1) as a eluent. Thus, 23.4 g of (5-bromo-3-chloro-pyridin-2-yl)-acetonitrile was obtained as a orange oil. 1H-NMR (CDCl3): 8.60 ppm (s, 1H), 7.92 ppm (s, 1H), 4.00 ppm (s, 2H).

1. customrose to 35° C
2. extractionwas extracted with two 1 L portions of diethyl ether
3. washThe combined organic phases were washed with brine
4. dry with materialdried over sodium sulfate
5. filtrationfiltered
6. concentrationconcentrated
7. custom29.4 g of crude material was obtained as a brown oil
8. customIt was purified by chromatography on silica gel