反应详情

The 476 g of crude 2-bromo-5-bromomethylpyridine from step 4 was dissolved in 4000 mL of dimethylformamide (DMF)/water (7:1) and treated with 168 g (2.58 mol) of potassium cyanide. The reaction was allowed to stir at ambient temperature for 72 h, concentrated in vacuo, and partitioned between ethyl acetate and water; the organic layer was washed with water, washed with brine, dried (MgSO4), and reconcentrated in vacuo to provide the crude nitrile. Purification by silica gel chromatography (Waters Prep-500A) using ethyl acetate/hexane (25:75) gave 109 g (32% from 2-bromo-5-picoline) of 2-bromo-5-cyanomethylpyridine as a yellowish orange solid: mp 55.5°-57.5° C.; NMR (CDCl3)δ3.74 (s, 2 H), 7.54 (d, J=8 Hz, 1 H), 7.59 (dd, J=8 and 2 HZ, 1 H), 8.35 (d, J=2 Hz, 1 H); MS (FAB) m/e (rel intensity) 199 (85), 197 (100).

1. concentrationconcentrated in vacuo
2. custompartitioned between ethyl acetate and water
3. washthe organic layer was washed with water
4. washwashed with brine
5. dry with materialdried (MgSO4)
6. customto provide the crude nitrile
7. customPurification by silica gel chromatography (Waters Prep-500A)