反应详情

A solution of 2,6-dibromopyridine (1.00 g, 4.22 mmol) in THF (40 mL) was cooled to −78° C. (dry-ice/acetone bath) and treated with nBuLi (2.64 mL of a 1.6M solution in hexanes, 4.22 mmol) drop-wise over 10 minutes under nitrogen. After 30 minutes at this temperature the pale yellow/green solution was treated with butyraldehyde (400 μL, 4.44 mmol) drop-wise over 5 minutes and the resulting orange/red solution stirred at this temperature for 1 hour. The solution was then allowed to warm slowly to 0° C. (ice/water bath) over 20 minutes and was then quenched by the drop-wise addition of aqueous HCl (2M, 4 mL). The resulting pale yellow solution was reduced to an oil, partitioned between EtOAc (100 mL) and aqueous HCl (2M, 100 mL), and the layers separated. The aqueous was re-extracted with EtOAc (100 mL) and the combined organic layer washed with water (150 mL), brine (150 mL), dried (MgSO4), filtered and reduced to an orange/yellow oil. Purification by SPE (silica) eluting with cyclohexane:EtOAc (gradient 100:1 to 2:1) afforded the title compound (626 mg).

1. customwas then quenched by the drop-wise addition of aqueous HCl (2M, 4 mL)
2. custompartitioned between EtOAc (100 mL) and aqueous HCl (2M, 100 mL)
3. customthe layers separated
4. extractionThe aqueous was re-extracted with EtOAc (100 mL)
5. washthe combined organic layer washed with water (150 mL), brine (150 mL)
6. dry with materialdried (MgSO4)
7. filtrationfiltered
8. customPurification by SPE (silica)
9. washeluting with cyclohexane