Tributylstannane → 2-(Tributylstannyl)pyrazine

n-Butyllithium (30.0 ml, 1.6M in hexanes, 48.0 mmol) was added dropwise to a cooled (−40° C.) solution of diisopropylamine (7 ml, 50.1 mmol) in tetrahydrofuran (30 ml), so as to maintain the temperature below −30° C. Once addition was complete, the solution was allowed to warm to room temperature for 2 minutes, then re-cooled to −70° C. Tri-n-butyltin hydride (12 ml, 45.8 mmol) was added dropwise over 10 minutes, and once addition was complete, the reaction was stirred at −60° C. for 2 hours. A solution of 2-chloropyrazine (5.0 g, 43.7 mmol) in tetrahydrofuran (5 ml) was added, and the reaction allowed to warm to room temperature. Aqueous ammonium chloride solution was added to quench the reaction, followed by dilution with ethyl acetate. The resulting suspension was filtered through Celite®, and the filtrate separated. The organic phase was washed with brine, dried (MgSO4), and evaporated under reduced pressure. The residual oil was purified by column chromatography on silica gel using an elution gradient of pentane:ethyl acetate (100:0 to 90:10) to afford the title compound, (800 mg, 5%) as a yellow oil.

1. temperatureso as to maintain the temperature below −30° C
2. additionOnce addition
3. temperaturere-cooled to −70° C
4. additiononce addition
5. temperatureto warm to room temperature
6. customto quench
7. customthe reaction
8. filtrationThe resulting suspension was filtered through Celite®
9. customthe filtrate separated
10. washThe organic phase was washed with brine
11. dry with materialdried (MgSO4)
12. customevaporated under reduced pressure
13. customThe residual oil was purified by column chromatography on silica gel using an elution gradient of pentane:ethyl acetate (100:0 to 90:10)

ORD record

ord-2933d093be96459187da1b1fd22e9180

Source dataset

uspto-grants-2001_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06333330B1