1,2-Dibromoethane → tert-Butyl (3-bromopyridin-2-yl)carbamate

Temperature

-78 °C

2-t-Butoxycarbonylaminopyridine (10 g, 51.5 mmol) was dissolved in tetrahydrofuran (80 mL), and cooled to -78° C. N-butyllithium (120 mmol, 80 mL of 1.49M in hexanes) was added dropwise over a period of 1 h After stirring for an additional 15 min at -78° C. and then for 2.5 h at -10° C., the solution was recooled back down to -78° C. and 1,2-dibromoethane (77.2 mmol, 6.65 mL) was added dropwise over a period of 15 min via syringe. The solution was allowed to warm to room temperature. The reaction was quenched with 100 mL of saturated ammonium chloride and was extracted with ethyl acetate (3×). The organic layers were collected, dried over magnesium sulfate, filtered, and concentrated. The resulting solid was purified by flash chromatography on silica gel (25% ethyl acetate/hexanes) giving 4.5 g (32%) of the titled product as a light brown solid: mp 120°-121° C.; IR (KBr, cm-1) 3191, 2980, 1729, 1521, 1442, 1365, 1272, 1166, 1032; 1H NMR (300 MHZ, DMSO-d6) δ 9.28 (s, 1H), 8.34 (m, 1H), 8.05 (m, 1H), 7.15 (m, 1H), 1.39 (s, 9H); MS (FD) m/e 272 (M+), 274 (M+2); UV (EtOH) 280 nm (ε=4047), 230 nm (ε=9067), 204 nm (ε=16385).

1. waitfor 2.5 h at -10° C.
2. customwas recooled back down to -78° C.
3. temperatureto warm to room temperature
4. customThe reaction was quenched with 100 mL of saturated ammonium chloride
5. extractionwas extracted with ethyl acetate (3×)
6. customThe organic layers were collected
7. dry with materialdried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated
10. customThe resulting solid was purified by flash chromatography on silica gel (25% ethyl acetate/hexanes)

ORD record

ord-858cd5e776ba4a358501e952cea7ba93

Source dataset

uspto-grants-1997_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05658907