Sodium Chloride → 5-Bromo-2-(2,2,5,5-tetramethyl-1,2,5-azadisilolidin-1-yl)pyridine

Temperature

-78 °C

In a 500 mL three-necked flask, 5-bromopyridin-2-amine (5 g, 28.9 mmol) was combined with THF (80 ml) to give a light yellow solution. Cooled to −78° C. and n-butyllithium in hexane (18.2 ml, 29.2 mmol) was added via syringe. The reaction was stirred at −78° C. for 1 hr, then 1,2-bis(chlorodimethylsilyl)ethane (6.22 g, 28.9 mmol) was added dropwise over 15 min. After stirring for 90 min at −78° C., n-butyllithium in hexane (18.2 ml, 29.2 mmol) was added. The reaction was allowed to warm to 25° C. and stirred for 2 hr. The reaction mixture was diluted with 50 mL sat NaCl and extracted with diethyl ether (2×200 mL). The organic layers were combined, washed with H2O (1×25 mL), sat NaCl (1×25 mL), dried over MgSO4 and concentrated in vacuo. The crude brown oil was purified by vacuum distillation (1 mm Hg, 170° C.). The product solidified upon cooling to give 4.89 g (54%) of the title compound as a white crystalline solid. 1H NMR (300 MHz, CHLOROFORM-d) δ: 8.15 (d, J=2.6 Hz, 1H), 7.47 (dd, J=8.9, 2.5 Hz, 1H), 6.47 (d, J=8.7 Hz, 1H), 0.83 (s, 4H), 0.24-0.38 (m, 12H).

1. customto give a light yellow solution
2. stirringAfter stirring for 90 min at −78° C.
3. temperatureto warm to 25° C.
4. stirringstirred for 2 hr
5. additionThe reaction mixture was diluted with 50 mL
6. extractionextracted with diethyl ether (2×200 mL)
7. washwashed with H2O (1×25 mL)
8. dry with materialdried over MgSO4
9. concentrationconcentrated in vacuo
10. distillationThe crude brown oil was purified by vacuum distillation (1 mm Hg, 170° C.)
11. temperatureupon cooling

ORD record

ord-6477167a9d7747219af368a9368aa419

Source dataset

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08940741B2