Reacción #9472

Ecuación de reacción

ammonium chloride

3-bromo-5-(tert-butyldimethylsilanyloxymethyl)pyridine

triisopropyl borate

n-Butyllithium

→

3-Bromo-5-(tert-butyldimethylsilanyloxymethyl)pyridine

5-(tert-butyldimethylsilanyloxymethyl)pyridine-3-boronic acid

Rendimiento 143.4%

Disolventes

water

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.ADDITIONwas added dropwise over a period of 1.5 hours
2. 2
   Temperaturato warm to ambient temperature
3. 3
   OtroThe aqueous layer was separated
4. 4
   Extracciónextracted with diethyl ether
5. 5
   ConcentraciónThe combined organic fractions were concentrated under reduced pressure, and methanol
6. 6
   workup.ADDITIONwas added to the resulting oil
7. 7
   OtroA solid formed
8. 8
   Otroisolated by filtration
9. 9
   Otrodried under reduced pressure

Procedimiento

3-Bromo-5-(tert-butyldimethylsilanyloxymethyl)pyridine was prepared according to the published procedure (Zhang, N. et al, J. Med. Chem., 45, 2832–2840 (2002)). Under a nitrogen atmosphere, a solution of 3-bromo-5-(tert-butyldimethylsilanyloxymethyl)pyridine (28.70 g, 94.94 mmol) and triisopropyl borate (26.3 mL, 114 mmol) in dry THF was cooled to −70° C. n-Butyllithium (45.6 mL, 114 mmol) was added dropwise over a period of 1.5 hours. The reaction was stirred for an additional 30 minutes and then allowed to warm to −20° C. Dilute aqueous ammonium chloride was added, and the mixture was allowed to warm to ambient temperature. The aqueous layer was separated and extracted with diethyl ether. The combined organic fractions were concentrated under reduced pressure, and methanol was added to the resulting oil. A solid formed, which was stirred with water for two days, isolated by filtration, and dried under reduced pressure to provide 18.19 g of 5-(tert-butyldimethylsilanyloxymethyl)pyridine-3-boronic acid as a white solid.

Fuente