Reaktion #9472

Reaktionsgleichung

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

Ausbeute 143.4%

Lösungsmittel

water

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added dropwise over a period of 1.5 hours
2. 2
   Temperaturto warm to ambient temperature
3. 3
   SonstigeThe aqueous layer was separated
4. 4
   Extraktionextracted with diethyl ether
5. 5
   EinengenThe combined organic fractions were concentrated under reduced pressure, and methanol
6. 6
   workup.ADDITIONwas added to the resulting oil
7. 7
   SonstigeA solid formed
8. 8
   Sonstigeisolated by filtration
9. 9
   Sonstigedried under reduced pressure

Vorschrift

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.

Quelle