Triisopropyl borate → (5-(((tert-Butyldimethylsilyl)oxy)methyl)pyridin-3-yl)boronic acid

HRID 1907973Notes

Reaction equation

HRID 1907973 reaction equation
[Br:1][C:2]1[CH:3]=[N:4][CH:5]=[C:6]([CH2:8][O:9][Si:10]([C:13]([CH3:16])([CH3:15])[CH3:14])([CH3:12])[CH3:11])[CH:7]=1.[B:17](OC(C)C)([O:22]C(C)C)[O:18]C(C)C.C([Li])CCC.[Cl-].[NH4+]>C1COCC1.O>[Br:1][C:2]1[CH:3]=[N:4][CH:5]=[C:6]([CH2:8][O:9][Si:10]([C:13]([CH3:16])([CH3:15])[CH3:14])([CH3:11])[CH3:12])[CH:7]=1.[Si:10]([O:9][CH2:8][C:6]1[CH:7]=[C:2]([B:17]([OH:22])[OH:18])[CH:3]=[N:4][CH:5]=1)([C:13]([CH3:16])([CH3:15])[CH3:14])([CH3:12])[CH3:11]

Participants

8

Reactant 4

HCID 21531Triisopropyl borateHCID 25517Ammonium ChlorideHCID 219840913-Bromo-5-(((tert-butyldimethylsilyl)oxy)methyl)pyridineHCID 178418339Butyllithium

Product 2

HCID 219840913-Bromo-5-(((tert-butyldimethylsilyl)oxy)methyl)pyridineHCID 21984252(5-(((tert-Butyldimethylsilyl)oxy)methyl)pyridin-3-yl)boronic acidYield 143.4%

Reagents, catalysts & solvents 2

HCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-20 °C

Procedure

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.

Workup

  1. additionwas added dropwise over a period of 1.5 hours
  2. temperatureto warm to ambient temperature
  3. customThe aqueous layer was separated
  4. extractionextracted with diethyl ether
  5. concentrationThe combined organic fractions were concentrated under reduced pressure, and methanol
  6. additionwas added to the resulting oil
  7. customA solid formed
  8. customisolated by filtration
  9. customdried under reduced pressure

Sources & evidence

ORD record
ord-8fafae2776344cf5b1ac61c58fa7c497
Source dataset
uspto-grants-2013_12
Patent number
US08598192B2

Reaction notes

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