Triisopropyl borate → (5-cyano-1-methyl-1H-pyrrol-2-yl)boronic acid

HRID 1092648Notes

Reaction equation

HRID 1092648 reaction equation
[CH3:1][N:2]1[CH:6]=[CH:5][CH:4]=[C:3]1[C:7]#[N:8].C([O:12][B:13](OC(C)C)[O:14]C(C)C)(C)C.[Li+].CC([N-]C(C)C)C>C1COCC1>[C:7]([C:3]1[N:2]([CH3:1])[C:6]([B:13]([OH:14])[OH:12])=[CH:5][CH:4]=1)#[N:8]

Participants

5

Reactant 3

HCID 21531Triisopropyl borateHCID 20641111-Methylpyrrole-2-carbonitrileHCID 2724682Lithium diisopropylamide

Product 1

HCID 11708078(5-cyano-1-methyl-1H-pyrrol-2-yl)boronic acidYield 80.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
13 °C

Procedure

The solution of 1-methylpyrrole-2-carbonitrile (0.131 g, 1.23 mmol), triisopropylborate (250 μL, 1.08 mmol), and THF (4 mL) was cooled to about −4° C. and 2M LDA (0.6 mL, 1.2 mmol) was added dropwise from a syringe. The bath was removed and the suspension was allowed to warm to about 13° C. within about 2 hours. After cooling and quenching with water and 5% aqueous HCl, the product was extracted with diethylether. The organic layer was evaporated to give an oil which solidified upon standing to give 0.130 g (70% yield) of (5-cyano-1-methyl-1H-pyrrol-2-yl) boronic acid. 1H-NMR (DMSO-d6): δ 8.38, 6.87, 6.77, and 3.88.

Workup

  1. customThe bath was removed
  2. temperatureAfter cooling
  3. customquenching with water and 5% aqueous HCl
  4. extractionthe product was extracted with diethylether
  5. customThe organic layer was evaporated
  6. customto give an oil which

Sources & evidence

ORD record
ord-d65d4e8b70194cfd92dc80b9904f2bd4
Source dataset
uspto-grants-2012_03
Patent number
US08129523B2

Reaction notes

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