Hexane → Quinoline-3-boronic acid

HRID 2299035Notes

Reaction equation

HRID 2299035 reaction equation
C([Li])CCC.CCCCCC.Br[C:13]1[CH:14]=[N:15][C:16]2[C:21]([CH:22]=1)=[CH:20][CH:19]=[CH:18][CH:17]=2.C[O:24][B:25](OC)[O:26]C>CCOCC>[N:15]1[C:16]2[C:21](=[CH:20][CH:19]=[CH:18][CH:17]=2)[CH:22]=[C:13]([B:25]([OH:26])[OH:24])[CH:14]=1

Participants

6

Reactant 4

HCID 8058HexaneHCID 8470Trimethyl borateHCID 214133-BromoquinolineHCID 178418339Butyllithium

Product 1

HCID 2734663Quinoline-3-boronic acidYield 34%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Procedure

A 2.5M solution of n-butyllithium in hexane (4.4 ml, 11 mmol) was slowly added to a stirred solution of 3-bromoquinoline (2.08 g, 10 mmol) in anhydrous ether (20 ml), under nitrogen, at −75° C. After a further 20 minutes at −75° C., trimethylborate (1.46 ml, 13 mmol) was added, whereupon the red colour changed to yellow. The reaction mixture was allowed to warm to room temperature and quenched with water, followed by 1M aqueous sodium hydroxide solution (10 ml). The resulting mixture was stirred for 30 minutes and then glacial acetic acid added until a pH ˜5-6 was attained, which generated a gummy precipitate. Diisopropyl ether was added to this mixture, stirring continued for 1 hour and then the clear aqueous and organic phases were decanted from the solid and discarded. The solid residue was dissolved in ethyl acetate and the solution washed with water, dried (MgSO4) and evaporated under reduced pressure to give the title compound as a pale yellow solid (580 mg, 34%). Found: C, 62.74; H, 4.11; N, 7.92. C9H8BNO2 requires C, 62.49; H, 4.66; N, 8.10%. δ(DMSOd6): 7.59 (t,1H), 7.76 (t,1H), 7.98 (m,2H), 8.42 (brs,2H,exchangeable), 8.70 (s,1H), 9.18 (s,1H).

Workup

  1. customquenched with water
  2. additionglacial acetic acid added until a pH ˜5-6
  3. additionDiisopropyl ether was added to this mixture
  4. stirringstirring
  5. waitcontinued for 1 hour
  6. customthe clear aqueous and organic phases were decanted from the solid
  7. dissolutionThe solid residue was dissolved in ethyl acetate
  8. washthe solution washed with water
  9. dry with materialdried (MgSO4)
  10. customevaporated under reduced pressure

Sources & evidence

ORD record
ord-170e58079c254ccbaf50ec9d55d82e69
Source dataset
uspto-grants-2002_12
Patent number
US06495568B1

Reaction notes

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