Tributyl borate → HCID 21955917, compound

HRID 2212972Notes

Reaction equation

HRID 2212972 reaction equation
Br[C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][CH:6]=[C:5]2[C:11]#[N:12].[H-].[K+].C([Li])CCC.C([O:24][B:25](OCCCC)[O:26]CCCC)CCC>C1COCC1>[C:11]([C:5]1[C:4]2[C:8](=[CH:9][CH:10]=[C:2]([B:25]([OH:26])[OH:24])[CH:3]=2)[NH:7][CH:6]=1)#[N:12]

Participants

6

Reactant 4

HCID 12712Tributyl borateHCID 82127Potassium hydrideHCID 36233545-Bromo-3-cyanoindoleHCID 178418339Butyllithium

Product 1

HCID 21955917HCID 21955917, compound

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-78 °C

Procedure

A solution of 5-bromo-3-cyanoindole (4.00 g, 18.1 mMol) in THF (20 mL) was added to a suspension of potassium hydride (2.28 g, 35% mineral oil dispersion, 19.9 mMol) in anhydrous THF (50 mL) at 0° C. After stirring for 15 min, the solution was cooled to −78° C., whereupon some precipitation occurred. A solution of n-butyllithium (2.5 M in hexanes, 16 mL) was slowly added via syringe. The resulting mixture was stirred at −78° C. for 15 minutes and then tributylborate (9.16 g, 39.8 mMol) was added. The mixture was removed from the cooling bath, stirred for 15 minutes, carefully quenched with water, and concentrated in vacuo. The residue was vigorously mixed with 1 N hydrochloric acid and extracted three times with ethyl acetate. The ethyl acetate layers were extracted three times with 1 N sodium hydroxide. The combined aqueous extracts were made acidic with concentrated hydrochloric acid to give 3-cyano-5-indolylboronic acid as a light tan precipitate which was collected by filtration and dried under vacuum (1.82 g, 55%). 1H-NMR (400 MHz, DMSO) δ 12.19 (1H, br s), 6.05 (1H, d, J=5.2 Hz), 8.24 (1H, d, J=2.8 Hz), 8.17 (1H, d, 6.4 Hz), 7.69 (1H, d, J=8.2 Hz), 7.49 (1H, d, J=8.2 Hz).

Workup

  1. stirringThe resulting mixture was stirred at −78° C. for 15 minutes
  2. customThe mixture was removed from the cooling bath
  3. stirringstirred for 15 minutes
  4. customcarefully quenched with water
  5. concentrationconcentrated in vacuo
  6. additionThe residue was vigorously mixed with 1 N hydrochloric acid
  7. extractionextracted three times with ethyl acetate
  8. extractionThe ethyl acetate layers were extracted three times with 1 N sodium hydroxide

Sources & evidence

ORD record
ord-ea47a31cf2584a91b695081b241490d2
Source dataset
uspto-grants-2006_09
Patent number
US07105516B2

Reaction notes

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