Triisopropyl borate → 2-(5-borono-1H-indol-3-yl)acetic acid

HRID 2110710Notes

Reaction equation

HRID 2110710 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[CH2:11][C:12]([OH:14])=[O:13].C([Li])(C)(C)C.[B:20](OC(C)C)([O:25]C(C)C)[O:21]C(C)C>C1COCC1>[C:12]([CH2:11][C:5]1[C:4]2[C:8](=[CH:9][CH:10]=[C:2]([B:20]([OH:25])[OH:21])[CH:3]=2)[NH:7][CH:6]=1)([OH:14])=[O:13]

Participants

5

Reactant 3

HCID 21531Triisopropyl borateHCID 967345-Bromo-3-indoleacetic acidHCID 178418306HCID 178418306, compound

Product 1

HCID 576360782-(5-borono-1H-indol-3-yl)acetic acidYield 21.4%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

To a solution of (5-bromo-1H-indol-3-yl)-acetic acid (1 g, 3.94 mmol) in THF (66 mL) at −78 ° C. is added tert-butyl lithium (1.7 M in pentane, 11.6 mL, 19.7 mmol) dropwise and stirred at −78° C. for 30 minutes. at −30° C. for 1 hour. Cooled down to −78° C. again and treated dropwise with triisopropyl borate (4.53 mL, 19.7 mmol). The reaction mixture is allowed to warm to room temperature during 1 hour quenched with 2 N hydrochloric acid. This mixture is extracted with ether. The extract is dried over sodium sulfate and concentrate to obtain an oil which is subjected to silica gel chromatography affording 3-carboxymethyl-1H-indol-5-yl boronic acid (185 mg, 20%) as a solid.

Workup

  1. waitat −30° C. for 1 hour
  2. temperatureCooled down to −78° C. again
  3. temperatureto warm to room temperature during 1 hour
  4. customquenched with 2 N hydrochloric acid
  5. extractionThis mixture is extracted with ether
  6. dry with materialThe extract is dried over sodium sulfate
  7. concentrationconcentrate
  8. customto obtain an oil which

Sources & evidence

ORD record
ord-06a28623686d4cc08ac85003d149f1a2
Source dataset
uspto-grants-2009_04
Patent number
US07517889B2

Reaction notes

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