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

HRID 216183Notes

Reaction equation

HRID 216183 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
-30 °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 2N 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. temperatureCooled down to −78° C. again
  2. temperatureto warm to room temperature during 1 hour
  3. customquenched with 2N hydrochloric acid
  4. extractionThis mixture is extracted with ether
  5. dry with materialThe extract is dried over sodium sulfate
  6. concentrationconcentrate
  7. customto obtain an oil which

Sources & evidence

ORD record
ord-79c8e14816874338911ae4501bb00c4f
Source dataset
uspto-grants-2012_06
Patent number
US08193183B2

Reaction notes

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