Hydrochloric Acid → 2-oxo-2,3-Dihydrobenzooxazole-5-boronic acid

HRID 2218712Notes

Reaction equation

HRID 2218712 reaction equation
[Li]CCCC.Br[C:7]1[CH:8]=[CH:9][C:10]2[O:14][C:13](=[O:15])[NH:12][C:11]=2[CH:16]=1.C[O:18][B:19](OC)[O:20]C.Cl>C1COCC1>[O:15]=[C:13]1[NH:12][C:11]2[CH:16]=[C:7]([B:19]([OH:20])[OH:18])[CH:8]=[CH:9][C:10]=2[O:14]1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 268532-Benzoxazolinone, 5-bromo-HCID 178418339Butyllithium

Product 1

HCID 597704982-oxo-2,3-Dihydrobenzooxazole-5-boronic acid

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-40 °C

Procedure

Add n-BuLi (1.6M in hexanes, 8.76 mL, 14.02 mmol) portionwise (exotherm) to a solution of 5-bromo-3H-benzooxazol-2-one (1.00 g, 4.67 mmol) in dry THF (28 mL) at −78° C. under N2. Stir at −40° C. for 1 h and add trimethylborate (1.94 g, 18.68 mmol) at once. Warm up to room temperature overnight. Add 1N aqueous HCl (50 mL) and stir for 3 h at room temperature. Extract into ethyl acetate, dry (MgSO4) and concentrate organics to a brown solid. Triturate with hexanes/toluene and collect 766 mg (92%) of the title compound as a brown powder. MS (ES) 179 (M+H), 177 (M−H); HPLC shows 80% purity.

Workup

  1. temperatureWarm up to room temperature overnight
  2. stirringstir for 3 h at room temperature
  3. extractionExtract into ethyl acetate
  4. dry with materialdry (MgSO4)
  5. concentrationconcentrate organics to a brown solid
  6. customTriturate with hexanes/toluene
  7. customcollect 766 mg (92%) of the title compound as a brown powder

Sources & evidence

ORD record
ord-3da80063118e4650b8db0663edad9d61
Source dataset
uspto-grants-2008_08
Patent number
US07411072B2

Reaction notes

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