Hydrochloric Acid → (4-(Benzo[d]oxazol-2-yl)phenyl)boronic acid

HRID 1097167Notes

Reaction equation

HRID 1097167 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([C:8]2[O:9][C:10]3[CH:16]=[CH:15][CH:14]=[CH:13][C:11]=3[N:12]=2)=[CH:4][CH:3]=1.C([Li])CCC.[B:22](OC)([O:25]C)[O:23]C.Cl>C1COCC1>[O:9]1[C:10]2[CH:16]=[CH:15][CH:14]=[CH:13][C:11]=2[N:12]=[C:8]1[C:5]1[CH:6]=[CH:7][C:2]([B:22]([OH:25])[OH:23])=[CH:3][CH:4]=1

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 8470Trimethyl borateHCID 128467152-(4-Bromophenyl)benzo(d)oxazoleHCID 178418339Butyllithium

Product 1

HCID 57958561(4-(Benzo[d]oxazol-2-yl)phenyl)boronic acid

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

First, 5.5 g (20 mmol) of 2-(4-bromophenyl)benzoxazole was put into a 300 mL three-neck flask and the atmosphere in the flask was substituted by nitrogen. 120 mL of THF was added and cooled to −78° C. under a nitrogen stream. After cooling, 13 mL (22 mmol) of 1.6 M n-butyllithium was dripped to this solution, and the mixture was stirred at the same temperature for 2 hours. After a certain time, 4.4 mL (40 mmol) of trimethyl borate was added to this solution, and the temperature of the solution was raised to room temperature, and then, the solution was stirred for 16 hours. After a certain time, 100 mL of 1M hydrochloric acid was added and stirred for 1 hour. An aqueous layer of the obtained mixture was extracted with ethyl acetate. The obtained extract was washed with a saturated saline together with the organic layer and then dried over magnesium sulfate. The obtained mixture was subjected to gravity filtration, and the obtained filtrate was concentrated to give a solid. The obtained solid was recrystallized with ethyl acetate/hexane, so that 3.3 g of target white powder was obtained with a yield of 69%.

Workup

  1. temperatureAfter cooling
  2. temperaturethe temperature of the solution was raised to room temperature
  3. stirringthe solution was stirred for 16 hours
  4. stirringstirred for 1 hour
  5. extractionAn aqueous layer of the obtained mixture was extracted with ethyl acetate
  6. extractionThe obtained extract
  7. washwas washed with a saturated saline together with the organic layer
  8. dry with materialdried over magnesium sulfate
  9. filtrationThe obtained mixture was subjected to gravity filtration
  10. concentrationthe obtained filtrate was concentrated
  11. customto give a solid
  12. customThe obtained solid was recrystallized with ethyl acetate/hexane, so that 3.3 g of target white powder
  13. customwas obtained with a yield of 69%

Sources & evidence

ORD record
ord-72a8be1e2ded4c17a1735cbd119ffdec
Source dataset
uspto-grants-2012_03
Patent number
US08142911B2

Reaction notes

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