Hydrochloric Acid → 2-tert-Butyl-7-nitro-6-phenyl-1,3-benzoxazole-4-carboxylic Acid

HRID 17516Notes

Reaction equation

HRID 17516 reaction equation
Br[C:2]1[C:3]([N+:18]([O-:20])=[O:19])=[C:4]2[O:8][C:7]([C:9]([CH3:12])([CH3:11])[CH3:10])=[N:6][C:5]2=[C:13]([C:15]([OH:17])=[O:16])[CH:14]=1.[C:21]1(B(O)O)[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1.C(=O)([O-])[O-].[Na+].[Na+].Cl>C1(C)C=CC=CC=1.C(O)C.C1C=CC([P]([Pd]([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)([P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)[P](C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C(OCC)(=O)C>[C:9]([C:7]1[O:8][C:4]2[C:5](=[C:13]([C:15]([OH:17])=[O:16])[CH:14]=[C:2]([C:21]3[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=3)[C:3]=2[N+:18]([O-:20])=[O:19])[N:6]=1)([CH3:12])([CH3:11])[CH3:10]

Participants

9

Reactant 4

HCID 313Hydrochloric AcidHCID 10340Sodium CarbonateHCID 66827Phenylboronic AcidHCID 685852286-Bromo-2-tert-butyl-7-nitro-1,3-benzoxazole-4-carboxylic Acid

Product 1

HCID 685849732-tert-Butyl-7-nitro-6-phenyl-1,3-benzoxazole-4-carboxylic AcidYield 140.6%

Reagents, catalysts & solvents 4

HCID 178418397HCID 178418397, compoundCatalystHCID 702EthanolSolventHCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Conditions

Temperature
85 °C

Procedure

6-Bromo-2-tert-butyl-7-nitro-1,3-benzoxazole-4-carboxylic acid (I-222) (2.15 g, 6.27 mmol), phenylboronic acid (1.53 g, 12.53 mmol) and aqueous 2 M sodium carbonate solution (20 ml) were suspended in toluene (40 ml) and ethanol (30 ml). Tetrakis(triphenylphosphine)palladium(0) (724 mg, 0.63 mmol) was added at room temperature to the suspension. The mixture was stirred at 85° C. for 22 hours, then cooled to room temperature. The reaction liquid was fractionated with ethyl acetate and aqueous 1 M hydrochloric acid solution. The organic layer was washed with saturated brine, and dried over anhydrous sodium sulfate. The insoluble matter was removed by filtration, the solvent was evaporated away and the resulting residue was purified by middle-pressure liquid chromatography (eluent, chloroform:methanol=9:1) to obtain the entitled compound (3.00 g) as a brown gel. This was used in the next reaction as such.

Workup

  1. temperaturecooled to room temperature
  2. customThe reaction liquid
  3. washThe organic layer was washed with saturated brine
  4. dry with materialdried over anhydrous sodium sulfate
  5. customThe insoluble matter was removed by filtration
  6. customthe solvent was evaporated away
  7. customthe resulting residue was purified by middle-pressure liquid chromatography (eluent, chloroform:methanol=9:1)

Sources & evidence

ORD record
ord-7bc785322e494398b3aafb9ffc3a2b38
Source dataset
uspto-grants-2010_06
Patent number
US07737166B2

Reaction notes

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