Hydrochloric Acid → 2-(4-Chlorophenyl)benzoxazole-4-carboxylic acid

HRID 506236Notes

Reaction equation

HRID 506236 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[O:9][C:10]3[C:11](=[C:13]([C:17]([O:19]C)=[O:18])[CH:14]=[CH:15][CH:16]=3)[N:12]=2)=[CH:4][CH:3]=1.C1COCC1.[OH-].[Li+].Cl>C(OCC)(=O)C.O.CO>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([C:8]2[O:9][C:10]3[C:11](=[C:13]([C:17]([OH:19])=[O:18])[CH:14]=[CH:15][CH:16]=3)[N:12]=2)=[CH:6][CH:7]=1

Participants

8

Reactant 4

HCID 313Hydrochloric AcidHCID 3939Lithium HydroxideHCID 8028TetrahydrofuranHCID 68459315Methyl 2-(4-chlorophenyl)benzoxazole-4-carboxylate

Product 1

HCID 596258542-(4-Chlorophenyl)benzoxazole-4-carboxylic acidYield 90.3%

Reagents, catalysts & solvents 3

HCID 887MethanolSolventHCID 962WaterSolventHCID 8857Ethyl AcetateSolvent

Procedure

A 100 mL round bottom flask equipped with a magnetic stirrer was charged with methyl 2-(4-chlorophenyl)benzoxazole-4-carboxylate (0.50 g, 1.74 mmol), THF (10 mL), methanol (10 mL), lithium hydroxide (0.08 g, 3.48 mmol) and water (10 mL). The reaction was stirred at room temperature for 18 hours. After this time, the reaction was diluted with ethyl acetate (50 mL) then acidified to pH 4 with 2 N HCl. The aqueous layer was extracted with ethyl acetate (2×25 mL). The organic layers were then combined and washed with brine (1×25 mL), dried with sodium sulfate, filtered and concentrated to dryness in vacuo to yield 2-(4-chlorophenyl)benzoxazole-4-carboxylic acid (0.43 g, 90% yield) as a white solid: 1H NMR (500 MHz, CDCl3) δ 11.53 (bs, 1H), 8.26 (d, J=8.5 Hz, 2H), 8.18 (d, J=8.0 Hz, 1H), 7.84 (d, J=8.0 Hz, 1H), 7.58 (d, J=8.5 Hz, 2H), 7.55 (t, J=8.0 Hz, 1H); MS (ESI) m/z 274 [M+H]+

Workup

  1. customA 100 mL round bottom flask equipped with a magnetic stirrer
  2. extractionThe aqueous layer was extracted with ethyl acetate (2×25 mL)
  3. washwashed with brine (1×25 mL)
  4. dry with materialdried with sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated to dryness in vacuo

Sources & evidence

ORD record
ord-abde0d572f164f278a125d46e7c1dae4
Source dataset
uspto-grants-2010_08
Patent number
US07781430B2

Reaction notes

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