Boron tribromide → 5-[5-(5-Chloro-2-hydroxy-phenyl)-oxazol-2-yl]-pentanoic acid methyl ester

HRID 1616586Notes

Reaction equation

HRID 1616586 reaction equation
[CH3:1][O:2][C:3](=[O:22])[CH2:4][CH2:5][CH2:6][CH2:7][C:8]1[O:9][C:10]([C:13]2[CH:18]=[C:17]([Cl:19])[CH:16]=[CH:15][C:14]=2[O:20]C)=[CH:11][N:12]=1.B(Br)(Br)Br>C(Cl)Cl>[CH3:1][O:2][C:3](=[O:22])[CH2:4][CH2:5][CH2:6][CH2:7][C:8]1[O:9][C:10]([C:13]2[CH:18]=[C:17]([Cl:19])[CH:16]=[CH:15][C:14]=2[OH:20])=[CH:11][N:12]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 591677555-[5-(5-Chloro-2-methoxy-phenyl)-oxazol-2-yl]-pentanoic acid methyl ester

Product 1

HCID 684878995-[5-(5-Chloro-2-hydroxy-phenyl)-oxazol-2-yl]-pentanoic acid methyl esterYield 82%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Conditions

Temperature
-78 °C

Procedure

Dissolve 5-[5-(5-chloro-2-methoxy-phenyl)-oxazol-2-yl]-pentanoic acid methyl ester (4.174 g, 12.89 mmol) in 50 mL of CH2Cl2 and cool the solution to −78° C. Add boron tribromide (48.9 mL of a 1M solution in CH2Cl2) dropwise to the reaction and allow it to warm to ambient temperature and allow it to stir for 27 hours. Cool the reaction to −78° C. and quench it by adding 100 mL of MeOH dropwise to the reaction mixture. Allow the reaction to warm to ambient temperature and stir for 19 hours. Concentrate the reaction mixture in vacuo. Dissolve the residue in CH2Cl2 and wash it with saturated aqueous NaHCO3 and brine. Dry the organic layer with MgSO4. Filter off the drying agent and concentrate in vacuo to afford a crude residue. Purify the residue using silica gel chromatography eluting with hexanes/ethyl acetate mixtures to afford 3.26 g of the titled product (82%): mass spectrum: m/z=310.09 (M+H).

Workup

  1. temperatureto warm to ambient temperature
  2. temperatureCool
  3. customthe reaction to −78° C.
  4. customquench it
  5. additionby adding 100 mL of MeOH dropwise to the reaction mixture
  6. customthe reaction
  7. temperatureto warm to ambient temperature
  8. stirringstir for 19 hours
  9. concentrationConcentrate the reaction mixture in vacuo
  10. dissolutionDissolve the residue in CH2Cl2
  11. washwash it with saturated aqueous NaHCO3 and brine
  12. dry with materialDry the organic layer with MgSO4
  13. filtrationFilter off the drying agent
  14. concentrationconcentrate in vacuo
  15. customto afford a crude residue
  16. customPurify the residue
  17. washeluting with hexanes/ethyl acetate

Sources & evidence

ORD record
ord-ff0e0a97ee1b45689f75ea8b81027512
Source dataset
uspto-grants-2014_07
Patent number
US08765796B2

Reaction notes

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