C[O:2][C:3](=[O:15])[C:4]1[CH:9]=[CH:8][CH:7]=[C:6]([O:10][S:11]([CH3:14])(=[O:13])=[O:12])[CH:5]=1.[OH-].[Na+]>C1COCC1.C(O)C>[CH3:14][S:11]([O:10][C:6]1[CH:5]=[C:4]([CH:9]=[CH:8][CH:7]=1)[C:3]([OH:15])=[O:2])(=[O:13])=[O:12]The above prepared 3-methanesulfonyloxy-benzoic acid methyl ester (3.81 g, 16 mmol) was dissolved in 100 ml of THF/ethanol=1/1 and treated with 50 ml of aq. NaOH (1M, 3 eq.). The mixture was stirred for 2 h at ambient temperature and was then poured onto crashed ice/AcOEt/HCl dil.; the organic layer was washed with water, dried over sodium sulfate, and evaporated to dryness to leave 3.38 g of the title compound as white solid.
Wird geladen…