反应详情

To the crude tert-butyl 3-methoxy-4-(1-methoxy-2-methyl-1-oxopropan-2-yl)benzoate from Step 2 was added DCM (1 mL) followed by TFA (540 μL, 7.0 mmol). The reaction was allowed to stir for 2 h before it was concentrated in vacuo. The residue was dissolved in DMF, filtered and was purified by prep-HPLC (MeOH:H2O, 1-99% in an HCl modifier) to give 3-methoxy-4-(1-methoxy-2-methyl-1-oxopropan-2-yl)benzoic acid. ESI-MS m/z calc. 252.1, found 253.2 (M+1)+; Retention time: 2.45 minutes (4 min run).

1. concentrationwas concentrated in vacuo
2. dissolutionThe residue was dissolved in DMF
3. filtrationfiltered
4. customwas purified by prep-HPLC (MeOH