C[O:2][C:3](=[O:30])[C:4]1[CH:9]=[C:8]([O:10][CH3:11])[C:7]([C:12]([CH3:15])([CH3:14])[CH3:13])=[CH:6][C:5]=1[C:16]1[C:17]([O:22][CH2:23][C:24]2[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=2)=[N:18][CH:19]=[CH:20][CH:21]=1.C1COCC1.[OH-].[Na+].Cl>CO.O>[CH2:23]([O:22][C:17]1[C:16]([C:5]2[CH:6]=[C:7]([C:12]([CH3:13])([CH3:15])[CH3:14])[C:8]([O:10][CH3:11])=[CH:9][C:4]=2[C:3]([OH:30])=[O:2])=[CH:21][CH:20]=[CH:19][N:18]=1)[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1step 3—To a suspension of 66 (960 mg, 2.36 mmol) in MeOH (15 mL), H2O (10 mL), and THF (10 mL) was added NaOH (1.00 g, 23.6 mmol). The reaction mixture was heated at 70° C. overnight and gradually became homogeneous. The mixture was cooled to 0° C., acidified to pH 3 with 1.0 M aq HCl and thrice extracted with EtOAc. The combined extracts were dried (MgSO4), filtered and concentrated under reduced pressure to afford 895 mg (97%) of 2-(2-benzyloxypyridin-3-yl)-4-tert-butyl-5-methoxybenzoic acid (68) as a beige solid.
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