[OH:1][C:2]1[C:11]([CH:12]([CH3:14])[CH3:13])=[CH:10][C:5]([C:6]([O:8]C)=[O:7])=[C:4]([O:15][CH2:16][O:17][CH3:18])[CH:3]=1.[OH-].[K+]>CO.O>[OH:1][C:2]1[C:11]([CH:12]([CH3:13])[CH3:14])=[CH:10][C:5]([C:6]([OH:8])=[O:7])=[C:4]([O:15][CH2:16][O:17][CH3:18])[CH:3]=1The crude methyl 4-hydroxy-5-isopropyl-2-(methoxymethyloxy)benzoate was dissolved in methanol (20 ml) and water (8 ml), aqueous potassium hydroxide (50% w/v, 5 ml) was added and the mixture was stirred and held at reflux for 16 hours. Upon cooling to room temperature the organic solvent was removed in vacuo and the residue acidified by the addition of 2M hydrochloric acid (30 ml). The organic material was extracted with ethyl acetate (2×20 ml) and the combined organic extracts were evaporated in vacuo to afford a yellow oil that was subjected to column chromatography on a Strata-NH2 cartridge. Elution with 2M ammonia in methanol afforded crude 4-hydroxy-5-isopropyl-2-(methoxymethyloxy)benzoic acid (180 mg, 25%) as a pale grey solid that was used without further purification. MS: [M+Na]+ 263.
Wird geladen…
