p-Toluenesulfonic acid → Methyl 3,5-dihydroxy-4-methylbenzoate

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Reaction Steps

3,5-dihydroxy-4-methylbenzoic acid (5.0 g, 29.79 mmol, 1.0 eq) and PTSA (1.13 g, 5.94 mmol, 0.2 eq) were dissolved in 50 ml of methanol, and the mixture was heated to reflux for 6 h. Methanol was evaporated. The resultant solid was washed with 10% sodium bicarbonate solution. The aqueous solution was extracted thrice with ethyl acetate. The combined organic layer was dried over sodium sulphate and evaporated under vacuum. Yield: 5.25 g (96%). 1H NMR (400 MHz, DMSO-d6): δ 1.98 (s, 3H), 3.78 (s, 3H), 6.93 (s, 2H), 9.53 (s, 2H). LCMS: (ES+) m/z=183 (M+H) Method: Column: Phenomenex Luna C18 (4.6×30) mm, 5 micron Mphase A: 10% MeOH-90% H2O-10 mM NH4OAc Mphase B: 90% MeOH-10% H2O-10 mM NH4OAc

Provenance & Evidence