Lithium Hydroxide → 3-Formyl-4-methylbenzoic acid

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Reaction Steps

Under nitrogen, Pd(dppf) (72 mg, 89 μmol) was added to a solution of 3-formyl-4-trifluoromethanesulfonyloxy-benzoic acid methyl ester (2.80 g, 8.97 mmol) in dioxane (40 mL). The mixture was stirred at rt and dimethyl zinc (11.2 g, 13.5 mmol, 12.1 mL of a 1.2M solution in toluene) was added. The mixture was stirred at 75° C. for 1 h. The mixture was cooled to rt before a 2M aq. LiOH solution (40 mL) was added. The mixture was stirred at rt for 2 h before it was concentrated. The residue was dissolved in EA and extracted with 1M aq. NaOH and water. The aq. extracts were acidified by adding 2N aq. HCl (30 mL) and then extracted with EA. The org. extract was dried over Na2SO4, filtered and concentrated. The crude product was purified by prep. HPLC to give the title compound as a pale yellow powder (903 mg). LC-MS*: tR=0.27 min, [M−H]−=162.90; 1H NMR (D6-DMSO): δ 2.69 (s, 3H), 7.49 (d, J=7.8 Hz, 1H), 8.08 (dd, J=7.8, 1.8 Hz, 1H), 8.38 (d, J=1.8 Hz, 1H), 10.29 (s, 1H), 13.20 (s, 1H).

Provenance & Evidence