Methanol → Methyl 3,5-dimethoxy-4-methylbenzoate

関与物質

反応手順

Concentrated sulphuric acid (1 mL), was added dropwise to a solution of 4-methyl-3,5-dimethoxybenzoic acid (186) (5.01 g, 25.56 mmol) in refluxing methanol (20 mL). The reaction mixture was heated at reflux for a further 5 hours and then cooled to room temperature and concentrated to a third of its original volume. The concentrate was poured onto crushed ice (c. 150 mL) and allowed to stand for 30 minutes. The aqueous mixture was extracted with ethyl acetate (3×100 mL) and the combined organic phase washed with distilled water (3×100 mL), brine (2×100 mL) and dried over anhydrous MgSO4. Removal of excess solvent under reduced pressure afforded the product as a beige solid (187) (4.865 g, 23.17 mmol, 91%); 1H NMR (270 MHz, CDCl3) δ 7.21 (s, 2H), 3.91 (s, 3H), 3.86 (s, 6H), 2.13 (s, 3H); 13C NMR (67.8 MHz, CDCl3) δ 171.57, 167.28, 158.16, 158.10, 128.23, 120.39, 105.20, 104.70, 55.85, 52.13, 8.77, 8.66.

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