Dimethyl Sulfate → 1,2,3-Trimethoxy-5-(1-methoxyprop-2-ynyl)benzene

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a flame-dried 100 mL round-bottom flask was added NaH (0.240 mg, 6.0 mmol) that had been prewashed with pentane (3×15 mL) and dried. THF (48 mL) was added and the suspension cooled to 0° C. 1-(3,4,5-Trimethoxyphenyl)prop-2-yn-1-ol (1.11 g, 5.0 mmol) in THF (2.0 mL) was added dropwise and the reaction stirred at 0° C. for 25 min. Me2SO4 (0.571 mL, 6.0 mmol) was added and the reaction stirred at 0° C. for 20 min. Water (10 mL) was added, and the layers were separated. The aqueous layer was extracted with Et2O (20 mL). The combined organics were washed with brine (20 mL), dried over anhydrous Na2SO4, and concentrated. The residue was purified by flash chromatography (SiO2, 20 g) using 10% EtOAc in hexanes as the eluent to afford 1,2,3-Trimethoxy-5-(1-methoxyprop-2-ynyl)benzene as a colorless oil (1.06 g, 90%): Rf=0.18 (4:1, Hex:EtOAc); 1H NMR (CDCl3) δ 6.75 (s, 2H), 5.01 (d, J) 2.2 Hz, 1H), 3.88 (s, 6H), 3.84 (s, 3H), 3.45 (s, 3H), 2.68 (d, J) 2.2 Hz, 1H); 13C NMR (CDCl3) δ 153.4, 138.2, 133.7, 104.4, 81.3, 76.0, 73.1, 61.0, 56.3, 56.2; HRFAB [M+Li] 243.1208 (calculated C13H16O4Li: 243.1209).

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