Acetic Anhydride → 2,5-Cyclohexadien-1-one, 4-(acetyloxy)-4-phenyl-

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Reaction Steps

To 4-hydroxy-4-phenyl-2,5-cyclohexadienone (0.335 g, 1.8 mmol), acetic anhydride (0.276 g, 2.7 mmol, 1.5 equivalents) and triethylamine (0.273 g, 2.7 mmol, 1.5 equivalents) dissolved in dichloromethane (20 mL) was added 4-dimethylaminopyridine (DMAP) (0.044 g, 0.36 equivalents). The reaction mixture was stirred for 24 hours at room temperature, washed with 1 M HCl (20 mL) then saturated sodium hydrogen carbonate solution (2×20 mL) and the organic layer dried over magnesium sulphate. Removal of the solvent in vacuo gave an oil which was dissolved in ether, filtered and the solvent removed in vacuo to gave the title compound as a white solid. The yield was 62%; mp 100–101° C. (lit. 106–109° C.); 1H NMR (CDCl3) δ 7.48–7.36 (5H, m, ArH); 6.99 (2H, d, J 19.2 Hz, H-3, H-5); 6.36 (2H, d, J 10.2 Hz, H-2, H-6); 2.22 (3H, s, O2CCH3).

Provenance & Evidence