Hydrochloric Acid → 5,7-Dihydroxy-8-acetyl-4-propyl-coumarin

Participants

Reaction Conditions

Reaction Steps

To a mixture of 5,7-dihydroxy-4-propyl-coumarin (2.06 g 9.36 mmol) and anhydrous AICI3 (2.53 g, 18.7 mmol) was added 1,2-dichloroethane (120 mL). The resulting suspension was heated to 75° C. with vigorous stirring. After 30 minutes of stirring, a brown slurry was obtained, then nitrobenzene was introduced into the mixture resulting in an orange colored solution. A solution of anhydrous AICI3 (2.53 g, 18.7 mmol) and acetic anhydride (0.88 mL, 9.36 mmol) in 1,2-dichloroethane (40 mL) was added dropwise over a period of 1-2 hours. After addition, the mixture was allowed to stir at 75° C. for another two hours and subsequently cooled to room temperature. The resulting mixture was poured into ice and 1 N HCl. The precipitated product was filtered and then taken into ethyl acetate and the aqueous solution was extracted throughly with ethyl acetate (3×100 mL). The combined ethyl acetate extracts were dried over Na2SO4 and the solvent was removed under reduced pressure. The resulting solid was purified by column chromatography (1:1 hexane/ethyl acetate) yielding 5,7-dihydroxy-8-acetyl-4-propyl-coumarin (0.30 g, 12%): mp. 221-224° C.; 1H NMR (DMSO-d6) δ 0.94 (t, 3H), 1.58 (sextet, 2H), 2.66 (s, 3H) 2.87 (t, 2H), 6.01 (s, 1H), 6.29 (s, 1H).

Provenance & Evidence