2-(Bromomethyl)acrylic acid ethyl ester → 4-((2-Methyl-4-methylene-5-oxotetrahydro-2-furanyl)methoxy)-2H-chromen-2-one

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Reaction Steps

To a solution of 1a (0.655 g, 3 mmol) in dry tetrahydrofuran (60 ml) were added activated zinc powder (0.255 g, 3.9 mmol), hydroquinone (6 mg), and ethyl 2-(bromomethyl)acrylate (0.78 g, 4 mmol). The mixture was reflued under nitrogen atmosphere for 36 h. (monitored by TLC). After cooling it was poured into an ice-cold 5% HCl solution (300 ml) and extracted with CH2Cl2 (75 ml×3). The dichloromethane extracts were combined and washed with saline, dried over Na2SO4, and then evaporated to give a residual solid which was crystallized from ethyl acetate to afford the title compound (0.656 g, 76.4%) as a pale yellow crystal. mp: 161°-162° C.; IR(KBr) νmax : 1766, 1703, 1627; UV (CHCl3) λmax (log ε): 306 (3.79), 276 (4.01), 266 (4.05); 1H-NMR (CDCl3): δ1.64 (s, 3H, 5'-CH3), 2.88 (dt, 1H, 4'-H), 3.19 (dt, 1H, 4'-H), 4.08, 4.20 (two d, 2H, OCH2), 5.67 (s, 1H, 3-H), 5.75 (t, 1H, vinylic H), 6.38 (t, 1H, vinylic H), 7.12-7.33 (m, 2H, 6 and 8-H), 7.51-7.65 (m, 2H, 5 and 7-H). Anal. Calcd for C16H14O5 : C, 67.13; H, 4.93. Found: C, 67.14; H, 5.01.

Provenance & Evidence