4-(2',3'-Dimethoxyphenyl) 3-phenylbutyric acid → 5,6-Dimethoxy-3-phenyl-3,4-dihydronaphthalen-1(2H)-one

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Reaction Conditions

Reaction Steps

4-(2',3'-Dimethoxyphenyl)-3-phenylbutyric acid (37 g, 123 mmol), from Step 5, was added dropwise to 200 g of polyphosphoric acid heated to 100° C. The resultant mixture was stirred and heated at 100° C. for 0.25 h. A mixture of 100 g of ice and 200 mL of water was added to the reaction mixture. The precipitate which formed was filtered, washed with 3×75 mL of water and dissolved in 300 mL of methylene chloride. The methylene chloride solution was dried over anhydrous magnesium sulfate, filtered and concentrated to give 28 g (81% yield) of 5,6-dimethoxy-3-phenyl-1,2,3,4-tetrahydronaphthalen-1 -one, m.p; 127°-128° C.; 1H NMR (CDCl3) δ: 2.75-3.0 (m, 3H), 3.3-3.5 (m, 2H), 3.8 (s, 3H), 3.95 (s, 3H), 6.93 (d, 1H), 7.25-7.4 (m, 5H), 7.9 (d, 1H).

Provenance & Evidence