Formic Acid → 6-(4-Carboxymethyl-phenylethynyl)-4,4,7-trimethyl-1,2,3,4-tetrahydro-naphthalene-1-carboxylic acid ethyl ester

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Reaction Steps

A solution of 6-(4-tert-butoxycarbonylmethyl-phenylethynyl)-4,4,7-trimethyl-1,2,3,4-tetrahydro-naphthalene-1-carboxylic acid ethyl ester (Intermediate 194, 0.23 g, 0.5 mmol) in 1,4-dioxane (1 mL) was treated with formic acid (3 mL) and the resulting reaction mixture was stirred at ambient temperature for 6 h. Water was added and the reaction mixture was extracted with ethyl acetate (×2). The combined organic phase was washed with water, dried over anhydrous magnesium sulfate, filtered and evaporated to an oil. Preparative reverse phase HPLC using 10% water in acetonitrile as the mobile phase afforded the title compound (0.15 g, 74%). 1H NMR (300 MHz, CDCl3): δ 7.48 (s, 1H), 7.46 (br d, 2H), 7.23 (br d, 2H), 6.96 (s, 1H), 4.17 (q, 2H, J=7.0 Hz), 3.73 (t, 1H, J=5.8 Hz), 3.54 (br s, 2H), 2.40 (s, 3H), 2.29-1.95 (m, 2H), 1.85-1.77 (m, 1H), 1.62-1.44 (m, 1H), 1.31 (s, 3H), 1.26 (s, 3H), 1.25 (t, 3H, buried).

Provenance & Evidence