Acetic Acid → 4-(5-Cyclopropylamino-8,8-dimethyl-5,6,7,8-tetrahydro-naphthalene-2-ylethynyl)-benzoic acid ethyl ester

Participants

Reaction Steps

A solution of 4-(8,8-dimethyl-5-oxo-5,6,7,8-tetrahydro-naphthalene-2-ylethynyl)-benzoic acid ethyl ester (Intermediate 14, 0.14 g, 0.4 mmol) in 3 mL of dichloromethane and 2 mL of acetonitrile was treated with cyclopropyl amine (1 mL, 14.45 mmol). After 5 minutes, acetic acid (1 mL) was added followed by sodium cyanoborohydride (0.13 g, 2 mmol). The reaction was stirred overnight at ambient temperature. It was then diluted with water and saturated aqueous sodium carbonate solution and extracted with dichloromethane (×2). The combined organic extract was dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to an oil. Flash column chromatography over silica gel (230-400 mesh) using 20% ethyl acetate in hexane as the eluent afforded the title compound (0.1 g, 62%) as a pale yellow solid. 1H-NMR (300 MHz, CDCl3): δ 0.30-0.60(m, 4H), 1.28(s, 3H), 1.35 (s, 3H), 1.30(t, J=7.1 Hz, 3H), 1.55-1.61(m, 1H), 1.83-2.05(m, 3H), 2.25 (quintet, J=3.0 Hz, 1H), 3.80 (t, J=4.9 Hz, 1H), 4.39(q, J=7.1 Hz, 2H), 7.27-7.36(m, 2H), 7.52 (s, 1H), 7.55(d, J=8.3 Hz, 2H), 8.03(d, J=8.5 Hz, 2H).

Provenance & Evidence