1,3-Cyclohexanedione → 4-(3-Methoxyphenyl)-2-methyl-4,6,7,8-tetrahydro-5(1H)-quinolone

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Reaction Steps

A solution of 1-(3-methoxyphenyl)but-1-en-3-one (2.07 g), 1,3-cyclohexanedione (1.37 g) and ammonium acetate (1.39 g) in ethanol (20 mL) was stirred at reflux for 10 hours. The reaction was worked up as described in Example 8 and purified by chromatography (10% v/v ethyl ether in methylene chloride) to yield the title compound (1.14 g) as an off-white solid. Recrystallization from ethanol/hexane gave analytically pure material, mp 164°-167° C.; NMR: 1.71 (s,3, CH3), 1.82-1.88 (m,2, CH2), 2.13-2.17 (m,2, CH2), 2.40-2.44 (m,2, CH2) 3.67 (s,3, CH3), 4.35 (d,1, J=4.8, CH), 4.60 (d,1, J=4.6, CH), 6.64-6.66 (m,2, Ar), 6.71 (d,1, J=7.7, Ar), 7.12 (dd,1, J=7.7, 3.8, Ar), 8.41 (s,1, NH); (CI, CH4)MS: m/z=270(M+1). Analysis for C17H19NO2.0.5H2O: Calculated: C, 73.36; H, 7.24; N, 5.03. Found: C, 73.49; H, 6.98; N, 4.93.

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