Ethanol → 2-Methyl-4-(4-methylphenyl)-4,6,7,8-tetrahydro-5(1H)-quinolone

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Reaction Steps

A mixture of 4-(4-methyphenyl)-3-butene-2-one (5.0 g), 1,3-cyclohexanedione (3.66 g), ammonium acetate (3.61 g) and 100 mL of ethanol were heated at reflux overnight and then cooled to room temperature. The solvent was evaporated and the residue was partitioned between water and ethyl acetate. The organic layer was dried, filtered, and evaporated to obtain an amber oil. Chromatography, with hexane:ethyl acetate (1:1) as the eluent, and trituration from ether provided the title compound as an off-white solid (2.0 g); mp 196°-198° C.; NMR: 1.73 (s,3, CH3), 1.87-1.98 (m,2, CH2), 2.14-2.16 (m,2, CH2), 2.22 (s,3, CH3), 2.43-2.49 (m,2, CH2), 4.34 (d,1, CH), 4.57 (d,1, CH), 7.01 (s,4, Ar), 8.40 (s,1, NH); (CI, CH4) MS: m/z=254(M+1). Analysis for C17H19NO: Calculated C, 80.60; H, 7.56; N, 5.53; Found: C, 80.24; H, 7.68; N, 5.36.

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