Dimedone → Ethyl 7,7-dimethyl-5-oxo-4-(5-phenylthiophen-2-yl)-2-propyl-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate

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Reaction Steps

To a solution of dimedone (0.70 g, 5.0 mmole) in hot ethanol (15 ml) was added 5-phenyl-2-thiophenecarboxaldehyde (0.940 g, 5.0 mmole), ethyl propylacetoacetate (0.80 ml, 5.0 mmole) and lastly ammonium acetate (0.770 g, 10.0 mmole). The mixture was held at reflux for 48 h. No precipitate was observed. The ethanol was removed in vacuo to provide a crude viscous material which was subjected to a 100 g SiO2 flash column using 40% ethyl acetate:hexanes as eluent. The desired product (1.54 g, 68%) was obtained as a yellow amorphous solid. Rf=0.37 in 1:1 ethyl acetate:hexanes. 1H NMR (400 MHz; CDCl3) δ 7.5 (bd, 2H, J=7.0 Hz); 7.32-7.25 (m, 2H); 7.19 (at, 1H, J=7.4 Hz); 7.04 (d, 1H, J=7.4 Hz); 6.8 (d, 1H, J=3.5 Hz); 6.38 (bs, 1H); 5.41 (s, 1H); 4.22-3.90 (m, 2H); 2.90-2.80 (m, 1H); 2.72-2.63 (m, 1H); 2.35 (d, 1H, J=16.8 Hz); 2.25 (d, 1H, J=16.8 Hz); 2.3-2.2 (m, 2H); 1.74-1.62 (m, 2H); 1.25 (at, 3H, J=7.0 Hz); 1.07 (s, 3H); 1.02 (s, 3H); 1.01 (at, 3H, J=7.0 Hz); 1.05-0.95 (m, 2H). LC MS shows MH+ at 450; 2M+H at 899 and 2M+Na at 921.

Provenance & Evidence