Diethyl Ether → 3-Phthalimido-3-(4-butoxy-3-methoxyphenyl)propionic acid

Participants

Reaction Steps

To a stirred solution of 3-amino-3-(4-butoxy-3-methoxyphenyl)propionic acid (1.31 g, 4.98 mmol) and sodium carbonate (0.554 g, 5.23 mmol) in a mixture of 100 mL of water and 100 mL of acetonitrile (mixture was warmed gently to dissolve solid, small amount of brown solid did not dissolve removed by filtration) was added N-carbethoxyphthalimide (1.09 g, 4.98 mmol). The mixture was stirred for 1 hour, then partially concentrated in vacuo to remove the acetonitrile. The pH was adjusted to 0-1 with 4 N Hydrochloric acid. An oil formed, 3 mL of ether was added and the mixture stirred overnight. The oil did not solidify and was extracted in methylene chloride. The organic layer was dried (sodium sulfate) and concentrated to a yellow oil which was purified by flash chromatography (silica gel, 5/95 methanol/methylene chloride) to afford 1.02 g of 3-phthalimido-3-(4-butoxy-3-methoxyphenyl)propionic acid containing an unidentified impurity as a yellow oil which slowly crystallized: 1H NMR (DMSO-d6)δ 7.95-7.8 (m, 4H, Ar), 7.03 (s, 1H), 6.9 (m, 2H), 5.61 (dd, 1H, J=9, 6.7 Hz), 3.91 (t, 2H, J=6.4 Hz), 3.74 (s, 3H), 3.47 (dd, 1H, J=16.5, 6.7 Hz), 3.27 (dd, 1H, J=16.5, 6.7 Hz), 1.75-1.55 (m, 2H) 1.5-1.3 (m, 2H), 0.91 (t, 3H, J=7.3 Hz); 13C NMR (DMSO-d6)δ 171.8, 167.7, 148.8, 147.8, 134.6, 131.3, 131.1, 123.2, 119.3, 112.9, 111.4, 67.8, 55.5, 50.1, 30.8, 18.7, 13.6.

Provenance & Evidence