Potassium Carbonate → 6-Cyclopentyl-6-[2-(3-ethyl-4-hydroxy-phenyl)-ethyl]-dihydro-pyran-2,4-dione

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Reaction Steps

A mixture of acetic acid 4-[2-(2-cyclopentyl-4,6-dioxo-tetrahydro-pyran-2-yl)-ethyl]-2-ethyl-phenyl ester (0.92 g, 2.47 mmol, from Step 3), potassium carbonate (0.68 g, 4.9 mmol) in MeOH (10 mL) was stirred at rt for 1 h. The reaction mixture was partitioned between 1N HCl and EtOAc. The organic layer was washed with brine, dried over Na2SO4 and concentrated to a yellow oil. The oil was purified by silica gel chromatography (20% to 40% EtOAc in hexanes) to give the title compound (2.44 g, 59%). 1H NMR (CDCl3): δ 1.22 (t, 3H, J=7.6 Hz), 1.43-1.78 (br m, 8H), 1.87-2.01 (m, 2H), 2.28 (m, 1H), 2.57-2.63 (m, 4H), 2.76 (s, 2H), 3.42 (s, 2H), 4.63 (s, 1H), 6.68 (d, 1H, J=8.1 Hz), 6.84 (d, 1H, J=8.1 Hz), 6.90 (s, 1H). Anal. Calcd. For C20H26O4.0.25H2O: C, 71.72; H, 7.98. Found: C, 71.10; H, 7.99.

Provenance & Evidence