Methyl acetoacetate → 5-(3,6-dihydro-4-hydroxy-6-oxo-2-phenyl-2H-pyran-2-yl)pentanoic acid

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Reaction Steps

The title compound was prepared as described in General Method 1 using 25 nmol of methyl acetoacetate, 27.5 mmol of NaH 60% dispersion in oil, 26.25 mmol of 1.6M n-butyl lithium in hexane in 50 mL of tetrahydrofuran and 25 mmol of 5-benzoylpentanoic acid sodium salt in 100 mL of tetrahydrofuran. 5-Benzoylpentanoic acid sodium salt was prepared by reacting the acid (25 mmol) with hexane washed NaH (27.5 mmol) in tetrahydrofuran at 0° C. for 25 minutes. The crude solid was recrystallized from ethyl acetate (m.p. 136°-140° C.). 1H NMR (DMSO-d6) δ0.8-1.0 (m, 1H), 1.1-1.3 (m, 1H), 1.3-1.5 (m, 2H), 1.8-2.0 (m, 2H), 2.1 (t, 2H), 2.9 (ABq, 2H), 4.85 (s, 1H), 7.2-7.4 (m, 5H), 11.4 (bs, 1H), 12.0 (bs, 1H).

Provenance & Evidence