Methyl acetoacetate → 1-Methyl-1,3,4,9-tetrahydroindeno[2,1-c]pyran-1-acetic acid methyl ester

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Reaction Steps

To a solution of indene-3-ethanol (8 g) and methyl acetoacetate (6 g) in 250 ml of dry benzene containing hydrated alkali-aluminum silicate (Molecular Sieves No. 4, about 2 g) is added 1 ml of boron trifluoride-etherate and the mixture stirred at room temperature for 4 hr. An additional 1 ml of boron trifluoride-etherate is added, the reaction mixture is stirred at ambient temperature overnight and then heated at reflux for 1 hr. The hydrated alkali-aluminum silicate is collected and the filtrate washed with 10% solution of sodium bicarbonate and water. After drying over magnesium sulfate the benzene is removed under reduced pressure affording 1-methyl-1,3,4,9-tetrahydroindeno[2,1-c]pyran-1-acetic acid methyl ester, νmaxfilm 1724 cm-1.

Provenance & Evidence