Water → 4,7-dimethyl-1H-indene

Participants

Reaction Steps

23 g (1.0 mol) of sodium were dissolved in 250 ml of absolute methanol. A mixture of 45.6 g (0.40 mol) of 2,5-hexanedione and 39.7 g (0.60 mol) of cyclopentadiene was added dropwise at 0° C. in the course of 1-2 hours. After stirring at room temperature for 1 hour, 50 ml of H2O were added to the dark brown solution. The organic phase was diluted with about 1 l of diethyl ether. The aqueous phase was separated off. The organic phase was dried over sodium sulfate and evaporated. The oil which remained was chromatographed on silica gel 60. 44.2 g (76%) of the indene 1 could be eluted with hexane/methylene chloride (10:1), and is obtained as a colorless to pale yellow oil after the mobile phase has been stripped off under an oil pump vacuum. For the NMR data, see Table 1.

Provenance & Evidence