2,5-Hexanedione → HCID 12485849, compound

Reaction equation

[CH3:1][C:2]1[CH2:6][CH:5]=[CH:4][CH:3]=1.[CH3:7][C:8](=O)[CH2:9][CH2:10][C:11](=O)[CH3:12].[Na]>CO>[CH3:1][C:2]1[C:6]2[C:5](=[C:8]([CH3:7])[CH:9]=[CH:10][C:11]=2[CH3:12])[CH2:4][CH:3]=1

Participants

Procedure

A mixture of 12 g (150 mmol) of methylcyclopentadiene and 17.1 g (150 mmol) of 2,5-hexanedione was added dropwise to a solution of 8.6 g (975 mmol) of sodium in 200 ml of methanol at 0° C. in the course of 1 hour. After stirring at room temperature for 18 hours, the dark red mixture was poured onto ice-water and extracted with ether. After the extract had been dried over sodium sulfate, the solvent was stripped off and the oil which remained was chromatographed on 600 g of silica gel 60. Using hexane as the mobile phase, first 3.2 g (13%) of 3,4,7-trimethylindene and then 1.5 g (6%) of 2,4,7-trimethylindene were eluted in close succession. Subsequent recrystallization from hexane gave the pure products.