Hydrochloric Acid → 2,4,6-trimethyl-1H-indene

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Reaction Steps

20.4 g (117 mmol) of 2,5,7-trimethyl-1-indanone (1) were dissolved in 300 ml of a mixture of tetrahydrofuran/methanol (2:1), and 6.6 g (175 mmol) of NaBH4 were added at room temperature. The mixture was stirred for a further hour, 50 ml of half-concentrated HCl were added and the mixture was extracted with ether. The combined organic phases were dried over sodium sulfate and freed from the solvent. The residue was transferred to a distillation apparatus, and 13 g of magnesium sulfate were added. A vacuum of about 10 mbar was applied and the mixture was heated up until the product distilled over (130-150° C.). Distillation gave 17.7 g of the indene 2 as a colorless oil. The yield was 96%.

Provenance & Evidence