Sulfuric Acid → 4-(5-Bromo-2-ethylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione

Participants

Reaction Conditions

Reaction Steps

To an ice-cold solution of concentrated sulphuric acid (2 ml) is added a second solution of 2-(5-bromo-2-ethylphenyl)-4,4,6,6-tetramethyl-1,5-dioxaspiro[2.4]heptan-7-one (0.995 g, 2.82 mmol) in 1,2-dichloroethane (2 ml) dropwise over 5 minutes. This biphasic mixture is stirred vigorously for 1 hour at 0° C., then poured into ice-cold water (15 ml). This aqueous mixture is then concentrated under vacuum to remove all organic volatiles, producing a free-flowing solid. The solid is filtered, dried under vacuum, then washed with hexanes to afford 4-(5-bromo-2-ethylphenyl)-2,2,6,6-tetramethylpyran-3,5-dione (0.81 g) as a cream-coloured solid.

Provenance & Evidence