Sulfuric Acid → HCID 68731984, compound

Participants

Reaction Conditions

Reaction Steps

To an ice cold solution of mixture of 2-(4-bromo-2-ethylphenyl)-12,12-dimethyl-1,11-dioxadispiro[2.1.5.2]dodecan-4-one and 2-(4-bromo-2-ethylphenyl)-11,11-dimethyl-1,10-dioxadispiro[2.0.5.3]dodecan-12-one (15 g, 0.038 mol) in dichloromethane (7.5 ml) is added concentrated sulphuric acid (45 ml), dropwise, over 50-60 minutes, maintaining the temperature of the reaction mixture at 5-10° C. The reaction mixture is maintained at 5-10° C. for 10-15 minutes, quenched into crushed ice (225 g) and extracted with dichloromethane (3×100 ml). The organic phases are combined, washed with water and dried over anhydrous sodium sulfate. The mixture is filtered and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-(4-bromo-2-ethylphenyl)-2,2-dimethyl-1-oxaspiro[5.5]undecane-3,5-dione (3 g) as a white solid.

Provenance & Evidence