Hydrogen Peroxide → 4,4-Dimethyl-1,2,3,4-tetrahydronaphthalen-2-one

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Reaction Steps

To a stirred mixture of 30% hydrogen peroxide (5 ml) and 97% formic acid (20 ml) in a round bottom flask equipped with an additional funnel, thermometer, and an ice water bath was added 1,2-dihydro-1,1-dimethylnaphthalene (4.5 g, 28 mmoles) dropwise at 5° C. under a nitrogen atmosphere. When the addition was complete, the reaction vessel was raised above the cooling bath to allow the reaction temperature to rise to just below 35° C. at which point the flask was immersed again. In this manner the temperature of the reaction was maintained between 30° and 35° C. for 45 minutes. After this time the exothermic phase of the reaction ended and the mixture was allowed to cool to room temperature. A solution of 10% aqueous ferric sulfate was added in portions of a few milliliters each until cloudiness persisted in the stired mixture and then all solvent was removed under reduced pressure. The viscous brown residue was refluxed with 20% H2SO4 (20 ml) for 4 hours and then cooled, extracted three times with ether (75 ml each), dried over magnesium sulfate, filtered and evaporated to leave a brown oil. This was purified using silica gel column chromatography eluting with ethyl acetate:hexane (7:93) to give 4,4-dimethyl-2-tetralone. (3.4 g, 74%). Overall yield=40%.

Provenance & Evidence