Over 1.5 hours, methyllithium (531 mL 2 mol solution, 1.06 M) was added to a rapidly stirred solution of 3,5-dibenzyloxybenzoic acid (175 g, 0.532 M) in diethyl ether (250 mL) and tetrahydrofuran (1400 mL) at 15°–20°C. After stirring for another 0.75 hours at 10°–15°C, water (600 mL) was slowly added, maintaining the reaction temperature below 20°C. The aqueous layer was separated and extracted with diethyl ether (3 × 250 mL). The combined organic phases were washed with saturated sodium chloride solution (4 × 300 mL), dried over sodium sulfate, and concentrated under vacuum to give an oil that slowly crystallized from isopropyl ether. The crude product was recrystallized from diethyl ether-hexane to give 104.7 g. (59%) 3,5-Dibenzyloxyacetophenone; melting point 59°-61° C.
beige crystalline powder.
The product 3,5-dibenzyloxyacetophenone is widely used as intermediate in the production of a pharmaceutical for treatment of obesity, diabetes, glaucoma, AIDS, HIV infection, antiinflammatory effects, and also in the treatment of disorders which result from leukotriene, tranquilizers, hypotensives, diuretics, and antiglaucoma agents.[1]
3,5-Dibenzyloxyacetophenone is used in the synthesis of enantiomerically pure B-ring modified analogs of (-)-epicatechin gallate.
[1] Ganapati D. Yadav, Omprakash V. Badure. “Selective acylation of 1,3-dibenzyloxybenzene to 3,5-dibenzyloxyacetophenone over cesium modified dodecatungstophosphoric acid (DTP) on clay.” Applied Catalysis A: General 348 1 (2008): Pages 16-25.
