Diethyl Oxalate → Ethyl 2-(2,2-dimethylbenzo[1,2-d]-1,3-dioxan-6-yl)2-hydroxyacetate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

6-Bromo-2,2-dimethylbenzo[1,2-d]-1,3-dioxane (30.0 g) was dissolved in 610 ml of tetrahydrofuran, 136 ml of 1.56 M n-butyl lithium in hexane was added to the solution with stirring at -80° C., and the mixture was subjected to 15 minutes of reaction. With stirring at -80° C., the reaction solution was added to a solution of 21.6 g of diethyl oxalate in 200 ml of tetrahydrofuran, and the mixture was subjected to 1 hour of reaction. Then, 100 ml of ethanol and a solution of 1.40 g of sodium borohydride in 100 ml of ethanol were added in that order. The reaction solution was stirred at -30° C. for 30 minutes, 8.26 ml of acetic acid was added, and the mixture was stirred for 5 minutes. Then, a solution of 14.8 g of potassium bicarbonate in 50 ml of water was added, and the reaction solution was concentrated under reduced pressure. Water was added to the residue, and the mixture was extracted with ethyl acetate. The extract was washed with brine and then dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure and the resulting residue was purified by silica gel medium pressure liquid column chromatography (eluent: hexane/ethyl acetate=5/1) to give 25.1 g of ethyl 2-(2,2-dimethylbenzo[1,2-d]-1,3-dioxan-6-yl)2-hydroxyacetate in an oily form.

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