Ethyl orthoformate → Methyl (8-ethyl-1,4,7,9-tetraoxaspiro[4.5]dec-8-yl)acetate

関与物質

反応手順

The 1,3-dioxolan-2,2-diyldimethanol (4 g, 29.8 mmol), which was obtained at another time in the same manner as described in the steps (4a)-(4c), was mixed with methyl propionylacetate (5.6 ml, 44.6 mmol) and triethyl orthoformate (5.2 ml, 31.3 mmol), and p-toluenesulfonic acid monohydrate (163 mg, 0.856 mmol). The mixture was stirred at room temperature for 3 hours. To the mixture, a saturated aqueous solution of sodium hydrogen carbonate and ethyl acetate were added. The organic layer was washed with water twice and with an aqueous saline solution, dried over anhydrous sodium sulfate and concentrated. The obtained crude product was purified by silica gel column chromatography (elution solvent: heptane/ethyl acetate=1/0-3/1-1/1 gradient) and a desired fraction(s) was concentrated to obtain the title compound (2.63 g, yield: 35.8%) as a colorless oil.

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