Sulfuric Acid → methyl 3-(3,4-dihydro-7-hydroxy-2-methyl-4-oxo-8-propyl-2H-1-benzopyran-2-yl)propanoate

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反応手順

A mixture of the title compound of Example 3 (4.3 g, 14.7 mmole), 6 ml of trimethylorthoformate, and 1.4 ml of sulfuric acid was stirred at room temperature for two hours. The reaction mixture was poured onto stirred ice/water and extracted with ethyl acetate. The organic phase was washed with water, dried over magnesium sulfate, and concentrated to an oil. The oil was purified by chromatography on silica gel, giving 3.7 g of the title compound as a crystalline solid, m.p. 101.5°-102.5° Structure assignment was consistent with nmr and infrared spectra. ##STR9##

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