Hydrochloric Acid → ethyl 1-oxo-1,2,3,4-tetrahydronaphthalene-2-carboxylate

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Reaction Steps

A suspension of 10 g (0.0684 mole) of α-tetralone, 3.56 g (0.0890 mole) of 60% sodium hydride and 32 g (0.2709 mole) of diethyl carbonate was heated under reflux for 1 hour, then poured into water, adjusted with conc. hydrochloric acid to a pH of 1 to 2, and extracted with ether. The ether layer was washed with water and then dried over magnesium sulfate. After evaporation of the solvent, the crude product was purified by silica gel column chromatography (hexane/ethyl acetate=9/1) to obtain 8.6 g of ethyl 1,2,3,4-tetrahydro-1-oxo-2-naphthalenecarboxylate, which was dissolved in tetrahydrofuran (220 ml) and then 1.90 g (0.0475 mole) of 60% sodium hydroxide was added under ice-cooling. After stirring for 30 minutes, 10.0 g (0.0599 mole) of ethyl bromoacetate was added, followed by stirring for 3 hours at room temperature. The reaction mixture was poured into ice-water, extracted with ether, and then the extract was subjected to washing with water, drying and solvent evaporation in a conventional manner. The crude product obtained was purified by silica gel column chromatography (hexane/ethyl acetate=5/1) to obtain 9.03 g of the following ethyl 2-ethoxycarbonyl-1,2,3,4-tetrahydro-1-oxo-2-naphthaleneacetate ##STR13##

Provenance & Evidence