Diethyl Carbonate → Ethyl 7-methoxy-1-oxo-3,4-dihydro-2H-naphthalene-2-carboxylate

関与物質

反応条件

反応手順

The starting 7-methoxy-1,2,3,4-tetrahydronaphthalen-2-carboxylic acid, which is a known product, can be prepared as follows: a solution of 7-methoxy-3,4-dihydronaphthalene-1(2H)-one (66.4 g, 0.376 mol) in anhydrous tetrahydrofuran (350 ml) is added in 1 hour to a mixture of distilled diethylcarbonate (116 ml, 0.957 mol), 80% sodium hydride (39.7 g, 1.32 mol) and anhydrous tetrahydrofuran (350 ml) heated to 60° C. The thus obtained reaction mixture is refluxed for 4 hours and then cooled. Acetic acid is then added dropwise up to acidic pH and water is added until complete dissolution of the precipitate occurs. The solution is extracted with ethyl ether, the organic phase is washed with water and with a sodium bicarbonate solution, dried and evaporated to dryness. The thus obtained oily product is purified by distillation under reduced pressure yielding 90 g of 7-methoxy-1-oxo-1,2,3,4-tetrahydronaphthalen-2-carboxylic acid ethyl ester. B.p.0.4 mmHg 160°-165° C.

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