Hydrochloric Acid → Methyl 6-fluoro-1,2,3,4-tetrahydro-1-oxo-2-naphthalenecarboxylate

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Reaction Steps

Hexane washed sodium hydride (3.5 g of 60%, 88 mmole) was covered with 75 ml of tetrahydrofuran and 5.4 ml (64 mmole) of dimethylcarbonate was added in one portion. The solution was heated to reflux and 6-fluoro-3,4-dihydro-1(2H)-naphthlenone (7.2 g, 44 mmole) in 25 ml of tetrahydrofuran was added dropwise while maintaining reflux. After the addition was complete, the reaction was refluxed for 1.5 hours. The reaction was then cooled in an ice bath and 10% aqueous HCl solution was carefully added. The solution was diluted with ether and the aqueous phase was separated and extracted twice with ether. The combined organic phases were dried (MgSO4) and concentrated. The crude product was a pale yellow solid (9.6 g, 98% yield). 1H NMR (CDCl3) δ: 7.99 (1H, dd, J=6,8 Hz), 6.95 (2H, m) 3.83 (3H, s), 3.82 (1H, m), 2.81 (2H, m), 2.58 (2H, m). NMR complicated by signals from enol tautomer.

Provenance & Evidence