Hydrochloric Acid → 2-Amino-5-methoxytetralin

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Reaction Steps

First, 5-methoxy-1,2,3,4-tetrahydronaphthalen-2-one (17.6 g, 0.1 mol) is dissolved in methanol (800 ml) and 1,2-dichloroethane (200 ml), then it is mixed with ammonium acetate (77 g) and sodium cyanoborohydride (5.4 g) and stirred for 2 days at laboratory temperature. The reaction mixture is adjusted to pH 2 with concentrated hydrochloric acid and the solvent is distilled off in vacuo. The residue is dissolved in ethyl acetate/water. The aqueous phase is separated off, made alkaline with 50% sodium hydroxide solution with cooling and extracted twice with methylene chloride. The extract is dried, treated with Fuller's earth/activated charcoal and concentrated by evaporation. The residue is dissolved in acetone and the hydrochloride is precipitated with ethereal hydrochloric acid. Yield: 2 g. Mp: 260°-262° C. (decomp.).

Provenance & Evidence