Ammonia → N-(2-aminocarbonylethyl)-N-[2-(chroman-3-yl)ethyl]amine hydrochloride

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Reaction Steps

3 g (100 mmol) of N-[2-(chroman-3-yl)ethyl]-N-(2-methoxycarbonylethyl)-amine hydrochloride (example 4) are added to 20 ml of 5.5N methanolic ammonia solution. The mixture is stirred in a bomb tube for 12 hours at 60°. Subsequently, the reaction mixture is concentrated by evaporation, the resulting residue is dissolved in 2N hydrochloric acid, and the acidic solution is extracted with diethyl ether. The acidic aqueous phase is rendered alkaline with 2N sodium hydroxide solution and extracted with diethyl ether. The combined ethereal phases are washed in succession with water and saturated sodium chloride solution, dried over magnesium sulfate, and concentrated by evaporation, yielding the crude base in the form of an oil. The crude base is dissolved in a small amount of isopropanol. Ethereal hydrochloric acid is added to the isopropanol solution until the mixture gives a weakly acidic reaction. The precipitate is filtered off and recrystallized from isopropanol/diethyl ether, yielding 0.6 g of N-(2-aminocarbonylethyl)-N-[2-(chroman-3-yl)ethyl]amine hydrochloride melting at 220° to 222°.

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