Acetic Acid → 3-(p-Chlorobenzylamino)propyl(tetrahydrofuran-2-yl)phosphinic acid ethyl ester

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Reaction Steps

2.5 g of 3-(p-chlorobenzylamino)propyl(diethoxymethyl)phosphinic acid ethyl ester are dissolved in 10 ml of methanol, 0.36 g (0.53 ml)of a 35% aqueous formaldehyde solution is added, and the mixture is stirred at room temperature for one hour. 0.4 g of glacial acetic acid and 0.40 g of sodium cyanoborohydride are added, and the mixture is stirred at room temperature for 2 hours, concentrated by evaporation under reduced pressure, taken up in dichloromethane and washed with 5% aqueous sodium hydrogen carbonate solution. The organic phase is separated off, dried over sodium sulfate and concentrated by evaporation under reduced pressure. The oily residue is purified by chromatography on silica gel, yielding 3-(p-chlorobenzylamino)propyl(tetrahydrofuran-2-yl)phosphinic acid ethyl ester in the form of a colourless oil.

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