4-Methoxybenzyl azidoformate → 2-Methylene-5-(p-methoxybenzyloxycarbonyl)aminopentanoic acid

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Reaction Steps

To a solution of 8.8 g of 2-methylene-5-aminopentanoic acid hydrochloride in 100 ml of water is added with stirring 6.36 g of magnesium oxide, followed by a solution of 12.2 g of p-methoxybenzyloxycarbonyl azide in 100 ml of dioxane, and the resulting mixture is stirred at room temperature for 2 days. The reaction mixture is filtered, and the filtrate diluted with 200 ml of ethyl acetate, two equivalents of Dowex 50 ion exchange resin is added, and the mixture is stirred at room temperature for 2 hours. The resin is then filtered off and washed with water. The layers in the filtrate are separated and the aqueous layer is extracted twice with ethyl acetate. The combined organic layers are dried and concentrated in vacuo to give 18.2 g of 2-methylene-5-(p-methoxybenzyloxycarbonyl)aminopentanoic acid as an amber oil which crystallizes on standing. This is used without further purification.

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