Hydrochloric Acid → Benzyl 2(S)-tert-butoxycarbonylamino-5-nitro-4-oxopentanoate

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Reaction Steps

A solution A of 10 g (30.9 mmol) of 2(S)-tert-butoxycarbonylaminosuccinic acid 1-benzyl ester and 5.27 g (32.5 mmol) of 1,1′-carbonyldiimidazole in 100 ml of tetrahydrofuran is stirred at RT for 5 h. 18.8 g (30.9 mmol) of nitromethane are added dropwise to a solution B of 3.2 g (34.2 mmol) of potassium tert-butoxide in 100 ml of tetrahydrofuran at 0° C. Solution B is stirred while warming to RT, and then solution A is added dropwise at RT. The resulting mixture is stirred at RT for 16 h and adjusted to pH 2 using 20% hydrochloric acid. The solvent is evaporated. The remaining crude product is taken up in ethyl acetate/water. After separation of the phases, the organic phase is extracted twice with water, dried over sodium sulfate and concentrated. 13 g (99% of theory) of product are obtained.

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