Methyl iodide → (2S)-2-(((tert-butoxy)carbonyl)amino)-3-methoxypropanoic acid

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Reaction Steps

A sodium methanolate (NaOMe) solution was prepared by slowly adding MeOH (50 mL) to a suspension of sodium hydride (60% in mineral oil, 28 g, 0.71 mol) in dry THF (1.2 L) at 0° C. The resulting mixture was stirred at RT for 2 h. A portion of the NaOMe solution (320 mL) was added to (S)-2-(tert-butoxycarbonylamino)-3-hydroxypropanoic acid (36 g, 175 mmol) in dry THF (1.6 L), and the mixture was stirred at RT for 1 h. Methyl iodine (16 mL) was then added and the mixture was stirred at RT for 1 h. Another aliquot of NaOMe solution (540 mL) was added and the reaction mixture stirred at RT for 1 h. Additional methyl iodine (38 mL) in THF (200 mL) was added and the reaction mixture was stirred at RT for 36 h. Following reaction, the mixture was concentrated and the residue was dissolved in water and washed with diethyl ether (2×100 mL). The aqueous layer was acidified to pH 2 by the addition of solid citric acid and was extracted with EtOAc (3×200 mL) and dried over Na2SO4. The organic phase was concentrated, and the residue was dissolved in water and extracted with DCM (4×150 mL). The organic layers were combined and concentrated to give the title compound as an oil, which was used without further purification (10.9 g, 28%).

Provenance & Evidence