1,2-Dichloroethane → methyl (2S)-2-{[(tert-butoxy)carbonyl]amino}-3-(pyridin-3-yl)propanoate

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Reaction Conditions

Reaction Steps

(2S)—N-(tert-Butoxycarbonyl)-3-(pyridin-3-yl)alanine (25.00 g, 93.88 mmol) is dissolved in 300 ml of dichloromethane under argon. Methanol (11.4 ml, 9.02 g, 281 mmol, 3 equivalents) and one grain of DMAP are added. The mixture is then cooled to 0° C. EDC (19.80 g, 103 mmol, 1.1 equivalents) is added. After 5 min, the ice bath is removed and the mixture is left to stir at RT over 1 h. The mixture is then concentrated in vacuo, and ethyl acetate is added to the residue and the mixture is extracted against a saturated sodium hydrogen carbonate solution. The aqueous phase is reextracted once with ethyl acetate, then the combined organic phases are washed with 0.5 M citric acid and then once again with a saturated sodium hydrogen carbonate solution. The organic phase is dried over sodium sulfate, filtered and concentrated in vacuo. An oil remains, which crystallizes during drying in an oil-pump vacuum. Yield: 23.60 g (90% of theory).

Provenance & Evidence