Sodium Azide → ethyl (S)-4-azido-3-hydroxybutyrate

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Reaction Steps

To a mixture of ethyl (S)-4-chloro-3-hydroxybutyrate (1 93 g, 1.16 mol, optical purity:98.5% ee) and N,N-dimethylformamide (1.4 Lit.) is added sodium azide (151 g, 2.32 mol) and the mixture was stirred at 100°-110° C. for 2 hours. After cooling N,N-dimethylformamide was distilled off and to the residue was added water (1 Lit.). The mixture was extracted with ethyl acetate and the extract was dried over magnesium sulfate. By distillation off ethyl acetate under vacuo, there is obtained ethyl (S)-4-azido-3-hydroxybutyrate as a crude product (206 g). Then the crude product was dissolved in methanol (1 Lit.) and to it 5% palladium-carbon (10 g) was added. The mixture was stirred for 17 hours at room temperature under a hydrogen atmosphere. After the reaction was over, palladium-carbon was filtered off and the solvent was distilled off under vacuo. The resulting product was recrystallized from acetone-water to give (S)-4-hydroxy-2-pyrrolidone (99 g, 0.98 mol, yield:84%) as a colorless crystalline solid. Optical purity:98.3% ee, Specific rotation:[α]D22 -57.6°(c=1.00, H2O).

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