Triethylamine → N-[2-(ethoxycarbonyl)butyl]-N-ethoxycarbonylalanine

Participants

Reaction Steps

To a suspension of N-[2-(ethoxycarbonyl)butyl]alanine (21.7 g, 100 mmol) in acetone (250 mL) was added a solution of triethylamine (27.7 mL, 20.2 g, 200 mmol) in acetone (50 mL) followed by ethyl chloroformate (24.8 mL, 28.2 g, 260 mmol) at 0-5° C. After stirring for 2 h at ambient temperature the solvent was evaporated and the residue was stirred with a mixture of water (200 mL) and concentrated hydrochloric acid (2 mL) for 8 h at ambient temperature. The mixture was extracted with ethyl acetate (200 mL) and the solution in ethyl acetate was extracted with cold aqueous sodium hydroxide solution [prepared from ice (100 g) and aqueous sodium hydroxide solution (1N, 200 mL)]. Concentrated hydrochloric acid (15 mL) was added to the aqueous layer and the mixture was extracted with ethyl acetate (200 mL). After drying and evaporation N-[2-(ethoxycarbonyl)butyl]-N-ethoxycarbonylalanine (23.8 g, 82%) was obtained as a yellow oil which can be used in the next reaction without further purification.

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