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

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.

1. customwas evaporated
2. stirringthe residue was stirred with a mixture of water (200 mL) and concentrated hydrochloric acid (2 mL) for 8 h at ambient temperature
3. extractionThe mixture was extracted with ethyl acetate (200 mL)
4. extractionthe 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)]
5. additionConcentrated hydrochloric acid (15 mL) was added to the aqueous layer
6. extractionthe mixture was extracted with ethyl acetate (200 mL)
7. customAfter drying
8. customevaporation N-[2-(ethoxycarbonyl)butyl]-N-ethoxycarbonylalanine (23.8 g, 82%)
9. customwas obtained as a yellow oil which
10. customcan be used in the next reaction without further purification

ORD record

ord-84ea3a3d547e45d5ab5c532bf1c91f9c

Source dataset

uspto-grants-2008_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07326794B2