Benzyl Bromide → (S)-benzyl 2-(dibenzylamino)pentanoate

Participants

Reaction Conditions

Reaction Steps

Sodium hydroxide (0.513 Kg; 12.82 moles) and potassium carbonate (1.77 Kg, 12.82 moles) were dissolved in water (7.5 L) and cooled to 0° C. The resulting solution was treated with (S)-2-aminopentanoic acid (L-norvaline, 0.75 Kg; 6.41 moles) slowly at between 0-5° C. The stirred suspension was heated at 90° C. and benzyl bromide (4.385 Kg, 25.64 moles) was added dropwise. Heating was continued for a further 12 hours at 90° C. The reaction mixture was then cooled to ambient temperature, and extracted with ethyl acetate (2×6 liters). The layers were separated and the aqueous phase extracted twice with ethyl acetate. The combined organic extracts were dried over sodium sulfate, and the solvent removed under reduced pressure to obtain 3.3 Kg of crude (S)-benzyl 2-(dibenzylamino)pentanoate, a compound of formula (3), as a brown oil. This material was used in the next reaction without further purification.

Provenance & Evidence