L-Valine → Boc-L-Valine

Boc-ON (13.55 g, 55 mmol) was added portionwise to a mixture of L-valine (5.86 g, 50 mmol), triethylamine (7.59 g, 10.4 ml, 75 mmol), H2O (30 ml) and p-dioxane (30 ml). A clear solution (yellowish) was obtained after stirring the suspension at 25° for 1 hour. After stirring for 4 hours more, water (75 ml) and ethyl acetate (100 ml) were added. The aqueous layer was separated and washed with ethyl acetate (150 ml). The colorless aqueous phase was acidified to pH 3 with cold 1 N HCl. Boc-Val was extracted with ethyl acetate (3×75 ml). The combined extracts were washed with saturated NaCl and then dried (Na2SO4 /MgSO4). Solvent removal on a rotary evaporator under reduced pressure followed by drying under high vacuum gave a highly viscous oil: 10.51 g (96.8%).

1. customA clear solution (yellowish) was obtained
2. stirringAfter stirring for 4 hours more
3. customThe aqueous layer was separated
4. washwashed with ethyl acetate (150 ml)
5. extractionBoc-Val was extracted with ethyl acetate (3×75 ml)
6. washThe combined extracts were washed with saturated NaCl
7. dry with materialdried (Na2SO4 /MgSO4)
8. customSolvent removal
9. customon a rotary evaporator under reduced pressure
10. customby drying under high vacuum
11. customgave a highly viscous oil

ORD record

ord-492921d713b7483d92242157f1dbf21b

Source dataset

uspto-grants-1983_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04384994