Hydrochloric Acid → 3-{[(Tert-butoxy)carbonyl]amino}-2-hydroxypentanoic acid

(1S)-(2-Cyano-1-ethyl-2-hydroxyethyl)carbamic acid tert-butyl ester (10 g, 46.7 mmol) was dissolved in 1,4-dioxane (100 mL). Anisole (5 mL) was added and then concentrated HCl (100 mL). The reaction mixture was heated under reflux for 24 h. The reaction mixture was evaporated to dryness under vacuum and re-dissolved in 100 mL water. The solution was washed with ether and then neutralized with saturated aqueous NaHCO3. Di-tert-butyl dicarbonate (10 g, 46 mmol) was added with 1,4-dioxane (200 mL), and the reaction mixture was stirred at ambient temperature for 24 h. The dioxane was removed under vacuum and the remaining aqueous solution was washed with ether. The solution was acidified with 1N HCl and extracted with ethyl acetate. The combined organic layers were washed with brine, dried with magnesium sulfate and evaporated to yield 3-tert-butoxycarbonylamino-2-hydroxypentanoic acid (4.5 g) as yellowish oil.

1. temperatureThe reaction mixture was heated
2. temperatureunder reflux for 24 h
3. customThe reaction mixture was evaporated to dryness under vacuum
4. dissolutionre-dissolved in 100 mL water
5. washThe solution was washed with ether
6. customThe dioxane was removed under vacuum
7. washthe remaining aqueous solution was washed with ether
8. extractionextracted with ethyl acetate
9. washThe combined organic layers were washed with brine
10. dry with materialdried with magnesium sulfate
11. customevaporated

ORD record

ord-99736c8c3cca47fd8569ff4212236bd6

Source dataset

uspto-grants-2010_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07662849B2