Hydrochloric Acid → 3-Methoxy-2-methoxycarbonylamino-3-methyl-butyric acid

2-tert-Butoxycarbonylamino-3-methoxy-3-methyl-butyric acid was dissolved in dioxane (40 mL) and HCl (4N in dioxane, 5.4 mL, 21.6 mmol) was added at room temperature. The resulting solution was stirred at room temperature for 18 hours and the concentrated to dryness. The solid was dissolved in THF (14 mL) and cooled to 0° C. in an external ice/brine bath. Aqueous sodium hydroxide (6.25M, 1.9 mL, 11.76 mmol) and methyl chloroformate (0.5 mL, 5.88 mmol) were added at 0° C. Upon completion of the addition, the solution was removed from the ice bath and allowed to warm to room temperature, and stirred. After 18 hours, the crude reaction mixture was adjusted to pH 1 with 1N HCl and extracted twice with diethyl ether. The combined organic layers were washed with brine, dried with magnesium sulfate and concentrated to give 3-Methoxy-2-methoxycarbonylamino-3-methyl-butyric acid (0.653 g, 65%) as an off-white solid.

1. concentrationthe concentrated to dryness
2. dissolutionThe solid was dissolved in THF (14 mL)
3. temperaturecooled to 0° C. in an external ice/brine bath
4. additionUpon completion of the addition
5. customthe solution was removed from the ice bath
6. temperatureto warm to room temperature
7. stirringstirred
8. waitAfter 18 hours
9. customthe crude reaction mixture
10. extractionextracted twice with diethyl ether
11. washThe combined organic layers were washed with brine
12. dry with materialdried with magnesium sulfate
13. concentrationconcentrated

ORD record

ord-62ac7ce740cf48a581ec7cde34a409a4

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08273341B2