4-Methylmorpholine → Ethyl 2-[(4-tert-butoxy-4-oxobutanoyl)amino]-3-oxobutanoate

Temperature

0 °C

4-Tert-butoxy-4-oxobutanoic acid (1.7 g) and N-methylmorpholine (1.1 mL) were dissolved in tetrahydrofuran (60 mL), and the solution was cooled to 0° C. Isobutyl chloroformate (1.3 mL) was added thereto, and the mixture was stirred at 0° C. for 30 minutes. A solution of ethyl 2-amino-3-oxobutanoate hydrochloride (1.8 g) in N,N-dimethylformamide (30 mL) was added thereto, and the mixture was stirred at 0° C. for 5 minutes. Then, N-methylmorpholine (1.1 mL) was added thereto, and the mixture was stirred at room temperature for 20 hours. Ethyl acetate was added to the reaction solution, and the organic layer was washed with water and dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the obtained residue was purified by silica gel column chromatography (Moritex Corporation, elution solvent: hexane/ethyl acetate) to obtain the title compound (2.2 g) as a yellow oil (yield: 72%).

1. stirringthe mixture was stirred at 0° C. for 5 minutes
2. stirringthe mixture was stirred at room temperature for 20 hours
3. washthe organic layer was washed with water
4. dry with materialdried over sodium sulfate
5. distillationThe solvent was distilled off under reduced pressure
6. customthe obtained residue was purified by silica gel column chromatography (Moritex Corporation, elution solvent: hexane/ethyl acetate)

ORD record

ord-e8e35b0c0a584da5a6bf7ab1ef4f8de0

Source dataset

uspto-grants-2015_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09212170B2