2-Methoxyethanol → 4-[2-(2-Methoxyethoxy)phenyl]-2,2-dimethyl-5-oxopiperazine-1-carboxylic acid t-butyl ester

Temperature

100 °C

518 mg of 1,1′-(azodicarbonyl)dipiperidine (2.05 mmol), 156 mg of 2-methoxyethanol (2.05 mmol) and 0.42 ml of tributylphosphine (2.05 mmol) were added to a solution of 400 mg of 4-(2-hydroxyphenyl)-2,2-dimethyl-5-oxopiperazine-1-carboxylic acid t-butyl ester obtained in Example (10d) (1.36 mmol) in toluene (14 ml), and the mixture was stirred at 100° C. for three hours. The reaction mixture was cooled and then water was added, followed by extraction with ethyl acetate. Then, the organic layer was washed with brine and then dried over anhydrous sodium sulfate. After filtration, the solvent was evaporated under reduced pressure, and the residue was purified by silica gel column chromatography (elution solvent:n-hexane/ethyl acetate=1/2) to obtain 444 mg of 4-[2-(2-methoxyethoxy)phenyl]-2,2-dimethyl-5-oxopiperazine-1-carboxylic acid t-butyl ester (yield: 86%).

1. temperatureThe reaction mixture was cooled
2. extractionfollowed by extraction with ethyl acetate
3. washThen, the organic layer was washed with brine
4. dry with materialdried over anhydrous sodium sulfate
5. filtrationAfter filtration
6. customthe solvent was evaporated under reduced pressure
7. customthe residue was purified by silica gel column chromatography (elution solvent:n-hexane/ethyl acetate=1/2)

ORD record

ord-e05219e15b8441bebfc89f653dfcb2cf

Source dataset

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08158790B2