2,2,6,6-Tetramethylpiperidine → HCID 57517762, compound

Temperature

0 °C

n-BuLi (26 mmol, 16.3 mL of a 1.6M solution in hexanes) was added dropwise to a solution of 2,2,6,6-tetramethylpiperidine (26 mmol, 4.4 mL) in THF (150 mL) at 0° C. After stirring for 30 min at 0° C., the solution was cooled to −78° C. and a solution of 2-methoxypyrazine (20 mmol, 1.93 mL) in THF (30 mL) was added dropwise. After stirring at −78° C. for 15 min, a suspension of 5-chloroisatin (10 mmol, 1.82 g) in THF (50 mL) was added. The reaction mixture was stirred at 0° C. for 2 h, then saturated ammonium chloride solution was added. The mixture was extracted three times with ethyl acetate, and the collected extracts were washed with saturated brine. The organic phase was dried over magnesium sulfate, filtered and concentrated under reduced pressure. Purification by crystallization from diethyl ether yielded 1.14 g of the required intermediate.

1. temperaturethe solution was cooled to −78° C.
2. stirringAfter stirring at −78° C. for 15 min
3. additionwas added
4. stirringThe reaction mixture was stirred at 0° C. for 2 h
5. extractionThe mixture was extracted three times with ethyl acetate
6. washthe collected extracts were washed with saturated brine
7. dry with materialThe organic phase was dried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated under reduced pressure
10. customPurification
11. customby crystallization from diethyl ether

ORD record

ord-5409af6db68041a5b0ae74670a621fad

Source dataset

uspto-grants-2013_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08580842B2