2,2,6,6-Tetramethylpiperidine → (2,3,4-Trimethoxy-6-methylphenyl)(5-bromo-4-chloro-2-methoxy-3-pyridyl)methanol

Temperatur

0 °C

18.3 ml of n-butyllithium (1.57 mol/l hexane solution, 27 mmol) was dropwise added at 0° C. to a solution having 3.84 g (27 mmol) of 2,2,6,6-tetramethylpiperidine dissolved in 36 ml of tetrahydrofuran under an argon stream, followed by stirring at 0° C. for 30 minutes. The obtained solution was cooled to −78° C., and a solution having 6.10 g (27 mmol) of 5-bromo-4-chloro-2-methoxypyridine dissolved in 24 ml of tetrahydrofuran was added, followed by stirring at the same temperature for 2 hours to prepare 5-bromo-4-chloro-2-methoxy-3-pyridyllithium. Then, a solution having 5.50 g (26 mmol) of 2,3,4-trimethoxy-6-methylbenzaldehyde dissolved in 24 ml of tetrahydrofuran was added, followed by stirring at the same temperature for 1 hour. To the reaction mixture, 37 ml of a saturated ammonium chloride aqueous solution and then 150 ml of water were added, and the temperature was increased to room temperature, followed by extraction with ethyl acetate (150 ml each) three times. The organic layer was washed with a saturated sodium chloride solution (100 ml), dried over magnesium sulfate and subjected to filtration, and the solvent was distilled off under reduced pressure. The obtained crude product was purified by silica gel chromatography to obtain 6.53 g (yield: 56%) of (2,3,4-trimethoxy-6-methylphenyl)(5-bromo-4-chloro-2-methoxy-3-pyridyl)methanol.

1. temperatureThe obtained solution was cooled to −78° C.
2. additionwas added
3. stirringby stirring at the same temperature for 2 hours
4. additionwas added
5. stirringby stirring at the same temperature for 1 hour
6. temperaturethe temperature was increased to room temperature
7. extractionfollowed by extraction with ethyl acetate (150 ml each) three times
8. washThe organic layer was washed with a saturated sodium chloride solution (100 ml)
9. dry with materialdried over magnesium sulfate
10. filtrationsubjected to filtration
11. distillationthe solvent was distilled off under reduced pressure
12. customThe obtained crude product
13. customwas purified by silica gel chromatography

ORD-Eintrag

ord-5a24d1cbc5674db3b5743f89f7a28f88

Quelldatensatz

uspto-grants-2014_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08653113B2