Trifluoroacetic acid → 5-(4-Acetylpiperazin-1-yl)pyridine-2-carbaldehyde

Temperature

0 °C

To a solution of tert-butyl 4-(6-formylpyridin-3-yl)piperazine-1-carboxylate (270.4 mg, 0.9281 mmol) in dichloromethane (2.5 ml) was added trifluoroacetic acid (2.5 ml) at 0° C. After stirring at 0° C. for 1 hr, the reaction mixture was concentrated under reduced pressure. Anhydrous dichloromethane (2.5 ml) was added to the residue, acetic anhydride (0.105 ml, 1.114 mmol) was added, and the mixture was stirred at room temperature for 1 hr. Saturated aqueous sodium hydrogen carbonate solution was added, and the mixture was extracted 5 times with ethyl acetate. The combined organic layer was dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (methanol:dichloromethane=1:30) to give 5-(4-acetylpiperazin-1-yl)pyridine-2-carbaldehyde (147.0 mg, yield 67.9%) as a slightly yellow solid.

1. concentrationthe reaction mixture was concentrated under reduced pressure
2. additionwas added
3. stirringthe mixture was stirred at room temperature for 1 hr
4. extractionthe mixture was extracted 5 times with ethyl acetate
5. dry with materialThe combined organic layer was dried over anhydrous magnesium sulfate
6. filtrationfiltered
7. concentrationthe filtrate was concentrated under reduced pressure
8. customThe residue was purified by silica gel column chromatography (methanol:dichloromethane=1:30)

ORD record

ord-79e8c52cde6d40469cd55320980d1d1c

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08999989B2