Acetic Acid → HCID 22458230, compound

A solution of (2E)-N-methoxy-N-methyl-3-(pyridin-4-yl)prop-2-enamide (2.00 g), 5% rhodium/carbon (containing water (50%), 0.4 g) and acetic acid (1.25 g) in methanol (40 mL) was stirred for 4 hr under ice-cooling under a hydrogen atmosphere (5 atm). The reaction mixture was allowed to cool to room temperature and filtered, and the filtrate was concentrated under reduced pressure. The residue was dissolved in a mixed solvent of THF (25 mL) and water (10 mL), di-tert-butyl dicarbonate (4.36 g) and 2M aqueous sodium hydroxide solution (25 mL) were added, and the mixture was stirred at room temperature for 15 hr. The reaction mixture was diluted with ethyl acetate and water, and extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (2.59 g).