反应详情

To a stirred solution of 3-methyl-5-phenyl-2,4-pentadienal (16.5 g) in ethanol (330 mL) was added dropwise a solution of silver nitrate (19.28 g) in water (160 mL) followed by dropwise addition of an aqueous sodium hydroxide (25 g, 80 mL) solution. The resulting mixture was allowed to stir for an additional five hours and then filtered. The solid was washed with ethanol. The combined filtrate was concentrated in vacuum. The residue was dissolved in water (200 mL). The aqueous solution was extracted with ether (300 mL) twice and acidified with 6 N hydrochloric acid (74 mL). The solid formed was filtered and recrystallized from methanol (40 mL) to yield 2.65 g of the desired 3-methyl-5-phenyl-2,4-pentadienoic acid. 1H NMR (acetone-d6, 300 MHz), δ(ppm) 7.60 (d, 2H), 7.35 (m, 3H), 7.06 (m, 2H), 6.02 (broad s, 1H), 2.50 (s, 3H).

1. filtrationfiltered
2. washThe solid was washed with ethanol
3. concentrationThe combined filtrate was concentrated in vacuum
4. dissolutionThe residue was dissolved in water (200 mL)
5. extractionThe aqueous solution was extracted with ether (300 mL) twice
6. customThe solid formed
7. filtrationwas filtered
8. customrecrystallized from methanol (40 mL)