Ethyl cyanoacetate → 2-Cyano-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-propenoic acid

To a solution of 2 g (11.0 mmol) of syringaldehyde and 1.2 ml (11.3 mmol) of ethyl cyanoacetate in 30 ml of ethanol was added 2 ml of piperidine, and the mixture was stirred at room temperature for 16 hours. The solution was evaporated under reduced pressure, subsequently the residue was acidified by adding 1N hydrochloric acid and extracted with 200 ml of ethyl acetate. The organic layer was washed with water, and concentrated under reduced pressure. A formed precipitate was washed with ethanol, and then dissolved in a mixed solvent of tetrahydrofuran and methanol (30 ml, 20 ml). To the solution was added potassium hydroxide solution (3.0 g/30 ml), and the mixture was stirred at room temperature for 1.5 hours. A 100 ml of water and 50 ml of ethyl acetate was added to the solution for separation of each layer. An aqueous layer was acidified with conc. hydrochloric acid, and a formed precipitate was filtrated to give 1.4 g (yield 51.1%) of objective α-cyano-3,5-dimethoxy-4-hydroxycinnamic acid.

1. customThe solution was evaporated under reduced pressure
2. additionby adding 1N hydrochloric acid
3. extractionextracted with 200 ml of ethyl acetate
4. washThe organic layer was washed with water
5. concentrationconcentrated under reduced pressure
6. washA formed precipitate was washed with ethanol
7. dissolutiondissolved in a mixed solvent of tetrahydrofuran and methanol (30 ml, 20 ml)
8. additionTo the solution was added potassium hydroxide solution (3.0 g/30 ml)
9. stirringthe mixture was stirred at room temperature for 1.5 hours
10. additionA 100 ml of water and 50 ml of ethyl acetate was added to the solution for separation of each layer
11. filtrationa formed precipitate was filtrated

ORD record

ord-c4a6d4885de94b95bd149e0a56f05150

Source dataset

uspto-grants-1995_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05478856