反应详情

6.50 g (24 mmol) of 3-oxo-4-phenyl-3,4-dihydropyrido[2,3-b]pyrazine-2-carboxylic acid was dissolved in dichloromethane (100 mL), and to this solution, N,N-dimethylformamide (0.5 mL) and 3.8 g (30 mmol) of oxalyl chloride were added sequentially. The mixture was stirred for one hour at room temperature. After confirming the completion of the reaction, the solvent was distilled off under reduced pressure. The obtained residue was dissolved in dichloromethane (30 mL), and this solution was added dropwise at 0° C. over 5 minutes to a solution prepared by dissolving 2.7 g (24 mmol) of 1,3-cyclohexanedione and 2.5 g (24 mmol) of triethylamine in dichloromethane (30 mL). The reaction solution was returned to room temperature and stirred for 3 hours, and then acetone cyanohydrin (1 mL) and 2.5 g (24 mmol) of triethylamine were added thereto. The mixture was stirred for 12 hours at room temperature. After confirming the completion of the reaction, water (50 mL) was added to the reaction solution, the reaction solution was adjusted to pH 12 using a 10% aqueous solution of sodium hydroxide, and the reaction solution was separated. The aqueous layer was adjusted to pH 1 by adding 6 N hydrochloric acid, and then the aqueous layer was extracted with dichloromethane. The obtained organic layer was dried over anhydrous magnesium sulfate, and then the solvent was distilled off under reduced pressure. The residue thus obtained was washed with methanol, to obtain 6.5 g (yield: 73%) of 2-(2-hydroxy-6-oxo-1-cyclohexenecarbonyl)-4-phenyl-pyrido[2,3-b]pyrazin-3(4H)-one.

1. customthe completion of the reaction
2. distillationthe solvent was distilled off under reduced pressure
3. dissolutionThe obtained residue was dissolved in dichloromethane (30 mL)
4. additionthis solution was added dropwise at 0° C. over 5 minutes to a solution
5. customprepared
6. customwas returned to room temperature
7. stirringstirred for 3 hours
8. stirringThe mixture was stirred for 12 hours at room temperature
9. additionwas added to the reaction solution
10. customthe reaction solution was separated
11. additionby adding 6 N hydrochloric acid
12. extractionthe aqueous layer was extracted with dichloromethane
13. dry with materialThe obtained organic layer was dried over anhydrous magnesium sulfate
14. distillationthe solvent was distilled off under reduced pressure
15. customThe residue thus obtained
16. washwas washed with methanol