反应详情

温度

100 °C

2.4 g (10.3 mmol) of ethyl 1-methyl-2-oxo-1,2-dihydroquinoxaline-3-carboxylate and 4.2 g (10.4 mmol) of Lawesson's reagent were added to toluene (50 mL), and the mixture was stirred for a day while maintaining the liquid temperature at 100° C. The reaction mixture was cooled to room temperature, and then the solvent was distilled off under reduced pressure. Chloroform was added to the residue, the insoluble was separated by filtration, and the filtrate was concentrated under reduced pressure. The residue thus obtained was dissolved in ethanol (300 mL), 4.9 g of a 25% aqueous solution of sodium hydroxide was added at room temperature, and the mixture was stirred for a day at room temperature. The reaction mixture was concentrated under reduced pressure, water was added thereto, and the mixture was adjusted to pH 1 using 10% hydrochloric acid. A solid precipitated therefrom was collected by filtration, and was washed with water. The solid thus obtained was dried, and this solid was dissolved in chloroform (50 mL). 1.7 g (13.4 mmol) of oxalyl chloride and one droplet of N,N-dimethylformamide were added to the solution, and the reaction solution was stirred for 2 hours at room temperature, and concentrated under reduced pressure. The residue thus obtained was dissolved in chloroform (20 mL), 0.84 g (7.49 mmol) of 1,3-cyclohexanedione and 0.83 g (8.20 mmol) of triethylamine were added thereto, and the mixture was stirred for one hour at room temperature. 0.83 g (8.20 mmol) of triethylamine and 0.64 g (7.52 mmol) of acetone cyanohydrin were further added at room temperature, and the mixture was stirred for two days at room temperature. The reaction mixture was washed with 10% hydrochloric acid, and dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue thus obtained was purified by silica gel chromatography (developing solvent: ethyl acetate/chloroform=1/1). The resulting solid was washed with ethyl acetate, to obtain 0.40 g of 3-hydroxy-2-(1-methyl-2-thioxo-1,2-dihydroquinoxaline-3-car bonyl)-2-cyclohexen-1-one as a yellow powder (melting point 300° C. or above).

1. temperatureThe reaction mixture was cooled to room temperature
2. distillationthe solvent was distilled off under reduced pressure
3. additionChloroform was added to the residue
4. customthe insoluble was separated by filtration
5. concentrationthe filtrate was concentrated under reduced pressure
6. customThe residue thus obtained
7. stirringthe mixture was stirred for a day at room temperature
8. concentrationThe reaction mixture was concentrated under reduced pressure, water
9. additionwas added
10. customA solid precipitated
11. filtrationtherefrom was collected by filtration
12. washwas washed with water
13. customThe solid thus obtained
14. customwas dried
15. dissolutionthis solid was dissolved in chloroform (50 mL)
16. stirringthe reaction solution was stirred for 2 hours at room temperature
17. concentrationconcentrated under reduced pressure
18. customThe residue thus obtained
19. stirringthe mixture was stirred for one hour at room temperature
20. stirringthe mixture was stirred for two days at room temperature
21. washThe reaction mixture was washed with 10% hydrochloric acid
22. dry with materialdried over anhydrous magnesium sulfate
23. distillationthe solvent was distilled off under reduced pressure
24. customThe residue thus obtained
25. customwas purified by silica gel chromatography (developing solvent: ethyl acetate/chloroform=1/1)
26. washThe resulting solid was washed with ethyl acetate