合成策略通式 具体应用案例 实验操作 制备化合物7In a 25 mL round-bottom flask, cyclohexanone (1 mL, 9.64 mmol), ethyl cyanoacetate (43 g, 19.73 mmol), and methanol (5 mL) were combined. Then, aqueous ammonia (3.5 mL, 87.90 mmol) was added dropwise while stirring the mixture at −5 to 0 °C for 12h. The temperature was then raised to 20−25 °C and maintained there while being stirred for 24 h. Following the addition of water (6 mL), the mixture was heated to 60 °C. After dropwise addition of sulfuric acid to bring the pH level to 2−3, the temperature was reduced to below 5 °C. 2,4-Dioxo-3- azaspiro(5,5)undecane-1,5-dicarbonitrile was precipitated, filtered, dried, and washed with water (yield: 80%).
制备化合物8Compound 8 was synthesized according to the method described by Schön et al.9 A 25 mL round-bottom flask containing sulfuric acid (40−80%) (4 mL, 70 mmol) was heated at 70−75 °C, and 7 (1g, 4.3 mmol) was added gradually to this solution. The reaction mixture was heated to 80−120 °C and maintained for 18−26 h. Then, the reaction mixture was cooled, and water (6 mL) was added and stirred for 1 h at room temperature. Then, the solids were filtered, washed with water, and dried at 60 °C for 5 h. Finally, after three replications, 8 was obtained in 89.25 ± 1.31% yield as a gray powder 参考文献https://doi.org/10.1021/acs.oprd.4c00086
