反应详情

温度

82 °C

To a 500 mL three-necked flask fitted with a mechanical stirrer, 3 g of sodium hydroxide pellets and 50 mL of 2-butanol are charged and heated to 82° C. To this solution, a slurry of 200 mL of 2-butanone, 15 g of the benzotriazole N-oxide prepared in Example 4, and 0.67 g of 2,3-dichloro-1,4-naphthoquinone is added over 40 minutes. The mixture is refluxed at 88° C. for five hours while distilling off 2-butanone. Additional 2-butanol (50 mL) is added to replace what is lost during distillation of the 2-butanone. After cooling the reaction mixture to ambient temperature, 25 g of water and 30 mL of ethyl acetate are added at which time the pH is reduced to 2 with 30% aqueous sulfuric acid. After splitting off the aqueous layer, the solvent is removed by distillation and the crude solid purified by silica gel chromatography using heptane/ethyl acetate as the eluent. After collecting the desired fractions and crystallization from methanol/toluene, 14 g of the tide compound is obtained after drying as a light yellow solid melting at 172-173° C. The structure is confirmed by 1H nmr and mass spectroscopy.

1. customTo a 500 mL three-necked flask fitted with a mechanical stirrer
2. temperatureThe mixture is refluxed at 88° C. for five hours
3. distillationwhile distilling off 2-butanone
4. additionAdditional 2-butanol (50 mL) is added
5. distillationis lost during distillation of the 2-butanone
6. temperatureAfter cooling the reaction mixture to ambient temperature
7. addition25 g of water and 30 mL of ethyl acetate are added at which time the pH
8. customthe solvent is removed by distillation
9. customthe crude solid purified by silica gel chromatography
10. customAfter collecting the desired
11. customfractions and crystallization from methanol/toluene