反应详情

温度

50 °C

Compound (2) (20 g, 88.9 mmols) was dissolved in THF (150 ml), and nitric acid (6.7 ml, 60% aq. solution, 1 eq) was added. Diethylether was added to the clear solution until it remained turbid, and the mixture was left in the freezer for crystallization. The white crystals of nitrate (quantit. yield) were added in small portions to well-chilled sulfuric acid (150 ml), never allowing the temperature to reach 10° C., whereafter the mixture was warmed at 50° C. for 10 min. The resulting brown solution was poured onto ice and neutralized with solid sodium hydrogen carbonate. The organic material was extracted with chloroform (3×200 ml), and after drying over sodium sulphate, the chloroform extract was flash chromatographed using 4% ethanol/chloroform as a solvent. The appropriate fractions were collected and evaporated yielding a pure yellow solid

1. waitthe mixture was left in the freezer for crystallization
2. customto reach 10° C., whereafter the mixture
3. extractionThe organic material was extracted with chloroform (3×200 ml)
4. dry with materialafter drying over sodium sulphate
5. extractionthe chloroform extract
6. customchromatographed
7. customThe appropriate fractions were collected
8. customevaporated
9. customyielding a pure yellow solid