反应详情

The compound (4.00 g) obtained in Example 31, dimethylformamide (80 ml) and triethylamine (3.9 ml) were cooled to 0° C. Ethyloxalyl chloride (2.7 ml) was gradually added dropwise and the mixture was stirred at 0° C.-room temperature for 2.5 hours. After the stirring, chloroform (50 ml) was added and the mixture was stirred at 0° C. for 30 minutes. The reaction mixture was poured into water and extracted with chloroform. The extract was washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was distilled away under reduced pressure to give a pale-yellow liquid. This liquid was subjected to silica gel column chromatography (chloroform-methanol) and recrystallization from ethanol to give 1.22 g of white powdery crystals (yield 19%).

1. stirringthe mixture was stirred at 0° C. for 30 minutes
2. extractionextracted with chloroform
3. washThe extract was washed with saturated brine
4. dry with materialdried over anhydrous magnesium sulfate
5. distillationThe solvent was distilled away under reduced pressure
6. customto give a pale-yellow liquid
7. customThis liquid was subjected to silica gel column chromatography (chloroform-methanol) and recrystallization from ethanol