反应详情

A mixture of 0.3 g (0.66 mmol) of the compound prepared in Step A, 10 ml of dimethylformamide and 0.34 g (1.30 mmol) of triphenyiphosphine was stirred at room temperature for 5 min, then 0.20 ml (1.27 mmol) of diethyl azodicarboxylate was added and stirring was continued for 24 h. After dilution with sodium chloride solution the precipitated product was filtered off, dried and purified by column chromatography using silica gel (MN Kieselgel 60) as adsorbent and a mixture of chloroform-methanol (99:1) as eluent. The residue obtained on concentration was crystallized by refluxing in ethanol to yield 0.12 g (42%) of the title compound; Mp.: 254-255° C.

1. stirringstirring
2. waitwas continued for 24 h
3. filtrationAfter dilution with sodium chloride solution the precipitated product was filtered off
4. customdried
5. custompurified by column chromatography
6. additiona mixture of chloroform-methanol (99:1) as eluent
7. customThe residue obtained on concentration
8. customwas crystallized
9. temperatureby refluxing in ethanol