反応 #481603

反応方程式

Sodium hydroxide

triphenyl phosphine

ethyl-2-bromopropionate

benzene

phenolphthalein

→

triphenyl methyl carbethoxy methylene phosphorane

反応条件

後処理

1. 1
   その他at room temperature
2. 2
   抽出Extraction with benzene, concentration of the benzene
3. 3
   抽出extract
4. 4
   workup.ADDITIONthe addition of petroleum ether (60-80° C.)

実験手順

Monodemethylation of 3,4,5-trimethoxy benzaldehyde using sulphuric acid at 40° C. for 8 hours as described above in Example 1 yields syringaldehyde. The Wittig salt is prepared by reaction of triphenyl phosphine and ethyl-2-bromopropionate in benzene media at 70-75 ° C. for 8 hours and subsequent basification with 1N Sodium hydroxide to phenolphthalein end point at room temperature. Extraction with benzene, concentration of the benzene extract and the addition of petroleum ether (60-80° C.) yield triphenyl methyl carbethoxy methylene phosphorane as a solid product. Condensation of 3,5-Dimethoxy-4-hydroxy benzaldehyde (Syringaldehyde) with triphenyl methyl carbethoxy methylene phosphorane is performed at reflux temperature in xylene for seven hours and after work up, yields the title compound.

出典