反应详情

To 350 ml. of ethanol, 105 ml. of water and 70 ml. of 50% aqueous sodium hydroxide is added 46.5 g. of ethyl 3,7,11-trimethyldodeca-2,4-dienoate (40% cis, trans and 60% trans, trans). The mixture is refluxed for about 19 hours. After cooling, ethanol is removed under reduced pressure and water added followed by extraction with ether to yield 3,7,11-trimethyldodeca-2,4-dienoic acid containing about 58% trans, trans isomer. Conversion of the thus-obtained acid to the S-benzyl-isothiouronium salt recrystallized from aqueous methanol, and regeneration of the acid with ether-aqueous hydrochloric acid provides crystalline trans, trans, 3,7,11-trimethyldodeca-2,4-dienoic acid.

1. temperatureThe mixture is refluxed for about 19 hours
2. temperatureAfter cooling
3. customethanol is removed under reduced pressure and water
4. additionadded
5. extractionfollowed by extraction with ether