反应详情

To a mixture of 2.6 g (0.02 mole) of 2,2-dimethyl-4-pentenoic acid (XII) and 50 ml of hexamethylphosporic triamide a solution of 1.2 g (0.03 mole) of sodium hydroxide in 3.6 ml of water is added. The reaction mixture is stirred at room temperature for 1 hour and then 1.2 ml (2.4 g, 0.012 mole) of 1,3-dibromopropane are added. The mixture is stirred at room temperature for 4 hours, then poured onto 100 ml of 5 % aqueous hydrochloric acid and extracted twice with 50 ml of diethyl ether each. The organic phase is washed twice with 25 ml of water each, dried over sodium sulfate and the solvent is distilled off under reduced pressure. The crude product thus obtained is purified by chromatography on a silica gel column eluted with a 7:3 mixture of hexane and diethyl ether. Thus 2.03 g of the desired compound are obtained in the form of a colourless oil. Yield: 68.5%. According to TLC chromatography using the above-specified eluent Rf =0.6.

1. additionis added
2. stirringThe mixture is stirred at room temperature for 4 hours
3. extractionextracted twice with 50 ml of diethyl ether each
4. washThe organic phase is washed twice with 25 ml of water each,
5. dry with materialdried over sodium sulfate
6. distillationthe solvent is distilled off under reduced pressure
7. customThe crude product thus obtained
8. customis purified by chromatography on a silica gel column
9. washeluted with a 7:3 mixture of hexane and diethyl ether