Synthesis
3.77 g of di-tert-butyl malonic acid was dissolved in 25 g of tert-butanol, and 1.96 g of potassium tert-butoxide and 2 g of 1,5-dibromopentane were added. The mixture was then heated to 45°C. 0.32 g of potassium tert-butoxide was added, and the mixture was stirred continuously for 1 hour. When the HPLC area percentage of di-tert-butyl malonic acid was less than 1%, 14 g of 10% aqueous acetic acid solution was added to remove the potassium tert-butoxide. 20 g of methyl tert-butyl ether was added to extract the resulting tetraester compound, and the organic layer was collected. This methyl tert-butyl ether layer was washed with 30 g of water, 30 g of 5% sodium bicarbonate aqueous solution, and 30 g of water. The water in the methyl tert-butyl ether layer was then removed with sodium sulfate. The sodium sulfate was removed by filtration, and the methyl tert-butyl ether was removed at 45°C. Finally, 3.11 g of ethyl 7-bromoheptanoate was obtained.
Figure 7. Synthetic Route of Ethyl 7-Bromoheptanoate
