反应详情

26 g of acetoacetic acid ethyl ester and 15 g of pyrrolidine were boiled in 70 ml of toluene on a water separator until the theoretical quantity of water was separated. The solution was added drop by drop at -40° C. to a suspension of 8.6 g of sodium amide in 300 ml of liquid ammonia. By heating to room temperature, the ammonia was removed. After the reaction solution had been cooled again to 0° C., isopropyl iodide dissolved in 100 ml of toluene was added at the same temperature. The solution was allowed to react for 3 hours at 0° C. The reaction solution was poured into 200 ml of water. The phases were separated and the toluene of the organic phase was removed using a rotary evaporator. Of the residue, 1.2 g of the first runnings was then distilled off at 1.5 torr (2×102Pa) and up to a still temperature of 60° C., which contained above all 2 -isopropyl acetoacetic acid ethyl ester. The brownish oil remaining behind was dissolved in 70 ml of methylene chloride, and 21 g of concentrated hydrochloric acid was added. The material was hydrolyzed for 1.5 hours at ambient temperature. The two phases were separated. The organic phase was dried, the solvent was removed and the residue was distilled. 28.1 g of 5-methyl-3-oxohexanoic acid ethyl ester (82 percent) was obtained.

1. customwas separated
2. additionThe solution was added drop by drop at -40° C.
3. additionto a suspension of 8.6 g of sodium amide in 300 ml of liquid ammonia
4. customthe ammonia was removed
5. temperatureAfter the reaction solution had been cooled again to 0° C.
6. dissolutionisopropyl iodide dissolved in 100 ml of toluene
7. additionwas added at the same temperature
8. customto react for 3 hours at 0° C
9. customThe phases were separated
10. customthe toluene of the organic phase was removed
11. customa rotary evaporator
12. distillationOf the residue, 1.2 g of the first runnings was then distilled off at 1.5 torr (2×102Pa) and up to a still temperature of 60° C., which
13. dissolutionThe brownish oil remaining behind was dissolved in 70 ml of methylene chloride
14. addition21 g of concentrated hydrochloric acid was added
15. customThe two phases were separated
16. customThe organic phase was dried
17. customthe solvent was removed
18. distillationthe residue was distilled