1,2-Dibromoethane → tert-Butyl 1-acetylcyclopropanecarboxylate

Temperature

60 °C

A mixture of tert-butyl acetoacetate (497 mL, 3.00 mol), 1,2-dibromoethane (310 mL, 3.60 mmol), potassium carbonate (1.106 k g, 8.00 mmol), and dimethylformamide (2.0 L) was stirred in a water bath at 30° C. for 1.5 hours, in a water bath at 60° C. for 3.5 hours, and in a water bath at 30° C. for 4 days. The reaction mixture was separated by filtration through celite, and the residue on the celite was washed with diethylether (3.5 L). The filtrate and the diethylether used for the washing were combined and added to water (2 L), and the organic layer was separated. The aqueous layer was extracted with diethylether (2 L), and water (1 L) was added to the resulting aqueous layer, and further extraction was conducted by adding diethylether (2 L). All organic layers were combined, and washed with 10% aqueous solution of citric acid (2 L), water (2 L×3), and saturated aqueous solution of sodium chloride (2 L×3), and dried by adding anhydrous sodium sulfate. After removing the dessicating agent by filtration, the solvent was removed by distillation under reduced pressure, and the residue was distilled under reduced pressure to obtain 371.8 g of the target compound (10 mmHg, distillation fraction of 72 to 78° C., 2.02 mol, 67%) as a colorless transparent oil.

1. waitin a water bath at 30° C. for 4 days
2. customThe reaction mixture was separated by filtration through celite
3. washthe residue on the celite was washed with diethylether (3.5 L)
4. additionadded to water (2 L)
5. customthe organic layer was separated
6. extractionThe aqueous layer was extracted with diethylether (2 L), and water (1 L)
7. additionwas added to the resulting aqueous layer, and further extraction
8. additionby adding diethylether (2 L)
9. washwashed with 10% aqueous solution of citric acid (2 L), water (2 L×3), and saturated aqueous solution of sodium chloride (2 L×3)
10. customdried
11. additionby adding anhydrous sodium sulfate
12. customAfter removing the dessicating agent
13. filtrationby filtration
14. customthe solvent was removed by distillation under reduced pressure
15. distillationthe residue was distilled under reduced pressure

ORD record

ord-7bd01e9b11eb472b8afa90e871a4536e

Source dataset

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08211910B2