Diethyl Oxalate → Ethyl 2,4-dioxoheptanoate

Temperature

0 °C

Sodium (11.5 g, 500 mmol) was added to ethanol (130 mL) in portions at room temperature with vigorous stirring. After sodium got dissolved, the solution was cooled to 0° C. Methyl propyl ketone (53.0 mL, 500 mmol) was added dropwise and the stirring was continued for further 15-20 min. Diethyl oxalate (68.0 mL, 500 mmol) was added dropwise to the resulting solution at 0° C. and the stirring was continued for another 15 min at 0° C. The reaction mixture was then allowed to attain room temperature and the stirring was continued for further 12 h at this temperature. The reaction mixture was then kept in refrigerator for 24 h. The solvent was removed under vacuum at room temperature. The resulting residue was diluted with dil. hydrochloric acid on an ice bath and extracted the aqueous layer with diethyl ether (4×50 mL). The combined ether extracts were washed with water, brine, dried (Na2SO4) and concentrated under vacuum. The crude mass was chromatographed on silica gel using 3% ethyl acetate in pet. ether as eluent to yield the title compound (60.0 g, 64.5%).

1. waitthe stirring was continued for another 15 min at 0° C
2. customto attain room temperature
3. waitthe stirring was continued for further 12 h at this temperature
4. waitThe reaction mixture was then kept in refrigerator for 24 h
5. customThe solvent was removed under vacuum at room temperature
6. additionThe resulting residue was diluted with dil. hydrochloric acid on an ice bath
7. extractionextracted the aqueous layer with diethyl ether (4×50 mL)
8. washThe combined ether extracts were washed with water, brine
9. dry with materialdried (Na2SO4)
10. concentrationconcentrated under vacuum
11. customThe crude mass was chromatographed on silica gel using 3% ethyl acetate in pet. ether as eluent

ORD record

ord-c666ea985e424bd495755a6c2c968bf7

Source dataset

uspto-grants-2002_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06444816B1