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A solution of 37.80 of diethyl malonate dissolved in 20 ml of absolute ethanol was added dropwise to a solution of sodium ethoxide prepared by gradually adding 3.00 g of metallic sodium to 30 ml of absolute ethanol. To the mixture was added a solution of 30.01 g of 1-bromo-5-(2-methoxyethoxy)methoxypentane (prepared as described in Preparation 40) dissolved in 10 ml of absolute ethanol. The mixture was heated under reflux for 21 hours, after which it was allowed to cool, and then the solvent was distilled off. The residue was mixed with water, and the mixture was extracted three times with ethyl acetate. The combined extracts were washed with water, dried and concentrated by evaporation under reduced pressure. The residue was subjected to column chromatography through 850 g of silica gel, and 32.78 g of the title compound was obtained from the fractions eluted with a 4:1 by volume mixture of hexane and ethyl acetate, as a colorless oil.

1. customprepared
2. temperatureThe mixture was heated
3. temperatureunder reflux for 21 hours
4. temperatureto cool
5. distillationthe solvent was distilled off
6. additionThe residue was mixed with water
7. extractionthe mixture was extracted three times with ethyl acetate
8. washThe combined extracts were washed with water
9. customdried
10. concentrationconcentrated by evaporation under reduced pressure