ethyl 2,4-dioxooctanoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of sodium (9.3 g) in ethanol (200 ml) was added dropwise a mixture of diethyl oxalate (60 g) and 2-hexanone (40.9 g) with stirring. The reaction mixture was allowed to stand at room temperature for 45 hours. To a mixture of 1N-hydrochloric acid (500 ml) and hexane (500 ml) was added dropwise the reaction mixture with stirring vigorously. After the addition, water (500 ml) was added. The organic layer was washed with water (100 ml ×3), dried, and the solvent was removed by evaporation in vacuo. The residue was distilled under reduced pressure and the distillate at the boiling point of 110° to 111° C. (6 mmHg) was collected to give the desired product (57 g, 70%). was added dropwise the reaction mixture with stirring vigorously was added The organic layer was washed with water (100 ml ×3) dried the solvent was removed by evaporation in vacuo The residue was distilled under reduced pressure the distillate at the boiling point of 110° to 111° C. (6 mmHg) was collected

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of ethyl oxalate (97.21 g) and hexan-2-one (66.58 g) was added dropwise to a solution of sodium ethoxide (50.1 g) in ethanol (160 ml) at reflux. The resultant mixture was heated at reflux for 2 h. The cooled reaction mixture was poured into a stirring mixture of ice (500 g) and water (100 ml) and the resultant slurry adjusted to pH 1.5(conc.H2SO4). The two layers were separated and the bottom layer extracted with toluene (2×200 ml). The combined organics were washed with brine (200 ml), dried and concentrated in vacuo to give a residue (107 g) which was purified by distillation to afford the title compound as a colourless liquid (67.2 g). at reflux at reflux for 2 h The cooled reaction mixture The two layers were separated the bottom layer extracted with toluene (2×200 ml) The combined organics were washed with brine (200 ml) dried concentrated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To an ethanol (100 ml) solution of ethyl 2,4-dioxooctanoate (20 g) (K. Seki et al., Chem. Pharm. Bull., 32, 1568(1984)) was added, under ice-cooling, methoxyamine hydrochloride (8.4 g), and the mixture was stirred for one hour, then it was stirred for further 15 hours at room temperature. The reaction mixture was concentrated under reduced pressure, to which was added a saturated aqueous solution of sodium hydrogencarbonate, followed by extraction with ether. The extract solution was dried over anhydrous sodium sulfate, then the solvent was distilled off under reduced pressure. The residue was purified by column chromatography on silica gel to afford the title compound as a colorless oil (16.6 g, 72%). cooling The reaction mixture was concentrated under reduced pressure, to which was added a saturated aqueous solution of sodium hydrogencarbonate followed by extraction with ether The extract solution was dried over anhydrous sodium sulfate the solvent was distilled off under reduced pressure The residue was purified by column chromatography on silica gel