methyl 4-cyclopropyl-2,4-dioxobutanoate

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

Procedure: To a solution of cyclopropyl methyl ketone (5 g, 59.4 mmol) in MeOH (75 mL) was added sodium methoxide (4.8 g, 54.0 mmol) at rt. After a 15 min stirring, dimethyl oxalate (7 g, 59.4 mmol) was added. The reaction mixture was stirred for 16 h at rt and concentrated. The residue was taken up in a saturated aqueous solution of ammonium chloride and extracted with EtOAc. The organic layers were dried (Na2SO4), filtered, and concentrated. The residue was purified by silica gel column chromatography (hexane/EtOAc, 95:5) to provide 5 g of the title compound. Rf=0.59 (hexane/EtOAc, 4:1); 1H NMR (300 MHz, CDCl3) δ ppm 1.00-1.30 (m, 4H), 1.80-1.95 (m, 1H), 3.85 (s, 3H), 6.48 (s, 1H), 14.2-15.0 (br. s, 1H). The reaction mixture was stirred for 16 h at rt concentrated extracted with EtOAc The organic layers were dried (Na2SO4) filtered concentrated The residue was purified by silica gel column chromatography (hexane/EtOAc, 95:5)

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

Procedure: To a solution of cyclopropyl methyl ketone (5 g, 59.4 mmol) in MeOH (75 mL) was added sodium methoxide (4.8 g, 54.0 mmol) at rt. After a 15 min stirring, dimethyl oxalate (7 g, 59.4 mmol) was added. The reaction mixture was stirred for 16 h at rt and concentrated. The residue was taken up in a saturated aqueous solution of ammonium chloride and extracted with EtOAc. The organic layers were dried (Na2SO4), filtered, and concentrated. The residue was purified by silica gel column chromatography (hexane/EtOAc, 95:5) to provide 5 g of the title compound. Rf=0.59 (hexane/EtOAc, 4:1); 1H NMR (300 MHz, CDCl3) δ ppm 1.00-1.30 (m, 4H), 1.80-1.95 (m, 1H), 3.85 (s, 3H), 6.48 (s, 1H), 14.2-15.0 (br. s, 1H). The reaction mixture was stirred for 16 h at rt concentrated extracted with EtOAc The organic layers were dried (Na2SO4) filtered concentrated The residue was purified by silica gel column chromatography (hexane/EtOAc, 95:5)

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

Procedure: To a solution of cyclopropyl methyl ketone (5 g, 59.4 mmol) in MeOH (75 mL) was added sodium methoxide (4.8 g, 54.0 mmol) at rt. After a 15 min stirring, dimethyl oxalate (7 g, 59.4 mmol) was added. The reaction mixture was stirred for 16 h at rt and concentrated. The residue was taken up in a saturated aqueous solution of ammonium chloride and extracted with EtOAc. The organic layers were dried (Na2SO4), filtered, and concentrated. The residue was purified by silica gel column chromatography (hexane/EtOAc, 95:5) to provide 5 g of the title compound. Rf=0.59 (hexane/EtOAc, 4:1); 1H NMR (300 MHz, CDCl3) δ ppm 1.00-1.30 (m, 4H), 1.80-1.95 (m, 1H), 3.85 (s, 3H), 6.48 (s, 1H), 14.2-15.0 (br. s, 1H). The reaction mixture was stirred for 16 h at rt concentrated extracted with EtOAc The organic layers were dried (Na2SO4) filtered concentrated The residue was purified by silica gel column chromatography (hexane/EtOAc, 95:5)