1-(2-Methyl-1,3-dioxolan-2-yl)propan-2-one

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A solution of 2-methyl-2-(2-oxopropyl)-1,3-dioxolane (49 g) and diethyl oxalate (55 ml) in ethanol (50 ml) was added over 30 minutes to a stirred, cooled, solution of sodium ethoxide prepared by dissolving sodium (9.4 g) in ethanol (150 ml). The solution was stirred for 5 hours at room temperature and then acidified with 5M hydrochloric acid (200 ml) and then stirred for a further hour. The mixture was diluted with water (800 ml) and extracted with ethyl acetate, the extract was dried and evaporated and the residue was distilled under vacuum (bp 110°-120° C./0.2 mm). The distillate (53.8 g) was crystallised from ether-petroleum ether 40°-60° C. to give ethyl 6-methyl-4-oxo-4H-pyran-2-carboxylate (mp 35°-38° C.). cooled stirred for a further hour extracted with ethyl acetate the extract was dried evaporated the residue was distilled under vacuum (bp 110°-120° C./0.2 mm) The distillate (53.8 g) was crystallised from ether-petroleum ether 40°-60° C.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A solution of 2-methyl-2-(2-oxopropyl)-1,3-dioxolane (49 g) and diethyl oxalate (55 ml) in ethanol (50 ml) was added over 30 minutes to a stirred, cooled, solution of sodium ethoxide prepared by dissolving sodium (9.4 g) in ethanol (150 ml). The solution was stirred for 5 hours at room temperature and then acidified with 5M hydrochloric acid (200 ml) and then stirred for a further hour. The mixture was diluted with water (500 ml) and extracted with ethyl acetate, the extract was dried and evaporated and the residue was distilled under vacuum (bp 110°-120° C./0.2 mm). The distillate (53.8 g) was crystallized from ether-petroleum ether 40°-60° C. to give ethyl 6-methyl-4-oxo-4H-pyran-2-carboxylate (mp 35°-38° C.). cooled stirred for a further hour extracted with ethyl acetate the extract was dried evaporated the residue was distilled under vacuum (bp 110°-120° C./0.2 mm) The distillate (53.8 g) was crystallized from ether-petroleum ether 40°-60° C.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A solution of 2-methyl-2-(2-oxopropyl)-1,3-dioxolane (49 g) and diethyl oxalate (55 ml) in ethanol (50 ml) was added over 30 minutes to a stirred, cooled, solution of sodium ethoxide prepared by dissolving sodium (9.4 g) in ethanol (150 ml). The solution was stirred for 5 hours at room temperature and then acidified with 5 M hydrochloric acid (200 ml) and then stirred for a further hour. The mixture was diluted with water (800 ml) and extracted with ethyl acetate, the extract was dried and evaporated and the residue was distilled under vacuum (bp 110°-120° C./0.2 mm). The distillate (53.8 g) was crystallised from ether-petroleum ether 40°-60° C. to give ethyl 6-methyl-4-oxo-4H-pyran-2-carboxylate (mp 35°-38° C.). cooled stirred for a further hour extracted with ethyl acetate the extract was dried evaporated the residue was distilled under vacuum (bp 110°-120° C./0.2 mm) The distillate (53.8 g) was crystallised from ether-petroleum ether 40°-60° C.

反応条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

実験手順: A solution of 2-methyl-2-(2-oxopropyl)-1,3-dioxolane (49 g) and diethyl oxalate (55 ml) in ethanol (50 ml) was added over 30 minutes to a stirred, cooled, solution of sodium ethoxide prepared by dissolving sodium (9.4 g) in ethanol (150 ml). The solution was stirred for 5 hours at room temperature and then acidified with 5M hydrochloric acid (200 ml) and then stirred for a further hour. The mixture was diluted with water (800 ml) and extracted with ethyl acetate, the extract was dried and evaporated and the residue was distilled under vacuum (bp 110°-120° C./0.2 mm). The distillate (53.8 g) was crystallised from ether-petroleum ether 40°-60° C. to give ethyl 6-methyl-4-oxo-4H-pyran-2-carboxylate (mp 35°-38° C.). cooled stirred for a further hour extracted with ethyl acetate the extract was dried evaporated the residue was distilled under vacuum (bp 110°-120° C./0.2 mm) The distillate (53.8 g) was crystallised from ether-petroleum ether 40°-60° C.