3,3,4,4,4-pentafluorobutan-2-one

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

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

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

Procedure: Methyl pentafluoroethyl ketone (3.9 g, 0.02407 mole) (JACS, 78, 2268-70 [1956]) was stirred in concentrated sulphuric acid (10 ml) at room temperature under a dry-ice condenser. Bromine (1.92 g; 0.012035 mole) was added slowly over two hours with vigorous stirring. The mixture was then stirred for one hour at room temperature and then at 50° C. for one hour. The resulting amber solution was distilled at atmospheric pressure, yielding one main fraction of 4.41 g (76%), boiling at 94-97° C. The mass spectrum confirmed the structure, showing parent ions at 240 and 242 m/e corresponding to C4H2BrF5O (2 isotopes of Br). at 50° C. for one hour The resulting amber solution was distilled at atmospheric pressure yielding one main fraction of 4.41 g (76%), boiling at 94-97° C

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

Procedure: To a stirred suspension of potassium t-butoxide (44.8 g., 0.4 mole) in dry ether (400 ml.) is added ethyl pentafluoropropionate (76.8 g., 0.4 mole) over a period of about 15 minutes. Most of the solid dissolves. A solution of pentafluoroethyl methyl ketone (64.8 g., 0.4 mole) in dry ether (60 ml.) is added slowly, and after stirring the mixture for 2 hours at room temperature, it is allowed to stand overnight. A solution of glacial acetic acid (27.2 ml.) in water (120 ml.) is added with stirring and external cooling (ice-bath). Then a warm solution of copper acetate (56.0 g., 0.28 mole) in water (532 ml.) is added slowly with stirring and cooling. The ether is distilled off, and the copper salt of the product is collected by filtration, washed with water, drained thoroughly, and then washed with petroleum ether. The copper derivative is suspended in ether (200 ml.) and decomposed by treatment with 15% sulphuric acid (450 ml.). The aqueous layer is separated and extracted with more ether (3 × 50 ml.). The combined ethereal extract is dried, first over anhydrous sodium sulphate and then over anhydrous calcium sulphate. Evaporation of the ether gives the product which is purified by fractionational distillation at atmospheric pressure. Most of the solid dissolves to stand overnight with stirring external cooling (ice-bath) with stirring cooling The ether is distilled off the copper salt of the product is collected by filtration washed with water washed with petroleum ether The aqueous layer is separated extracted with more ether (3 × 50 ml.) The combined ethereal extract is dried, first over anhydrous sodium sulphate Evaporation of the ether gives the product which is purified by fractionational distillation at atmospheric pressure

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

Procedure: To a stirred suspension of potassium t-butoxide (44.8 g., 0.4 mole) in dry ether (400 ml.) is added ethyl pentafluoropropionate (76.8 g., 0.4 mole) over a period of about 15 minutes. Most of the solid dissolves. A solution of pentafluoroethyl methyl ketone (64.8 g., 0.4 mole) in dry ether (60 ml.) is added slowly, and after stirring the mixture for 2 hours at room temperature, it is allowed to stand overnight. A solution of glacial acetic acid (27.2 ml.) in water (120 ml.) is added with stirring and external cooling (ice-bath). Then a warm solution of copper acetate (56.0 g., 0.23 mole) in water (532 ml.) is added slowly with stirring and cooling. The ether is distilled off, and the copper salt of the product is collected by filtration, washed with water, drained thoroughly, and then washed with petroleum ether. The copper derivative is suspended in ether (200 ml.) and decomposed by treatment with 15% sulphuric acid (450 ml.). The aqueous layer is separated and extracted with more ether (3 × 50 ml.). The combined ethereal extract is dried, first over anhydrous sodium sulphate and then over anhydrous calcium sulphate. Evaporation of the ether gives the product which is purified by fractionational distillation at atmospheric pressure. Most of the solid dissolves to stand overnight with stirring external cooling (ice-bath) with stirring cooling The ether is distilled off the copper salt of the product is collected by filtration washed with water washed with petroleum ether The aqueous layer is separated extracted with more ether (3 × 50 ml.) The combined ethereal extract is dried, first over anhydrous sodium sulphate Evaporation of the ether gives the product which is purified by fractionational distillation at atmospheric pressure