4,4,5,5,5-pentafluoro-3-oxopentanenitrile

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

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

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

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

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred mixture of 4,4,5,5,5-pentafluoro-3-oxopentanenitrile (500 mg, 2.66 mmol) and phenylhydrazine hydrochloride (386 mg, 2.66 mmol) in ethanol (5 mL) was heated at 90° C. for 4 h. The reaction mixture was concentrated under reduced pressure, and the obtained oil purified by silica gel flash column chromatography (eluting with a gradient of 100% petroleum ether to 10% ethyl acetate in petroleum ether) to afford 3-(perfluoroethyl)-1-phenyl-1H-pyrazol-5-amine (320 mg, 43%) as a solid. 1H NMR (400 MHz, CDCl3) δ 7.51-7.60 (m, 4H), 7.45 (m, 1H), 5.91 (s, 1H), 3.96 (brs, 2H); LC-MS (ESI) m/z 278 (M+H)+. The reaction mixture was concentrated under reduced pressure the obtained oil purified by silica gel flash column chromatography ( eluting with a gradient of 100% petroleum ether to 10% ethyl acetate in petroleum ether)

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred suspension of sodium hydride (15.6 g of a 60% dispersion in mineral oil, 0.39 mol) in THF (100 mL) was heated to 50° C. To this was added a mixture of ethyl 2,2,3,3,3-pentafluoropropanoate (25 g, 0.13 mol) and dry acetonitrile (5.3 g, 0.13 mol), dropwise, and the resulting colorless suspension was heated at 50° C. for 4 h. After cooling to rt the reaction mixture was concentrated under reduced pressure and the residue poured into water (100 mL) and extracted with diethyl ether (100 mL). The aqueous layer was separated, acidified to pH 2 with aqueous 2 M HCl and extracted with diethyl ether (2×200 mL). The combined diethyl ether layers were dried over magnesium sulfate then concentrated under reduced pressure to afford 4,4,5,5,5-pentafluoro-3-oxopentanenitrile an orange oil (17 g) which was used in the next step without further purification. To this was added dropwise, and the resulting colorless suspension was heated at 50° C. for 4 h After cooling to rt the reaction mixture was concentrated under reduced pressure the residue poured into water (100 mL) extracted with diethyl ether (100 mL) The aqueous layer was separated extracted with diethyl ether (2×200 mL) The combined diethyl ether layers were dried over magnesium sulfate then concentrated under reduced pressure

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

Procedure: Heat a mixture of 4,4,5,5,5-pentafluoro-3-oxo-pentanenitrile (4 g, 21.4 mmol) and p-tolyl-hydrazine (10 g, 64.1 mmol) in ethanol (20 mL) to 95° C. in a sealed tube apparatus for 15 hours. After cooling to room temperature, remove the solvent under reduced pressure to give a brown residue. Subject residue to silica gel chromatography eluting with ethyl acetate and hexanes to give the title compound (3.24 g, 52% yield, ES+(m/z) 292.1 [M+H]). Heat remove the solvent under reduced pressure to give a brown residue Subject residue to silica gel chromatography eluting with ethyl acetate and hexanes

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

Procedure: Heat a mixture of 4,4,5,5,5-pentafluoro-3-oxo-pentanenitrile (4 g, 21.4 mmol) and p-tolyl-hydrazine (10 g, 64.1 mmol) in ethanol (20 mL) to 95° C. in a sealed tube apparatus for 15 hours. After cooling to room temperature, remove the solvent under reduced pressure to give a brown residue. Subject residue to silica gel chromatography eluting with ethyl acetate and hexanes to give the title compound (3.24 g, 52% yield, ES+(m/z) 292.1 [M+H]). Heat remove the solvent under reduced pressure to give a brown residue Subject residue to silica gel chromatography eluting with ethyl acetate and hexanes

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred mixture of 4,4,5,5,5-pentafluoro-3-oxopentanenitrile (500 mg, 2.66 mmol) and phenylhydrazine hydrochloride (386 mg, 2.66 mmol) in ethanol (5 mL) was heated at 90° C. for 4 h. The reaction mixture was concentrated under reduced pressure, and the obtained oil purified by silica gel flash column chromatography (eluting with a gradient of 100% petroleum ether to 10% ethyl acetate in petroleum ether) to afford 3-(perfluoroethyl)-1-phenyl-1H-pyrazol-5-amine (320 mg, 43%) as a solid. 1H NMR (400 MHz, CDCl3) 87.51-7.60 (m, 4H), 7.45 (m, 1H), 5.91 (s, 1H), 3.96 (brs, 2H); LC-MS (ESI) m/z 278 (M+H)+. The reaction mixture was concentrated under reduced pressure the obtained oil purified by silica gel flash column chromatography ( eluting with a gradient of 100% petroleum ether to 10% ethyl acetate in petroleum ether)

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred suspension of sodium hydride (15.6 g of a 60% dispersion in mineral oil, 0.39 mol) in THF (100 mL) was heated to 50° C. To this was added a mixture of ethyl 2,2,3,3,3-pentafluoropropanoate (25 g, 0.13 mol) and dry acetonitrile (5.3 g, 0.13 mol), dropwise, and the resulting colorless suspension was heated at 50° C. for 4 h. After cooling to rt the reaction mixture was concentrated under reduced pressure and the residue poured into water (100 mL) and extracted with diethyl ether (100 mL). The aqueous layer was separated, acidified to pH 2 with aqueous 2 M HCl and extracted with diethyl ether (2×200 mL). The combined diethyl ether layers were dried over magnesium sulfate then concentrated under reduced pressure to afford 4,4,5,5,5-pentafluoro-3-oxopentanenitrile an orange oil (17 g) which was used in the next step without further purification. To this was added dropwise, and the resulting colorless suspension was heated at 50° C. for 4 h After cooling to rt the reaction mixture was concentrated under reduced pressure the residue poured into water (100 mL) extracted with diethyl ether (100 mL) The aqueous layer was separated extracted with diethyl ether (2×200 mL) The combined diethyl ether layers were dried over magnesium sulfate then concentrated under reduced pressure

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred suspension of sodium hydride (15.6 g of a 60% dispersion in mineral oil, 0.39 mol) in THF (100 mL) was heated to 50° C. To this was added a mixture of ethyl 2,2,3,3,3-pentafluoropropanoate (25 g, 0.13 mol) and dry acetonitrile (5.3 g, 0.13 mol), dropwise, and the resulting colorless suspension was heated at 50° C. for 4 h. After cooling to rt the reaction mixture was concentrated under reduced pressure and the residue poured into water (100 mL) and extracted with diethyl ether (100 mL). The aqueous layer was separated, acidified to pH 2 with aqueous 2 M HCl and extracted with diethyl ether (2×200 mL). The combined diethyl ether layers were dried over magnesium sulfate then concentrated under reduced pressure to afford 4,4,5,5,5-pentafluoro-3-oxopentanenitrile an orange oil (17 g) which was used in the next step without further purification. To this was added dropwise, and the resulting colorless suspension was heated at 50° C. for 4 h After cooling to rt the reaction mixture was concentrated under reduced pressure the residue poured into water (100 mL) extracted with diethyl ether (100 mL) The aqueous layer was separated extracted with diethyl ether (2×200 mL) The combined diethyl ether layers were dried over magnesium sulfate then concentrated under reduced pressure

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