2-methyl-2-(4,4,4-trifluorobutylsulfonyl)propanoic acid

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

Procedure: To a solution of 170 g (585.6 mmol) of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid ethyl ester in THF (3.4 L) are added 225.4 g (1756.8 mmol) of potassium trimethylsilanolate in portions over 0.5 h. The reaction is stirred at room temperature for 18 h. The reaction mixture is acidified with 2M aqueous HCl solution (2 L) to pH 2 and extracted with DCM (2×2 L). The combined organic extracts are dried (Na2SO4) and filtered. The filtrate is concentrated under reduced pressure to afford 143 g of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid as yellow solids. Yield: 93%; ES-MS: m/z 261 [M−H]. 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 1.71 (6 H, s), 2.18-2.28 (2 H, m), 2.30-2.42 (2 H, m), 3.38 (2 H, t, J=7.48 Hz), 6.96 (1 H, br. s.). extracted with DCM (2×2 L) The combined organic extracts are dried (Na2SO4) filtered The filtrate is concentrated under reduced pressure

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

Procedure: To a solution of 170 g (585.6 mmol) of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid ethyl ester in THF (3.4 L) are added 225.4 g (1756.8 mmol) of potassium trimethylsilanolate in portions over 0.5 h. The reaction is stirred at room temperature for 18 h. The reaction mixture is acidified with 2M aqueous HCl solution (2 L) to pH 2 and extracted with DCM (2×2 L). The combined organic extracts are dried (Na2SO4) and filtered. The filtrate is concentrated under reduced pressure to afford 143 g of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid as yellow solids. Yield: 93%; ES-MS: m/z 261 [M−H]. 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 1.71 (6 H, s), 2.18-2.28 (2 H, m), 2.30-2.42 (2 H, m), 3.38 (2 H, t, J=7.48 Hz), 6.96 (1 H, br. s.). extracted with DCM (2×2 L) The combined organic extracts are dried (Na2SO4) filtered The filtrate is concentrated under reduced pressure

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

Procedure: To 100 mg (0.38 mmol) of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid (intermediate 5) in toluene (4.07 mL) are added 55.3 μL (0.76 mmol) thionyl chloride and 3.10 μL (0.04 mmol) DMF. The solution is stirred at reflux for 1 h. In a second flask 78.7 μL (0.46 mmol) DIPEA are added to 63.4 mg (0.42 mmol) of 2-(5-amino-isoxazol-3-yl)-2-methyl-propionitrile (intermediate 7) in toluene (2.03 mL). The mixture is stirred at RT for 5 min, then added to the acid chloride and stirring is continued at RT for 16 h. The reaction mixture is purified by HPLC-MS to afford 78.7 mg of N-[3-(cyano-dimethyl-methyl)-isoxazol-5-yl]-2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionamide. Yield: 52%; ESI-MS: 396 [M+H]+; HPLC (Rt): 1.14 min (method G); 1H-NMR (400 MHz, DMSO-d6): 1.68 (s, 6H), 1.70 (s, 6H), 1.86-1.91 (m, 2H), 2.47-2.52 (m, 2H), 3.34-3.40 (m, 2H), 6.57 (s, 1H), 11.64 (s, 1H) ppm. at reflux for 1 h The mixture is stirred at RT for 5 min stirring The reaction mixture is purified by HPLC-MS

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

Procedure: To a solution of 170 g (585.6 mmol) of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid ethyl ester in THF (3.4 L) are added 225.4 g (1756.8 mmol) of potassium trimethylsilanolate in portions over 0.5 h. The reaction is stirred at room temperature for 18 h. The reaction mixture is acidified with 2M aqueous HCl solution (2 L) to pH 2 and extracted with DCM (2×2 L). The combined organic extracts are dried (Na2SO4) and filtered. The filtrate is concentrated under reduced pressure to afford 143 g of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid as yellow solids. Yield: 93%; ES-MS: m/z 261 [M−H]. 1H NMR (500 MHz, CHLOROFORM-d) δ ppm 1.71 (6 H, s), 2.18-2.28 (2 H, m), 2.30-2.42 (2 H, m), 3.38 (2 H, t, J=7.48 Hz), 6.96 (1 H, br. s.). extracted with DCM (2×2 L) The combined organic extracts are dried (Na2SO4) filtered The filtrate is concentrated under reduced pressure

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

Procedure: To 100 mg (0.38 mmol) of 2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionic acid (intermediate 5) in toluene (4.07 mL) are added 55.3 μL (0.76 mmol) thionyl chloride and 3.10 μL (0.04 mmol) DMF. The solution is stirred at reflux for 1 h. In a second flask 78.7 μL (0.46 mmol) DIPEA are added to 63.4 mg (0.42 mmol) of 2-(5-amino-isoxazol-3-yl)-2-methyl-propionitrile (intermediate 7) in toluene (2.03 mL). The mixture is stirred at RT for 5 min, then added to the acid chloride and stirring is continued at RT for 16 h. The reaction mixture is purified by HPLC-MS to afford 78.7 mg of N-[3-(cyano-dimethyl-methyl)-isoxazol-5-yl]-2-methyl-2-(4,4,4-trifluoro-butane-1-sulfonyl)-propionamide. Yield: 52%; ESI-MS: 396 [M+H]+; HPLC (Rt): 1.14 min (method G); 1H-NMR (400 MHz, DMSO-d6): 1.68 (s, 6H), 1.70 (s, 6H), 1.86-1.91 (m, 2H), 2.47-2.52 (m, 2H), 3.34-3.40 (m, 2H), 6.57 (s, 1H), 11.64 (s, 1H) ppm. at reflux for 1 h The mixture is stirred at RT for 5 min stirring The reaction mixture is purified by HPLC-MS