Lithium hydroxide, monohydrate → 3-(5-(3,5-dichloro-4-fluorophenyl)-5-(trifluoromethyl)-4,5-dihydroisoxazol-3-yl)-5,6-dihydro-4H-cyclopenta[c]thiophene-1-carboxylic acid

Beteiligte Stoffe

Reaktionsschritte

Stir a mixture of 3-[5-(3,5-Dichloro-4-fluoro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-5,6-dihydro-4H-cyclopenta[c]thiophene-1-carboxylic acid methyl ester (26 g, 54.1 mmol) and LiOH—H2O (4.54 g, 0.108 mmol) in water (200 mL) and THF (400 mL) at 50° C. for 0.5 hour. After removal of organic solvent under vacuum, dilute the residue with ice water (100 mL). Acidify the aqueous mixture with conc. HCl to pH=1, and extract the resultant mixture with EtOAc (200 mL×3). Purify the residue by silica gel chromatograph (EtOAc:MeOH 6:1) to afford 3-[5-(3,5-Dichloro-4-fluoro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-5,6-dihydro-4H-cyclopenta[c]thiophene-1-carboxylic acid as a white solid (23 g, 91.7% for 2 steps). MS (m/z): 468 (M+1).

Herkunft & Nachweise