Hydrochloric Acid → HCID 66732123, compound

Participants

Reaction Conditions

Reaction Steps

Cis-methyl 2-(3,5-difluoro-4-(trifluoromethyl)phenyl)-4-(3-ethoxy-3-oxopropanoyl)-piperidine-1-carboxylate (1.489 g, 3.40 mmol) was dissolved in MeOH (15 mL) and cooled to −40° C. Sodium hydroxide (0.896 mL, 3.40 mmol) dissolved in water (1.500 mL) was added and the reaction stirred at −40° C. for 20 min. Hydroxylamine (50% by weight in water, 0.209 mL, 3.40 mmol) was added and stirring continued for 3.5 h at −40° C. The reaction mixture was then added to a prewarmed 80° C. solution of hydrogen chloride (17.59 mL, 105.54 mmol) and stirred for 20 min. The solvent was evaporated in vacuo. DCM (100 mL) and water (100 mL) were added, shaken and the phases separated. The organic phase was dried with a phase separator and evaporated in vacuo. The compound was purified by preparative HPLC on a Kromasil C8 column (10 μm 250×50 ID mm) using a gradient of 20-65% Acetonitrile in H2O/MeCN/AcOH 95/5/0.2 buffer over 30 minutes with a flow of 100 mL/min. Cis-methyl 2-(3,5-difluoro-4-(trifluoromethyl)phenyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate (0.594 g, 42.9%) was isolated as a white solid. 1H NMR (600 MHz, cdcl3) δ 1.82-1.89 (m, 1H), 2.08-2.16 (m, 1H), 2.19-2.27 (m, 1H), 2.32-2.38 (m, 1H), 3.04-3.11 (m, 1H), 3.34-3.41 (m, 1H), 3.68 (s, 3H), 4.09-4.15 (m, 1H), 5.04-5.08 (m, 1H), 5.57 (s, 1H), 6.80 (d, 2H).

Provenance & Evidence