HCID 22171031, compound → HCID 69196644, compound

Participants

Reaction Conditions

Reaction Steps

To a 3-neck round bottom flask fitted with an air condenser was added 3-[5-(3,4-dichloro-phenyl)-1-(2,4-dichloro-phenyl)-1H-pyrazol-3-yl]-propionic acid (1.0 g, 2.3 mmol, 1.0 equiv) and toluene (23 mL) under nitrogen. The mixture was heated to 80° C. then N,N-dimethyl-di-tert-butylacetal (2.36 g, 11.6 mmol, 5.0 equiv) was added dropwise (neat). The reaction mixture was heated at 80° C. for 1 h then additional N,N-dimethyl-di-tert-butylacetal (2.36 g, 11.6 mmol, 5.0 equiv) was added. This mixture was stirred at 80° C. for 2 h then cooled to room temperature and partitioned between water (100 mL) and ether (100 mL). The organic layer was washed with 1 M sodium hydroxide (50 mL), water (50 mL) then brine (50 mL), dried (Na2SO4), and concentrated under reduced pressure. The crude material was then purified by flash chromatography (20% ethyl acetate/hexanes) to afford the desired ester (1.1 g, >99%). HPLC: Rt=3.59 (Method A). MS (ESI): mass calculated for C22H20Cl4N2O2, 484.03; m/z found, 485.0 [M+H]+. 1H NMR (500 MHz, DMSO-d6): 7.81 (d, J=2.2 Hz, 1H), 7.65 (d, J=8.5 Hz, 1H), 7.61-7.59 (m, 2H), 7.48 (d, J=2.2 Hz, 1H), 7.05 (dd, J=8.2, 1.9 Hz, 1H), 6.71 (s, 1H), 2.87 (t, J=7.4 Hz, 2H), 2.61 (t, J=7.4 Hz, 2H), 1.38 (s, 9H).

Provenance & Evidence