ethyl 3-(3,5-dichlorophenyl)-3-oxopropanoate → (S)-ethyl 4-(1-(3-(3,5-dichlorophenyl)-5-oxo-4,5-dihydro-1H-pyrazol-1-yl)ethyl)benzoate

Participants

Reaction Steps

Ethyl 3-(3,5-dichlorophenyl)-3-oxopropanoate (4.2 g, 16.1 mmol) and {(1S)-1-[4-(ethoxycarbonyl)phenyl]ethyl}hydrazinium trifluoroacetate (5.2 g, 16.1 mmol) were heated in dry acetonitrile (100 ml) to 85° C. for 1 hr. The solvent was removed under reduced pressure, and the residue purified by column chromatography (SiO2, 20% ethyl acetate in hexanes) to give ethyl 4-{(1S)-1-[3-(3,5-dichlorophenyl)-5-oxo-4,5-dihydro-1H-pyrazol-1-yl]ethyl}benzoate as a white solid. NMR (500 MHz, CDCl3) δ: 1.38 (t, J=7.1 Hz, 3H); 1.78 (d, J=7.0 Hz, 3H); 3.55 (d, J 22.6 Hz, 1H); 3.60 (d, J=22.6 Hz, 1H); 4.36 (q, J=7.1 Hz, 2H); 5.57 (q, J=7.0 Hz, 1H); 7.39 (t, J=1.9 Hz, 1H); 7.50 (d, J=8.4 Hz, 2H). 7.52 (d, J=1.9 Hz, 2H); 8.02 (d, J=8.4 Hz, 2H). MS C20H18Cl2N2O3 Cald: 404.07; Obsd (M+1): 405.20.

Provenance & Evidence