Triethylamine → methyl 1-(2-chlorophenyl)-5-(5-(3-(methylsulfonyl)phenyl)-1,3,4-oxadiazol-2-yl)-1H-pyrazole-3-carboxylic acid

Participants

Reaction Steps

To an ice cooled stirred solution of compound 7 from Example 2 (750 mg, 2.67 mmol) and 3-(methylsulfonyl)benzohydrazide 3 from Example 1 (575 mg, 2.67 mmol) in dichloromethane (25 mL) was added imidazolinium chloride (902 mg, 5.34 mmol) and stirred for 30 min. Triethyl amine (1.5 mL, 10.68 mmol) was added to the reaction mixture slowly over a period of 30 min, allowed to attain room temperature and stirring continued for over night. Water (50 mL) added to the reaction mixture and extracted with 10% methanol in dichloromethane (50 mL×3). The combined organic layer was washed saturated sodium bicarbonate solution, brine, dried over sodium sulphate and concentrated. The crude reaction mixture on column chromatographic purification using 2% methanol in dichoromethane afforded the title compound 11 (350 mg, 50%). LCMS: 459.25 (M+1)+; HPLC: 93.72% (@210 nm-370 nm) (Rf; 6.704; Method: Column: YMC ODS-A 150 mm×4.6 mm×5μ; Mobile Phase: A; 0.05% TFA in water/B; 0.05% TFA in acetonitrile; Inj. Vol: 10 μL, Col. Temp.: 30° C.; Flow rate: 1.4 m/min.; Gradient: 5% B to 95% B in 8 min, Hold for 1.5 min, 9.51-12 min 5% B); 1H NMR (CDCl3, 400 MHz) δ 8.28 (s, 1H), 8.26 (d, 1H), 8.11 (d, 1H, J=7.6 Hz), 7.75-7.71 (m, 2H), 7.62-7.50 (m, 4H), 4.02 (s, 3H), 3.09 (s, 3H).

Provenance & Evidence