Acetic Acid → tert-Butyl 3-[5-(5-trifluoromethyl-2-hydroxyphenyl)-1H-pyrazol-1-yl]azetidine-1-carboxylate

Participants

Reaction Steps

To a stirred solution of crude tert-butyl 3-hydrazinoazetidine-1-carboxylate, (Preparation 31, 5.7 g, 0.03 mol) in ethanol (66 mL) at 0° C. was added acetic acid (6.6 mL) dropwise. Then (2E)-3-(dimethylamino)-1-[2-hydroxy-5-(trifluoromethyl)phenyl]prop-2-en-1-one, (Preparation 33, 6.4 g, 24.7 mmol) was added portionwise and allowed to stir at ambient temperature for 20 hours. The reaction mixture was concentrated in vacuo and neutralised with aqueous sodium bicarbonate solution. The mixture was extracted with ethyl acetate (150 mL). The combined organic layer was washed with water (100 mL), saturated aqueous sodium chloride solution (50 mL) and dried over anhydrous sodium sulphate. After concentration of organic layer in vacuo, the crude product was washed with 20% v/v ethyl acetate in hexane to afford the title compound as a white solid (7.4 g, 64%)

Provenance & Evidence