Phosphorus tribromide → 3-(Bromomethyl)-5-(4-chlorophenyl)-1-(4-methoxyphenyl)-1H-pyrazole

Participants

Reaction Steps

To a solution of compound 3 (3.14 g, 10 mM) in benzene (100 ml) was added PBr3 (1.35 g, 5 mM) in benzene (10 ml) dropwise with stirring. The reaction mixture was refluxed 1 hr, cooled, poured into ice water (100 ml)and extracted with Et2O (2×100 ml). The combined organic layer was washed with 10% NaHCO3, dried (Na2SO4), filtered and concentrated to give a tan oilwhich crystallized on standing to afford compound 5, mp=88°-90° C., MS, (DCI) m/e 377 (M+1).

Provenance & Evidence