N-Iodosuccinimide → 5-Amino-4-iodo-3-methyl-1-(2,4,6-trichlorophenyl)pyrazole

Participants

Reaction Steps

A stirred solution of 5-amino-3-methyl-1-(2,4,6-trichlorophenyl)pyrazole (WO-A-94/13643; 35 g) and N-iodosuccinimide (29 g) in acetonitrile (450 ml) was heated under reflux for 1.5 hours, then the reaction mixture allowed to cool and evaporated under reduced pressure. The residue was dissolved in dichloromethane and the solution washed successively with aqueous sodium thiosulphate solution, water and brine, then dried (Na2SO4) and evaporated under reduced pressure. The resulting dark coloured solid was triturated with hexane to yield the title compound as a pale orange solid, m.p. 135-137° C. δ(CDCl3): 2.25 (s,3H), 3.67 (br.s,2H), 7.49 (s,2H). MS (thermospray): M/Z [M+H] 401.4; C10H7Cl3 lN3 +H requires 401.88.

Provenance & Evidence