To a solution of N-methyl-N-[2-nitro-5-(2-chloro-4-trifluoromethylphenoxy)phenyl]hydroxyamine (500 mg, 1.38 mmol) in methylene chloride (2 ml) is added pyridine (0.16 ml, 2.00 mmol) and benzene (3 ml), followed by α,α-dichloropropionyl chloride (328 mg, 1.5 eq.). The mixture is stirred at RT for 2 hours. The resulting reaction mixture is then taken up in methylene chloride, washed, dried and evaporated to dryness. The crude product is purified by prep. TLC to yield N-methyl-N-[2-nitro-5-(2-chloro-4-trifluoromethylphenoxy)phenyl]-α,α-dichloropropionyloxyamine. nmr (CDCl3) τ7.77(S,3H,COC Cl2CH3), 6.67(S, 3H, NCH3).
