Synthesis and spin trapping properties of 1,1-dimethyl-3-(trifluoromethyl)-1H-isoindole N-oxide

We have achieved an efficient synthesis of 1,1-dimethyl-3-(trifluoromethyl)-1H-isoindole N-oxide (2) in 39% yield by seven steps from 2-bromobenzoic acid (3). This compound serves as a spin trap reagent, giving a strong and stable ESR signal of the radical adduct of 2 in the presence of i-amyloxy radical generated by UV photolysis of i-amyl nitrite.