Succinimidylation and nitration of aromatic compounds by photolysis with N-nitrosuccinimide

Abstract

N-Nitrosuccinimide (S-NO₂) engages in weak charge transfer complexes with aromatic compounds (ArH). Upon photolysis with light of λ > 345 nm in dichloromethane, electron transfer within the charge transfer complex leads to the triad [ArH˙⁺ S^– NO₂] from which products of eventual Succinimidylation and/or nitration develop by initial attack of succinimide anion upon the radical cation. Photolysis in the presence of trifluoroacetic acid (0.4 mol dm^–3) causes inactivation of S^– by protonation, making EPR detection of ArH˙⁺ or radical cations formed by its further transformations possible. In acetonitrile, trifluoroacetic acid is too weak effectively to protonate S^–, whereas addition of stronger acids again leads to the development of EPR spectra of ArH˙⁺ in the case of 9,10-dimethylanthracene, the intensity increasing with decreasing pK of the acid.

An X-ray crystal structure is reported for N-nitrosuccinimide.