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.