Preparation of naphthoquinone imines as NIR dyes

Article abstract of DOI:10.1016/0040-4020(95)00163-3

N-Arylphthalimides can be converted to isoindoles by a two electron reduction and silylation. Cycloaddition with acetylenic dienophiles leads to naphthoquinonemonoimines, which show absorption maxima in the NIR region up to 800 nm.