Functionalization of N-arylmaleimides by sp3 C–H bonds of hydroacridines(qinolines)

Abstract

The catalyst-free sp3 C–H functionalization of tetrahydroacridine(quinolines) derivatives has been achieved using a Michael-type reaction with N-arylmaleimides. This method enables the facile synthesis of biologically important N-aryl bearing tetrahydroacridine(quinolines) moieties in a single step with high yields. The reaction occurs under non-catalytic conditions by heating of hydroacridines(quinolines) in DMSO within 4 h at 100–1200C. The reaction between starting compounds allows synthesizing (3S/4R)-3-[(3R/4S)-9-chloroacridine(quinoline)-4-yl]-1(-N-aryl)pyrrolidine-2,5-diones with a good yield. The structure of compounds was proved by spectral methods of analysis. The 1H NMR spectrum shows characteristic signals of protons of the CH-groups in acridine(quinoline) (3.4–3.5 ppm) and pyrrolidine (3.8–3.9 ppm) cycles. It is interesting to note that the main direction of the fragmentation is the Michael retro-reaction, which is accompanied by the elimination of 1-(2-nitrophenyl)-1H-pyrrole-2,5-dione and leads to the formation of m/z ions of starting chloroacridines(quinolines).