Simple preparation of new N-(6-methyl-2-nitrophenyl-1,2,3,4- tetrahydroquinolin-4-yl) pyrrolidin-2-ones and their spectroscopic analysis

Objectives. To prepare new N-(1,2,3,4-tetrahydroquinolin-4-yl) pyrrolidin-2-one molecules and to characterize them by spectroscopic methods. Materials and methods. All reagents were purchased from Aldrich, commercial grade. The purity of the products and the composition of the reaction mixtures were monitored by thin layer chromatography over Silufol UV 254 chromatoplates (0.25 mm). Product isolation and purification were performed by column chromatography (SiO 2) using ethyl acetate. Results. Preparation of new N-(2nitrophenyl-1,2,3,4-tetrahydroquinolin-4-yl) pyrrolidin-2-ones has been achieved via the one-pot synthesis, based on a BiCl 3-catalyzed imino Diels-Alder cycloaddition reaction of toluidine, N-vinylpyrrolidin-2-one and 4-nitro- or 3-nitrobenzaldehydes. The structure of the pyrrolidine derivatives was confirmed by 1 H NMr and 13 C NMr studies, in addition to inverse-detected 2D NMr experiments and monocrystal X-ray diffraction. Conclusions. An efficient, economic, and fast synthetic route (multi-component imino Diels-Alder reaction) was employed in the construction of several new tetrahydroquinoline derivatives, useful and attractive rigid skeleton with well-defined stereochemistry.