An efficient stereo-controlled synthesis of bis-pyrimido-[4,5-d]-pyrimidine derivatives via aza-Diels-Alder methodology and their preliminary bioactivity

The one-pot synthesis of novel fused bis-pyrimido-[4,5-d]pyrimidine derivatives by a three-component reaction of 6-[(dimethylamino)methylene]1,3-dimethylaminouracil, terephthalaldehyde and amino derivatives has been depicted. The structures of the compounds were established by studying various spectroscopic methods and single-crystal X-ray crystallography. The long range W-coupling constant in H-1-NMR spectra is an infrequent example, where our synthesized novel compounds show such a distinctive constant. The synthetic strategy provides an efficient way to synthesise bis-pyrimidine-fused heterocycles that can be explored for further potential pharmaceutical or biological activities.