Research Info

The reaction between 6-aminouracils and isatins having no substitution on nitrogen was carried out in acetic acid at 80°C. This was followed by the oxidative decarboxylation of the resulting intermediates in the presence of Pb(OAc)4, resulting in the synthesis of the corresponding 6-aminouracil substituted pyrimido[4,5-b]quinolines with good to excellent yields. Additionally, the reaction of 6-aminouracils, isatin derivatives, and 1,3-dimethylbarbituric acid yielded similar results, and the corresponding products were efficiently obtained with symmetric and asymmetric structures. Furthermore, N-substituted isatins were also subjected to the reaction conditions and the resulted spirooxindoles prepared, showing resistance against oxidation with (Pb(OAc)4. Notably, the condensation reaction of N-substituted isatins with N-arylaminouracils was also investigated, leading to spiro[indoline-3,5’-pyrimido[4,5-b]quinoline] derivatives