Synthesis of Fused Pyrimidines and Purines by Vicarious Nucleophilic Substitution of Hydrogen (A Microreview)

Fused pyrimidines can be easily synthesized from the corresponding ortho-aminobenzylamine derivatives or their heteroanalogues. Often the limiting factor for the above syntheses is the difficulty encountered in obtaining the key intermediates or their precursors. Recently, this problem was successfully solved in several ways by the use of vicarious nucleophilic substitution of hydrogen (VNS). As a result, many quinazolines and new bicyclic and tricyclic heteroaromatic compounds and their mono-N-oxides were obtained, when starting from nitroarenes. These approaches were also successfully applied to the synthesis of purines with the use of 4-nitroimidazole derivatives.