SNH methodology and new approaches to condensed heterocyclic systems

The review surveys the reactions of electron-deficient azaaromatic compounds with mono- and bifunctional nucleophilies in which a nucleophilic attack at the unsubstituted CH carbon of an aromatic ring is one of the key steps. Use of the S-N(H) methodology for the synthesis of fused heterocyclic systems by means of nucleophilic addition-addition A(N)-A(N), addition-substitution of hydrogen A(N)-S-N(H), tandem substitution of hydrogen S-N(H)-S-N(H), and other strategies will be discussed. Intramolecular S-N(H) reactions will also be considered as effective synthetic tools to obtain condensed heterocyclic systems.