Microwave assisted synthesis of 2′-/3′-azaflavones/azaflavonones and their N-alkyl derivatives

2′-Azaflavonone (6) and 3′-azaflavonone (7); were synthesized by a simple environmentally friendly microwave-assisted one-pot method for the cyclization of 2′-hydroxy β′-2-azachalcanon-β-ol (1), 2′-hydroxy (E)-2-azachalcone (2), 2′-hydroxy (E)-3-azachalcone (3) under solventless conditions using K-10 clay. In addition to these synthesis, 3-(pyridin-2-yl methyl)-2′-azaflavone (8) and 3-(pyridin-3-yl methyl)-3′-azaflavone (9) were synthesized using silica-supported sodium hydrogen sulphate then the treatment with base, respectively. Additionally, for antimicrobial activities N-alkyl substituted 3′-azaflavonium and 2′-azaflavonium bromides (10-12) were prepared from compounds 3, 4 - 5 and 8 - 9.