Synthesis and antimicrobial activity of some annelated quinazoline derivatives

A highly efficient and versatile synthetic approach to the synthesis of annelated quinazoline derivatives viz [1,2,4]triazino[4,3-c]quinazoline 5-7,[1,3,5]triazino[1,2-c]quinazoline 11,thiazolidinylquinazoline 9,quinazolino[4,3-b] quinazolin-8-one 12 and imidazoquinazolines 14a,b,15. Also, a variety of pyrazolylquinazolines 19-21, pyrimidinylquinazolines 22a,b were obtained via a sequence of heterocyclisation reactions of 4-methyl-N-[4-(4-oxo-3,4-dihydroquinazolin-2-yl)phenyl]benzenesulfonamide (2) with different reagents. The new compounds were synthesised with the objective of studying their antimicrobial activity.