Novel 4- [pyrazol-1-yl] -, 1,2,4-triazolo [4,3-c] -, triazolo [1,5-c] and tetrazolo [1,5-c] quinazolines: synthesis for potential biological activities

Several 4-pyrazolylquinazolines, 1,2,4-triazolo [4,3-c] quinazolines, and 1,2,4-triazolo [1,5-c] quinazolines of potential biological activities were prepared by cyclization of 4-hydrazino-2-methylquinazoline and 4-hydrazino-2-phenylquinazoline with mono- and 1,3-dicarbonyl compounds. The 5-phenyl-1,2,4-triazolo [4,3-c] quinazolines were also obtained by an alternative route involving cyclization of 4-chloro-2-phenylquinazoline with aroylhydrazines. The tetrazolo [1,5-c] quinazolines were synthesized by cyclization of the amidrazones with nitrous acid or by cyclization of 4-chloro-2-phenylquinazoline with sodium azide