Aminoazoles in heterocyclic synthesis. Synthesis of some new pyrimidobenzimidazoles and pyrazolonopyridines as well as triazolo- tetrazolo- and pyrazolo-pyrimidines of pharmaceutical interest

The reactivity of 3-cinnamoylindole, 3-cinnamoylantipyrine and 1-(3-methyl-1-phenyl-5-pyrazolon-4-yl)-4- antipyrin-4-yl)-prop-2-ene-1 one(la-c) towards 2- aminobenzimidazole, 3-amino-1,2,4-triazole, 5-aminotetrazole monohydrate, 5-amino-3-phenylpyrazole and 3-amino-1-phenyl-2- pyrazolin-5-one to give the fused heterocycles 2a-c, 4a,b, 5a,b, 8a,b, and 10a-c has been investigated. Structures of the synthesized compounds were confirmed by both the analytical and the spectral data (IR, UV and ¹H NMR).