Facile synthesis of some new pyrazolo [3,4-b] pyrazines and their antifungal activity

The synthesis of new pyrazolo[3,4-b]pyrazines and related heterocycles has been reported. The key intermediate 1,6-diphenyl-3-methyl-1H-pyrazolo[3,4-b]pyrazine-5-carbonitrile 2 was obtained in one pot synthesis from the reaction of 5-amino-3-methyl-4-nitroso-1-phenylpyrazole 1 with benzoylacetonitrile. Modest antifungal activity was shown for some of the prepared compounds.