The synthesis of indeno[2,1-e]pyrazolo[3,4-b]pyrazin-5-onewas achieved by intramolecular FriedeleCrafts
reaction of the acid chloride 3-methyl-1,6-diphenyl-1H-pyrazolo[3,4-b] pyrazine-5-carboxylic acid chloride
(4) using AlCl3 in boiling CS2. Compound 4 proved to be a versatile compound for the synthesis of several
Indenopyrazolopyrazinone derivatives. The antibacterial and antifungal activities of selected derivatives
were evaluated.