Synthesis and antimicrobial of new anthraquinone derivatives incorporating pyrazole moiety

Treatment of 2-cyano-N-(9,10-dioxo-9,10-dihydro-anthracen-2-yl)-acetamide (1) with phenyl isothiocyanate/dimethylsulphate afforded the corresponding ketene N,S-acetal 2 which upon treatment with hydrazine hydrate and 4-aminoantipyrine afforded the pyrazolo derivatives 3 and 4, respectively. 3-aminopyrazole derivative 3 was utilized as key intermediate for the synthesis of pyrazolo[3,4-d]pyrimidine 5, pentaaza-as-indacene 6, triaza-cyclopenta[c]phenanthrene 7, pyrazolo[1,5-a]pyrimidine 8, 9 and (dimethyl-pyrrol-1-yl)pyrazole 10 derivatives. Furthermore, treatment of 1 with DMF/DMA gave the corresponding acrylamide derivative 11 which upon treatment with hydrazine hydrate afforded the corresponding 3-aminopyrazole derivative 12. Moreover, coupling of 1 with 4,6-dimethyl-1H-pyrazolo[3,4-b]pyridin-3-diazonium chloride gave the hydrazone derivative 13 which upon cyclization with acetic acid afforded the corresponding pentaaza-fluorene derivative 14. Representative compounds of the synthesized products were evaluated as antimicrobial agents. Some of these compounds exhibited promising activities.