Aly, M. R. El SayedSaad, H. AAli, R. SAl Osaimi, A. G2019-12-012019-12-012017-061070-3632https://doi.org/10.1134/S1070363217060202https://link.springer.com/article/10.1134/S1070363217060202Accession Number: WOS:000407053200020Synthesis of new fused systems of triazino[5,6-b]indole starting with preparation of 3-amino[1,2,4]-triazino[5,6-b]indole 1 by reaction of isatin with 2-aminoguanidinium carbonate in boiling acetic acid is presented [1]. Intermediate compound 1 reacted with aldehyde, ethyl chloroformate, triethyl orthoformate, and ninhydrine and gave new heterotetracyclic nitrogen systems, such as 3-(N (2)-guanidinylimino)indole-2(1H)-one 2, 3-(N-ethoxycarbonylamino)-4H-[1,2,4]triazino[5,6-b]indole 3, 3-(N-ethoxymethyleneamino)-4H-[1,2,4]-triazino[5,6-b]indole 4, 3-(hydrazinothiocarbonylamino)-4H-[1,2,4]triazino[5,6-b]indole 5, respectively. N-(1,3-dioxoindene-2-ylidene)-4H-[1,2,4]triazino[5,6-b]indol-3-amine 6 was synthesized by reaction of compound 1 with aldehyde, ethyl chloroformate, triethyl orthoformate, and ninhydrine. New fused indole systems, pyrimido[2',1':3,4][1,2,4]triazino[5,6-b]indol-3(4H)-one 8, 9, 11, 12 and 1H-imidazo[2',1':3,4][1,2,4]triazino-[5,6-b]indol-2(3H)-one 10, were synthesized in the reaction of the intermediate 1 with bifunctional compounds. Structures of the products were elucidated from their elemental analysis and spectral data (IR, H-1 and C-13 NMR and mass spectra). Antimicrobial activity of some synthesized compounds was tested.en-USbiological activitypyrimido[2 ',1 ':3,4]-[1,2,4]triazino[5,6-b]indole[1,2,4]triazino[5,6-b]indol-3-amineimidazo[2 ',1 ': 3,4][1,2,4]triazino[5,6-b]indoleINDOLE1,2,4-TRIAZINESAGENTSSynthesis and Antimicrobial Activity of Novel Fused [1,2,4]Triazino[ 5,6-b]indole DerivativesArticlehttps://doi.org/10.1134/S1070363217060202