AcycloC-Nucleoside Analogs. Regioselective Annellation of a Triazole Ring to 5-Methyl-1,2,4-Triazino[5,6-b]Indole and Formation of Certain 3-Poly Hydroxyalkyl Derivatives

Synthesis and antimicrobial screening of novel 1,3-dioxolanes linked to N-5 of 5H-[1,2,4]triazino[5,6-b]indole-3-thiol

“…The discovery of 1,3-dioxolanes linked to thymidine (7), 5-substituted uracil (8) and cytosine (9), [11][12][13][14][15] as potential anti-HIV agents without acute cellular toxicity has attracted our attention to synthesize novel 1,3-dioxolanes linked to SYNTHESIS AND ANTIMICROBAL SCREENING OF NOVEL 1,3-DIOXOLANES 3 different heterocyclic bases. In continuation of our work on triazino-indoles, [16][17][18][19] herein an efficient methodology is reported for the synthesis of some biologically active 1,3-dioxolanes bearing 1H-indole-2,3-dione (10), 5H-1,2,4-triazino [5,6b]indole-3-thiol, and its 3-alkylthio derivatives (11, Fig. 2).…”

“…RASHEED and EL ASHRYA green synthesis of the cyclized compound 5-[(2,2-dimethyl-1,3-dioxolan--4-yl)methyl]-2,5-dihydro-3H-1,2,4]-triazino[5,6-b]indole-3-thione(18) was achieved by the dehydrative cyclization of 17 in aqueous potassium carbonate. The reaction was completed in 7 h at reflux and the yield reached 75 %.…”

Regioisomeric Formation of the Linear 1,2,4-Triazolo[4′,3′: 2,3][1,2,4]Triazino[5,6-b]Indole from 3-Hydrazino-1,2,4-Triazino[5,6-b]Indole Derivatives

“…6 The fusion of a heterocyclic ring to the 1,2,4-triazine ring via a functional group on position-3 may take place at N-2 or N-4 to give a linear 1,2,[12][13][14][15][16] or angular 17-20 fused heterocycles, respectively. 1,2,21 On the other hand, the regioselectivity was reversed by introducing a methyl group at N-5 or C-8 of the triazinoindole ring, 25,26 when angular isomers were formed. 1,2,21 On the other hand, the regioselectivity was reversed by introducing a methyl group at N-5 or C-8 of the triazinoindole ring, 25,26 when angular isomers were formed.…”

“…b]indoles,25,26 the introduction of an allyl group instead of the methyl group on N-5 of the indole ring or a bromine atom on the respective 8-position caused a change in the site of cyclization of the respective hydrazones to give the linear isomers. Thus, reaction of 5 or 6 with acetaldehyde gave the 5-allyl-3-ethylidenehydrazino-1,2,4-triazino-[5,6-b]indole (7) and 8-bromo-3-ethylidenehydrazino-1,2,4triazino[5,6-b]indole (8), respectively.…”

“…6 The fusion of a heterocyclic ring to the 1,2,4-triazine ring via a functional group on position-3 may take place at N-2 or N-4 to give a linear 1,2,[12][13][14][15][16] or angular [17][18][19][20] fused heterocycles, respectively. It has been found that the regioselective annelation of a triazole to a triazine ring 1,2,[21][22][23][24] can be achieved by the cyclisation of 3-hydrazino-5H-1,2,4-triazino[5,6-b]indole either via the dehydrative cyclisation of the respective hydrazide or the dehydrogenative cyclisation of the hydrazones to the linear isomer 10H 1,2,21 On the other hand, the regioselectivity was reversed by introducing a methyl group at N-5 or C-8 of the triazinoindole ring, 25,26 when angular isomers were formed. In the present work the cyclisation of 3-hydrazino-5H-1,2,4-triazino[5,6-b]indoles, with 5-allyl or 8-bromo substituents, with some one-carbon inserting reagents has been investigated in order to find the effect of these substituents on the site of cyclisation.…”