Synthesis of imidazo[4,5-a]acridones and imidazo[4,5-a]acridines as potential antibacterial agents

Design, Synthesis, Fluorescence Properties and Antibacterial Activities of New 8-Chloro-3-Alkyl-3H-Pyrazolo[4,3-a]acridine-11-Carbonitriles

“…Experimental details of the tests can be found in our earlier studies. [17][18][19][20][21] The antimicrobial tests performed on compounds 3a-e and 4a-d confirmed that they are effective against both Grampositive and Gram-negative bacteria and some showed greater inhibitory activity against a number of Gram-positive and Gram-negative bacteria than the well known antibacterial agents Ampicillin and Sulfamethoxazole.…”

“…Gratifyingly, compound 3d with a butyl group was the most potent of the tested compounds against Grampositive and Gram-negative bacteria in this work and all biological research work that we have reported previously. [16][17][18][19][20][21] We propose that the chain lengths and chlorine substituent might change the binding characteristics of ligands to their respective receptors and, thereby, improve the biological activities.…”

“…Based on these aspects and in continuation with our research work on the synthesis of new fluorescent nitrogen heterocycles [10][11][12][13][14][15] and bioactive [16][17][18][19][20][21] nitrogen heterocyclic compounds, we now decided to examine the transformation of alkylated 5-nitro-1H-indazoles and 2-(4-chlorophenyl) acetonitrile to new 8-chloro-3-alkyl-3H-pyrazolo [4,3-a]acridine-11-carbonitriles in basic media and to evaluate their spectroscopic properties and biological activities.…”

Synthesis of new fluorescent compounds from 5-nitro-1H-indazole

“…The new 3-alkyl-3H-pyrazolo[4,3-a]acridin-11-carbonitrile 3a-d were synthesized via the nucleophilic substitution of hydrogen of 1-alkyl-1H-indazole 1a, b with arylacetonitriles 2a, b in basic MeOH solution and then intramolecular electrophilic aromatic substitution in moderate yields 16,[17][18][19][20][21][22] (Scheme 1). When R' is an electron withdrawing group such as NO2 group, the yield of the reaction is very low, since the corresponding conjugated base is a weak nucleophile.…”

“…15 We have previously described a process for the relatively feasible production of some new fluorescent compounds 16,17 by reacting the imidazo[1,2-a]pyridine with arylacetonitriles via nucleophilic substitution of hydrogen. [18][19][20][21] Now we describe here the syntheses of new fluorescent heterocyclic compounds from nitro derivatives of indazole by this method and evaluation of their spectroscopic properties.…”