Saioa Ancizu

New 3-methylquinoxaline-2-carboxamide 1,4-di-N-oxide derivatives as anti-Mycobacterium tuberculosis agents.

Mycobacterium tuberculosis (M.Tb) is a bacillus capable of causing a chronic and fatal condition in humans known as tuberculosis (TB). It is estimated that there are 8 million new cases of TB per year and 3.1 million infected people die annually. Thirty-six new amide quinoxaline 1,4-di-N-oxide derivatives have been synthesized and evaluated as potential anti-tubercular agents, obtaining biological values similar to the reference compound, Rifampin (RIF).

New 1,4-di-N-oxide-quinoxaline-2-ylmethylene isonicotinic acid hydrazide derivatives as anti-Mycobacterium tuberculosis agents

The increase in the prevalence of drug-resistant tuberculosis cases demonstrates the need of discovering new and promising compounds with antimycobacterial activity. As a continuation of our research and with the aim of identifying new antitubercular drugs candidates, a new series of quinoxaline 1,4-di-N-oxide derivatives containing isoniazid was synthesized and evaluated for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Moreover, various drug-like properties of new compounds were predicted. Taking into account the biological results and the promising drug-likeness profile of these compounds, make them valid leads for further experimental research.

Synthesis and antimycobacterial activity of new quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives

As a continuation of our research and with the aim of obtaining new anti-tuberculosis agents which can improve the current chemotherapeutic anti-tuberculosis treatments, forty-three new quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives were synthesized and evaluated for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis strain H(37)Rv. Active compounds were also screened to assess toxicity to a VERO cell line. Results indicate that compounds with a methyl moiety substituted in position 3 and unsubstituted benzyl substituted on the carboxamide group provide an efficient approach for further development of anti-tuberculosis agents.

Synthesis and biological evaluation of new quinoxaline derivatives as antioxidant and anti-inflammatory agents

We report the synthesis, anti‐inflammatory, and antioxidant activities of novel quinoxaline and quinoxaline 1,4‐di‐N‐oxide derivatives. Microwave‐assisted methods have been used to optimize reaction times and to improve yields. The tested compounds presented important scavenging activities and promising in vitro inhibition of soybean lipoxygenase (LOX). Two of the best LOX inhibitors (compounds 7b and 8f) were evaluated as in vivo anti‐inflammatory agents using the carrageenin‐induced edema model. One of them (compound 7b) showed important in vivo anti‐inflammatory effect (41%) similar to that of indomethacin (47%) used as the reference drug.

Heterocyclic-2-carboxylic Acid (3-Cyano-1,4-di-N-oxidequinoxalin-2-yl)amide Derivatives as Hits for the Development of Neglected Disease Drugs

Neglected diseases represent a major health problem. It is estimated that one third of the world population is infected with tuberculosis (TB). Besides TB, Chagas disease, affects approximately 20 million people. Quinoxalines display great activities against TB and Chagas. Forty new quinoxaline 1,4-di-N-oxide derivatives have been prepared and tested against M. tuberculosis and T. cruzi. Carboxylic acid quinoxaline 1,4-di-N-oxides (CAQDOs) 5 and 17 showed MIC values on the same order as the reference antituberculosis drug, rifampicin. Meanwhile, CAQDOs 12 and 22 presented IC50 values in the same order as the anti-chagasic drug, nifurtimox.

Synthesis and Antiplasmodial Activity of 3-Furyl and 3-Thienylquinoxaline-2-carbonitrile 1,4-Di-N-oxide Derivatives †

The aim of this study was to identify new compounds active against Plasmodium falciparum based on our previous research carried out on 3-phenyl-quinoxaline-2-carbonitrile 1,4-di-N-oxide derivatives. Twelve compounds were synthesized and evaluated for antimalarial activity. Eight of them showed an IC50 < 1 μM against the 3D7 strain. Derivative 1 demonstrated high potency (IC50= 0.63 µM) and good selectivity (SI=10.35), thereby becoming a new lead-compound.

New quinoxaline derivatives as potential MT₁ and MT₂ receptor ligands.

Ever since the idea arose that melatonin might promote sleep and resynchronize circadian rhythms, many research groups have centered their efforts on obtaining new melatonin receptor ligands whose pharmacophores include an aliphatic chain of variable length united to an N-alkylamide and a methoxy group (or a bioisostere), linked to a central ring. Substitution of the indole ring found in melatonin with a naphthalene or quinoline ring leads to compounds of similar affinity. The next step in this structural approximation is to introduce a quinoxaline ring (a bioisostere of the quinoline and naphthalene rings) as the central nucleus of future melatoninergic ligands.

Substitutions of Fluorine Atoms and Phenoxy Groups in the Synthesis of Quinoxaline 1,4-di-N-oxide Derivatives

The unexpected substitution of fluorine atoms and phenoxy groups attached to quinoxaline or benzofuroxan rings is described. The synthesis of 2-benzyl- and 2-phenoxy-3-methylquinoxaline 1,4-di-N-oxide derivatives was based on the classical Beirut reaction. The tendency of fluorine atoms linked to quinoxaline or benzofuroxan rings to be replaced by a methoxy group when dissolved in an ammonia saturated solution of methanol was clearly demonstrated. In addition, 2-phenoxyquinoxaline 1,4-di-N-oxide derivatives became 2-aminoquinoxaline 1,4-di-N-oxide derivatives in the presence of gaseous ammonia.