Arylsulfonyl acridinyl derivatives acting on Plasmodium falciparum

Acridine and Its Derivatives: Synthesis, Biological, and Anticorrosion Properties

The phenomenon of corrosion threatens metallic components, human safety, and the economy. Despite being eco-friendly and promising as a corrosion inhibitor, acridine has not been explored to its full potential. In this review, we have discussed multiple biological activities that acridines have been found to show in a bid to prove that they are environmentally benign and much less toxic than many inhibitors. Some synthetic routes to acridines and substituted acridines have also been discussed. Thereafter, a multitude of acridines and substituted acridines as corrosion inhibitors of different metals and alloys in various corrosive media have been highlighted. A short mechanistic insight into how acridine-based compounds function as corrosion inhibitors have also been included. We believe this review will generate an impression that there is still much to learn about previously reported acridines. In the wake of recent surges to find efficient and non-toxic corrosion inhibitors, acridines and their analogs could be an appropriate answer.

Decoding the reaction mechanism of the cyclocondensation of ethyl acetate2-oxo-2-(4-oxo-4H-pyrido [1.2-a] pyrimidin-3-yl) polyazaheterocycle and ethylenediamine using bond evolution theory

We investigated the flow of electron density along the cyclocondensation reaction between ethyl acetate 2-oxo-2-(4-oxo-4H-pyrido[1.2-a]pyrimidin-3-yl) polyazaheterocycle (1) and ethylenediamine (2) at the ωB97XD/6-311++G(d,p)computational method within of bond evolution theory (BET). The exploration of potential energy surface shows that this reaction has three channels (1-3) with the formation of product 3 via channel-2 (the most favorable one) as the main product and this is in good agreement with experimental observations. The BET analysis allows identifying unambiguously the main chemical events happening along channel-2. The mechanism along first step (TS2-a) is described by a series of four structural stability domains (SSDs), while five SSDs for the last two steps (TS2-b and TS2-c). The first and third steps can be summarized as follows, the formation of N1-C6 bond (SSD-II), then, the restoration of the nitrogen N1 lone pair (SSD-III), and finally, the formation of the last O1-H1 bond (SSD-IV). For the second step, the formation of hydroxide ion is noted, as a result of the disappearance of V(C6,O7) basin and the transformation of C6-N1 single bond into double one (SSD-IV). Finally, the appearance of V(O7,H2) basin lead to the elimination of water molecule within the last domain is observed.

Dinuclear complexes, a one dimensional chain and a two dimensional layer of bismuth(iii) chalcogenones for C–S cross coupling reactions

The bismuth coordination polymers derived from organochalcogenone ligands and their catalytic applications in the synthesis of annulated heterocyclic aryl thioethers have been investigated.

Electrochemical study of fast blue BB. A green strategy for sulfination of fast blue BB

This research has led to the development of an environmentally friendly method for the synthesis of some new sulfone derivatives with high yields and without using any toxic reagents and solvents.

Ultrasound promoted one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones using dendrimer-attached phosphotungstic acid nanoparticles immobilized on nanosilica

A highly efficient and improved synthetic methodology for the preparation of 3,4-dihydropyrimidin-2(1H)-ones and thiones in the Biginelli reaction by condensation of β-dicarbonyl compounds, urea/thiourea and aromatic aldehydes using Dendrimer-PWAⁿ as a nanocatalyst under ultrasonic irradiation is reported. Compared with classical Biginelli reaction conditions, this new method has the advantage of easy reaction condition, short reaction time, excellent yields, recyclable green catalyst, reduced environmental impacts and absence of any tedious workup or purification. The catalyst can be easily recovered by filtration and reused for eight consecutive reaction cycles without significant loss of activity. Also, SEM and DLS images of the catalyst after reaction cycle were investigated.

Ethyl 2-[9-(5-bromo-2-hydroxyphenyl)-3,3,6,6-tetramethyl-1,8-dioxo-1,2,3,4,5,6,7,8,9,10-decahydroacridin-10-yl]acetate

In the title compound, C27H32BrNO5, the central 1,4-dihydropyridine ring adopts a shallow sofa conformation (with the C atom bearing the bromophenol ring as the flap), whereas the pendant cyclohexene rings both have twisted-boat conformations. The molecule features an intramolecular O—H...O hydrogen bond, which closes anS(8) ring. In the crystal, molecules are linked by C—H...O interactions, formingC(12) chains along thec-axis direction. The ethyl acetate grouping is disordered over two sets of sites in a 0.719 (11):0.281 (11) ratio.

Synthesis and biological evaluation of acridine derivatives as antimalarial agents

New N-alkylaminoacridine derivatives attached to nitrogen heterocycles were synthesized, and their antimalarial potency was examined. They were tested in vitro against the growth of Plasmodium falciparum, including chloroquine (CQ)-susceptible and CQ-resistant strains. This biological evaluation has shown that the presence of a heterocyclic ring significantly increases the activity against P. falciparum. The best compound shows a nanomolar IC(50) value toward parasite proliferation on both CQ-susceptible and CQ-resistant strains. The antimalarial activity of these new acridine derivatives can be explained by the two mechanisms studied in this work. First, we showed the capacity of these compounds to inhibit heme biocrystallization, a detoxification process specific to the parasite and essential for its survival. Second, in our search for alternative targets, we evaluated the in vitro inhibitory activity of these compounds toward Sulfolobus shibatae topoisomerase VI-mediated DNA relaxation. The preliminary results obtained reveal that all tested compounds are potent DNA intercalators, and significantly inhibit the activity of S. shibatae topoisomerase VI at concentrations ranging between 2.0 and 2.5 μM.

Acridine and acridinones: old and new structures with antimalarial activity

Since emergence of chloroquine-resistant Plasmodium falciparum and reports of parasite resistance to alternative drugs, there has been renewed interest in the antimalarial activity of acridines and their congeners, the acridinones. This article presents literature compilation of natural acridinone alkaloids and synthetic 9-substituted acridines, acridinediones, haloalcoxyacridinones and 10-N-substituted acridinones with antimalarial activity. The review also provides an outlook to antimalarial modes of action of some described compounds.

Synthesis of 9-anilinoacridine triazines as new class of hybrid antimalarial agents

There is challenge and urgency to synthesize cost-effective chemotherapeutic agents for treatment of malaria after the widespread development of resistance to CQ. In the present study, we synthesized a new series of hybrid 9-anilinoacridine triazines using the cheap chemicals 6,9-dichloro-2-methoxy acridine and cyanuric chloride. The series of new hybrid 9-anilinoacridine triazines were evaluated in vitro for their antimalarial activity against CQ-sensitive 3D7 strain of Plasmodium falciparum and their cytotoxicity were determined on VERO cell line. Of the evaluated compounds, two compounds 17 (IC(50)=4.21 nM) and 22 (IC(50)=4.27 nM) displayed two times higher potency than CQ (IC(50)=8.15 nM). Most of the compounds showed fairly high selectivity index. The compounds 13 and 29 displayed >96.59% and 98.73% suppression, respectively, orally against N-67 strain of Plasmodium yoelii in swiss mice at dose 100 mg/kg for four days.

Antimalarial acridines: synthesis, in vitro activity against P. falciparum and interaction with hematin

A series of acridine derivatives were synthesised and their in vitro antimalarial activity was evaluated against one chloroquine-susceptible strain (3D7) and three chloroquine-resistant strains (W2, Bre1 and FCR3) of Plasmodium falciparum. Structure-activity relationship showed that two positives charges as well as 6-chloro and 2-methoxy substituents on the acridine ring were required to exert a good antimalarial activity. The best compounds possessing these features inhibited the growth of the chloroquine-susceptible strain with an IC(50)0.07 microM, close to that of chloroquine itself, and that of the three chloroquine-resistant strains better than chloroquine with IC(50)0.3 microM. These acridine derivatives inhibited the formation of beta-hematin, suggesting that, like CQ, they act on the haem crystallization process. Finally, in vitro cytotoxicity was also evaluated upon human KB cells, which showed that one of them 9-(6-ammonioethylamino)-6-chloro-2-methoxyacridinium dichloride 1 displayed a promising antimalarial activity in vitro with a quite good selectivity index versus mammalian cell on the CQ-susceptible strain and promising selectivity on other strains.

Antiplasmodial activity of [(aryl)arylsulfanylmethyl]Pyridine

A series of [(aryl)arylsufanylmethyl]pyridines (AASMP) have been synthesized. These compounds inhibited hemozoin formation, formed complexes (K(D) = 12 to 20 muM) with free heme (ferriprotoporphyrin IX) at a pH close to the pH of the parasite food vacuole, and exhibited antimalarial activity in vitro. The inhibition of hemozoin formation may develop oxidative stress in Plasmodium falciparum due to the accumulation of free heme. Interestingly, AASMP developed oxidative stress in the parasite, as evident from the decreased level of glutathione and increased formation of lipid peroxide, H(2)O(2), and hydroxyl radical (.OH) in P. falciparum. AASMP also caused mitochondrial dysfunction by decreasing mitochondrial potential (DeltaPsim) in malaria parasite, as measured by both flow cytometry and fluorescence microscopy. Furthermore, the generation of .OH may be mainly responsible for the antimalarial effect of AASMP since .OH scavengers such as mannitol, as well as spin trap alpha-phenyl-n-tertbutylnitrone, significantly protected P. falciparum from AASMP-mediated growth inhibition. Cytotoxicity testing of the active compounds showed selective activity against malaria parasite with selectivity indices greater than 100. AASMP also exhibited profound antimalarial activity in vivo against chloroquine resistant P. yoelii. Thus, AASMP represents a novel class of antimalarial.

In vitro efficiency of new acridyl derivatives against Plasmodium falciparum

A series of new 9-substituted acridyl derivatives were synthesized and their in vitro antimalarial activity was evaluated against one chloroquine-sensitive strain (3D7) and three chloroquine-resistant strains [W2 (Indochina), Bre1 (Brazil) and FCR3 (Gambia)] of Plasmodium falciparum. Some compounds inhibit the growth of malarial parasite with IC50 <or= 0.20 microM.