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Twenty two diverse coumarin-triazole derivatives were synthesized by alkylation of 7-hydroxy-4-methyl-coumarin followed by click chemistry at 7-position. These compounds were evaluated for their in vitro antiplasmodial activity against chloroquine sensitive strain of Plasmodium falciparum (3D7). Compound 9 (7-[1-(2, 4-dimethoxy-phenyl)-1H- [1–3] triazol-4-ylmethoxy]-4-methyl-chromen-2-one) was found most active with IC 50 value 0.763 ± 0.0124 μg/mL. Further, the structure of compound 20 was characterized by single crystal X-ray diffraction. In view of impressive results, we considered it worthwhile to validate the results of in vitro antiplasmodial activity by assessing whether these compounds are capable of hampering the catalytic activity of DNA gyrase, thus preventing its supercoiling function. [ABSTRACT FROM AUTHOR]

Synthetic quinoline derivatives continue to be considered as candidates for new drug discovery if they act against CQ-resistant strains of malaria even after the widespread emergence of resistance to CQ. In this study, we explored the activities of two series of new 4-aminoquinoline derivatives and found them to be effective against Plasmodium falciparum under in vitro conditions. Further, we selected four most active derivatives 1m, 1o, 2c and 2j and evaluated their antimalarial potential against Plasmodium berghei in vivo . These 4-aminoquinolines cured BALB/c mice infected with P. berghei . The ED 50 values were calculated to be 2.062, 2.231, 1.431, 1.623 and 1.18 mg/kg of body weight for each of the compounds 1m, 1o, 2c, 2j and amodiaquine, respectively. Total doses of 500 mg/kg of body weight were well received. The study suggests that these new 4-aminoquinolines should be used for structure activity relationship to find lead molecules for treating multidrug-resistant Plasmodium falciparum and Plasmodium vivax . [ABSTRACT FROM AUTHOR]

The artemisinin resistance has posed a serious threat against malaria elimination lately. Past few years have seen important development of several peroxide based medicinal compounds and their derivatives such as trioxanes and tetraoxanes. Here, we report a rapid, one-pot method for synthesizing a new series of N -sulfonylpiperidine dispiro-1,2,4,5-tetraoxane analogs with diverse substitution on the tetraoxane ring i.e., various substituted alkyl and aryl sulfonyl chlorides, as well as cyclic, acyclic and aryl substituted ketones. All the synthesized tetraoxanes were characterized by spectroscopic (1H NMR,13C NMR), and spectrometric (High-resolution mass spectrometry) techniques and quantify by High Performance Liquid Chromatography (HPLC) analysis. The structure of compound 19 was confirmed by single crystal XRD. From the overall preliminary in vitro data, analogs 14, 16, 19, 20, 24, 41, and 44 exhibited potential IC 50 values in the nanomolar range between 4.7 ± 0.3 to 12.9 ± 1.1 nM against P. falciparum (Pf 3D7) strains of human malaria parasite. Furthermore, these selective analogs were evaluated in vivo for their antimalarial potential against P. berghei and results revealed that analogue 24 rapidly kills the infected cell at asexual erythrocytic stage, with activity comparable to positive control chloroquine. [Display omitted] • Synthesis ofg N -sulfonylpiperidine dispiro-1,2,4,5-tetraoxane analogs. • Compounds were characterized by various techniques such as 1H NMR, 13C NMR, HRMS (High-resolution mass Spectrometry) and single crystal X-ray diffraction (XRD) analysis. • Anti-plasmodial activities of the 41 analogs were evaluated against P. falciparum in vitro. • Selective analogs 14, 16, 19, 20, 24, 41 , and 44 were evaluated in vivo for their antimalarial potential against P. berghei and compound 24 exhibited the most potent fast killing antimalarial efficacy against asexual erythro-cytic stage. [ABSTRACT FROM AUTHOR]

A new simple and efficient fluorous coupling reagent TriTFET (2,4,6-tris-(2,2,2-trifluoro-ethoxy)-[1,3,5] triazene) has been designed and synthesized for the direct amidation. The use of 5 mol % of TriTFET is good for the amide synthesis from carboxylic acids with amines in moderate to excellent yields (72–96%). [ABSTRACT FROM AUTHOR]

Abstract: In an attempt to design and synthesize a new class of antimicrobials, dialkyne substituted 2-aminobenzothiazole was reacted with various substituted aryl azides to generate a small library of 20 compounds (3a–t) by click chemistry. Structures of the newly synthesized compounds were established on the basis of spectral data. These compounds were screened for their antibacterial activity against Gram+ bacteria (Staphylococcus aureus and Enterococcus faecalis), Gram− bacteria (Salmonella typhi, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Shigella boydii) and antifungal activity against Candida tropicalis, Candida albicans, Candida krusei, Cryptococcus neoformans) as well as molds (Aspergillus niger, Aspergillus fumigatus). The compound 3e showed maximum potency against all Gram+/gram− bacterial strains with MIC value 3.12 μg/ml, which is two fold more active as compared to standard drug ciprofloxacin (MIC 6.25 μg/ml). However, all compounds were found ineffective against S. boydii (clinical isolate). Further, only one compound 3n was found to be the most active against all fungal strains with MIC value in the range of 1.56 μg/ml–12.5 μg/ml while the remaining compounds showed moderate to weak antifungal activity. [Copyright &y& Elsevier]

Abstract: Fluoroquinolone analogs were synthesized by simple alkylation followed by click chemistry and evaluated for their antimalarial in vitro against chloroquine sensitive strain of Plasmodium falciparum while ciprofloxacin was used as standard. Our results showed that the compound 12 was found most active with IC50 value of 1.33 μg/mL while ciprofloxacin showed IC50 = 8.81 μg/mL. Therefore, screening of either known or unknown quinolone/fluoroquinolone analogs are worthwhile to find more potent antimalarial drugs which might prove useful in the treatment of mild or severe malaria in human either alone or in combination with existing antimalarial drugs. [Copyright &y& Elsevier]

Abstract: Use of artemisinin based combination therapies (ACTs) is increasing in treatment of malaria. Their extensive and indiscriminate deployment will ultimately lead to selection of resistance. Thus, alternate ACTs are needed. We reported in vitro antimalarial potential of chalcone derivatives. A few potent chalcones were selected for their antimalarial interaction in combination with artemisinin in vitro. Combinations evaluated show synergistic or additive interactions. Chalcones act on broad range of asexual stages of the parasite. The synergistic combinations decrease hemozoin formation in parasitized erythrocytes. These combinations do not affect new permeation pathways induced in the host cells. This is the first report showing antiplasmodial interactions between artemisinin and synthetic chalcone azole derivatives. Thus, chalcones and artemisinin combinations open the possibility of novel ACTs. [Copyright &y& Elsevier]

Abstract: The synthesis of novel 1,3-diaryl propenone derivatives and their antimalarial activity in vitro against asexual blood stages of human malaria parasite, Plasmodium falciparum, are described. Chalcone derivatives were prepared via Claisen–Schmidt condensation of substituted aldehydes with substituted methyl ketones. Antiplasmodial IC50 (half maximal inhibitory concentration) activity of these compounds ranged between 1.5 and 12.3μg/ml. The chloro-series, 1,2,4-triazole substituted chalcone was found to be the most effective in inhibiting the growth of P. falciparum in vitro while pyrrole and benzotriazole substituted chalcones showed relatively less inhibitory activity. This is the first report on antiplasmodial activity of chalcones with azoles on acetophenone ring. [Copyright &y& Elsevier]

Emergence and spread of Plasmodium falciparum resistant to artemisinin-based combination therapy has led to a situation of haste in the scientific and pharmaceutical communities. Sincere efforts are redirected towards finding alternative chemotherapeutic agents that are capable of combating multidrug-resistant parasite strains. Extensive research yielded the concept of "Chimeric Bitherapy (CB)" which involves the linking of two molecules with individual pharmacological activity and exhibit dual mode of action into a single hybrid molecule. Current research in this field seems to endorse hybrid molecules as the next-generation antimalarial drugs and are more effective compared to the multi-component drugs because of the lower occurrence of drug-drug adverse effects. This review is an attempt to congregate complete survey on endoperoxide based hybrid antiplasmodial molecules that will give glimpse on the future directions for successful development and discovery of useful antimalarial hybrid drugs. [Display omitted] • "Chimeric Bitherapy (CB)" has been developed against endemic malaria to avoid the emergence of drug-resistant strains. • CB means connecting of two atoms via covalent linker which has individual intrinsic activity into a single hybrid molecule. • Chimeric hybrid (CH) has potential to prevent drug resistance due to their multiple mechanism of action. • CH plays a pivotal role in malaria eradication owing to good solubility, low toxicity and increased biopharmaceutical efficacy. • Hybrid drugs are more superior than the combination drugs as they have lower occurrence of drug-drug adverse effects. [ABSTRACT FROM AUTHOR]