- Flavones as isosteres of 4(1H)-quinolones: Discovery of ligand efficient and dual stage antimalarial lead compounds
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Malaria is responsible for nearly one million deaths annually, and the increasing prevalence of multi-resistant strains of Plasmodium falciparum poses a great challenge to controlling the disease. A diverse set of flavones, isosteric to 4(1H)-quinolones, were prepared and profiled for their antiplasmodial activity against the blood stage of P. falciparum W2 strain, and the liver stage of the rodent parasite Plasmodium berghei. Ligand efficient leads were identified as dual stage antimalarials, suggesting that scaffold optimization may afford potent antiplasmodial compounds.
- Rodrigues, Tiago,Ressurrei??o, Ana S.,Da Cruz, Filipa P.,Albuquerque, Inês S.,Gut, Jiri,Carrasco, Marta P.,Gon?alves, Daniel,Guedes, Rita C.,Dos Santos, Daniel J.V.A.,Mota, Maria M.,Rosenthal, Philip J.,Moreira, Rui,Prudêncio, Miguel,Lopes, Francisca
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p. 872 - 880
(2013/11/19)
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- Facile synthesis of new substituted aryl and heteroarylflavones by thermal and microwave assisted Suzuki-Miyaura coupling reaction
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Microwave assisted Suzuki-Miyaura coupling of 4′-bromoflavone 5 with substituted aryl and heteroarylboronic acids 6a-m gives high yields of aryl and heteroarylflavones 7a-m. Couplings have been carried out by three methods i) conventional heating with Pd(OCOCH3)2 catalyst, in solvent DMF(N,N-dimethylformamide) and base, aqueous Na2CO3 (2N) for 6-12 hr, at 110°C, yield 30-70%, ii) conventional heating with Pd[(C6H5)3P]4 catalyst, in DMF and base, aq. Na2CO3 (2N) for 6-12 hr, at 110°C, yield 40-72% and iii) Microwave heating with Pd[(C6H5)3P] 4 catalyst, in solvent (DMF+H2O, 5:2) and base, aq. Na2CO3 (2N) for 2-9 min, yield 50-87%. The substrate 4′-bromoflavone 5 has been synthesized from o-hydroxyacetophenone 1 in 3 steps. Esterification of 1 with 4-bromobenzoyl chloride 2 with montmorillonite-KSF catalyst, DCE (1,2-dichloroethane) and Et3N (triethylamine) which gives 2-(4- bromobenzoyloxy)acetophenone 3. Baker-Venkataraman rearrangement of 3 with pyridine and KOH further gives 1-(4-bromophenyl)-3-(2- hydroxyphenyl)propane-1,3-dione 4, followed by cyclization of 4 with methanolic sulfuric acid (2.5%) which yields 4'-bromoflavone 5, yield 82%.
- Joshi, Vidya,Govind Hatim, Jaywant
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p. 1002 - 1010
(2012/10/18)
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