- Pd(II)-Catalyzed Synthesis of Alkylidene Phthalides via a Decarbonylative Annulation Reaction
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An unprecedented Pd(II)-catalyzed decarbonylative C-H/C-C activation and annulation reaction, which proceeds via intramolecular cyclization, is reported. This reaction of hydroxynaphthoquinones with disubstituted alkynes provides good yields of substituted alkylidene phthalides, which are the key intermediates for the synthesis of bioactive natural products.
- Borthakur, Somadrita,Baruah, Swagata,Sarma, Bipul,Gogoi, Sanjib
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supporting information
p. 2768 - 2771
(2019/04/16)
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- 1,4-Naphthoquinones potently inhibiting P2X7 receptor activity
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P2X7 receptor (P2X7R) is an ATP-gated ion-channel with potential therapeutic applications. In this study, we prepared and searched a series of 1,4-naphthoquinones derivatives to evaluate their antagonistic effect on both human and murine P2X7 receptors. W
- Faria,Oliveira,Salles,Oliveira,von Ranke,Bello,Rodrigues,Castro,Louvis,Martins,Ferreira
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p. 1361 - 1372
(2017/11/17)
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- Synthesis, characterization and biological activities of 3-aryl-1,4-naphthoquinones-green palladium-catalysed Suzuki cross coupling
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Quinones are important scaffolds that are present in a variety of natural products or synthetic bioactive molecules. Arylation is an important strategy for accomplishing structural modifications, leading to new potential candidates for use as drugs. In the present work, palladium-catalysed, ligandless and phosphine-free Suzuki coupling reactions between 2-hydroxy-3-iodo-1,4-naphthoquinone and boronic acids were employed to prepare several 2-hydroxy-3-aryl-1,4-naphthoquinones in aqueous conditions using microwave irradiation or conventional heating. Because of the biological activities of quinones, which are related to their ability to accept electrons to form semiquinones and hydroquinones, the electrochemical behaviour of the synthesized molecules was investigated. The Osiris and Molinspiration Cheminformatics programs, utilizing in silico analyses, imply that these naphthoquinones are candidates for use as drugs which was reinforced by the outcomes of the in vitro antifungal and trypanocidal activity tests. Our in vitro data indicated a MIC value of 8 μg mL-1 against Candida albicans ATCC 24433 strains, and an EC50 of 0.67 μM with respect to trypanocidal activity against Trypanosoma cruzi epimastigote strains (Y).
- Louvis, Aline Da R.,Silva, Nayane A. A.,Semaan, Felipe S.,Da Silva, Fernando De C.,Saramago, Gabriela,De Souza, Laís C. S. V.,Ferreira, Bruno L. A.,Castro, Helena C.,Salles, Juliana P.,Souza, André L. A.,Faria, Robson X.,Ferreira, Vitor F.,Martins, Daniela De L.
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p. 7643 - 7656
(2016/09/28)
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- Styryl and functionalized aryl derivatives of lawsone through metal-free cross-coupling of its BF3-activated phenyliodonium ylide with cinnamaldehydes and arylaldehydes
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Phenyliodonium ylide of lawsone activated with BF3?Et2O reacts with cinnamaldehydes to afford 2-hydroxy-3-styryl-1,4-naphthoquinones in good to excellent yields and relatively high level of stereospecificity through deformylation of the aldehydes. The product yield is diminished with a methoxy substituted cinnamaldehyde and becomes zero with a dimethoxy substituted substrate giving rise to another product, 2-hydroxy-3-aryl-1,4-naphthoquinone. The reaction of the same ylide with salicylic aldehydes forms 2-hydroxy-3-(2-hydroxyaryl)-1,4-naphthoquinones and/or benzo[d]naphtha[2,1-b]furano-5,6-diones, depending on the reaction conditions applied. Plausible reaction mechanisms explaining the formation of these products are proposed. The products showed potent antioxidant activity and inhibited lipoxygenase.
- Malamidou-Xenikaki, Elizabeth,Tsanakopoulou, Maria,Chatzistefanou, Maria,Hadjipavlou-Litina, Dimitra
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p. 5650 - 5661
(2015/08/03)
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- 1,4-naphthoquinone cations as antiplasmodial agents: Hydroxy-, acyloxy-, and alkoxy-substituted analogues
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Cations of hydroxy-substituted 1,4-naphthoquinones were synthesized and evaluated as antiplasmodial agents against Plasmodium falciparum. The atovaquone analogues were found to be inactive as antagonists of parasite growth, which was attributed to ionization of the acidic hydroxyl moiety. Upon modification to an alkoxy substituent, the antiplasmodial activity was restored in the sub-100 nM range. Optimal inhibitors were found to possess IC50 values of 17.4-49.5 nM against heteroresistant P. falciparum W2.
- Lu, Xiao,Altharawi, Ali,Gut, Jiri,Rosenthal, Philip J.,Long, Timothy E.
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supporting information
p. 1029 - 1033
(2013/02/22)
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- Arylation of lawsone through BF3-mediated coupling of its phenyliodonium ylide with activated arenes and aromatic aldehydes
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Phenyliodonium ylide of lawsone, activated by BF3·Et 2O, reacts with electron-rich arenes to afford the corresponding 2-aryl-3-hydroxy-1,4-naphthoquinones, in a coupling reaction without metal catalysts. The same type of products, in greater variety and higher yields, are obtained from the reaction of the BF3·Et2O- activated ylide with aromatic aldehydes in a synthetically and mechanistically interesting deformylation reaction.
- Glinis, Elias,Malamidou-Xenikaki, Elizabeth,Skouros, Haris,Spyroudis, Spyros,Tsanakopoulou, Maria
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experimental part
p. 5786 - 5792
(2010/09/09)
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- Regiospecific synthesis of unsymmetrical 2,3-Diarylquinones via stepwise Pd(O)-Catalyzed couplings of arylstannanes to doubly activated quinone equivalents
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Coupling of arylstannanes to 2-phenyliodonio-1,4-naphthoquinone-3-oxide in the presence of a tetrakis(triphenylphosphine)palladium(O)-cuprous iodide catalyst yields 3-aryl-2-hydroxy-1,4-naphthoquinones which are converted to the corresponding 3-aryl-2-trifluoromethanesulfonyloxy-1,4-naphthoquinone and coupled to a different arylstannane to yield unsymmetrical 2,3-diaryl-1,4-naphthoquinones in good yields.
- Stagliano, Kenneth W.,Malinakova, Helena C.
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p. 6617 - 6620
(2007/10/03)
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- 1,4-Naphthoquinones, XXVI: Phenyl-1,4-naphthoquinone derivatives with the hydroxylation patterns of bioflavonoids
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Flavonoids with special hydroxylation patterns are inhibitors of cylooxygenase and lipoxygenases of the arachidonic acid cascade. To get metabolically more stable compounds with higher lipophilicity and with a similar molecular topography 2-phenyl-1,4-nap
- Wurm,Gurka
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p. 739 - 743
(2007/10/03)
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