Química

URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/11782

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Bismuth(III) complexes with 2-acetylpyridine- and 2-benzoylpyridine-derived hydrazones: Antimicrobial and cytotoxic activities and effects on the clonogenic survival of human solid tumor cells
(Bioorganic & Medicinal Chemistry, 2016-07-01) Piló, Elisa D. L.; Ferreira, Isabella P.; Recio-Despaigne, Angel A.; Silva, Jeferson G. Da; Ramos, Jonas P.; Marques, Lucas B.; Prazeres, Pedro H. D. M.; Takahashi, Jacqueline A.; Souza-Fagundes, Elaine M.; Rocha, Willian; Beraldo, Heloisa
Complexes [Bi(2AcPh)Cl2]·0.5H2O (1), [Bi(2AcpClPh)Cl2] (2), [Bi(2AcpNO2Ph)Cl2] (3), [Bi(2AcpOHPh)Cl2]·2H2O (4), [Bi(H2BzPh)Cl3]·2H2O (5), [Bi(H2BzpClPh)Cl3] (6), [Bi(2BzpNO2Ph)Cl2]·2H2O (7) and [Bi(H2BzpOHPh)Cl3]·2H2O (8) were obtained with 2-acetylpyridine phenylhydrazone (H2AcPh), its -para-chloro-phenyl- (H2AcpClPh), -para-nitro-phenyl (H2AcpNO2Ph) and -para-hydroxy-phenyl (H2AcpOHPh) derivatives, as well as with the 2-benzoylpyridine phenylhydrazone analogues (H2BzPh, H2BzpClPh, H2BzpNO2Ph, H2BzpOHPh). Upon coordination to bismuth(III) antibacterial activity against Gram-positive and Gram-negative bacterial strains significantly improved except for complex (4). The cytotoxic effects of the compounds under study were evaluated on HL-60, Jurkat and THP-1 leukemia, and on MCF-7 and HCT-116 solid tumor cells, as well as on non-malignant Vero cells. In general, 2-acetylpyridine-derived hydrazones proved to be more potent and more selective as cytotoxic agents than the corresponding 2-benzoylpyridine-derived counterparts. Exposure of HCT-116 cells to H2AcpClPh, H2AcpNO2Ph and complex (3) led to 99% decrease of the clonogenic survival. The IC50 values of these compounds were three-fold smaller when cells were cultured in soft-agar (3D) than when cells were cultured in monolayer (2D), suggesting that they constitute interesting scaffolds, which should be considered in further studies aiming to develop new drug candidates for the treatment of colon cancer.
Calix[n]arenes: active organocatalysts for the synthesis of densely functionalized piperidines by one-pot multicomponent procedure
(Tetrahedron Letters, 2016-05-11) Liberto, N.; Palermo, V.; Sathicq, A.; Fernandes, S.; Langer, P.; Jios, J.; Romanelli, G.
An efficient, suitable and high yielding method has been developed for the synthesis of different densely functionalized piperidine derivatives via pseudo-five component, one-pot domino reaction through a combination of b-ketoesters, aromatic aldehydes, and various amines using p-sulfonic acid calix[n]arenes as catalysts. The reaction was carried out in refluxing methanol, affording very good yields of the expected piperidine. Atomic economy, environmentally benign procedure, reuse of catalysts, and short reaction time are some of the important features of this protocol.
The natural flavone fukugetin as a mixed-type inhibitor for human tissue kallikreins
(Bioorganic & Medicinal Chemistry Letters, 2016-03-01) Santos, Marcelo H. dos; Santos, Jorge A. N.; Kondo, Márcia Y.; Freitas, Renato F.; Ramalho, Teodorico C.; Assis, Diego M.; Juliano, Luiz; Juliano, Maria A.; Puzer, Luciano
The human tissue kallikreins (KLK1–KLK15) comprise a family of 15 serine peptidases detected in almost every tissue of the human body and that actively participate in many physiological and pathological events. Some kallikreins are involved in diseases for which no effective therapy is available, as for example, epithelial disorders, bacterial infections and in certain cancers metastatic processes. In recent years our group have made efforts to find inhibitors for all kallikreins, based on natural products and synthetic molecules, and all the inhibitors developed by our group presented a competitive mechanism of inhibition. Here we describe fukugetin, a natural product that presents a mixed-type mechanism of inhibition against KLK1 and KLK2. This type of inhibitor is gaining importance today, especially for the development of exosite-type inhibitors, which present potential to selectively inhibit the enzyme activity only against specific substrate.
Palladium-catalyzed hydrodehalogenation of butenolides: An efficient and sustainable access to β-arylbutenolides
(Tetrahedron Letters, 2017-07-19) Karak, Milandip; Barbosa, Luiz C.A.; Maltha, Celia R.A.; Silva, Thiago M.; Boukouvalas, John
Several α-unsubstituted β-arylbutenolides have been prepared in 69–92% yield by reductive dehalogenation of α-halo-β-arylbutenolides. The latter were assembled in a single-step from α,β-dihalobutenolides, which are accessible on a large-scale from biomass-derived furfural. Our dehalogenation protocol is illustrated by a new synthesis of the marine antibiotics rubrolide E and F, and 3″-bromorubrolide F.