Publications by authors named "Ruben M Carballo"

The n → π* interactions were studied in amides and thioamides systems models, through the analysis of the electron density topology along with the Natural Bonding Orbital (NBO) approach. The effect of the dispersion terms was assessed using different DFT functionals. The NBO, independent gradient model (IGM), and the analysis of the reduced density gradient outcomes show that dispersion forces play a significant role in the strength of n → π* interactions.

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A direct, catalytic, and complementary method to obtain 2-substituted homoallyl sulfonyl amides is described, starting from sulfonyl amides, aldehydes, and allyltrimethylsilane using iron(III) chloride as a sustainable catalyst. The scope of the process and the reactivity in aza-Prins cyclization is evaluated and supported by density functional theory (DFT) studies. Finally, an evaluation of the antiproliferative activity for this family of sulfonyl amides is also included.

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Pentacyclic triterpenes are found in a great variety of natural products and constitute an organic template for the development of new derivative compounds with therapeutic applications. In the present work, lupeol acetate isolated from L. fruit was used as a template for the synthesis of novel -alkyl-arylsulfonamide derivatives, and their synergistic effects with metronidazole against strains of were tested.

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The present paper sought to investigate the in vitro and in vivo anti-inflammatory effects of the methanolic extract (ME), hexane-ethyl acetate fraction E (FE) found in Chrysophyllum cainito fruits (CCF), as well the lupeol acetate (LA) obtained from FE on lipopolysaccharide (LPS)-stimulated mouse peritoneal macrophages. The macrophages were treated with ME, FE or LA at various concentrations and the viability of cells was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method. Production of pro-inflammatory (IL-1β, IL-6, and TNF-α) and anti-inflammatory (IL-10) cytokines, as well as the nitric oxide (NO) and hydrogen peroxide (HO) levels was determined using macrophages treated with ME, FE or LA at various concentrations and stimulated with LPS as an in vitro model.

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Trichomoniasis, caused by the protozoan Trichomonas vaginalis, is the most prevalent non-viral sexually transmitted infection that affects over 170 million people worldwide. The only type of drug recommended for the therapeutic control of trichomoniasis is the 5-nitroimidazoles, although there have been reports of some undesirable side effects and clinical resistance. Hence, the need for the search for new tricomonicidal agents is necessary.

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Herein we describe a salicylaldehyde-annulation reaction as a plug and play toolkit to diversify the complexity of naturally occurring ketones. The protocol entails the transformation of the polycyclic natural ketone into its propargyl vinyl ether derivative (two synthetic steps) and its microwave-assisted imidazole-catalyzed domino rearrangement to generate the salicylaldehyde ring. This annexed unit allows further synthetic transformations: e.

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A highly efficient, diastereoselective, iron(III)-catalyzed intramolecular hydroamination/cyclization reaction involving α-substituted amino alkenes is described. Thus, enantiopure trans-2,5-disubstituted pyrrolidines and trans-5-substituted proline derivatives were synthesized by means of a combination of enantiopure starting materials, easily available from l-α-amino acids, with sustainable metal catalysts such as iron(III) salts. The scope of this methodology is highlighted in an enantiodivergent approach to the synthesis of both (+)- and (-)-pyrrolidine 197B alkaloids from l-glutamic acid.

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The title compound, (C9H9N2S)2[PdCl4], consists of two monoprotonated 2-amino-4-phenyl-1,3-thia-zole molecules and one tetra-chlorido-palladate anion. The organic molecules exhibit a dihedral angle between the main rings planes of 31.82 (9)°.

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There are two independent mol-ecules in the asymmetric unit of the title compound, C24H22N2O4S3. In each, the sulfonamide N atoms reveal nearly a trigonal-planar geometry with two S atoms of the O=S=O groups and one C atom of the thia-zole ring; the angles around the N atoms are between 117.00 (13) and 123.

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A series of functionalized N-sulfonyl-piperidines and N-sulfonyl-tetrahydropyridines were evaluated for their antiproliferative activity against the representative panel of human solid tumor cells A2780 (ovarian), SW1573 (non-small cell lung) and WiDr (colon). The SAR study showed for WiDr cells a correlation between the biological activity and the length of the N-sulfonyl group, the nature of the substituents and the type of alkyl side chain. Further QSAR studies indicate that the size and nature of the N-sulfonyl group, the atomic polarizability (MP) and the partition coefficient are the most important descriptors for the activity.

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An efficient alkene aza-Cope-Mannich cyclization between 2-hydroxy homoallyl tosylamine and aldehydes in the presence of iron(III) salts to obtain 3-alkyl-1-tosyl pyrrolidines in good yields is described. The process is based on the consecutive generation of a γ-unsaturated iminium ion, 2-azonia-[3,3]-sigmatropic rearrangement, and further intramolecular Mannich reaction. Iron(III) salts are also shown to be excellent catalysts for the new aza-Cope-Mannich cyclization using 2-hydroxy homopropargyl tosylamine.

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A new Prins cyclization process that builds up one carbon-carbon bond, one heteroatom-carbon bond, and one halogen-carbon bond, (in an oxa- and azacycle) relies on an iron catalyst system formed from Fe(acac)3 and trimethylsilyl halide. The method displays a broad substrate scope and is economical, environmentally friendly, and experimentally simple. This catalytic method permits the construction of chloro, bromo and iodo heterocycles, by the suitable combination of iron(III) source, the corresponding trimethylsilyl halide and the solvent, in high yields.

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Novel antiproliferative beta'-acyloxy-alpha,beta-unsaturated ketones were obtained by means of an iron(III)-catalyzed multicomponent domino process (ABB' 3CR). The most active derivatives displayed GI(50) values in the range of 0.5-3.

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A series of trans-2-alkyl-4-halopiperidines and 2-alkyl-4-halo-1,2,5,6-tetrahydropyridines were prepared by means of an iron(III) catalyzed process. The in vitro antiproliferative activities were examined in the human solid tumor cell lines A2780 (ovarian cancer), SW1573 (non-small cell lung cancer), and WiDr (colon cancer). The results on the biological activity revealed that, in general, the 2-alkyl-4-halo-1,2,5,6-tetrahydropyridine analogs are more potent than the trans-2-alkyl-4-halopiperidine derivatives.

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[reaction: see text] A new iron(III) halide-promoted aza-Prins cyclization between gamma,delta-unsaturated tosylamines and aldehydes provides six-membered azacycles in good to excellent yields. The process is based on the consecutive generation of gamma-unsaturated-iminium ion and further nucleophilic attack by the unsaturated carbon-carbon bond. Homoallyl tosylamine leads to trans-2-alkyl-4-halo-1-tosylpiperidine as the major isomer.

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