RESUMO

A protocol involving the irradiation of some 3-(2-alkenyl)estrone and 3-(2-alkenyl)-17-norestrone derivatives under a nitrogen atmosphere in organic solvents (both hexane and MeOH) followed by base-mediated intramolecular oxa-Michael cyclization reaction was investigated under steady-state conditions. The solvent effect and nature of the acyl group on the preparative photoreaction were studied and the multiplicity of the excited state was also demonstrated. The ortho-regioisomers were obtained in modest to good yields. Intramolecular based-mediate cyclization reaction of these synthons led to the formation of a set of novel substituted 4-chromanone moieties fused to estrone (and 17-norestrone) in good yields. This two-step sequential procedure involving a photochemical/intramolecular thermal cyclization strategy will be useful for the preparation of wide heterocyclic-fused-steroid compounds.

RESUMO

In this work, we describe how stereochemically complex polycyclic compounds can be generated by applying a synthetic sequence comprising an intramolecular Ugi reaction followed by a Pictet-Spengler cyclization on steroid-derived scaffolds. The resulting compounds, which combine a fragment derived from a natural product and a scaffold not found in nature. are both structurally distinct and globally similar to natural products at the same time, and interrogate an alternative region of the chemical space. One of the new compounds showed significant antiproliferative activity on HepG2 cells through a caspase-independent cell-death mechanism, an appealing feature when new antitumor compounds are searched.

Assuntos

Antineoplásicos/farmacologia , Produtos Biológicos/farmacologia , Caspases/metabolismo , Isoquinolinas/farmacologia , Piperazinas/farmacologia , Esteroides/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Morte Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Células Hep G2 , Humanos , Isoquinolinas/síntese química , Isoquinolinas/química , Estrutura Molecular , Piperazinas/síntese química , Piperazinas/química , Estereoisomerismo , Esteroides/síntese química , Esteroides/química

RESUMO

Evolution of metabolism is a longstanding yet unresolved question, and several hypotheses were proposed to address this complex process from a Darwinian point of view. Modern statistical bioinformatic approaches targeted to the comparative analysis of genomes are being used to detect signatures of natural selection at the gene and population level, as an attempt to understand the origin of primordial metabolism and its expansion. These studies, however, are still mainly centered on genes and the proteins they encode, somehow neglecting the small organic chemicals that support life processes. In this work, we selected steroids as an ancient family of metabolites widely distributed in all eukaryotes and applied unsupervised machine learning techniques to reveal the traits that natural selection has imprinted on molecular properties throughout the evolutionary process. Our results clearly show that sterols, the primal steroids that first appeared, have more conserved properties and that, from then on, more complex compounds with increasingly diverse properties have emerged, suggesting that chemical diversification parallels the expansion of biological complexity. In a wider context, these findings highlight the worth of chemoinformatic approaches to a better understanding the evolution of metabolism.

Assuntos

Quimioinformática , Seleção Genética , Eucariotos , Evolução Molecular , Genoma , Filogenia

RESUMO

Direct irradiation of estrone aryl and methyl sulfonates in different organic solvents under nitrogen atmosphere was investigated under steady-state conditions. The estrone derivatives reacted efficiently through the photo-Fries rearrangement reaction involving [1;3]-sulfonyl migration providing the ortho-sulfonyl estrone derivatives and estrone as the photoproducts. In addition, estrone and 2-arylsulfonyl estrone derivatives were epimerized involving a Norrish Type-I reaction. Chemical quenching and photosensitization experiments on the photoreaction have been also carried out to establish the photoreactive excited state. Likewise, the solvent effect and the nature of the sulfonyl group on the photoreactions have been also studied.

RESUMO

The Rho GTPase Rac1 is involved in the control of cytoskeleton reorganization and other fundamental cellular functions. Aberrant activity of Rac1 and its regulators is common in human cancer. In particular, deregulated expression/activity of Rac GEFs, responsible for Rac1 activation, has been associated to a metastatic phenotype and drug resistance. Thus, the development of novel Rac1-GEF interaction inhibitors is a promising strategy for finding new preclinical candidates. Here, we studied structure-activity relationships within a new family of N,N'-disubstituted guanidine as Rac1 inhibitors. We found that compound 1D-142, presents superior antiproliferative activity in human cancer cell lines and higher potency as Rac1-GEF interaction inhibitor in vitro than parental compounds. In addition, 1D-142 reduces Rac1-mediated TNFα-induced NF-κB nuclear translocation during cell proliferation and migration in NSCLC. Notably, 1D-142 allowed us to show for the first time the application of a Rac1 inhibitor in a lung cancer animal model.

Assuntos

Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Desenvolvimento de Medicamentos , Guanidina/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Proteínas rac1 de Ligação ao GTP/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/química , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Guanidina/síntese química , Guanidina/química , Humanos , Hidroxilação , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade , Proteínas rac1 de Ligação ao GTP/metabolismo

RESUMO

Herein, the synthesis and characterization of the first family of multipodal ligands with a Tröger's base framework designed for the preparation of luminescent lanthanide(III) complexes are reported. Eight ligands were designed and synthesized using different strategies, including alkylation reactions, amide couplings, and Ugi multicomponent reactions. All the ligands bear carboxylate groups for the coordination of the lanthanide(III) ions, with the lanthanide(III)-sensitizing units consisting of the Tröger's base framework itself or attached benzamides. Upon irradiation of the chromophoric ligands, green terbium(III) emission was efficiently generated, whereas europium(III) emission was negligible. The geometry and substitution pattern of the ligands allow control of the stoichiometry of the species formed and the TbIII luminescence sensitization efficiency, showing that para-substitution patterns are more efficient than meta substitution for the formation of coordination compounds with lower TbIII /ligand ratio. We propose that the species formed are self-assembled 2:2 or 2:4 metallosupramolecular structures.

RESUMO

Herein, the design, synthesis, and characterization of a phenhomazine ligand are described. The ligand has six pendant acetate arms designed for the combined coordination of copper(II) and lanthanide(III) ions, with the perspective of developing a "turn-off" copper sensor. The key step for the ligand preparation was the one-step endomethylene bridge fission of a diamino Tröger's base with a concomitant alkylation. Fluorescence and absorption spectroscopies as well as nuclear magnetic resonance (NMR) experiments were performed to analyze and understand the coordination properties of the ligand. Transition metal coordination was driven by the synergistic effect of the free nitrogen atoms of the diazocinic core and the two central acetate arms attached to those nitrogen atoms, whereas lanthanide coordination is performed by the external acetate arms, presumably forming a self-assembled 2:2 metallosupramolecular structure. The terbium complex shows the typical green emission with narrow bands and long luminescence lifetimes. The luminescence quenching produced by the presence of copper(II) ions was analyzed. This work sets, therefore, a starting point for the development of a phenhomazine-based "turn-off" copper(II) sensor.

RESUMO

Reports on structural diversification of steroids by means of multicomponent reactions (MCRs) have significantly increased over the last decade. This review covers the most relevant strategies dealing with the use of steroidal substrates in MCRs, including the synthesis of steroidal heterocycles and macrocycles as well as the conjugation of steroids to amino acids, peptides and carbohydrates. We demonstrate that steroids are available with almost all types of MCR reactive functionalities, e.g., carbonyl, carboxylic acid, alkyne, amine, isocyanide, boronic acid, etc., and that steroids are suitable starting materials for relevant MCRs such as those based on imine and isocyanide. The focus is mainly posed on proving the amenability of MCRs for the diversity-oriented derivatization of naturally occurring steroids and the construction of complex steroid-based platforms for drug discovery, chemical biology and supramolecular chemistry applications.

RESUMO

Irradiation of a series of 3-acylestrones under a nitrogen atmosphere in cyclohexane, acetonitrile (MeCN), and methanol (MeOH) was investigated under steady-state conditions. The molecules underwent the photo-Fries rearrangement, with concomitant homolytic fragmentation of the ester group and [1;3]-acyl migration. This pathway afforded the ortho-acyl estrone derivatives, the main photoproducts, together with estrone. During the irradiation of 3-benzoyl estrone, epimerization of estrone through the Norrish type I reaction occurred, providing lumiestrone as the photoproduct. This photoreaction involves the fragmentation of the C-α at the carbonyl group (C-17) of the steroid. On the other hand, epimerization of ortho-regioisomer 2-acetyl estrone occurred during the irradiation of 3-acetyl estrone. Photosensitization with acetone and chemical quenching with N, N, N, N-tetramethyldiazetinedioxide of the photo-Fries reaction confirmed that the photoreaction took place from the singlet excited state while the Norrish type I reaction proceeds efficiently from the triplet excited state. Solvent effects, as well as the nature of the acyl group on the photoreactions, were also studied.

RESUMO

A pseudo-five-multicomponent reaction involving an isocyanide, a primary amine, two molecules of formaldehyde and water is reported, which gives N,N'-substituted 4-imidazolidinones when trifluoroethanol is used as the solvent. The reaction proceeds with good yields and with a wide variety of amines and isocyanides, providing an efficient new entry to these heterocycles. A preliminary study of the reaction mechanism suggests that trifluoroethanol, although acting as the solvent, is directly involved as a reagent in the reaction pathway.