This work describes the route to prepare a novel core-shell catalyst based on 1,4-diazabicyclo[2,2,2]octane (DABCO) supported magnetic nanoparticles (MNPs). The morphology and composition of the obtained catalysts were characterized by Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), quantum design vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM). These nanomaterials presented high performance as a basic catalyst for Knoevenagel condensation between malononitrile and aldehydes, leading to products with excellent yields (84-99%) and short reaction times (5-60 min). Furthermore, it was also efficient in the condensation of isatins with 4-phenylthiosemicarbazide, resulting in isatin-β-thiosemicarbazones with high yields (81-94%) and short times (60-180 min). It is worth mentioning that the catalyst was recovered and reused in these two kinds of reactions after six cycles without significant yield loss.

Cancer treatment represents one of the main scientific study targets today, mainly due to the pronounced side effects arising from chemotherapy. This study reports the synthesis, characterization, and anticancer activity of ten compounds from the Morita-Baylis-Hillman reaction. Ethylene glycol diacrylate was used as a double Michael acceptor in reactions with isatin derivatives to give homodimers of 3-hydroxyindolin-2-one core, recognized in the literature for its extensive pharmacological profile. The use of 1,4-diazabicyclo[2,2,2]octane (DABCO) as a catalyst and room temperature were the optimal conditions for the study reaction. The isolated yields were up to 63%, with most reaction times inferior to 24 h, some as fast as 15 min. The anticancer potential of the synthesized dimers was evaluated in vitro against three cancer strains, resulting in average inhibitory concentrations up to 0.72 µM. It was also found that the best performing homodimers are more active than their monomeric counterparts. Considering the promising selectivity indices observed, the preliminary results obtained here act as a basis for broader tests regarding the effectiveness of homodimeric adducts against cancer cells.

Morita-Baylis-Hillman adducts (MBHA) is a class of polyfunctional molecules that has been standing out due to their versatility and expressive biological activities. Therefore, this paper describes the synthesis and antiproliferative activity of some new MBHA/7-choroquinoline hybrids. The Michael acceptors were obtained starting from 4,7-dichloroquinoline which were submitted to the Morita-Baylis-Hillman reaction with ortho, meta and para-nitrobenzaldehyde. The in vitro screening of the synthetized MBHA against NCI-H292, HCT-116 and MCF-7 cancer cells suggests the influence of the spacer chain in its inhibition potential. The 50% inhibitory concentration (IC50) obtained in the antiproliferative assay using MCF-7, HCT-116, HL-60 and NCI-H292 cancer cells indicate expressive cytotoxic potential of the adducts containing nitro group in the ortho position, with IC50 of 4.60 µmol L-1. MBHA/7-choroquinoline hybrids were more active than MBHA described in literature, indicating the improvement of the cytotoxic effect due to 7-chloroquinoline moiety in the molecular structure, with maximum selectivity index values of 11.89.

O processo de biorredução enzimática do grupo nitro é de grande importância para a ação molecular de nitrocompostos aromáticos biologicamente ativos. Os métodos eletroquímicos são considerados ferramentas úteis para a simulação de processos metabólicos in vivo. No presente trabalho, realizaram-se estudos eletroquímicos em meio aprótico (N, N-dimetilformamida (DMF) mais perclorato de tetrabutilamônio (TBAP) 0,1 mol L-1) utilizando-se as técnicas de voltametria cíclica (CV), de pulso diferencial (DPV) e de onda quadrada (SWV) de 12 adutos de Morita-Baylis-Hillman (MBHA) com atividade leishmanicida significativa. Para facilitar a análise, os adutos foram agrupados em quatro classes de acordo com a cadeia lateral. Os estudos de CV evidenciam duas ondas referentes à redução do grupo nitro e uma ou duas outras ondas (em potencial mais negativo) relativas à redução da função carbonila α,β-insaturada ou da olefina ativada por grupos nitrila. Adutos orto-substituídos apresentam maior facilidade de redução quando comparados aos demais isômeros (meta e para) em função, provavelmente, da ligação de hidrogênio entre o grupo nitro e a hidroxila benzílica, o que estabiliza mais o produto eletrogerado do que o composto de partida. Derivados orto também mostram uma maior atividade leishmanicida em comparação com seus isômeros em cada série. Estudos conformacionais usando HF/6-31+G(d)/PCM como nível de cálculo evidenciaram este efeito. Valores calculados de dureza molecular (N) e de cargas atômicas (Q N) explicam corretamente os dados experimentais obtidos.

Enzymatic bioreduction of nitro groups plays an important role on the activity of biologically active nitroaromatic compounds. Electrochemical methods are useful tools to simulate in vivo metabolic processes. This work presents electrochemical studies in aprotic media (N, N-dimethylformamide (DMF) plus tetrabutylammonium perchlorate (TBAP) 0.1 mol L-1) using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV) of twelve Morita-Baylis-Hillman adducts (MBHA) with significant leishmanicidal activity. To facilitate the analysis, the molecules were grouped in four classes according to the side chain. CV studies show three up to four reduction waves, in which the first two waves are related to nitro group reduction. The other waves (presenting more negative potential) refer to the reduction of the α,β-unsaturated carbonyl or to the nitrile activated olefin side-chain. Ortho adducts present facilitated reduction in comparison to the other isomers (meta and para) possibly due to hydrogen bond formation between the benzylic-OH and the nitro group, which stabilizes the reduction product (anion radical nitro) more efficiently than the original compound. Ortho derivatives also present higher leishmanicidal activity upon comparison to the other derivatives of each class. Conformational studies using HF/6-31+G(d)/PCM as a calculation level highlight this effect. Molecular hardness (N) and atomic charges (Q N) values corroborate the obtained experimental data.