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The behavior of poryphyrins as dipolarophiles in 1,3-dipolar cycloadditions with azomethine ylides was studied. Cycloaddition reactions with azomethine ylides can also be used as a strategy for selective synthesis of novel mixed isobacteriochlorins.

Research has been conducted on the azomethine ylide produced by the reaction of N-methylglycine with (beta-formyl-meso-tetraphenylporphyronato)nickel(II). The reaction of azomethine ylide with dipolarophiles carried out to generate beta-substituted-meso-tetraphenylporphyrins is described.

Fromthe core of the earth to the core of the archetypal organometalliccompound ferrocene, iron and its compounds contribute to create manyaspects of our reality: the earth’s magnetism, hemoglobin’srespiratory function, and a myriad of life-essential biochemical reactions.This review deals with synthetic iron compounds from the literature,in particular ferrocene and derivatives, which are potential new anticanceragents. Cytotoxic ferrocenes are among the most promising metal-baseddrugs for cancer chemotherapy. There is a vast range of reported compounds,herein classified into three categories, according to their chemicalnature and supramolecular organization. The first comprises ferroceniumsalts and ferrocene derivatives, from simple functionalized ferrocenesto elaborate iron-based mimics of organic drugs, the second includesheterometallic complexes (with two or more metal centers), in whichferrocene has the role of an ancillary ligand, and the third comprisescytotoxic ferrocenes associated with carrier systems, namely aqueous-solublepolymers, multilayer micelles, and cyclodextrins. [ABSTRACT FROM AUTHOR]

The potential and the limitations of combining two-dimensional nuclear magnetic resonance (2D NMR) techniques to deliver new qualitative information on the substructures present in water-soluble organic compounds (WSOC) from fine atmospheric aerosols collected during Winter and Spring/Summer seasons are highlighted in this study. The WSOC fractions were extracted from quartz filter samples and further separated into hydrophobic acids and hydrophilic acids fractions by using a XAD-8/XAD-4 isolation procedure. Despite different spectral resolution, it was found that the aliphatic material of both samples includes mostly long-chain (carbons greater than 3 or 4) and branched mono- and dicarboxylic acids, carbonyl, and ester structural types. The presence of such structural fragments could be associated to secondary organic aerosol formation. It has been further demonstrated that spectral signatures typical of anhydrosugars from cellulose and methoxyphenols from lignin can be identified among the carbohydrate and aromatic moieties of the Winter sample. Their presence highlights the major influence of biomass burning on atmospheric particulate matter collected during colder periods. The data reported here demonstrate the success of 20 NMR-techniques- to investigate aerosol WSOC composition, as well as to evaluate aerosol source fingerprints. [ABSTRACT FROM AUTHOR]

In micellar solutions, one-electron reduction of •O 2−radical-anions by 3-alkylpolyhydroxyflavones (FnH) with alkyl chains of n= 1, 4, 6, 10 carbons produces phenoxyl radicals ( •Fn) identical to those obtained by one-electron oxidation by •Br 2−radical-anions or by repair of tryptophan radicals. In cetyltrimethylammonium bromide (CTAB), F1H localizes in the Stern layer, and alkyl chains of other FnH solubilize in the hydrophobic interior, interacting with cetyl tails. This interaction produces more compact micelles with lower intramicellar fluidity, as suggested by the increase in the pseudo-first-order rate constant of •Fn formation ( k1) from ∼390 s −1for n= 1 to 610 s −1for n= 10, leading to an intramicellar bimolecular rate constant of 1 × 10 5M −1s −1. Additionally, •F1 and •F4 decay by intermicellar bimolecular reaction (2 k= 20 and 2 × 10 5M −1s −1, respectively) whereas other •Fn radicals are stable over seconds due to increased localization with regards to the Stern layer. In contrast, the thick uncharged hydrophilic palisade layer and the compact hydrophobic core of Triton X100 micelles are responsible for a much higher microviscosity resulting in a decrease in k1from ∼15.6 s −1for n= 1 to 9.6 s −1for n= 10. [ABSTRACT FROM AUTHOR]

Malaria, leishmaniasis, and sleeping sickness are potentially fatal diseases that represent a real health risk for more than 3,5 billion people. New antiparasitic compounds are urgent leading to a constant search for novel scaffolds. Herein, pyrazino[2,1- b ]quinazoline-3,6-diones containing indole alkaloids were explored for their antiparasitic potential against Plasmodium falciparum , Trypanosoma brucei , and Leishmania infantum . The synthetic libraries furnished promising hit compounds that are species specific ( 7, 12 ) or with broad antiparasitic activity ( 8 ). Structure-activity relationships were more evident for Plasmodium with anti-isomers (1 S ,4 R ) possessing excellent antimalarial activity, while the presence of a substituent on the anthranilic acid moiety had a negative effect on the activity. Hit compounds against malaria did not inhibit β-hematin, and in silico studies predicted these molecules as possible inhibitors for prolyl-tRNA synthetase both from Plasmodium and Leishmania . These results disclosed a potential new chemotype for further optimization toward novel and affordable antiparasitic drugs., Competing Interests: The authors declare no competing financial interest., (© 2022 American Chemical Society.)

The impact of inhalable fine particulate matter (PM 2.5 , aerodynamic diameter <2.5 μm) on public health is of great concern worldwide. Knowledge on their harmful effects are mainly due to studies carried out with whole air particles, with the contribution of their different fractions remaining largely unknown. Herein, a set of urban PM 2.5 samples were collected during daytime and nighttime periods in autumn and spring, aiming to address the seasonal and day-night variability of water-soluble organic matter (WSOM) composition. In vitro analysis of the oxidative and pro-inflammatory potential of WSOM samples was carried out in both acute (24 h) and chronic (3 weeks) exposure setups using Raw264.7 macrophages as cell model. Findings revealed that the structural composition of WSOM samples differs between seasons and in a day-night cycle. Cell exposure resulted in an increase in the transcription of the cytoprotective Hmox1 and pro-inflammatory genes Il1b and Nos2 , leading to a moderate pro-inflammatory status. These macrophages showed an impaired capacity to subsequently respond to a strong pro-inflammatory stimulus such as bacterial lipopolysaccharide, which may implicate a compromised capacity to manage harmful pathogens. Further investigation on aerosol WSOM could help to constrain the mechanisms of WSOM-induced respiratory diseases and contribute to PM 2.5 regulations.

Waste swamps, stagnant water, and poor hygiene practices result in the proliferation of mosquitoes that may cause transmissible and infectious diseases such as malaria, typhoid, cholera, and Zika virus sickness. It has been shown that composites of the traditional natural fibers cotton, viscose, and linen and a Ti-bearing metal-organic framework, NH 2 -MIL-125, are very effective against mosquitoes in the absence of any conventional insecticides. In our study, prior to coating with NH 2 -MIL-125 crystals, the fabrics were modified with 3-glycidyloxypropyltrimethoxysilane. The composite materials were characterized by powder X-ray diffraction, UV-vis spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis. The latter, in particular, has shown the uniform coating of the fabrics with NH 2 -MIL-125 crystals. The modified fabrics have excellent antimosquito properties, attracting and killing them.

Biphasic systems composed of aprotic ionic liquids (ILs) allow the development of new separation processes constituted only by nonvolatile solvents. Six pairs of cholinium- and phosphonium-based ILs were found to be able to form biphasic systems, and the respective liquid-liquid phase diagrams were determined. Although IL anions do not seem to control the phase separation phenomenon, they play an important role in defining the size of the biphasic region. A linear dependence of the ILs mutual solubilities with the IL anions volume was found, supporting the relevance of the entropy of mixing. With the exception of the system formed by ILs with a common anion, the remaining liquid-liquid systems display a significant ion exchange extent between the phases, which inversely depends on the ILs cohesive energy. It is finally shown that four-phase systems with a remarkable performance in the separation of mixtures of dyes can be prepared.

Alzheimer's disease is characterized by pathological aggregation of protein tau and amyloid-β peptides, both of which are considered to be toxic to neurons. Naturally occurring dietary flavonoids have received considerable attention as alternative candidates for Alzheimer's therapy taking into account their antiamyloidogenic, antioxidative, and anti-inflammatory properties. Experimental evidence supports the hypothesis that certain flavonoids may protect against Alzheimer's disease in part by interfering with the generation and assembly of amyloid-β peptides into neurotoxic oligomeric aggregates and also by reducing tau aggregation. Several mechanisms have been proposed for the ability of flavonoids to prevent the onset or to slow the progression of the disease. Some mechanisms include their interaction with important signaling pathways in the brain like the phosphatidylinositol 3-kinase/Akt and mitogen-activated protein kinase pathways that regulate prosurvival transcription factors and gene expression. Other processes include the disruption of amyloid-β aggregation and alterations in amyloid precursor protein processing through the inhibition of β-secretase and/or activation of α-secretase, and inhibiting cyclin-dependent kinase-5 and glycogen synthase kinase-3β activation, preventing abnormal tau phosphorylation. The interaction of flavonoids with different signaling pathways put forward their therapeutic potential to prevent the onset and progression of Alzheimer's disease and to promote cognitive performance. Nevertheless, further studies are needed to give additional insight into the specific mechanisms by which flavonoids exert their potential neuroprotective actions in the brain of Alzheimer's disease patients.