Removal of methyl orange wastewater by Ugi multicomponent reaction functionalized UiO-66-NS

The efficient and rapid removal of organic dyes from wastewater remains a complex and challenging task. In this study, UiO-66-NH₂ was prepared by solvothermal synthesis, and then, UiO-66-NS was prepared by compounding L-cysteine with UiO-66-NH₂ via the Ugi reaction for the efficient removal of methyl orange. UiO-66-NS was prepared by the addition of 1 mmol L-cysteine and showed good adsorption of methyl orange with 92.00% removal. Pseudo-second-order kinetics and Langmuir isotherms more accurately described the adsorption process of UiO-66-NS on methyl orange, which indicated that the adsorption process was dominated by monolayer adsorption of chemical reactions, and the maximum adsorption amounts of UiO-66-NS on methyl orange were 242.72 mg/g at 298 K. In addition, UiO-66-NS exhibited ultrahigh stability in acidic, neutral, and alkaline media (pH = 3-10), but its adsorption of methyl orange after 5 cycles was only 59.53% of the maximum adsorption amount. The adsorption mechanism is primarily electrostatic adsorption of UiO-66-NS with methyl orange, hydrogen bonding, and π-π interactions. This atomically economical Ugi multicomponent reaction provides new ideas for the preparation of structurally designable adsorbents with excellent performance.

The Synthesis and Evaluation of Aminocoumarin Peptidomimetics as Cytotoxic Agents on Model Bacterial E. coli Strains

This work presents the successful synthesis of a library of novel peptidomimetics via Ugi multicomponent reaction. Most of these peptidomimetics contain differently substituted aminocoumarin; 7-amino-4-methylcoumarin and 7-amino-4-(trifluoromethyl) coumarin. Inspired by the biological properties of coumarin derivatives and peptidomimetics, we proposed the synthesis of coumarin incorporated peptidomimetics. We studied the potential of synthesized compounds as antimicrobial drugs on model E. coli bacterial strains (k12 and R2–R4). To highlight the importance of coumarin in antimicrobial resistance, we also synthesized the structurally similar peptidomimetics, using benzylamine. Preliminary cellular studies suggest that the compounds with coumarin derivatives have more potential as antimicrobial agents compared to the compounds without coumarin. We also analyzed the effect of aldehyde, free acid group and ester group on the course of their antimicrobial properties.

Synthesis and biological evaluation of novel 1,4-benzodiazepin-3-one derivatives as potential antitumor agents against prostate cancer

A novel tumor suppressing agent was discovered against PC-3 prostate cancer cells from the screening of a 1,4-benzodiazepin-3-one library. In this study, 96 highly diversified 2,4,5-trisubstituted 1,4-benzodiazepin-3-one derivatives were prepared by a two-step approach using sequential Ugi multicomponent reaction and simultaneous deprotection and cyclization to afford pure compounds bearing a wide variety of substituents. The most promising compound showed a potent and selective antiproliferative activity against prostate cancer cell line PC-3 (GI₅₀ = 10.2 µM), but had no effect on LNCAP, LAPC4 and DU145 cell lines. The compound was initially prepared as a mixture of two diastereomers and after their separation by HPLC, similar antiproliferative activities against PC-3 cells were observed for both diastereomers (2S,5S: GI₅₀ = 10.8 µM and 2S,5R: GI₅₀ = 7.0 µM). Additionally, both diastereomers showed comparable stability profiles after incubation with human liver microsomes. Finally, in vivo evaluation of the hit compound with the chick chorioallantoic membrane xenograft assay revealed a good toxicity profile and significant antitumor activity after intravenous injection.

Structure-Acid Lability Relationship of N-Alkylated α,α-Dialkylglycine Obtained via a Ugi Multicomponent Reaction

Using the classical Ugi four-component reaction to fuse an amine, ketone, carboxylic acid, and isocyanide, here we prepared a short library of N-alkylated α,α-dialkylglycine derivatives. Due to the polyfunctionality of the dipeptidic scaffold, this highly steric hindered system shows an interesting acidolytic cleavage of the C-terminal amide. In this regard, we studied the structure-acid lability relationship of the C-terminal amide bond (cyclohexylamide) of N-alkylated α,α-dialkylglycine amides 1a–n in acidic media and, afterward, it was established that the most important structural features related to its cleavage. Then, it was demonstrated that electron-donating effects in the aromatic amines, flexible acyl chains (Gly) at the N-terminal and the introduction of cyclic compounds into dipeptide scaffolds, increased the rate of acidolysis. All these effects are related to the ease with which the oxazolonium ion intermediate forms and they promote the proximity of the central carbonyl group to the C-terminal amide, resulting in C-terminal amide cleavage. Consequently, these findings could be applied for the design of new protecting groups, handles for solid-phase synthesis, and linkers for conjugation, due to its easily modulable and the fact that it allows to fine tune its acid-lability.

Synthesis of new ferulic/lipoic/comenic acid-melatonin hybrids as antioxidants and Nrf2 activators via Ugi reaction

Aim: Oxidative stress has been implicated in the pathogenesis of many neurodegenerative diseases, and particularly in Alzheimer's disease. Results: This work describes the Ugi multicomponent synthesis, antioxidant power and Nrf2 pathway induction in antioxidant response element cells of (E)-N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-3-(4-hydroxy-3-methoxyphenyl)acryl amides 8a-d, N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-5-(1,2-dithiolan-3-yl)pentanamides 8e-h and N-(2-((2-(1H-indol-3-yl)ethyl)amino)-2-oxoethyl)-N-(2-(5-(benzyloxy)-1H-indol-3-yl)ethyl)-5-hydroxy-4-oxo-4H-pyran-2-carboxamides 8i,j. Conclusion: We have identified compounds 8e and 8g, showing a potent antioxidant capacity, a remarkable neuroprotective effect against the cell death induced by H₂O₂ in SH-SY5Y cells, and a performing activation of the Nrf2 signaling pathway, as very interesting new antioxidant agents for pathologies that curse with oxidative stress.

Synthesis and preliminary biological evaluation of a small library of hybrid compounds based on Ugi isocyanide multicomponent reactions with a marine natural product scaffold

A mixture-based combinatorial library of five Ugi adducts (4-8) incorporating known antitubercular and antimalarial pharmacophores was successfully synthesized, starting from the naturally occurring diisocyanide 3, via parallel Ugi four-center three-component reactions (U-4C-3CR). The novel α-acylamino amides obtained were evaluated for their antiinfective potential against laboratory strains of Mycobacterium tuberculosis H37Rv and chloroquine-susceptible 3D7 Plasmodium falciparum. Interestingly, compounds 4-8 displayed potent in vitro antiparasitic activity with higher cytotoxicity in comparison to their diisocyanide precursor 3, with the best compound exhibiting an IC50 value of 3.6 nM. Additionally, these natural product inspired hybrids potently inhibited in vitro thromboxane B2 (TXB2) and superoxide anion (O2(-)) generation from Escherichia coli lipopolysaccharide (LPS)-activated rat neonatal microglia, with concomitant low short-term toxicity.

Structures, semisyntheses, and absolute configurations of the antiplasmodial α-substituted β-lactam monamphilectines B and C from the sponge Svenzea flava

Bioassay-guided fractionation of the Caribbean sponge Svenzea flava collected near Mona Island, off the west coast of Puerto Rico, led to the isolation of two isocyanide amphilectane-type diterpenes named monamphilectines B and C (2 and 3). Attached to the backbone of each of these compounds is the first α-substituted monocyclic β-lactam ring to be isolated from a marine organism. The molecular structures of 2 and 3 were established by spectroscopic methods and then confirmed unequivocally by chemical correlation and comparison of physical and chemical data with the natural products. The new β-lactams were successfully synthesized in one step, starting from the known diisocyanide 4, via parallel Ugi four-center three-component reactions (U-4C-3CR) that also established their absolute stereostructures. Interestingly, compounds 2 and 3 exhibited activities in the low nanomolar range against the human malaria parasite Plasmodium falciparum.

Synthesis and biological activity of N-substituted-tetrahydro-γ-carbolines containing peptide residues

The synthesis of novel peptide conjugates of N-substituted-tetrahydro-γ-carbolines has been performed using the sequence of the Ugi multicomponent reaction and Cu(I)-catalyzed click chemistry. The effect of obtained γ-carboline-peptide conjugates on the rat liver mitochondria was evaluated. It was found that all compounds in the concentration of 30 µM did onot induce depolarization of mitochondria but possessed some inhibitory effect on the mitochondria permeability transition. The original N-substituted-tetrahydro-γ-carbolines containing an terminal alkyne group demonstrated a high prooxidant activity, whereas their conjugates with peptide fragments slightly inhibited both autooxidation and the t-BHP-induced lipid peroxidation.