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A new method for the synthesis of previously unknown ethyl 2-amino-1-(aryl)-5-(arylcarbamoyl)-6-oxo-1,6-dihydropyridine-3-carboxylates by a reaction of ethyl 2-cyano-3-ethoxyacrylate with N1,N3-diarylmalonamides was developed. The antibacterial activity of some of the synthesized compounds was assayed. [ABSTRACT FROM AUTHOR]

2,3,3-Trimethoxyhexadecahydropyrano[2,3-c][1]oxacyclohexadecene-5,16-dione, used in the synthesis of a 16-membered macrolide, was obtained using an approach alternative to the previously published two-step procedure, which consisted in the decarboxylation of the Michael adduct of levoglucosenone and 2-(ethoxycarbonyl)cyclododecan-one under the action of ButOK in ButOH. A regiospecific Baeyer—Villiger reaction was discovered to proceed under the action of H2O2 in the presence of p-TsOH, which was accompanied by the dioxolane protective group removal and the C(4)(O)—C(5) bond cleavage with the formation of a γ-lactone ring. Treatment with ButOK resulted in the fragmentation of the difficult-to-enolize 2-(ethoxycarbonyl)cyclododecanone fragment of the molecule with the C(1′)—C(2′)(O) bond cleavage and the formation of a linear substituent at the carbohydrate residue with a terminal carboxy group. The latter transformation represented an alternative route for the preparation of 4-alkylated levoglucosenone derivatives substituted at the keto group. [ABSTRACT FROM AUTHOR]

A series of Michael adducts of malononitrile and sulfonamide chalcones were synthesized, characterized, and evaluated for their antifilarial activity. Out of 14 compounds, N-(4-(4,4-dicyano-3-p-tolylbutanoyl)phenyl)benzenesulfonamide showed favorable drug-likeness properties with marked antifilarial effects at micro-molar dosages. Apoptosis in Brugia malayi microfilariae was confirmed by EB/AO staining, MTT assay, and cytoplasmic cytochrome c ELISA. Since chalcone and folate synthesis pathways share the same substrate, we hypothesize a structural analogy-based inhibition of folate metabolism by this compound. Molecular docking against a pre-validated BmDHFR protein showed more favorable thermodynamic parameters than a positive control, epicatechin-3-gallate. The compound significantly suppressed the DHFR activity in a parasite extract in vitro. Our hypothesis is also supported by a significant reversal of DHFR inhibition by folate addition, which indicated a plausible mechanism of competitive inhibition. These results demonstrate that targeting filarial folate metabolism through DHFR with consequent apoptosis induction might be rewarding for therapeutic intervention. This study reveals a novel rationale of the structural analogy-based competitive inhibition of DHFR by Michael adducts of sulfonamide chalcones. [ABSTRACT FROM AUTHOR]

Median overall survival is very low in patients with glioblastoma (GBM), largely because these tumors become resistant to therapy. Recently, we found that a decrease in the cytosolic labile iron pool underlies the acquisition of radioresistance. Both cytosolic and mitochondrial iron are important for regulating ROS production, which largely facilitates tumor progression and response to therapy. Here, we investigated the role of the mitochondrial iron transporters mitoferrin-1 (MFRN1) and mitoferrin-2 (MFRN2) in GBM progression. Analysis of The Cancer Genome Atlas database revealed upregulation of MFRN1 mRNA and downregulation of MFRN2 mRNA in GBM tumor tissue compared with non-GBM tissue, yet only the tumor expression level of MFRN1 mRNA negatively correlated with overall survival in patients. Overexpression of MFRN1 in glioma cells significantly increased the level of mitochondrial iron, enhanced the proliferation rate and anchorage-independent growth of these cells, and significantly decreased mouse survival in an orthotopic model of glioma. Finally, MFRN1 overexpression stimulated the upregulation of glutathione, which protected glioma cells from 4-hydroxynonenal-induced protein damage. Overall, these results demonstrate a mechanistic link between MFRN1-mediated mitochondrial iron metabolism and GBM progression. Manipulation of MFRN1 may provide a new therapeutic strategy for improving clinical outcomes in patients with GBM. [ABSTRACT FROM AUTHOR]

The Michael addition reaction between dithiomalondianilide (N,N′-diphenyldithiomalondiamide) and arylmethylidene Meldrum's acids, accompanied by subsequent heterocyclization, was investigated along with factors affecting the mixture composition of the obtained products. The plausible mechanism includes the formation of stable Michael adducts which, under the studied conditions, undergo further transformations to yield corresponding N-methylmorpholinium 4-aryl-6-oxo-3-(N-phenylthio-carbamoyl)-1,4,5,6-tetrahydropyridin-2-thiolates and their oxidation derivatives, 4,5-dihydro-3H-[1,2]dithiolo[3,4-b]pyridin-6(7H)-ones. The structure of one such product, N-methylmorpholinium 2,2-dimethyl-5-(1-(2-nitrophenyl)-3-(phenylamino)-2-(N-phenylthiocarbamoyl)-3-thioxopropyl)-4-oxo-4H-1,3-dioxin-6-olate, was confirmed via X-ray crystallography. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Ganoderma triterpenoids (GTs), a class of major active constituents of Ganoderma fungi, possess diverse structures and remarkable activities. In the present study, nine new GTs, namely applanoids A—I (1—9), were isolated from the medicinal fungus of Ganoderma applanatum. Their structures including absolute configurations were established by comprehensive spectroscopic analyses and ECD calculation. Applanoids A—E (1—5) represent the first example of GTs with 6/6/5/6/5 pentacyclic system and the formation of the ether ring between C‐15 and C‐20 involves Michael addition reaction. Furthermore, compounds 1—8 were evaluated for their human pregnane X receptor (hPXR) agonistic activity using dual‐luciferase reporter gene assay, and the results showed that compounds 1, 2 and 4 can dose‐dependently activate hPXR. This investigation further illustrated the structural diversity of GTs and provided new insights for searching PXR agonists from GTs. [ABSTRACT FROM AUTHOR]

A series of Michael adducts of malononitrile and sulfonamide chalcones were synthesized, characterized, and evaluated for their antifilarial activity. Out of 14 compounds, N-(4-(4,4-dicyano-3-p-tolylbutanoyl)phenyl)benzenesulfonamide showed favorable drug-likeness properties with marked antifilarial effects at micro-molar dosages. Apoptosis in Brugia malayi microfilariae was confirmed by EB/AO staining, MTT assay, and cytoplasmic cytochrome c ELISA. Since chalcone and folate synthesis pathways share the same substrate, we hypothesize a structural analogy-based inhibition of folate metabolism by this compound. Molecular docking against a pre-validated BmDHFR protein showed more favorable thermodynamic parameters than a positive control, epicatechin-3-gallate. The compound significantly suppressed the DHFR activity in a parasite extract in vitro. Our hypothesis is also supported by a significant reversal of DHFR inhibition by folate addition, which indicated a plausible mechanism of competitive inhibition. These results demonstrate that targeting filarial folate metabolism through DHFR with consequent apoptosis induction might be rewarding for therapeutic intervention. This study reveals a novel rationale of the structural analogy-based competitive inhibition of DHFR by Michael adducts of sulfonamide chalcones.

Median overall survival is very low in patients with glioblastoma (GBM), largely because these tumors become resistant to therapy. Recently, we found that a decrease in the cytosolic labile iron pool underlies the acquisition of radioresistance. Both cytosolic and mitochondrial iron are important for regulating ROS production, which largely facilitates tumor progression and response to therapy. Here, we investigated the role of the mitochondrial iron transporters mitoferrin-1 (MFRN1) and mitoferrin-2 (MFRN2) in GBM progression. Analysis of The Cancer Genome Atlas database revealed upregulation of MFRN1 mRNA and downregulation of MFRN2 mRNA in GBM tumor tissue compared with non-GBM tissue, yet only the tumor expression level of MFRN1 mRNA negatively correlated with overall survival in patients. Overexpression of MFRN1 in glioma cells significantly increased the level of mitochondrial iron, enhanced the proliferation rate and anchorage-independent growth of these cells, and significantly decreased mouse survival in an orthotopic model of glioma. Finally, MFRN1 overexpression stimulated the upregulation of glutathione, which protected glioma cells from 4-hydroxynonenal-induced protein damage. Overall, these results demonstrate a mechanistic link between MFRN1-mediated mitochondrial iron metabolism and GBM progression. Manipulation of MFRN1 may provide a new therapeutic strategy for improving clinical outcomes in patients with GBM.

The Michael addition reaction between dithiomalondianilide (N,N′-diphenyldithiomalondiamide) and arylmethylidene Meldrum’s acids, accompanied by subsequent heterocyclization, was investigated along with factors affecting the mixture composition of the obtained products. The plausible mechanism includes the formation of stable Michael adducts which, under the studied conditions, undergo further transformations to yield corresponding N-methylmorpholinium 4-aryl-6-oxo-3-(N-phenylthio-carbamoyl)-1,4,5,6-tetrahydropyridin-2-thiolates and their oxidation derivatives, 4,5-dihydro-3H-[1,2]dithiolo[3,4-b]pyridin-6(7H)-ones. The structure of one such product, N-methylmorpholinium 2,2-dimethyl-5-(1-(2-nitrophenyl)-3-(phenylamino)-2-(N-phenylthiocarbamoyl)-3-thioxopropyl)-4-oxo-4H-1,3-dioxin-6-olate, was confirmed via X-ray crystallography.

A procedure for the preparation of an adduct of levoglucosenone and resorcinol was developed involving ultrasonic irradiation in the presence of K2CO3 and 18-crown-6 ether in toluene. In vitro anticoagulant and antiplatelet activity of the adduct was studied. [ABSTRACT FROM AUTHOR]

4-hydroxy-2,3-trans-nonenal (C9H16O2), also known as 4-hydroxy-2E-nonenal (C9H16O2; HNE) is an α,β-unsaturated hydroxyalkenal. HNE is a major aldehyde, formed in the peroxidation process of ω-6 polyunsaturated fatty acids (ω-6 PUFAs), such as linoleic and arachidonic acid. HNE is not only harmful but also beneficial. In the 1980s, the HNE was regarded as a “toxic product of lipid peroxidation” and the “second toxic messenger of free radicals”. However, already at the beginning of the 21st century, HNE was perceived as a reliable marker of oxidative stress, growth modulating factor and signaling molecule. Many literature data also indicate that an elevated level of HNE in blood plasma and cells of the animal and human body is observed in the course of many diseases, including cancer. On the other hand, it is currently proven that cancer cells divert to apoptosis if they are exposed to supraphysiological levels of HNE in the cancer microenvironment. In this review, we briefly summarize the current knowledge about the biological properties of HNE.

Levoglucosenone reacted with α-ethoxycarbonyl- and α-nitrocyclododecanones, leading to the formation of diastereomeric Michael adducts in high yields. Methods were developed for the denitration of the respective nitroadducts by treatment with Raney nickel and Bu3SnH, allowing to optimize the synthesis of a 16-membered chiral macrolide. [ABSTRACT FROM AUTHOR]

The reactions of alkyl 3-nitroacrylates with certain heterocyclic CH acids such as 1,3-dimethylpyrimidine-2,4,6(1Н,3Н,5Н)-trione, 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, 4-hydroxy-6-methyl-2H-pyran-2-one, and 4-hydroxy-2H-chromen-2-one occur in the presence of the Rodionov catalyst to form the Michael adducts. The products structure has been confirmed by 1H, 13C{1H}, and 1Н-15N HMBC NMR as well as IR spectroscopy methods. [ABSTRACT FROM AUTHOR]

The oxidation of diastereomeric Michael adducts of levoglucosenone and cyclohexanone with 5 equiv of H2O2 in isopropanol at 60°C results in selective formation of a γ-lactone. The reaction with 50 equiv of H2O2 under the same conditions gave a 6-ketononano-9-lactone annulated to the γ-lactone ring. The keto group in the latter reacts with tosylhydrazine to form a hydrazone, unlike what is the case with 6-ketononano-9-lactones annulated to the pyran ring. [ABSTRACT FROM AUTHOR]

With the goal of obtaining fused dilactones, the carbohydrate moiety of diastereoisomeric Michael adducts of levoglucosenone and cyclohexanone was converted to δ-lactone and its derivatives fused to an octahydrochromene fragment. The subsequent oxidative cleavage of the C-C bridge in the latter by the action of pyridiniun chlorochromate (PCC) afforded nonano-9-lactone fused at the C6-C7 bond to δ-lactone or methyl-δ-lactol. The presence of a carbonyl group in the carbohydrate moiety was found to prevent C-C bond cleavage. [ABSTRACT FROM AUTHOR]

The addition of lithium enolates and TMS ethers of cyclohexanone and cyclododecanone to levoglucosenone in the presence of Lewis acids was studied. It was established that the optimal way to obtain of Michael adducts involves the reaction levoglucosenone at −78°C with lithium enolates of cyclohexanone and cyclododecanone in the presence of ZnCl2. Additional amounts of Michael adducts can be obtained by treatment of 1,2-adducts with lithium diisopropylamine. 1,2-Adducts are best prepared by the reaction of the corresponding lithium enolates with levoglucosenone in the presence of Ti(Oi-Pr)4. [ABSTRACT FROM AUTHOR]

A one-step procedure has been developed for the synthesis of previously unknown ethyl 5-(arylcarbamoyl)-6-methyl-2-oxo-1,2-dihydropyridine-3-carboxylates by reaction of ethyl 2-cyano-3-ethoxyprop-2-enoate with acetoacetanilides in the presence of a catalytic amount of piperidine in ethanol at room temperature. [ABSTRACT FROM AUTHOR]

The reaction of (ethoxymethylidene)cyanoacetic ester with arylamides of acetoacetic acid proceeds under heating in the presence of triethylamine or at room temperature in the presence of sodium ethoxide. According to the NMR and IR data, the intermediate adduct undergoes no other transformations but azacyclization which predominantly involves the cyano group and forms ethyl 5-acetyl-1-aryl-6-hydroxy-2-imino-1,2-dihydropyridine-3-carboxylates in yields of 30–78%. In some cases, 5-acetyl-1-aryl-2-hydroxy-6-oxo-1,6-dihydropyridine-3-carbonitriles resulting from cyclization involving the ethoxycarbonyl group were isolated as minor products (3–12%). [ABSTRACT FROM AUTHOR]

The Michael adducts of levoglucosenone and cyclohexanone were used to develop a rapid synthesis of nonano-9-lactones fused to a pyran ring containing a pharmacophoric dichloromethylene substituent. The key step in the synthesis is a cleavage, under the action of pyridinium chlorochromate, of the bridge in the hexahydrochroman formed by the etherification of the keto function by the hydroxyl group in the 1,6-anhydro bridge, which accompanies the cleavage the latter bridge in the levoglucosenone–cyclohexanone Michael adduct. It was established that the presence of the dichloromethylene substituent in the pyran ring does not significantly affect the cleavage of the hexahydrochroman bridge. [ABSTRACT FROM AUTHOR]

This review on recent research advances of the lipid peroxidation product 4-hydroxy-nonenal (HNE) has four major topics: I. the formation of HNE in various organs and tissues, II. the diverse biochemical reactions with Michael adduct formation as the most prominent one, III. the endogenous targets of HNE, primarily peptides and proteins (here the mechanisms of covalent adduct formation are described and the (patho-) physiological consequences discussed), and IV. the metabolism of HNE leading to a great number of degradation products, some of which are excreted in urine and may serve as non-invasive biomarkers of oxidative stress.

Abstract: A highly efficient strategy for the kinetic resolution of Michael adducts was realized using a chiral N‐heterocyclic carbene catalyst. The kinetic resolution provides a new convenient route to single diastereomers of cyclohexenes and Michael adducts in good yields with high enantiomeric excesses (up to 99 % ee with a selectivity factor of up to 458). This “two flies with one swat” concept allows the synthesis of these two synthetically valuable compound classes at the same time by a single transformation. [ABSTRACT FROM AUTHOR]

A synthetic route was developed consisting of 10 steps for the synthesis of ketodecanolide with native topology in 11% overall yield, starting from Michael adducts of levoglucosenone and cyclohexanone. [ABSTRACT FROM AUTHOR]

Oxidative stress is involved in various and numerous pathological states including several age-related neurodegenerative diseases. Peroxidation of the membrane lipid bilayer is one of the major sources of free radical-mediated injury that directly damages neurons causing increased membrane rigidity, decreased activity of membrane-bound enzymes, impairment of membrane receptors and altered membrane permeability and eventual cell death. Moreover, the peroxidation of polyunsaturated fatty acids leads to the formation of aldehydes, which can act as toxic by-products. One of the most abundant and cytotoxic lipid -derived aldehydes is 4-hydroxy 2-nonenal (HNE). HNE toxicity is mainly due to the alterations of cell functions by the formation of covalent adducts of HNE with proteins. A key marker of lipid peroxidation, HNE-protein adducts, were found to be elevated in brain tissues and body fluids of Alzheimer disease, Parkinson disease, Huntington disease and amyotrophic lateral sclerosis subjects and/or models of the respective age-related neurodegenerative diseases. Although only a few proteins were identified as common targets of HNE modification across all these listed disorders, a high overlap of these proteins occurs concerning the alteration of common pathways, such as glucose metabolism or mitochondrial function that are known to contribute to cognitive decline. Within this context, despite the different etiological and pathological mechanisms that lead to the onset of different neurodegenerative diseases, the formation of HNE-protein adducts might represent the shared leit-motif, which aggravates brain damage contributing to disease specific clinical presentation and decline in cognitive performance observed in each case. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlight • Iron oxide nanoparticles are obtained by hydrothermal route. • Iron oxide nanoparticles promote Michael addition at low catalyst loading. • C C bond are formed. • Low catalyst loading for full atom-economy reaction. Abstract Several iron oxides nanoparticles (Fe 2 O 3 @Fe 2 O 3 , Fe°@Fe 2 O 3 , GO@Fe 2 O 3 and calcinated Fe 2 O 3) have been assessed as catalysts in the 1,4-addition of a cyclic β-ketoester onto methyl vinyl ketone under neat conditions. It appeared that calcinated Fe 2 O 3 NP are efficient catalysts at 1 mol% loading for the Michael addition of 1,3-dicarbonyl compounds onto various enones. [ABSTRACT FROM AUTHOR]

The analysis of oxidative stress-induced post-translational modifications remains challenging due to the chemical diversity of these modifications, the possibility of the presence of positional isomers and the low stoichiometry of the modified proteins present in a cell or tissue proteome. Alcoholic liver disease (ALD) is a multifactorial disease in which mitochondrial dysfunction and oxidative stress have been identified as being critically involved in the progression of the disease from steatosis to cirrhosis. Ethanol metabolism leads to increased levels of reactive oxygen species (ROS), glutathione depletion and lipid peroxidation. Posttranslational modification of proteins by electrophilic products of lipid peroxidation has been associated with governing redox-associated signaling mechanisms, but also as contributing to protein dysfunction leading to organelle and liver injury. In particular the prototypical α,β-unsaturated aldehyde, 4-hydroxy-2-nonenal (HNE), has been extensively studied as marker of increased oxidative stress in hepatocytes. In this study, we combined a LC-MS label-free quantification method and affinity enrichment to assess the dose-dependent insult by HNE on the proteome of rat liver mitochondria. We used a carbonyl-selective probe, the ARP probe, to label HNE-protein adducts and to perform affinity capture at the protein level. Using LC-MS to obtain protein abundance estimates, a list of protein targets was obtained with increasing concentration of HNE used in the exposure studies. In parallel, we performed affinity capture at the peptide level to acquire site-specific information. Examining the concentration-dependence of the protein modifications, we observed distinct reactivity profiles for HNE-protein adduction. Pathway analysis indicated that proteins associated with metabolic processes, including amino acid, fatty acid and glyoxylate and dicarboxylate metabolism, bile acid synthesis and TCA cycle, showed enhanced reactivity to HNE adduction. Whereas, proteins associated with oxidative phosphorylation displayed retardation toward HNE adduction. We provide a list of 31 protein targets with a total of 61 modification sites that may guide future targeted LC-MS assays to monitor disease progression and/or intervention in preclinical models of ALD and possibly other liver diseases with oxidative stress component.

Hydroxy-alkenals, such as 4-hydroxy-2(E)-nonenal (4-HNE; from n-6 fatty acids), are degradation products of fatty acid hydroperoxides, including those generated by free radical attack of membrane polyunsaturated fatty acyl moieties. The cytotoxic effects of hydroxy-alkenals are well known and are mainly attributable to their interaction with different molecules to form covalent adducts. Indeed, ethanolamine phospholipids (PEs) can be covalently modified in a cellular system by hydroxy-alkenals, such as 4-HNE, 4-hydroxy-2(E)-hexenal (4-HHE; from n-3 fatty acids), and 4-hydroxy-dodecadienal (4-HDDE; from the 12-lipoxygenase product of arachidonic acid), to form mainly Michael adducts. In this study, we describe the formation of PE Michael adducts in human blood platelets in response to oxidative stress and in retinas of streptozotocin-induced diabetic rats. We have successfully characterized and evaluated, for the first time, PEs coupled with 4-HHE, 4-HNE, and 4-HDDE by gas chromatography-mass spectrometry measurement of their ethanolamine moieties. We also report that aggregation of isolated human blood platelets enriched with PE-4-hydroxy-alkenal Michael adducts was altered. These data suggest that these adducts could be used as specific markers of membrane disorders occurring in pathophysiological states with associated oxidative stress and might affect cell function.

Prostaglandins (PGs) are produced via cyclooxygenases, which are enzymes that play a major role in neuroinflammation. Epidemiological studies show that chronic treatment with low levels of cyclooxygenase inhibitors (nonsteroidal anti-inflammatory drugs (NSAIDs)) lowers the risk for Alzheimer's disease (AD) and Parkinson's disease (PD) by as much as 50%. Unfortunately, inhibiting cyclooxygenases with NSAIDs blocks the synthesis of downstream neuroprotective and neurotoxic PGs, thus producing adverse side effects.We focus on prostaglandin J2 (PGJ2) because it is highly neurotoxic compared to PGA1, D2, and E2. Unlike other PGs, PGJ2 and its metabolites have a cyclopentenone ring with reactive α,β-unsaturated carbonyl groups that form covalent Michael adducts with key cysteines in proteins and GSH. Cysteine-binding electrophiles such as PGJ2 are considered to play an important role in determining whether neurons will live or die. We discuss in vitro and in vivo studies showing that PGJ2 induces pathological processes relevant to neurodegenerative disorders such as AD and PD. Further, we discuss our work showing that increasing intracellular cAMP with the lipophilic peptide PACAP27 counteracts some of the PGJ2-induced detrimental effects. New therapeutic strategies that neutralize the effects of specific neurotoxic PGs downstream from cyclooxygenases could have a significant impact on the treatment of chronic neurodegenerative disorders with fewer adverse side effects. [ABSTRACT FROM AUTHOR]

This review on recent research advances of the lipid peroxidation product 4-hydroxy-nonenal (HNE) has four major topics: I. the formation of HNE in various organs and tissues, II. the diverse biochemical reactions with Michael adduct formation as the most prominent one, III. the endogenous targets of HNE, primarily peptides and proteins (here the mechanisms of covalent adduct formation are described and the (patho-) physiological consequences discussed), and IV. the metabolism of HNE leading to a great number of degradation products, some of which are excreted in urine and may serve as non-invasive biomarkers of oxidative stress. [ABSTRACT FROM AUTHOR]

Membrane transporters are involved in enormous number of physiological and pathological processes. Under oxidative stress they become targets for reactive oxygen species and its derivatives which cause protein damage and/or influence protein function(s). The molecular mechanisms of this interaction are poorly understood. Here we describe a novel lipid-mediated mechanism by which biologically important reactive aldehydes (RAs; 4-hydroxy-2-nonenal, 4-hydroxy-2-hexenal and 4-oxo-2-nonenal) modify the activity of several membrane transporters. We revealed that investigated RAs covalently modify the membrane lipid phosphatidylethanolamine (PE), that lead to the formation of different membrane active adducts. Molecular dynamic simulations suggested that anchoring of PE-RA adducts in the lipid headgroup region is primarily responsible for changes in the lipid membrane properties, such as membrane order parameter, boundary potential and membrane curvature. These caused the alteration of transport activity of mitochondrial uncoupling protein 1, potassium carrier valinomycin and ionophore CCCP. In contrast, neither direct protein modification by RAs as previously shown for cytosolic proteins, nor its insertion into membrane bilayers influenced the studied transporters. Our results explain the diversity of aldehyde action on cell proteins and open a new field in the investigation of lipid-mediated effects of biologically important RAs on membrane receptors, channels and transporters. [ABSTRACT FROM AUTHOR]

[Display omitted] Base-promoted intramolecular aldol condensation of diastereomeric Michael adducts of levoglucosenone and cyclododecanone affords 12-hydroxy-14,20-dioxatetra-cyclo[9.6.1.112,17.113,16]icosan-18-one as a mixture of three diastereomers. The products thus obtained are promising for synthesizing 14-membered macrocyclic compounds, including cembranoids and their analogues. [ABSTRACT FROM AUTHOR]

A series of Michael-type analogues were generated on the C-ring of α-santonin (α-methylene-γ-butyrolactone) upon reaction with various thiols. All the thiol adducts synthesized were evaluated for their anticancer activity against four human cancer cell lines (PC-3, HCT-15, A-549 and MCF-7). Bioassay results indicated that even though most of the synthesized compounds exhibited a good anticancer activity against various cancer cells in vitro , some of the compounds like 9e , 9g and 9q were found to be the most promising analogues in this series, with compound 9e showing IC 50 values of 1.5 μM, 0.6 μM, 2.4 μM and 1.2 μM on PC-3, MCF-7, A-549 and HCT-116 cell lines respectively. Further, flow cytometry studies showed that MCF-7 cells treated with the compounds 9e, 9g and 9q were arrested in the sub G1 phase of the cell cycle in a concentration dependent manner. These lead molecules were further studied for NF-κB, p65 transcription factor inhibitory activity which confirmed concentration dependent inhibition against NF-κB, p65 with analogue 9e showing 57% inhibition at 2 μM, 9g showing 62% inhibition at 3 μM and 9q showing 54% inhibition at 2 μM concentration. [ABSTRACT FROM AUTHOR]

Inhibition of microsomal prostaglandin E synthase-1 (mPGES-1) results in decreased production of proinflammatory PGE 2 and can lead to shunting of PGH 2 into the prostaglandin D 2 (PGD 2 )/15-deoxy-Δ 12,14 -prostaglandin J 2 (15dPGJ 2 ) pathway. 15dPGJ 2 forms Michael adducts with thiol-containing biomolecules such as GSH or cysteine residues on target proteins and is thought to promote resolution of inflammation. We aimed to elucidate the biosynthesis and metabolism of 15dPGJ 2 via conjugation with GSH, to form 15dPGJ 2 -glutathione (15dPGJ 2 -GS) and 15dPGJ 2 -cysteine (15dPGJ 2 -Cys) conjugates and to characterize the effects of mPGES-1 inhibition on the PGD 2 /15dPGJ 2 pathway in mouse and human immune cells. Our results demonstrate the formation of PGD 2 , 15dPGJ 2 , 15dPGJ 2 -GS, and 15dPGJ 2 -Cys in RAW264.7 cells after lipopolysaccharide stimulation. Moreover, 15dPGJ 2 -Cys was found in lipopolysaccharide-activated primary murine macrophages as well as in human mast cells following stimulation of the IgE-receptor. Our results also suggest that the microsomal glutathione S-transferase 3 is essential for the formation of 15dPGJ 2 conjugates. In contrast to inhibition of cyclooxygenase, which leads to blockage of the PGD 2 /15dPGJ 2 pathway, we found that inhibition of mPGES-1 preserves PGD 2 and its metabolites. Collectively, this study highlights the formation of 15dPGJ 2 -GS and 15dPGJ 2 -Cys in mouse and human immune cells, the involvement of microsomal glutathione S-transferase 3 in their biosynthesis, and their unchanged formation following inhibition of mPGES-1. The results encourage further research on their roles as bioactive lipid mediators., Competing Interests: Conflict of Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. P.-J. J. is engaged in Gesynta Pharma AB, a company that develops mPGES-1 inhibitors., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Antiproliferative activity of twenty one Michael adducts of aroylacrylic acids and cyclic amines ( $$N$$ -Me-piperazine, imidazole, 2-Me-imidazole, and indole) was tested toward five human tumor cell lines (HeLa, LS174, K562, FemX, MDA-MB-361) in vitro. Compounds exerted antiproliferative activity in the high to the single-digit micromolar concentrations, causing increase of the cell population fraction in S phase and apoptosis. $$N$$ -Me-piperazine and imidazole derivatives of aroylacrylic acids substituted with bulky alkyl substituents (2,4-di- $$i$$ -Pr-Ph-, 2,4,6-tri-Et-Ph-, or $$\beta $$ -tetrahydronaphthyl-) showed the best potency, while indole adducts were proved as the inferior antiproliferative agents. Few compounds showed significant selectivity, tumor versus healthy cells, with selectivity index $${\sim }60$$ for the most selective congener. An unbiased in silico distinction between more and less potent compounds was obtained from 3D QSAR models derived by alignment-independent GRIND-2 descriptors. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: Visible-light-induced aerobic oxidative cyanation of aza-Baylis–Hillman (aza-BH) adducts providing valuable allylic cyanides in good to excellent yields has been developed. The protocol involves in situ formation of 4π conjugated iminium ion intermediates, which undergo cyanation at the γ-position to afford Michael type adducts. This is the first example of visible-light-induced catalytic functionalization of aza-BH adducts using air (O2) as an economical and ecosustainable oxidant and TMSCN as a convenient and readily available cyanide source. [Copyright &y& Elsevier]

4-hydroxy-2,3-trans-nonenal (C9H16O2), also known as 4-hydroxy-2E-nonenal (C9H16O2; HNE) is an α,β-unsaturated hydroxyalkenal. HNE is a major aldehyde, formed in the peroxidation process of ω-6 polyunsaturated fatty acids (ω-6 PUFAs), such as linoleic and arachidonic acid. HNE is not only harmful but also beneficial. In the 1980s, the HNE was regarded as a "toxic product of lipid peroxidation" and the "second toxic messenger of free radicals". However, already at the beginning of the 21st century, HNE was perceived as a reliable marker of oxidative stress, growth modulating factor and signaling molecule. Many literature data also indicate that an elevated level of HNE in blood plasma and cells of the animal and human body is observed in the course of many diseases, including cancer. On the other hand, it is currently proven that cancer cells divert to apoptosis if they are exposed to supraphysiological levels of HNE in the cancer microenvironment. In this review, we briefly summarize the current knowledge about the biological properties of HNE. [ABSTRACT FROM AUTHOR]

The thermally activated or microwave-induced one-pot three-component condensation of arylglyoxal hydrates, 1,3-dimethylbarbituric acid, and guanidine salts or methylisothiuronium hydroiodide gave respectively 2-amino-5-aryl- and 5-aryl-2-methylsulfanylimidazoles containing a 1,3-dimethylbarbituric acid residue. An unexpected course for the condensation was discovered in the case of guanidine hydrochloride, leading to 5-(2-aryl-2-oxoethyl)-1,3-dimethylbarbituric acids. 2-Amino-2-arylimidazoles under the conditions of such three-component condensation formed Michael adducts involving 5-(2-aryl-2- oxoethylidene)-1,3-dimethylbarbituric acids and the C-5 atom of the imidazole ring. [ABSTRACT FROM AUTHOR]

10-Amino-7,11-dicyano-9-aza-3-azoniaspiro[5,5]undeca-7,10-diene-8-selenolates have been obtained by the interaction of N-alkylpiperidin-4-ones with 2 equiv. cyanoselenoacetamide or with malononitrile and cyanoselenoacetamide. Aminomethylation of the obtained compounds proceeded under mild conditions and led to the formation of 8'-selenoxo-3',5',7',11'-tetraazaspiro[piperidine-4,13'-tri-cyclo[7.3.1.0]tridec[2]ene]-1',9'-dicarbonitriles. The structure of 1-methyl-5',11'-di(4-methyl-phenyl)-8'-selenoxo-3',5',7',11'-tetraazaspiro[piperidine-4,13'-tricyclo[7.3.1.0]tridec[2]ene]-1',9'-di-carbonitrile was determined by X-ray structural analysis. [ABSTRACT FROM AUTHOR]

The addition of N-arylmaleimides or dimethyl acetylenedicarboxylate to 2-imidazolideneacetophenones proceeds at the most nucleophilic carbon atom of the acetophenone derivatives and results in a rearrangement to give derivatives of 5-oxo-2,3,5,6-tetrahydro-1H-pyrrolo[1,2-a]imidazole or imidazo[1,2-a]pyridine, respectively. In the case of 2-imidazolidenecyclopentanones and 2-imidazolidine-cyclohexanones, the reaction terminates upon the addition of imide or dimethyl acetylenedicarboxylate at the nitrogen atom of the imidazoline system. [ABSTRACT FROM AUTHOR]

Depending of the reaction conditions, reaction of levoglucosenone with diazocyclopropane generated in situ from N-cyclopropyl- N-nitrosourea under the action of bases involved either the carbonyl group to give oxaspiropentane (MeONa/MeOH, s-30 °C), or the double C=C bond to give l-pyrazoline (K2CO3, CH2Cl2, 5 °C). The latter readily reacted with diazocyclopropane at the C=O group or added as a C-nucleophile in a regio-and stereoselective Michael reaction to the C=C bond of levoglucosenone. The direction of reaction depended on the reactant ratio. The reaction of the levoglucosenone—diazomethane adduct with an excess of levoglucosenone in the presence of a base yielded similar product bearing two levoglucosenone moieties. [ABSTRACT FROM AUTHOR]

4-Aryl-3-cyano-6-phenylpyridine-2(1H)-thiones, used in the synthesis of substituted 2-alkylthiopyridines, thieno[2,3-b]pyridines, and 1,4-di(pyridin-2-ylthio)butane, have been synthesized by the condensation of arylmethylenecyanothioacetamides with benzoyl-1,1,1-trifluoroacetone. The reaction path includes the formation of the Michael adduct which undergoes loss of the acyl group. The structure of 3-cyano-2-methylthio-4-(1-naphthyl)-6-phenylpyridine has been studied by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Abstract: 4-Hydroxy-2-nonenal (HNE), a major lipid peroxidation product, reacts with histidine, lysine or cysteine residues of proteins to form hemiacetal Michael adducts and thus interferes with the functions of the proteins. Here we undertook to identify HNE-modified proteins in the target organ of a ferric nitrilotriacetate (Fe-NTA)-induced renal carcinogenesis model with histidine-specific HNEJ-2 antibody. Immunoaffinity column separation and sequencing identified one of the major modified proteins as actin. To further explore the characteristics of actin as an HNE acceptor, we produced four novel monoclonal antibodies against HNE-modified keyhole limpet hemocyanin. All these antibodies (HNEJ-1, 3–5) recognized histidine adducts, but were different from HNEJ-2 in recognizing lysine and cysteine adducts to some extent. Actin, albumin, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), metallothionein and superoxide dismutase were treated in vitro with HNE and evaluated with these antibodies. The results revealed that actin was most sensitive to HNE modification and metallothionein most resistant. Furthermore, the residue-specificity of GAPDH was in accord with that shown by our recent mass spectrometry data. Immunohistochemistry with the antibodies revealed cytoplasmic staining with or without nuclear staining in the renal proximal tubules after Fe-NTA administration. The results suggest that actin is a major target protein for HNE modification in vivo, and that our monoclonal antibodies are useful for evaluating the HNE adducts produced. [Copyright &y& Elsevier]

Abstract: A sensitive, selective, specific and rapid liquid chromatographic–electrospray ionization tandem mass spectrometric assay was developed and validated for the simultaneous determination in skeletal muscle of the Michael adducts between 4-hydroxy-trans-2-nonenal (HNE), one of the most reactive lipid peroxidation-driven unsaturated aldehyde, and glutathione (GSH) and the endogenous histidine-containing dipeptides carnosine (CAR) and anserine (ANS), with the final aim to use conjugated adducts as specific and unequivocal markers of lipid peroxidation. Samples (skeletal muscle homogenates from male rats) were prepared by protein precipitation with 1vol. of a HClO4 solution (4.2%; w/v) containing H-Tyr-His-OH as internal standard. The supernatant, diluted (1:1, v/v) in mobile phase, was separated on a Phenomenex Sinergy polar-RP column with a mobile phase of water–acetonitrile–heptafluorobutyric acid (9:1:0.01, v/v/v) at a flow rate of 0.2ml/min, with a run time of 12min. Detection was on a triple quadrupole mass spectrometer equipped with an ESI interface operating in positive ionization mode. The acquisitions were in multiple reaction monitoring (MRM) mode using the following precursor→product ion combinations: H-Tyr-His-OH (IS): m/z 319.2→156.5+301.6; GS-HNE: m/z 464.3→179.1+308.0; CAR-HNE: m/z 383.1→110.1+266.6; ANS-HNE: m/z 397.2→109.1+126.1. The method was validated over the concentration ranges 1.5–90 (GS-HNE) and 0.4–40 (CAR-HNE, ANS-HNE) nmoles/g wet tissue, and the LLOQ were 1.25 and 0.33pmoles injected respectively. The intra- and inter-day precisions (CV%) were <7.38% (≤10.90% at the LLOQs); intra- and inter-assay accuracy (RE%) was within±7.0% for all the concentrations (≤18% at the LLOQs). The method was applied to quantitate peptide-HNE Michael adducts in rat skeletal muscles exposed to oxidative stress to endogenously generate HNE, and the results indicate that CAR-HNE can be considered as an early, specific and stable marker of lipid peroxidation in excitable tissues. [Copyright &y& Elsevier]

New versatile enaminonitrile-type building blocks, 3-aminothieno[2,3- b ]pyridine-2-carbonitriles 3a,b, were synthesized from 3-cyanopyridine-2-(1 H )-thiones 1a,b. Interaction of 3a,b with triethyl orthoformate furnished the corresponding ethoxymethylideneamino derivatives 6a,b. Derivatives of heterocyclic systems having the pyrazole, pyrimidine, and pyridine rings were obtained from the key precursors 3a,b and 6a, respectively. [ABSTRACT FROM AUTHOR]

The effects of Michael adducts of 6-O-palmitoyl-L-ascorbic acid (compounds 1–4) on the phosphorylation-dependent response of stimulated monocytes and neutrophils was investigated. The pyranosyl derivative 3 increased the production of tumor necrosis factor-α in human monocytes stimulated with lipopolysaccharide (LPS). Compound 3 also enhanced the release of tumor necrosis factor-α from nonstimulated monocytes. Michael adducts 1–4 inhibited the formation of reactive oxygen species in fMLP-stimulated human neutrophils as measured by luminol chemiluminescence. Treatment with 6-O-palmitoyl-L-ascorbic acid (compound 5) also led to a decreased luminescence response of neutrophils. Results are discussed with respect to the inhibitory activity of Michael adducts of ascorbic acids towards protein phosphatases PP1/PP2A.Copyright © 2002 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The reaction of benzaldehyde, α-nitro ketone, and cyanothioacetamide in the presence of morpholine has given the novel 3,4- trans-2-R-5-cyano-2-hydroxy-3-nitro-4-phenyl-1,2,3,4-tetrahydropyridine-6-thiolates. It was found that the reaction occurs via the formation of 1-amino-2-cyano-4-nitro-5-oxo-3-phenyl-1,2-pentene-1-thiolate. In the case of α-nitroacetophenone, 3,4- trans-4,5- trans-5-cyano-2-hydroxy-3-nitro-2,4-diphenylhexahydropyridine-6(1H)-thione was also obtained. The use of α-nitroesters in place of the nitro ketones in the reaction leads to morpholinium 2-aryl-1-carbethoxy-3-cyano-1-nitro-3-thiocarbamoylpropyl-1-ates as the single product. [ABSTRACT FROM AUTHOR]

Oxidation of plasma low-density lipoprotein (oxLDL) generates the lipid peroxidation product 4-hydroxy-2 nonenal (HNE) and also reduces proteolytic degradation of oxLDL and other proteins internalized by mouse peritoneal macrophages in culture. This leads to accumulation of undegraded material in lysosomes and formation of ceroid, a component of foam cells in atherosclerotic lesions. To explore the possibility that HNE contributes directly to the inactivation of proteases, structure-function studies of the lysosomal protease cathepsin B have been pursued. We found that treatment of mouse macrophages with HNE reduces degradation of internalized maleyl bovine serine albumin and cathepsin B activity. Purified bovine cathepsin B treated briefly with 15 μM HNE lost ∼76% of its protease activity and also developed immunoreactivity with antibodies to HNE adducts in Western blot analysis. After stabilization of the potential Michael adducts by sodium borohydride reduction, modified amino acids were localized within the bovine cathepsin B protein structure by mass spectrometric analysis of tryptic peptides. Michael adducts were identified by tandem mass spectrometry at cathepsin B active site residues Cys 29 (mature A chain) and His 150 (mature B chain). Thus, covalent interaction between HNE and critical active site residues inactivates cathepsin B. These results support the hypothesis that the accumulation of undegraded macromolecules in lysosomes after oxidative damage are caused in part by direct protease inactivation by adduct formation with lipid peroxidation products such as HNE. [ABSTRACT FROM AUTHOR]