Novel 3,5-diaryl pyrazolines and pyrazole as low-density lipoprotein (LDL) oxidation inhibitor

Engineering of a fluorescent chemogenetic reporter with tunable color for advanced live-cell imaging

Biocompatible fluorescent reporters with spectral properties spanning the entire visible spectrum are indispensable tools for imaging the biochemistry of living cells and organisms in real time. Here, we report the engineering of a fluorescent chemogenetic reporter with tunable optical and spectral properties. A collection of fluorogenic chromophores with various electronic properties enables to generate bimolecular fluorescent assemblies that cover the visible spectrum from blue to red using a single protein tag engineered and optimized by directed evolution and rational design. The ability to tune the fluorescence color and properties through simple molecular modulation provides a broad experimental versatility for imaging proteins in live cells, including neurons, and in multicellular organisms, and opens avenues for optimizing Förster resonance energy transfer (FRET) biosensors in live cells. The ability to tune the spectral properties and fluorescence performance enables furthermore to match the specifications and requirements of advanced super-resolution imaging techniques.

Isobornylchalcones as Scaffold for the Synthesis of Diarylpyrazolines with Antioxidant Activity

The pyrazoline ring is defined as a "privileged structure" in medicinal chemistry. A variety of pharmacological properties of pyrazolines is associated with the nature and position of various substituents, which is especially evident in diarylpyrazolines. Compounds with a chalcone fragment show a wide range of biological properties as well as high reactivity which is primarily due to the presence of an α, β-unsaturated carbonyl system. At the same time, bicyclic monoterpenoids deserve special attention as a source of a key structural block or as one of the pharmacophore components of biologically active molecules. A series of new diarylpyrazoline derivatives based on isobornylchalcones with different substitutes (MeO, Hal, NO2, N(Me)2) was synthesized. Antioxidant properties of the obtained compounds were comparatively evaluated using in vitro model Fe2+/ascorbate-initiated lipid peroxidation in the substrate containing brain lipids of laboratory mice. It was demonstrated that the combination of the electron-donating group in the para-position of ring B and OH-group in the ring A in the structure of chalcone fragment provides significant antioxidant activity of synthesized diarylpyrazoline derivatives.

Novel quinolinone-pyrazoline hybrids: synthesis and evaluation of antioxidant and lipoxygenase inhibitory activity

The present project deals with the investigation of structure-activity relationship of several quinolinone-chalcone and quinolinone-pyrazoline hybrids, in an effort to discover promising antioxidant and anti-inflammatory agents. In order to accomplish this goal, four bioactive hybrid quinolinone-chalcone compounds (8a-8d) were synthesized via an aldol condensation reaction, which were then chemically modified, forming fifteen new pyrazoline analogues (9a-9o). All the synthesized analogues were in vitro evaluated in terms of their antioxidant and soybean lipoxygenase (LOX) inhibitory activity. Among all the pyrazoline derivatives, compounds 9b and 9m were found to possess the best combined activity, whereas 9b analogue exhibited the most potent LOX inhibitory activity, with IC50 value 10 μM. The in silico docking results revealed that the synthetic pyrazoline analogue 9b showed high AutoDock Vina score (- 10.3 kcal/mol), while all the tested derivatives presented allosteric interactions with the enzyme.

Regioselective Synthesis and Stereochemical Structure of 1,2,8,9,13-Pentaazadispiro[4.1.4.3]Tetradeca-2,9-Dien-6-Ones

A facile regioselective synthetic approach towards 1,3,4,8,10,11-hexaaryl-13-methyl-1,2,8,9,13-pentaazadispiro [4.1.4.3]tetradeca-2,9-dien-6-ones 3a–g was achieved through the reaction of 3,5-bis(arylmethylene)-1-methyl-4-piperidinones 1a–f with nitrilimines (generated in situ by triethylamine dehydrohalogenation of the corresponding hydrazonoyl chlorides 2a,b). The stereochemical configuration of the isolated products was established to be 4 S, 5 R, 7 R, 11 S based on a single crystal X-ray diffraction study of 3b.

Synthesis and Stereochemical Structures of Novel Spiro[Benzocycloheptene-6(5H), 3′-[3H]Pyrazol]-5-Ones

Reaction of a variety of 6-arylmethylene-6,7,8,9-tetrahydro-5 H-benzocycloheptene-5-ones 1a–f with nitrilimines (generated in situ by triethylamine dehydrohalogenation of the corresponding hydrazonoyl chlorides 2) in refluxing benzene, afforded the corresponding spiro[benzocycloheptene-6(5 H),3′-[3 H]pyrazol]-5-ones 3a–h and not the isomeric forms spiro[benzocycloheptene-6(5 H),4′-[4 H]pyrazol]-5-ones 4 in a highly regioselective manner. The stereochemical configuration of the isolated products was established to be 3′ R, 4′ S based on single crystal X-ray diffraction of 3a.

Current progress on antioxidants incorporating the pyrazole core

The search of new antioxidants, as drugs candidates, is an active field of medicinal chemistry. The synthesis of compounds with antioxidant potential has increased in recent years and a high number of structurally diverse compounds have been published. This review aims to show the current state-of-the-art on the development of antioxidant compounds incorporating the pyrazole pharmacophore. It is a well-timed review driven by the increasing number of papers, on this issue, that have been published since the beginning of the 21st century (from 2000 to 2017). The aim is to look deeper into the structures already published in the literature containing the pyrazole core as the unique pharmacophore or combined with other pharmacophores and see the relationship between the presence of this five-membered nitrogen heterocycle and the behaviour of the compounds as potential antioxidant agents. An attempt was made to whenever possible establish structure-activity relationships that could help the design of new and more potent antioxidant agents containing this important pharmacophore.

Design, synthesis, topoisomerase I & II inhibitory activity, antiproliferative activity, and structure-activity relationship study of pyrazoline derivatives: An ATP-competitive human topoisomerase IIα catalytic inhibitor

A series of pyrazoline derivatives (5) were synthesized in 92-96% yields from chalcones (3) and hydrazides (4). Subsequently, topo-I and IIα-mediated relaxation and antiproliferative activity assays were evaluated for 5. Among the tested compounds, 5h had a very strong topo-I activity of 97% (Camptothecin, 74%) at concentration of 100 μM. Nevertheless, all the compounds 5a-5i showed significant topo II inhibitory activity in the range of 90-94% (Etoposide, 96%) at the same concentration. Cytotoxic potential of these compounds was tested in a panel of three human tumor cell lines, HCT15, BT474 and T47D. All the compounds showed strong activity against HCT15 cell line with IC50 at the range of 1.9-10.4 μM (Adriamycin, 23.0; Etoposide, 6.9; and Camptothecin, 7.1 μM). Moreover, compounds 5c, 5f and 5i were observed to have strong antiproliferative activity against BT474 cell lines. Since, compound 5d showed antiproliferative activity at a very low IC50 thus 5d was then selected to study on their mode of action with diverse methods of ATP competition assay, ATPase assay and DNA-topo IIα cleavable complex assay and the results revealed that it functioned as a ATP-competitive human topoisomerase IIα catalytic inhibitor. Further evaluation of endogenous topo-mediated DNA relaxation in cells has been conducted to find that, 5d inhibited endogenous topo-mediated pBR322 plasmid relaxation is more efficient (78.0 ± 4.7% at 50 μM) than Etoposide (36.0 ± 1.7% at 50 μM).

Crystal structure of 4-[5-(4-fluorophenyl)-3-(4-hydroxyphenyl)-4,5-dihydropyrazol-1-yl] benzenesulfonamide, C21H18FN3O3S

C21H18FN3O3S, monoclinic, P 21 (no. 4), a = 11.6665(3) Å, b = 5.7483(2) Å, c = 14.7695(4) Å, α = 90°, β = 103.841(1)°, γ = 90°, V = 961.72(5) Å3, Z = 2, R gt (F) = 0.0340, wR ref (F 2 ) = 0.0852, T = 296(2) K.

Synthesis of new thiazolylmethoxyphenyl pyrimidines and antihyperglycemic evaluation of the pyrimidines, analogues isoxazolines and pyrazolines

New thiazolylmethoxyphenyl pyrimidines (7a-g) have been conveniently synthesized with better yields by cyclocondensing 3-(4-((2-phenylthiazol-4-yl)methoxy)phenyl)-1-(4-substituted phenyl)prop-2-en-1-ones (4a-g) with thiourea in aqueous emulsion of tetradecyltrimethylammonium bromide (TTAB) at 80 °C. Antihyperglycemic activity of the new thiazolylmethoxyphenyl pyrimidines (7a-d), thiazolylmethoxyphenyl pyrazolines (5a-d) and thiazolylmethoxyphenyl isoxazolines (6a-d) has been evaluated in sucrose loaded rat model. Among these compounds; 5a, 5c, 6b, 7c and 7d have displayed noticeable antihyperglycemic activity. Pyrimidines and pyrazolines have displayed better antihyperglycemic activity than the analogues isoxazolines.

Synthesis, antibacterial and antifungal activity of some new pyrazoline and pyrazole derivatives

A series of 2-pyrazolines 5-9 have been synthesized from α,β-unsaturated ketones 2-4. New 2-pyrazoline derivatives 13-15 bearing benzenesulfonamide moieties were then synthesized by condensing the appropriate chalcones 2-4 with 4-hydrazinyl benzenesulfonamide hydrochloride. Ethyl [1,2,4] triazolo[3,4-c][1,2,4]triazino[5,6-b]-5H-indole-5-ethanoate (26) and 1-(5H-[1,2,4]triazino[5,6-b] indol-3-yl)-3-methyl-1H-pyrazol-5(4H)-one (32) were synthesized from 3-hydrazinyl-5H-[1,2,4]triazino[5,6-b]indole (24). On the other hand ethyl[1,2,4]triazolo[3,4-c][1,2,4]triazino[5,6-b]-5,10-dihydroquinoxaline- 5-ethanoate (27) and 1-(5,10-dihydro-[1,2,4]triazino[5,6-b]quinoxalin-3-yl)-3-methyl-1H-pyrazol-5(4H)-one (33) were synthesized from 3-hydrazinyl-5,10-dihydro-[1,2,4]triazino[5,6-b]quinoxaline (25) by reaction with diethyl malonate or ethyl acetoacetate, respectively. Condensation of 6,6-dimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indole-2-carbaldehyde (1') with compound 24 or 25 afforded the corresponding Schiff's bases 36 and 37, respectively. Reaction of the Schiff's base 37 with benzoyl hydrazine or acetic anhydride afforded benzohydrazide derivative 39 and the cyclized compound 40, respectively. Furthermore, the pyrazole derivatives 42-44 were synthesized by cyclization of hydrazine derivative 25 with the prepared chalcones 2-4. All the newly synthesized compounds have been characterized on the basis of IR and 1H-NMR spectral data as well as physical data. Antimicrobial activity against the organisms E. coli ATCC8739 and P. aeruginosa ATCC 9027 as examples of Gram-negative bacteria, S. aureus ATCC 6583P as an example of Gram-positive bacteria and C. albicans ATCC 2091 as an example of a yeast-like fungus have been studied using the Nutrient Agar (NA) and Sabouraud Dextrose Agar (SDA) diffusion methods. The best performance was found for the compounds 16, 17, 19 and 20.

Synthesis, biological evaluation, and docking studies of 3-(substituted)-aryl-5-(9-methyl-3-carbazole)-1H-2-pyrazolines as potent anti-inflammatory and antioxidant agents

A novel series of 3-(substituted)-aryl-5-(9-methyl-3-carbazole)-1H-2-pyrazolines (5a-o) has been synthesized and the structures of newly synthesized compounds were characterized by IR, (1)H NMR and mass spectral analysis. All the synthesized compounds were evaluated for their in vitro and in vivo anti-inflammatory activity, and also for their antioxidant activity. Compounds 5b, 5c, 5d and 5n were found to be selective COX-2 inhibitors. Compound 5c was found to potent inhibitor of the carrageenin induced paw edema in rats. Most of the compounds exhibited good DPPH and superoxide radical scavenging activity, while compounds 5c, 5d, 5i and 5k exhibited good hydroxyl radical scavenging activity. Molecular docking result, along with the biological assay data, suggested that compound 5c was a potential anti-inflammatory agent.

Novel benzoxazine and benzothiazine derivatives as multifunctional antihyperlipidemic agents

Atherosclerosis is a multifactorial disease with several mechanisms participating in its manifestation. To address this disorder, we applied a strategy involving the design of a single chemical compound able to simultaneously modulate more than one target. We hereby present the development of novel benzoxazine and benzothiazine derivatives that significantly inhibit in vitro microsomal lipid peroxidation and LDL oxidation as well as squalene synthase activity (IC(50) of 5-16 μM). Further, these compounds show antidyslipidemic and antioxidant properties in vivo, decreasing total cholesterol, LDL, triglyceride, and MDA levels of hyperlipidemic rats by 26-74%. Finally, by determination of their in vivo concentration (up to 24 h) in target tissues (blood/liver), it is shown that compounds reach their targets in the low micromolar range. The new compounds seem to be interesting multifunctional molecules for the development of a new pharmacophore for disease-modifying agents useful in the treatment of atherosclerosis.

Palladium-catalyzed ortho-arylation of O-phenylcarbamates with simple arenes and sodium persulfate

By palladium catalysis, the C-H bond functionalization of O-phenylcarbamates with simple arenes has been achieved using sodium persulfate (Na(2)S(2)O(8)), an inexpensive, easy-to-handle, and environmentally friendly oxidant. This oxidative cross-coupling involves two aromatic C-H bonds undergoing concomitant oxidation to furnish a new biaryl C-C linkage. Excellent reaction efficiencies and regioselectivities were observed with a range of electron-rich, electron-neutral, and electron-deficient arenes; minimal homocoupling of either component was observed. When two reactive C-H bonds are present on the O-phenylcarbamate, selective diarylation can be achieved via quadruple C-H bond functionalization. This work represents a rare example of using O-carbamates as directing groups for catalytic C-H bond activation. Additionally, a palladacycle obtained from an O-phenylcarbamate was prepared and fully characterized. This trifluoroacetate-bridged bimetallic Pd complex exhibits clean conversion to the ortho-arylation product upon treatment with simple arenes. The addition of trifluoroacetic acid (TFA) was found to be critical for successful cyclopalladation of O-phenylcarbamates. We propose this oxidative arene cross-coupling occurs via two discrete C-H bond activations, namely cyclopalladation and electrophilic metalation, within a Pd(0/II) catalytic cycle.

Synthesis of coumarin heterocyclic derivatives with antioxidant activity and in vitro cytotoxic activity against tumour cells

The aim of the present work was to synthesise coumarinyl heterocycles and to elucidate the potential role of these compounds as antioxidants and cytotoxic agents against Dalton's lymphoma ascites tumour cells (DLA) and Ehrlich ascites carcinoma cells (EAC). The synthesis of coumarin derivatives containing pyrazole, pyrazolone, thiazolidin-4-one, 5-carboxymethyl-4-thiazolidinone and 3-acetyl-1,3,4-oxadiazole ring is reported. 4-Methylcoumarinyl-7-oxyacetic acid hydrazide (1) reacted with arylazopropanes or hydrazono-3-oxobutyrate derivatives to form pyrazole (3a-c) and pyrazolone derivatives (5a-c). Heterocyclisation of Schiff's bases of 1 with thioglycolic acid, thiomalic acid or acetic anhydride afforded novel heterocyclic derivatives 4-thiazolidinones (7a-c), 5-carboxymethyl-4-thiazolidinones (8a-c) and oxadiazoles (9a-c), respectively. Some of the compounds showed promising antioxidant activity in vitro and cytotoxic activity against DLA cells and EAC cells.

The biology and chemistry of hyperlipidemia

Coronary arterial diseases are responsible for more deaths than all other associated causes combined. Elevated serum cholesterol levels leading to atherosclerosis can cause coronary heart disease (CHD). Reduction in serum cholesterol levels reduces the risk for CHD, substantially. Medicinal chemists all around the world have been designing, synthesizing, and evaluating a variety of new bioactive molecules for lowering lipid levels. This review summarizes the disorders associated with elevation of lipids in blood and the current strategies to control them. The emphasis has been laid in particular on the new potential biological targets and the possible treatments as well as the current ongoing research status in the field of lipid lowering agents.

Synthesis of Amino Substituted Pyrazoles

An efficient and convenient synthesis of substituted pyrazoles with aryl and heteroarylamino substituents attached to the C-3 and C-5 positions by the action of hydrazine hydrate on either ketene N,S-acetals or mixed N,N-aminals hydrate is reported.

Anti-atherosclerotic and anti-inflammatory activities of catecholic xanthones and flavonoids isolated from Cudrania tricuspidata

The catecholic xanthones and flavonoids 1-13 were isolated from the root bark of Cudrania tricuspidata. Compounds 1 and 3-8 exhibited significant antioxidant activity against low-density lipoprotein (LDL) oxidation in the thiobarbituric acid-reactive substance (TBARS) assay. Among them, prenylated flavonoids 10-12 showed an inhibitory effect on the NO production and iNOS expression in RAW264.7 cells. Also, compounds 1, 2, 5, 7, 9, and 11 preferentially inhibited hACAT-2 than hACAT-1, whereas compounds 3, 4, 6, and 8 showed a similar specificity against hACAT-1 and -2. However, flavonoids 10, 12, and 13 dominantly inhibited hACAT-2, not hACAT-1.

Novel bis(1-acyl-2-pyrazolines) of potential anti-inflammatory and molluscicidal properties

A variety of bis[3-aryl-4,5-dihydro-1H-pyrazol-1-carboxaldehydes] 4a-h were obtained via reaction of bis[1-aryl-2-propen-1-ones] 3a-h with hydrazine hydrate in refluxing formic acid. In addition, the corresponding bis[1-acetyl-3-aryl-4,5-dihydro-1H-pyrazoles] 4i-m were formed through conducting the reaction of 3 with hydrazine hydrate in refluxing acetic acid. The starting bis(2-propen-1-ones) 3a-h were prepared stereoselectively as E,E'-geometric isomer via condensation of bisbenzaldehydes 1a,b with (un)substituted acetophenones 2 in ethanolic KOH solution. Anti-inflammatory as well as ulcerogenic activities of the prepared pyrazolines were evaluated in vivo and compared with that of a standard drug (indomethacin). Many of the tested compounds show remarkable anti-inflammatory properties with an ulcerogenic liability (especially 4f, g, j, and k) lower than that of the standard used drug. Compound 4f was established to be the best effectively prepared anti-inflammatory active pyrazoline derivative and safer than indomethacin with respect to its ulcerogenic liability. Molluscicidal activity of the prepared compounds against Biomphalaria alexandrina snails (the intermediate host of Schistosoma mansoni) was screened. Where, some of the prepared compounds show considerable activities.

Iridoid glycosides isolated fromOldenlandia diffusa inhibit LDL-oxidation

An iridoid glycoside, oldenlandoside III (5) was isolated from the n-butanol fraction of methanol extracts of the aerial parts of Oldenlandia diffusa Roxb. along with six others previously characterized iridoid glycosides; geniposidic acid (1), scandoside (2), feretoside (3), 10-omicron-benzoylscandoside methyl ester (4), asperulosidic acid (6) and deacetylasperulosidic acid (7). Compounds 1, 2, and 7 inhibited LDL-oxidation, and showed 63.3+/-2.0, 62.2+/-1.6, and 63.8+/-1.5% inhibition, respectively, at a concentration of 20 microg/mL.