Next Article in Journal
A Comprehensive Review of Catalytic Hydrodeoxygenation of Lignin-Derived Phenolics to Aromatics
Previous Article in Journal
Effect of Synthetic Peptides Identified in the Bullfrog Skin on Inflammation and Oxidative Stress Control: An In Vitro Analysis
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Molecules
Volume 30
Issue 10
10.3390/molecules30102224
molecules-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Microwave Assisted Synthesis of Antioxidant Dihydro-Pyrazole Hybrids as Possible Lipoxygenase Inhibitors

by
Stergiani-Chrysovalanti Peitzika
,
Eirini Tsiampakari
and
Eleni Pontiki
*
Laboratory of Pharmaceutical Chemistry, School of Pharmacy, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
*
Author to whom correspondence should be addressed.
Molecules 2025, 30(10), 2224; https://doi.org/10.3390/molecules30102224
Submission received: 20 March 2025 / Revised: 14 May 2025 / Accepted: 15 May 2025 / Published: 20 May 2025
(This article belongs to the Section Medicinal Chemistry)
Browse Figures
Versions Notes

Abstract

Free radicals and inflammation have pivotal role in various degenerative diseases like cancer, rheumatoid arthritis, diabetes, cardiovascular and neurodegenerative disorders. Pyrazoles possess a wide range of biological activities such as antifungal, antituberculosis, antimicrobial, antiviral, anti-inflammatory, anti-convulsant, anticancer etc. In this present study a series of dibenzalacetones and the corresponding pyrazole hybrids were designed through bioisosterism, synthesized and biologically evaluated to highlight the importance of the extended conjugated system and substitution to the anti-inflammatory and antioxidant activity. The synthesis of dibenzalacetones was achieved via Claisen-Schmidt reaction. The dihydro-pyrazoles were synthesized from the substituted dibenzacetones and phenylhydrazines, hydrazine and semicarbazide under microwave irradiation optimizing reaction conditions. The synthesized compounds were spectroscopically characterized and evaluated for their anti-lipid peroxidation (AAPH) activity, their interaction with the free radical DPPH and the inhibition of soybean LOX. The novel derivatives were studied in terms of their physicochemical properties. Many of the dihydro-pyrazoles showed potent antioxidant properties and significant inhibition of soybean lipoxygenase as a result of their physicochemical features. Compounds 4a and 4b presented the most potent anti-lipid peroxidation abilities (98% and 97%), whereas compounds 2d and 2e have proved to be the most potent lipoxygenase inhibitors with IC50 values 2.5 μM and 0.35 μM. Moreover, docking studies with soybean lipoxygenase highlight the interactions of the novel derivatives with the enzyme.

Graphical Abstract

1. Introduction

Inflammation is a biological response of homeostasis to various harmful stimuli [1,2]. It is a defensive and survivor mechanism of the immune system [3], involving complex responses of inflammatory mediators and a strong accumulation of oxidative stress products and lipid mediators. The inflammatory process is strongly associated with the production of free radicals [4] leading to peroxides and other reactive oxygen species [5]. The implication of reactive oxygen species (ROS), e.g., superoxide anion, hydroxyl radical and hydrogen peroxide, in diseases associated with oxidative stress (e.g., cardiovascular diseases, coronary artery disease, inflammatory injury, cancer) has been extensively referred in the literature [6,7,8,9,10].
Inflammation is associated with various diseases like cancer, rheumatoid arthritis, diabetes, cardiovascular and neurodegenerative disorders [11,12]. Inflammatory cytokines and mediators such as phospholipids, arachidonic acid, leukotrienes, prostaglandins, tumor necrosis factor play crucial role in the above-mentioned pathways [13]. During inflammation arachidonic acid is metabolized to prostaglandins via cyclooxygenase and leukotrienes via lipoxygenase, the main enzymatic routes of the inflammatory process [14].
Lipoxygenases (LOXs) catalyze the deoxygenation of Polyunsaturated Fatty Acids (PUFA) containing a 1-cis,4-cis-pentadiene unit to form conjugated hydroperoxydienoic acids using atmospheric oxygen. In their active center they contain a non-heme iron atom essential for the enzymatic activity [15]. Six lipoxygenase isoforms exist 5-LOX, 8-LOX, 12A-LOX, 12B-LOX, 15A-LOX, 15B-LOX [16], among them 5-lipoxygenase (5-LOX) is the one strongly associated with the production of leukotrienes (LTs), the inflammatory mediators of arachidonic acid [17].
Dibenzalacetones have an aromatic ketone and an enone moiety and are an important component in a variety of biological compounds (Figure 1). Dibenzalacetones participate in a variety of chemical reactions and are intermediates in the synthesis of heterocyclic compounds such as, isoxazoles, quinolinones, thiadiazines and flavones [18]. They are also key intermediates in addition reactions such as cycloaddition and Michael addition due to the presence of enone functionality. In addition, dibenzalacetones show a wide range of biological activities [19], such as antifungal [20], antioxidant [21], antimalarial [22], analgesic [23] and anticancer [24,25].
Pyrazole is an aromatic heterocyclic system belonging to the azole class [26]. During the last decades, the development of synthetic strategies of pyrazoles and pyrazolines has gained much attention due to their biological applications. The most common synthetic methodology for pyrazoles and pyrazolines follows the cyclization of hydrazine with various electrophiles, including 1,3-dicarbonyl compounds, α,β-unsaturated carbonyl compounds and dihalides [27,28,29,30,31,32,33]. Pyrazoles are among the most important scaffolds possessing a wide variety of biological activities such as antifungal, antituberculosis, antimicrobial, antiviral, anti-inflammatory, anticonvulsant, anticancer and neuroprotective [34]. Furthermore, they act as inhibitors of the angiotensin-converting enzyme (ACE), as well as antagonists of the cholecystokinin receptor [34]. In addition, the pyrazole skeleton as well as pyrazoline are also associated with AChE inhibition and Alzheimer’s disease [35]. The privileged pyrazole scaffold is present in many drugs such as celecoxib (non steroidal anti-inflammatory drug), antipyrine (antipyretic), metamizole (painkiller, antipyretic and spasm reliever), fipronil (insecticide), tepoxalin (non steroidal anti-inflammatory drug used in veterinary medicine) and rimonabant (anorectic anti-obesity drug) (Figure 2).
A prerequisite in modern medicinal chemistry is the design and investigation of hybrid structures in order to optimize cost and efficiency [36]. The philosophy of hybrid drugs is the combination of two different pharmacophores or more in a single molecule, interacting simultaneously with multiple targets [37,38,39].The antiinflammatory activity of pyrazoles has been explored in recent literature using different protocols [40,41]. Moreover, Eid, N.M. and George, R.F. are focused on the synthesis of heterocyclic (methyl-substituted thienyl- and furyl-) curcumin derivatives [42]. The obtained dienones are converted into different pyrazolines in order to inverstigate the effect of these heterocyclic hybrids on the antiinflammatory activity. The results revealed promissing antiinflammatory activity for the new hybrids compared to indomethacin.
Based on the above study and in continuation of our group research work [40] and experience, a series of novel dihydro-pyrazole hybrids has been designed following bioisosteric replacements. The new hybrids were synthesized and evaluated for their antioxidant and lipoxygenase inhibitory activities in order to identify the crucial structural characteristics realated to the activity. The activities of dihydro-pyrazole hybrids were compared with the ones of the intermediate dibenzalacetones. Finally, the obtained novel compounds were subjected to molecular docking studies to define their potential interactions with soybean lipoxygenase.

2. Results

2.1. Chemistry

Dihydropyrazoles (2a–f, 3a–f, 4a–f), pyrazole-carboxamides (5a–e) and dihydro-pyrazol-ethanones (6a–e) were synthesized from the corresponding dibenzalacetones (1a–f) as depicted in Scheme 1.The synthesis of dibenzalacetones (1a–f) was achieved via Claisen-Schmidt reaction [42]. For the synthesis of the novel hybrids (2a–f, 3a–f, 4a–f, 5a–e and 6a–e) microwave irradiation was applied (Scheme 1) optimizing the litterature conditions [42,43]. Novel derivatives were characterized by melting point, IR, 1H NMR, 13C NMR spectra and HRMS or elemental analysis.
Compounds (1a–e) were obtained in medium to good yields (30–90%). Compounds 1a–e have been previously reported in the literature [44,45,46,47]. Compound 1f, was confirmed by IR, 13C NMR spectra and elemental analysis. IR spectra revealed absorption bands at 1700–1650 cm−1 (C=O stretch) and 1600–1500 cm−1 (C=C bond stretch) while the absorption band of C=N bond appears stronger. In the 1H NMR spectra trans-vinyl hydrogens appear at δ 7.00–8.00 ppm as doublets (d), with J-coupling constant of 15.9 Hz, while the the remaining aromatic protons at δ 7.00–8.00 ppm. In the 13C NMR spectrum of compound 1f all the carbons are recorded in the aromatic region i.e., at δ 120–150.
The dihydro-pyrazoles (2a–f, 3a–f, 4a–f) were obtained at yields 50–82%. Compounds 2a–d and 3a have been previously reported [43,48,49]. The structures of the novel derivatives were identified through 1H NMR, 13C NMR, IR and high-resolution mass spectrometry (HRMS). IR spectra presented the characteristic absorption bandsat 1600–1500 cm−1 (C=N and C=C bond stretch) and 1400–800 cm−1 (C-N bond stretch) [43,48,49]. The compounds bearing a CN-group present an additional absorption band at 2300–2000 cm−1. As for the 1H NMR data the proton of C5 of dihydropyrazole was recorded at δ 5.0 ppm, while the other two protons of C4 of dihydropyrazole were recorded slightly downfieldas a doublet of doublets (dd), due to the anisotropic effect of the chiral secondary carbon. The trans-vinyl hydrogens are recorded at δ 7.00–8.00 ppm as doublets (d), with J-coupling constant of 15.0–16.0 Hz. The 13C chemical shifts of the carbon atoms of dihydropyrazole are recorded at δ 43 (average value) for the -C4 and at δ 63 (average value) for the -C5 of dihydropyrazole at, while the aromatic ones at δ 100–165. In the HRMS spectra, the main ion presented was the [M + H]+.
The pyrazole-carboxamides (5a–e) and dihydro-pyrazol-ethanones (6a–e) were obtained at 8–51% yields. Compounds 5a–b, 5e and 6a–e have been previously reported [50,51,52,53]. The novel derivatives were characterised through 1H NMR, 13C NMR, IR, melting point and elemental analysis. In accordance with the literature [50,51,52,53] IR spectra present absorption bands at 1600–1500 cm−1 (C=N, C=C bond stretch) and 1400–800 cm−1 (C-N bond stretch), while the pyrazole-carboxamides (5c–d) present absorption bands at 3500–3300 cm−1 (N-H stretch) 1690–1630 cm−1 (C=O stretch) and 1600–1500 cm−1 (C=C bond stretch). Regarding the 1H NMR spectra, the protons of NH2 and CH3 groups are recorded Finally, 13C NMR spectra present the characteristic C=O peak.

2.2. Physicochemical Studies

2.2.1. Determination of Lipophilicity

Lipophilicity is a main physicochemical parameter for bioactive molecules, linking solubility, ligand-target binding interactions, membrane permeability absorption, distribution, bioavailability, metabolism, elimination and toxicological effects (ADMET), playing an important role in biological activity. The experimental values of lipophilicity RM were determined by reverse phase thin layer chromatography. For the experimental determination of lipophilicity the hydrophilic-lipid phase system is a mixture of methanol- water (90/10%). The theoretical lipophilicity values are determined by the Bioloom program (http://biobyte.com/bb/prod/bioloom.html, accessed on 8 April 2024) (Table 1). According to the calculated clog P values, the most lipophilic compounds are 3c, 3d and 3f while the less lipophilic ones are compounds 5a and 5b.

2.2.2. Theoretical Calculation of Physicochemical Properties

A qualitative assessment of a molecule’s potential to be an oral drug in terms of bioavailability is called “drug-likeness”. Table 2 lists the results of drug-likeness study of the synthesized compounds using the molinspiration platform (https://www.molinspiration.com/ accessed on 8 April 2024). In particular, the values miLogP indicate lipophilicity, TPSA the topological polar surface area, Natoms the number of atoms in the molecule, MW the molecular weight, nON is the number of hydrogen bond acceptors, nOHNH the number of hydrogen bond donors, Nviolations o the number of violations of the rule of five, Nrotb o the number of rotated bonds and Volume the molecular volume. Perusal of the results show that compounds 1a, 1b, 1e, 5a, 5b, 5e, 6a, 6b do not present any violation. However, from the whole sum of 34 compounds only nine have drug likeness. The rest violate lipophilicity and/or MW. TPSA is frequently employed to estimate/predict cellular absorption of drugs and the optimal values ranges between 60–140 Å2. Drugs with TPSA values lower than 90 Å2 permeate the BBB.

2.3. Biological Evaluation

The synthesized compounds were evaluated in vitro for their ability to interact with the stable free radical DPPH, inhibit linoleic acid peroxidation induced by AAPH and soybean lipoxygenase (Table 3).
The ability of the derivatives to interact with the stable free 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) at concentrations of 100 μM was examined after 20 and 60 min at 517 nm using nordihydroguaretic acid (NDGA) as reference compound. In general, the compounds present moderate to good antioxidant activity. It seems that the dibenzylacetones present satisfactory antioxidant activity compared to the hybrids at 60 min (1b, 1d and 1f). The existing activity of dibenzylacetones does not seem to be correlated with lipophilicity and molecular volume.
Compounds 2d and 3d show the best interaction among these series 45–53% at 60 min, while compounds 2a, 2b, 3a and 3c present moderate activity. Among the subgroup 2a–f presenting a benzene ring as substituent at position 1 of the pyrazolyl ring, compound 2c appears to be the most active. The presence of the dimethyl-amino group (2e and 3e) generally contributed positively to the interaction with the DPPH. Among the subgroup of 3a–f with the 4-bromobenzene substituent at position 1 of the pyrazolyl ring, the most active is compound 3e, possessing the dimethyl-amino. Compounds 2e and 3e are the most active among all the derivatives. Compound 4e, possessing a 4-cyanobenzyl substitution is almost inactive. Within the subgroup 4a–f with the 4-cyanobenzyl substitution at position 1 of the pyrazolyl ring, the most active is the chloro-substituted, 4d. For the majority of the compounds (1a, 1b, 1d, 6b, 6e and 5d) the interaction seems to be increased over time. Dichalcone with a chloro-substituent at the 4-position shows an increased interaction over time. However, the transformation to the dihydro-pyrazol-ethanone (6d) and the pyrazole-carboxamide (5d) lead to a decrease of the antioxidant activity in relation to the starting material (dichalcone).
The compounds show lower interaction with the stable free radical and lower antioxidant ability at 60 min. Lipophilicity does not influence activity. However, the bulk of these compounds could prevent their interaction with the free radical.
The ability of the compounds to inhibit AAPH-induced peroxidation of linoleic acid is another assay to investigate the antioxidant properties of the compounds. Azo compounds such as 2,2′-azobis dihydrochloride (2-amidinopropane) (AAPH) are capable of generating free radicals through spontaneous decomposition at 37 °C. The R- radicals react immediately with air-oxygen to produce peroxy radicals [58]. AAPH was therefore used as the radical initiator and sodium linoleate as substrate subjected to peroxidation. Measurements were carried out at 234 nm using a UV/V is spectrophotometer. Dichalcone 1i substituted with two phenyl groups presents the lowest lipophilicity. However, it shows the best activity (69%). Therefore, hydrophilic substituents offer an increase in activity.
The majority of compounds series 2a–f, 3a–f, 4a–f seems to exhibit very good inhibition against lipid peroxidation apart from compound 4f (12%). The most active compounds are 4a (98%) and 4b (97%) presenting better activity than the reference compound Trolox. These compounds present the lowest molecular refractivity within the series.
Lipophilicity seems to favor lipid peroxidation inhibitory activity. From series 2a–f bearing the 1-phenylpyrazole group, compounds 2d and 2e, substituted with a chlorine and dimethyl-amino groups seem to be more active in the series. Among compounds 3a–f possessing the 4-bromo-phenyl substituent at position 1 of the pyrazolyl ring, the most active are compounds 3e and 3f, with a dimethyl-amino and trifluoromethyl group respectively. In addition, from the 4-cyanosubstituted pyrazolines (4a–f) the most active are compounds 4a and 4b, substituted with a phenyl and 4-fluorinephenyl group, respectively. Among the phenyl substituted derivatives (2a, 3a, 4a) compounds 3a and 4a show the most pronounced inhibition of lipid peroxidation, and it appears that the phenyl substitution at position 1 of the heterocyclic ring leads to a rapid decrease in inhibitory activity (2a).
For the amide derivatives, the most significant inhibitory effect is exhibited by compound 5c, which is the 4-bromo-pyrazoline amide derivative. Bromine has the higher lipophilic π-contribution. Thus, the lipophilic contribution of the substituent in position 4 highly influences the increase of the antioxidant activity. Furthermore, for acetyl-derivatives, compound 6c (4-Br substituent) shows the best lipid peroxidation inhibition (71%). This effect is followed by compound 5c. In general, the acetyl-pyrazoline derivatives show improved inhibitory activity compared to the original chalcones apart from compounds 1a and 6a respectively. However, none of the synthesized compounds present higher inhibition compared to the reference compound.
All compounds appear to show medium to very good inhibitory activity against lipid peroxidation with the only exception of compound 5b (8%). Generally better activity is shown by compounds 4a and 4b.
Soybean lipoxygenase SLOX-1 at pH 9 is used in vitro. During this assay linoleic acid sodium salt is converted to the corresponding 13-hydroperoxide. The reaction is recorded photometrically at 234 nm using the UV-based enzyme assay [59]. This method does not provide quantitative results for the inhibition of mammalian 5-LOX. It is known that soybean LOX inhibitory activity induced by NSAIDs is qualitatively quite similar to the inhibition observed on the rat mast cells LOX and this assay may be used as a qualitative or semi-quantitative screen for such activity.
The best inhibition on SLOX is shown by the simple chalcone 1a (IC50 = 10 μM). The other dichalcones show low inhibitory activity ranging between 24–38%. Among the members of series 2a–f the most active compounds are 2d (2.5 μM) and 2e (0.35 μM) with a chlorine and dimethyl-amino substituent at 4-position respectively. The presence of electron donors substituents at the 4-position of the dibenzalketone groups influences the activity. The last one (2e) shows activity comparable to that of the reference compound NDGA (0.45 μM). For subgroup 3a–f possessing the 4-bromo-benzyl substitution at position 1 of the pyrazolyl ring, the most active is compound 3v, with a dimethyl-amino group. Similarly, among the compounds 4a–f which have 4-cyano-benzyl substitution at position 1 of the pyrazole ring, the most active is compound 4d, substituted with a chlorine. It is observed as in the case of antioxidant activity with the DPPH free radical, the most active compounds are those bearing the dimethylamino group, 2e and 3e. However, 4-cyano-substituted derivatives of dimethylamino-derived pyrazoles have appeared almost inactive 4e (6%). Additionally, the compounds bearing chlorine in their structure, 2d and 4d, exhibit high inhibitory activity against LOX. However, replacing 4-chloro with 4-bromo-substitution does not seem to favor the activity, 3d (11%).
Among the amide-derivatives the 4-chlorine substituted derivative (5d) presents the best inhibitory activity. Considering the acetyl pyrazoline derivatives, it appears that the presence of 4-dimethylamine substituent (6e) favors activity. Compound 6e, with the best IC50 = 40 μM shows the highest substituent molecular refractivity (MR) value. It seems that the presence of a bulky substituent leads to an increase in inhibition. From the literature it is highlighted that MR of the substituents often contributes to lipoxygenase inhibitory activity, indicating favorable polar interactions [60]. Similarly, for the amide derivatives the 4-Cl substituted derivative shows the best activity (IC50 = 80 μM).

2.4. Docking Simulation Soybean Lipoxygenase Studies

Docking studies were performed to soybean lipoxygenase-1 (PDB ID: 3PZW) complying with the experimentally used protocol. Lipoxygenases are hyperoxidases containing a “non-heme” iron per molecule catalyzing the conversion of free and esterified polyunsaturated fatty acids to hydroperoxides. Crystal structure of soybean lipoxygenase-1 (PDB ID: 3PZW) lacks a co-crystallized ligand and imposes the identification of potential allosteric binding sites apart from the iron-binding site and the substrate-binding cavity as referred in recent literature. Detsi, A. et al. [61] have identified using SiteMap’s three potential binding sites [62]. According to researchers Site 1 is placed between the amino terminal β-barrel (PLAT domain) and the α-helical domain where the catalytic iron is located while Sites 2 and 3 are placed to the α-helical domain. Additionally, Site 1 has been previously referred as potential binding site when blind docking is accomplished [61,63,64].
Based on previous findings in this present study, compounds were evaluated for the mode of binding to both the active site as well as the whole enzyme with the aim of performing a comprehensive study of all possible allosteric centers. It appears that the compounds besides binding in an allosteric manner show similarities in terms of the binding mode. Probably due to stereochemical hindrances they are not allowed to enter the active site of the enzyme, which is confirmed by earlier studies. On the basis of the above results, it is concluded that the compounds act allosterically thereby blocking the enzyme activity. The most active compound 2e presents a binding score of −9.7 kcal/mol and develops hydrophobic interactions with the amino acids Val126, Asn128, Leu246, Val520, Tyr525, Lys526, Pro530 and Trp772. Figure 3 shows the optimal binding mode of compound 2e to the enzyme lipoxygenase from soybean (PDB ID: 3PZW). The iron of the active site is shown as an orange sphere. Moreover, Figure 4 describes the ligand interaction diagram of compound 2e with soybean lipoxygenase (ID: 3PZW).

3. Experimental Section

3.1. Materials and Instruments

Analytical grade solvents, chemical and biochemical reagents have been used and purchased from commercial suppliers (Merck, Merck KgaA, Darmstadt, Germany, Fluka Sigma-Aldrich Laborchemikalien GmbH, Hannover, Germany, Alfa Aesar, Karlsruhe, Germany and Sigma, St. Louis, MO, USA). Soybean lipoxygenase, arachidonic acid (AA), 2,2-azinobis-2-methyl-propanimidamine HCl (AAPH) were obtained from Sigma Chemical, Co. Nordihydroguaretic acid (NDGA), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 6-Hydroxy-2,5,7,8-tetramethyl-chroman2-carboxylic acid (Trolox) were acquired from the Sigma-Aldrich Chemical Co. (St. Louis, MO, USA).
Melting points were determined on a MEL-Temp II (Lab. Devices, Holliston, MA, USA). In vitro tests were carried out using a UV-Vis spectra and recorded on a Perkin-Elmer 554 double-beam spectrophotometer (Perkin-Elmer Corporation Ltd., Lane Beaconsfield, Bucks, UK). Infrared spectra (KBr pellets) were recorded with Perkin-Elmer 597 spectrophotometer (Perkin-Elmer Corporation Ltd., Lane Beaconsfield, Bucks, UK). The 1H Nucleic Magnetic Resonance (1H-NMR) spectra were acquired on an Agilent 500/54 (DD2) at 500 MHz in CDCl3 using tetramethylsilane as an internal standard. Agilent 500/54 (DD2) 13C NMR spectra were acquired at 125 MHz in CDCl3 solutions with tetramethylsilane serving as an internal reference. Coupling constants J are expressed in Hz, and chemical shifts are reported in ppm. Thermo Fisher Scientific Inc., Waltham, MA, USA, used MeOH as the solvent to calculate mass spectra using an LC-PDA-MS Thermo Finnigan system (LC Pump Plus, Autosampler, Surveyor PDA Plus Detector) interfaced with an ESI MSQ Plus (Thermo Finnigan). Thin-layer chromatography using 5554 F254 Silica gel/TLC cards (Merck and Fluka Chemie GmbH Buchs, Steinheim, Switzerland) was used to monitor the reaction progress. Silica gel 60 F254 plates with a diameter of 2 mm were utilized for preparative thin layer chromatography (prep TLC) by Merck KgaA (ICH078057). Merck (20 × 20 cm) plates were used for the experimental assessment of the lipophilicity using reverse phase thin-layer chromatography (RP-TLC) TLC-Silica gel 60 F254 DC Kieselgel.

3.2. Chemistry General Procedure

3.2.1. Synthesis of Dibenzalacetones (1a–f)

The appropriate substituted benzaldehyde (0.02 mol) and acetone (0.01 mol) were dissolved in absolute ethanol (16 mL) [42]. After stirring, sodium hydroxide solution (10% w/v) is added dropwise with cooling till the pH of the solution, becomes alkaline. The mixture is stirred at room temperature for 1–24 h, monitoring the reaction with thin layer chromatography (TLC). After completion of the reaction, the formed precipitate was filtered, washed with water, dried and recrystallized from ethanol/water or abs. ethanol to obtain the final products. With the exception of compound 1f, all the others synthesized dibenzalacetones have been reported in the literature [44,45,46,47]. The identification of the compounds (1a–e) was carried out by the determination of the melting point and spectroscopic analysis through 1H NMR being in accordance with the literature [44,45,46,47].
(1E,4E)-1,5-diphenyl-1,4-pentadien-3-one (1a): The spectral data were in agreement with the literature data [44].
(1E,4E)-1,5-bis(4-fluorophenyl)-1,4-pentadien-3-one (1b): The spectral data were in agreement with the literature data [45].
(1E,4E)-1,5-bis(4-bromophenyl)-1,4-pentadien-3-oneone (1c): The spectral data were in agreement with the literature data [46].
(1E,4E)-1,5-bis(4-chlorophenyl)-1,4-pentadien-3-one (1d): The spectral data were in agreement with the literature data [46].
(1E,4E)-1,5-bis(4-dimethylamino phenyl)-1,4-pentadien-3-one (1e): The spectral data were in agreement with the literature data [47].
(1E,4E)-1,5-bis(4-(trifluoromethyl)phenyl)-1,4-pentadien-3-one (1f): Yield: 30%, yellowish solid, m.p.: 150–152 °C (recrystallisation from abs. C2H5OH). 1H NMR (500 MHz, CDCl3) δ 7.76 (d, J = 16.1 Hz, 2H, -CH=CHC(=O)CH=CH-), 7.73–7.67 (m, 8H, ArH), 7.14 (d, J = 15.9 Hz, 2H, -CH=CHC(=O)CH=CH-). 13C NMR (126 MHz, CDCl3): δ 188.2, 142.0, 138.1, 128.7, 127.3, 126.1 (q, J = 3.8 Hz), 123.9 (d, J = 271.3 Hz). IR (KBr, cm-1): 3400.6, 1655.9 (C=O), 1600.0 (C=C), 1320.3. Anal. C, H, N. Calc%: (C19H12F6O) C: 61.63, H: 3.27 Found%: C: 61.78, H: 3.36.

3.2.2. Synthesis of Dihydro-Pyrazoles (2a–f, 3a–f, 4a–f)

The litterature synthetic method [43] of the dihydro-pyrazoles was optimised using microwave irradation.
Equimolar amounts of the appropriate substituted dibenzelacetones and 4-substituted phenylhydrazine hydrochloride (1 mmol) in absolute ethanol (3 mL) are added in a microwave vial. Sodium hydroxide (2.5 mmol, 0.10 g) is then added and the pH of the solution urned to alkaline. The resulting micture was irradiated at 100 W, at 75 °C, for 30 min, monitoring the reactionby thin layer chromatography (TLC). The formed precipitate is filtered under vacuum, washed with water and cold ethanol, dried and recrystalised from absolute ethanol or ethanol-water or ethyl acetate and petroleum ether to obtain the final products 2a–f, 3a–f, 4a–f in pure form. Some of the synthesized pyrazoles have been reported in the literature [43,48,49,50,66].
(E)-1,5-Diphenyl-3-styryl-4,5-dihydro-1H-pyrazole (2a): The spectral data were in agreement with the literature data [43].
(E)-5-(4-fluorophenyl)-3-(4-(fluorostyryl)-1-phenyl-4,5-dihydro-1H-pyrazole (2b): The spectral data were in agreement with the literature data [48].
(E)-5-(4-bromophenyl)-3-(4-(bromostyryl)-1-phenyl-4,5-dihydro-1H-pyrazole (2c): The spectral data were in agreement with the literature data [49].
(E)-5-(4-chlorophenyl)-3-(4-(chlorostyryl)-1-phenyl-4,5-dihydro-1H-pyrazole (2d): The spectral data were in agreement with the literature data [49].
(E)-4-[2-(5-(4-dimethylamino)phenyl)]-1-phenyl-4,5-dihydro-(1H-pyrazol-3-yl)-vinyl)-N,N-dimethylaniline (2e): The spectral data were in agreement with the literature data [43].
(E)-1-phenyl-5-[(4-trifluoromethyl)-phenyl)]-3-[(4-trifluoromethyl)-styryl]-4,5-dihydro-1H-pyrazole (2f): Yield: 50%, yellow solid, m.p.: 188–190 °C (recrystallisation from C2H5OH/H2O). 1H NMR (500 MHz, CDCl3): δ 7.60 (t, J = 8.8 Hz, 3H, ArH), 7.53 (d, J = 8.2 Hz, 2H, ArH), 7.41 (d, J = 8.0 Hz, 2H), 7.30 (d, J = 16.3 Hz, 1H, -CH=CH-), 7.25–7.16 (m, 3H, ArH), 7.02–6.96 (m, 2H, ArH), 6.87–6.80 (m, 1H, ArH), 6.54 (d, J = 16.3 Hz, 1H, -CH=CH-), 5.36 (dd, J = 12.4, 6.6 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.76 (dd, J = 16.7, 12.4 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.01 (dd, J = 16.8, 6.6 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 147.7, 146.1, 143.7, 140.1, 131.1, 130.0, 129.7, 129.3, 126.5 (q, J = 3.8 Hz), 126.8, 126.3, 125.9 (q, J =3.8 Hz), 124.7 (d, J = 280 Hz), 123.9, 120.2, 113.6. IR (KBr, cm−1): 1594.4 (C=N), 1499.3 (C=C), 1320.3 (C-N), 1225.2, HRMS (MeOH) (ESI, m/z), (M.W. 460.1374) [M+H]+ = 461.11418.
(E)-1-(4-bromophenyl)-5-phenyl-3-styryl-4,5-dihydro-1H-pyrazole (3a): The spectral data were in agreement with the literature data [42].
(E)-1-(4-bromophenyl)-5-(4-fluorophenyl)-3-(4-fluorophenyl)-4,5-dihydro-1H-pyrazole (3b): Yield: 80%, orange solid, m.p.: 154–156 °C (recrystallisation from CH3CO2CH2CH3/petroleum ether). 1H NMR (500 MHz, CDCl3): δ 7.41 (dd, J = 8.9, 5.3 Hz, 2H, ArH), 7.27–7.19 (m, 2H, ArH), 7.10–7.12 (m, 2H, ArH), 7.09 (d, J = 16.4 Hz, 1H, -CH=CH-), 7.01–7.06 (m, 4H, ArH), 6.90 (d, J = 9.0 Hz, 2H, ArH), 6.52 (d, J = 16.4 Hz, 1H, -CH=CH-), 5.21 (dd, J = 12.2, 6.6 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.70 (dd, J = 16.8, 12.2 Hz, 1H, -CH2-, C4 of dihydropyrazole), 2.98 (dd, J = 16.8, 6.6 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 162.8 (d, J = 247.5 Hz), 162.4 (d, J = 245 Hz), 148.8, 142.6, 137.7 (d, J = 3.2 Hz), 132.8 (d, J = 3.1 Hz), 132.1, 129.0, 128.3 (d, J = 8.1 Hz), 127.6 (d, J = 8.1 Hz), 124.5, 121.2 (d, J = 2.6 Hz), 116.4 (d, J = 21.7 Hz), 114.7, 63.6, 42.5. IR (KBr, cm−1): 1594.4 (C=N), 1504.9 (C=C), 1328.7 (C-N), 1233.6., HRMS (MeOH) (ESI, m/z), (M.W. 438.0543) [M-147.0484 + K + 2MeOH]+ = 395.1118.
(E)-1-(4-bromophenyl)-5-(4-bromophenyl)-3-(4-bromophenyl)-4,5-dihydro-1H-pyrazole (3c): Yield: 52%, yellow solid, m.p.: 212–214 °C (recrystallisation from CH3CO2CH2CH3/petroleum ether). 1H NMR (500 MHz, CDCl3): δ 7.50–7.43 (m, 4H, ArH), 7.33–7.24 (m, 2H, ArH), 7.16 (d, J = 16.3 Hz, 1H, -CH=CH-), 7.12 (dd, J = 8.8, 2.8 Hz, 4H, ArH), 6.92–6.85 (m, 2H, ArH), 6.47 (d, J = 16.3 Hz, 1H, -CH=CH-), 5.20 (dd, J = 12.3, 6.6 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.70 (dd, J = 16.8, 12.3 Hz, 1H, -CH2-, C4 of dihydropyrazole), 2.98 (dd, J = 16.8, 6.5 Hz, 1H, C4 of dihydropyrazole).13C NMR (126 MHz, CDCl3): δ 151.4, 143.3, 135.9, 132.1, 132.0, 130.3, 130.2, 129.5, 128.2, 126.3, 121.9, 120.7, 105.7, 55.6, 40.6. IR (KBr, cm−1): 1591.6 (C=N), 1490.9 (C=C), 1320.3 (C-N). HRMS (MeOH) (ESI, m/z), (M.W. 557.8941) [M-195.9636 + Na]+ = 385.0917.
(E)-1-(4-bromo-phenyl)-5-(4-chloro-phenyl)-3-(4-chlorostyryl)-4,5-dihydro-1H-pyrazole (3d): Yield: 68%, yellowish solid, m.p.: 190–192 °C (recrystallisation from CH3CO2CH2CH3/petroleum ether). 1H NMR (500 MHz, CDCl3): δ 7.36 (d, J = 8.6 Hz, 2H, ArH), 7.34–7.28 (m, 4H, ArH), 7.21–7.14 (m, 3H, -CH=CH- and 2H ArH), 7.17–7.08 (m, 2H, ArH), 6.92–6.85 (m, 2H, ArH), 6.49 (d, J = 16.3 Hz, 1H, -CH=CH-), 5.21 (dd, J = 12.3, 6.6 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.70 (dd, J = 16.8, 12.3 Hz, 1H, -CH2-, C4 of dihydropyrazole), 2.97 (dd, J = 16.8, 6.6 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 148.6, 142.5, 140.3, 135.1, 134.1, 133.8, 132.0, 129.6, 129.2, 129.1, 127.9, 127.3, 124.6, 121.9, 114.7, 63.7, 42.3. IR (KBr, cm−1): 1591.6 (C=N), 1490.9 (C=C), 1400.0 (C-N), 1320.3. HRMS (MeOH) (ESI, m/z), (M.W. 469.9952) [M-154.9496 + MeOH + K]+ = 385.1446.
(E)-4-(1-(4-bromophenyl))-3-(4-dimethylamino)-styryl-4,5-dihydro-(1H-pyrazol-3-yl)-vinyl)-N,N-dimethylaniline (3e): Yield: 52%, orange solid, m.p.: 215–217 °C (recrystallisation from CH3CO2CH2CH3/petroleum ether). 1H NMR (500 MHz, CDCl3): δ 7.36–7.33 (m, 2H, ArH), 7.13–7.08 (m, 4H, ArH), 6.98–7.03 (m, 1H, ArH), 6.96–6.93 (m, 2H -CH=CH- and ArH), 6.65–6.70 (m, 4H, ArH), 6.50 (d, J = 16.3 Hz, 1H, CH=CH-), 5.09 (ddd, J = 10.8, 12.6, 3.4 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.64 (ddd, J = 16.0, 11.9, 3.5 Hz, 1H, -CH2-, C4 of dihydropyrazole), 2.99 (s, 7H, -CH2-, C4 of dihydropyrazole and 2 CH3 groups) 2.93 (s, 6H, 2 CH3 groups). 13C NMR (126 MHz, CDCl3): δ 150.5, 150.1, 143.4, 133.7, 129.8, 128.8, 128.0, 126.8, 125.0, 123.4, 117.3, 114.5, 113.0, 112.4, 63.8, 42.8, 40.7, 40.5. IR (KBr, cm−1): 1594.4 (C=N), 1493.7 (C=C), 1356.6 (C-N), 1328.7. HRMS (MeOH) (ESI, m/z), (M.W. 488.1576) [M-147.0922 + 2MeOH + K + H]+ = 445.0893.
(E)-1-(4-bromophenyl)-5-[(4-trifluoromethyl)-phenyl)]-3-[(4-trifluoromethyl)-styryl]-4,5-dihydro-1H-pyrazole (3f): Yield: 52%, yellow solid, m.p.: 177–179 °C (recrystallisation from C2H5OH/H2O). 1H NMR (500 MHz, CDCl3): δ 7.65–7.57 (m, 4H, ArH), 7.53 (dd, J = 8.5, 3.0 Hz, 2H, ArH), 7.38 (dd, J = 8.4, 3.1 Hz, 2H, ArH), 7.27 (d, J = 16.4 Hz, 1H, -CH=CH-), 7.18–7.11 (m, 2H, ArH), 6.89–6.92 (m, 2H), 6.56 (d, J = 16.4 Hz, 1H, -CH=CH-), 5.33 (dd, J = 12.3, 6.7 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.77 (dd, J = 16.8, 12.3 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.02 (dd, J = 16.8, 6.6 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 148.1, 145.5, 142.0, 139.8, 131.5, 129.1, 126.7, 126.4 (q, J = 3.8 Hz), 126.1, 125.8 (q, J = 3.8 Hz), 124.9, 123.5, 114.6, 63.7, 42.0. IR (KBr, cm−1): 1594.4 (C=N), 1493.7 (C=C), 1398.8 (C-N), 1323.1. HRMS (MeOH) (ESI, m/z), (M.W. 538.0479) [M + K]+ = 577.1337
(E)-4-(5-phenyl-3-styryl-4,5-dihydro-1H-pyrazo-1-yl)-benzonitrile (4a): The spectral data were in agreement with the literature data [42].
(E)-4-(5-(4-fluorophenyl)-3-(4-fluorostyryl)-4,5-dihydro-1H-pyrazo-1-yl)-benzonitrile (4b): Yield: 73%, yellow solid, m.p.: 228–230 °C (recrystallisation from C2H5OH). 1H NMR (500 MHz, CDCl3): δ 7.44–7.40 (m, 4H, ArH), 7.21–7.17 (m, 2H, ArH), 7.10 (d, J = 16.4 Hz, 1H, -CH=CH-), 7.02–7.07 (m, H), 6.97 (d, J = 8.5 Hz, 2H), 6.60 (d, J = 16.3 Hz, 1H, -CH=CH-), 5.30 (dd, J = 12.1, 5.5 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.75 (dd, J = 17.0, 12.1 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.04 (dd, J = 16.9, 5.5 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 150.9, 146.4, 141.6, 136.8, 133.8, 133.5, 132.4, 128.6 (d, J = 8.1 Hz), 127.4 (d, J = 8.1 Hz), 120.7, 120.2, 116.6 (d, J = 21.8 Hz), 116.1 (d, J = 21.8 Hz), 113.2, 101.1 62.8, 42.5. IR (KBr, cm−1): 2212.9 (C≡N), 1597.2 (C=N), 1507.7 (C=C), 1339.9 (C-N). HRMS (MeOH) (ESI, m/z) (M.W. 385.1391) [M + H]+ = 386.14546.
(E)-4-(5-(4-bromophenyl)-3-(4-bromostyryl)-4,5-dihydro-1H-pyrazol-1-yl)-benzonitrile (4c): Yield: 78%, yellow solid, m.p.: 250–252 °C (recrystallisation from CH3CO2CH2CH3/petroleum ether). 1H NMR (500 MHz, CDCl3): δ 7.48 (dd, J = 8.4, 1.6 Hz, 4H, ArH), 7.42 (d, J = 9.0 Hz, 2H, ArH), 7.31 (d, J = 8.6 Hz, 2H, ArH), 7.16 (d, J = 16.4 Hz, 1H, -CH=CH-), 7.09 (d, J = 8.4 Hz, 2H, ArH), 6.96 (d, J = 8.8 Hz, 2H, ArH), 6.56 (d, J = 16.4 Hz, 1H, -CH=CH-), 5.28 (dd, J = 12.2, 5.6 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.75 (dd, J = 17.0, 12.2 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.04 (dd, J = 17.1, 5.6 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 150.7, 146.2, 135.1, 133.7, 133.5, 132.8, 132.2, 128.3, 127.4, 121.5, 113.2, 101.4, 62.9, 42.3. IR (KBr, cm−1): 2212.9 (C≡N), 1600.0 (C=N), 1513.3 (C=C), 1328.7 (C-N). HRMS (MeOH) (ESI, m/z), (M.W. 504.9789) [M + H]+ = 505.9847.
(E)-4-(5-(4-chlorophenyl)-3-(4-chlorostyryl)-4,5-dihydro-1H-pyrazol-1-yl)-benzonitrile (4d): Yield: 75%, yellow solid, m.p.: 227–229 °C (recrystallisation from CH3CO2CH2CH3/petroleum ether). 1H NMR (500 MHz, CDCl3): δ 7.42 (d, J = 8.6 Hz, 2H, ArH), 7.38 (d, J = 8.6 Hz, 2H, ArH), 7.36–7.30 (m, 3H, -CH=CH- and 2H ArH), 7.18–7.12 (m, 3H, ArH), 6.97 (d, J = 8.6 Hz, 2H, ArH), 6.58 (d, J = 16.3 Hz, 1H, -CH=CH-), 5.30 (dd, J = 12.2, 5.5 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.75 (dd, J = 17.0, 12.2 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.04 (dd, J = 17.0, 5.5 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 147.7, 146.2, 143.7, 140.1, 131.1, 129.7, 129.3, 126.8, 126.5, 126.3, 125.9, 124.0, 120.2, 113.7, 63.9, 42.1. IR (KBr, cm−1): 2218.5 (C≡N), 1600.0 (C=N), 1510.5 (C=C), 1328.7 (C-N). HRMS (MeOH) (ESI, m/z), (M.W. 417.0800) [M + H]+ = 418.0863.
(E)-4-(5-(4-(dimethylamino)phenyl)-3-(4-(dimethylamino)styryl)-4,5-dihydro-1H-pyrazo-1yl)-benzonitrile (4e): Yield: 55%, orange solid, m.p.: 220–222 °C (recrystallisation from CH3CO2CH2CH3/petroleum ether). 1H NMR (500 MHz, CDCl3): δ 7.36 (dd, J = 14.9, 9.0 Hz, 4H, ArH), 7.07 (d, J = 8.9 Hz, 2H, ArH), 7.02–6.96 (m, 3H, -CH=CH- and 2H ArH), 6.69–6.65 (m, 4H, ArH), 6.57 (d, J = 16.3 Hz, 1H, -CH=CH-), 5.18 (dd, J = 11.9, 5.4 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.68 (dd, J = 17.5, 11.9 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.05 (dd, J = 16.8, 5.5 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.00 (s, 6H, 2 CH3 groups), 2.92 (s, 6H, 2 CH3 groups). 13C NMR (126 MHz, CDCl3): δ 152.4, 150.7, 146.8, 135.4, 133.3, 130.5, 128.2, 126.6, 124.4, 120.7, 116.5, 113.0, 112.9, 112.3, 99.7, 62.8, 42.7, 40.6, 40.4. IR (KBr, cm−1): 2207.3 (C≡N), 1597.20 (C=N), 1516.1 (C=C), 1334.3 (C-N). HRMS (MeOH) (ESI, m/z), (M.W. 435.2423) [M + H]+ = 436.2493.
(E)-4-(5-(4-(trifluoromethyl)phenyl)-3-(4-(trifluoromethyl)styryl)-4,5-dihydro-1H-pyrazol-1-yl)-benzonitrile (4f): Yield: 67%, yellowish solid, m.p.: 245–247 °C (recrystallisation from C2H5OH). 1H NMR (500 MHz, CDCl3): δ 1H NMR (500 MHz, CDCl3): δ 7.66–7.59 (m, 4H, ArH), 7.54 (d, J = 8.2 Hz, 2H, ArH), 7.44 (d, J = 8.8 Hz, 2H, ArH), 7.35 (d, J = 8.1 Hz, 2H, ArH), 7.27 (d, J = 16.4 Hz, 1H, -CH=CH-), 6.98 (d, J = 8.9 Hz, 2H, ArH), 6.64 (d, J = 16.4 Hz, 1H, -CH=CH-), 5.41 (dd, J = 12.3, 5.5 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.82 (dd, J = 17.0, 12.3 Hz, 1H, -CH2-, C4 of dihydropyrazole), 3.08 (dd, J = 17.0, 5.5 Hz, 1H, -CH2-, C4 of dihydropyrazole). 13C NMR (126 MHz, CDCl3): δ 150.3, 146.1, 144.8, 139.5, 133.6, 133.3, 127.0, 126.8 (q, J = 3.8 Hz), 126.1, 126.0 (q, J = 3.8 Hz), 123.1, 120.0, 113.3, 63.1, 42.2. IR (KBr, cm−1): 2212.9 (C≡N), 1602.8 (C=N), 1513.3 (C=C), 1328.7 (C-N). HRMS (MeOH) (ESI, m/z), (M.W. 485.1327) [M + H]+ = 486.1395.

3.2.3. Synthesis of Pyrazole-Carboxamides (5a–e)

To a vial suitable for microwave irradiation (Microwave Irradiation MWI) were added 0.5 mmol of the corresponding dibenzalacetone and 0.55 mmol of semicarbazide hydrochloride. Absolute ethanol (1.25 mL) is used as solvent. The reaction is irradiated at 200 W, at 75 °C for 20 min. The progress of the reaction is monitored by thin-layer chromatography (TLC). When the reaction is completed, the reaction mixture is decanted into a beaker containing cold deionized water and ice. A precipitate is formed which is collected by filtration under vacuum, washed with deionized water, dried and recrystallized from methanol/water or purified through preparative layer chromatography to give the final product.
(E)-5-phenyl-3-styryl-4,5-dihydro-1H-pyrazole-1-carboxamide (5a): The spectral data were in agreement with the literature data [50].
(E)-5-(4-fluorophenyl)-3-(4-fluorostyryl)-4,5-dihydro-1H-pyrazole-1-carboxamide (5b): Yield: 9%, m.p.: 97–99 °C (PLC 5/95 v/v CH3OH/CHCl3). 1H NMR (500 MHz, CDCl3): δ 1H NMR (500 MHz, CDCl3): δ 7.43 (dd, J = 8.9, 5.3 Hz, 2H, ArH), 7.20 (dd, J = 8.7, 5.2 Hz, 2H, ArH), 7.06 (t, J = 8.6 Hz, 2H, ArH), 7.01 (t, J = 8.7 Hz, 2H, ArH), 6.96 (d, J = 16.4 Hz, 1H, -CH=CH-), 6.68 (d, J = 16.4 Hz, 1H, -CH=CH-), 5.45 (dd, J = 12.0, 5.0 Hz, 1H, -CH-, C5 of dihydropyrazole), 3.62 (dd, J = 17.3, 12.0 Hz, 1H, -CH2-, C4 of dihydropyrazole), 2.99 (dd, J = 17.3, 5.1 Hz, 1H, -CH2-, C4 of dihydropyrazole).13C NMR (125 MHz, CDCl3): δ 163.2 (d, J = 248.8 Hz), 162.3 (d, J = 245 Hz), 155.3, 152.9, 138.3 (d, J = 3.2 Hz), 135.6, 132.0 (d, J = 3.4 Hz), 128.8 (d, J = 8.1 Hz), 127.3 (d, J = 8.1 Hz), 120.4 (d, J = 2.4 Hz), 116.1 (d, J = 21.9 Hz), 115.9 (d, J = 21.6Hz), 59.5, 41.8. Anal. C, H, N. Calc%: (C18H15F2N3O) C: 66.05, H: 4.62, N: 12.84 Found%: C: 65.97, H: 4.57, N: 12.64.
(E)-5-(4-bromophenyl)-3-(4-bromostyryl)-4,5-dihydro-1H-pyrazole-1-carboxamide (5c): Yield: 15%, m.p.: 170–172 °C (recrystallisation from CH3OH/H2O). 1H NMR (500 MHz, Methanol-d4): δ 1H NMR (500 MHz, CD3OD) δ 7.82 (s, 1H), 7.63 (d, J = 8.3 Hz, 2H), 7.55 (d, J = 8.5 Hz, 2H), 7.52 (d, J = 8.5 Hz, 1H), 7.49 (d, J = 8.4 Hz, 1H), 7.46 (d, J = 8.3 Hz, 2H), 7.17 (d, J = 15.9 Hz, 1H), 7.14 (s, 1H), 6.86 (d, J = 16.5 Hz, 1H), 5.41 (dd, J = 12.0, 5.1 Hz, 1H), 3.72 (dd, J = 17.6, 12.1 Hz, 1H), 3.03–2.97 (m, 1H). 13C NMR (125 MHz, CDCl3): δ 171.6, 152.4, 135.3, 135.1, 132.1, 132.0, 131.9, 131.3, 130.2, 128.3, 127.2, 121.1, 59.6, 41.5. IR (KBr, cm−1): 3465.6 (N-H stretch), 1670.7 (C=O stretch), 1588.7 (C=C bond stretch), 1487.8, 1400.8. Anal. C, H, N. Calc%: (C18H15Br2N3O) C: 48.14, H: 3.37, N: 9.36 Found%: C: 48.19, H: 3.41, N: 9.39.
(E)-5-(4-chlorophenyl)-3-(4-chlorostyryl)-4,5-dihydro-1H-pyrazole-1-carboxamide (5d): The spectral data were in agreement with the literature data [44].
(E)-5-(4-dimethylaminophenyl)-3-(4-dimethylaminostyryl)-4,5-dihydro-1H-pyrazole-1-carboxamide (5e): The spectral data were in agreement with the literature data [53].

3.2.4. Synthesis of Dihydro-Pyrazol-Ethanones (6a–e)

To a vial suitable for microwave irradiation were added 0.5 mmol of the corresponding dibenzalacetone and 1 mmol of 98% hydrazine monohydrate inglacial acetic acid (1.25 mL). The reaction is irradiated at 200 W, at 100 °C and for 20 min. The reaction is monitored by TLC. Upon completion, the reaction mixture is decanted into a beaker containing cold deionized water and ice. A precipitate is formed which is collected by filtration under vacuum, washed with deionized water, dried and recrystallized from methanol/water to obtain the final product.
(E)-5-phenyl-3-styryl-4,5-dihydro-1-H-pyrazol-1-ethan-1-one (6a): The spectral data were in agreement with the literature data [50].
(E)-5-(4-fluorophenyl)-3-(4-fluorostyryl)-4,5-dihydro-1-H-pyrazol-1-ethan-1-one (6b): The spectral data were in agreement with the literature data [52].
(E)-5-(4-bromophenyl)-3-(4-bromostyrene)-4,5-dihydro-1-H-pyrazol-1-ethan-1-one (6c): The spectral data were in agreement with the literature data [51].
(E)-5-(4-chlorophenyl)-3-(4-chlorostyryl)-4,5-dihydro-1-H-pyrazol-1-ethan-1-one (6d): The spectral data were in agreement with the literature data [50].
(E)-5-(4-dimethylaminophenyl)-3-(4-dimethylaminostyryl)-4,5-dihydro-1-H-pyrazol-1-ethan-1-one (6e): The spectral data were in agreement with the literature data [53].
1H-NMR and 13C-NMR of the novel synthesized derivatives can be found at the Supplementary Material.

3.3. Experimental of Physicochemical Studies

Experimental Determination of Lipophilicity by Reverse Phase Thin Layer Chromatography (RP-TLC)—Determination of RM Values

In this experiment, TLC silica gel 60 F254 1.05715.0001 commercial glass plates from Merck were used. The plates were first immersed in a 5% v/v solution of liquid paraffin in petroleum ether and left for 90 s to become completely impregnated with the stable lipophilic phase. They were then activated by standing for 30 min in an oven at 40 °C and kept there until the time of use. A 70% v/v MeOH/H2O mixture was used as the mobile phase. The mobile phase was saturated with a few drops of liquid paraffin before being used. The spots of the compounds were placed on the plate at a distance of 2 cm from the edges of the plate and also from each other. The development of the spots on the plates was carried out in closed chromatography chambers where the atmosphere is saturated with the mobile phase at room temperature. At the end of development, the solvent-formed front was marked and the plates are dried at 80 °C for about 20–30 min. The appearance of the spots was made under an ultraviolet light lamp. The Rf values were the average of 5–6 measurements for each compound and assuming that the compounds will have been rotated to different positions on the plates. The RM values were calculated from the corresponding Rf values according to the equation [67].
RM = log [(1/Rf) − 1]

3.4. Biological In Vitro Tests

For all biological tests, 10 mM stock solutions of the test compounds in DMSO were prepared and then diluted for the determination of the IC50 values. Measurements were performed twice and the average of these was used. The standard deviation was less than 10%.

3.4.1. Determination of the Reducing Activity of the Stable Radical DPPH

The tested compounds (0.1 mM final concentration) dissolved in DMSO were incubated with a solution of DPPH in absolute ethanol in absence of light. The absorbance at 20 and 60 min at 517 nm was recorded at room temperature [68,69]. NDGA was used as the reference compound.

3.4.2. Anti-Lipid Peroxidation (AAPH) Activity

The interaction of free radicals with cell membrane lipids induces free radical chain reactions, a process called lipid peroxidation [70]. 930 μL of a phosphate buffer solution (0.05 M, pH = 7.4), 10 μL of the sodium linolate solution (16 mM in a buffer solution of Tris-HCl pH = 9) and 10 μL of the tested compounds (stock solutions 100 μΜ) were mixed and the oxidative procedure started after the addition of 50 μL AAPH at 37 °C under air conditions. The conjugated diene’s absorbance was measured at 234 nm at a thermostable spectrophotometer (37 °C) according to previous publication [71].

3.4.3. Inhibition of Soybean Lipoxygenase

To a quartz cell, add 790 μL of Tris-HCl pH = 9.0 buffer, 200 μL of plant-derived lipoxygenase solution (1:9 × 10−4 w/v, in saline), 10 μL of the test compound solution and 100 μL of sodium linoleate solution (3 mM concentration). The absorbance was measured at 234 nm, where the change in absorbance due to the conversion of linoleic acid to 13-hydroxylinolenic acid was recorded. A solution of 790 μL of Tris-HCl pH = 9.0 buffer, 200 μL of a plant-derived lipoxygenase solution (1:9 × 10−4 w/v, in saline), 10 μL of DMSO and 100 μL of sodium linoleate solution (3 mM concentration) was used as a control. NDGA was used as a reference compound [72].

3.5. Molecular Docking and Pharmaco-Similarity Studies

3.5.1. Molecular Docking on Soybean Lipoxygenase

The visualization and preprocessing of the protein (PDB ID: 3PZW) was conducted using UCSF Chimera (version 1.15) [73]. Water molecules and extraneous crystallographic material were removed with Chimera. Modeller (v. 10.3) [74] was applied to add missing residues (Met1-Phe2-Ser3-Ala4-Gly5, Glu21-Val22-Asn23-Pro24-Asp25-Gly26-Ser27-Ala28-Val28-Asp29, Ile117-Ser118-Asn119-Gln120). Hydrogen atoms and charges were added with AmberTools [75,76]. The charge on iron was adjusted to +2.0 applying the 12–6 LJ nonbonded model [77]. Histidines His499, His504 and His690 coordinating iron were set neutral (δ-nitrogen protonated state). TIP3P explicit water model was used. The size of the box has a minimal distance of 12 Å between the solute and the edge of the box. Furthermore, the generation and minimization of ligand 3D coordinates were carried out using Open Babel (version 3.1.1) [78] with the MMFF94 force field [79] ACPYPE [80] was utilized to produce the ligand topologies and parameters using AnteChamber (AmberTools v. 22.10) [81] The energy minimization of the protein was performed using GROMACS (v. 4.6.5) [82]. AutoDock Vina (v. 1.2.3) [83] was used to dock the ligands into the protein. This was achieved by configuring a grid box center x = 1.35 Å, y = 14.3 Å and z = −34.60 Å and size of x = 100 Å, y = 70 Å and z = 70 Å. Moreover, the exhaustiveness parameter was configured with the value of 10 and 20 docking modes were generated as maximum output. UCSF Chimera utilized to analyze the docking results.

3.5.2. Study of Drug-Likeness of Molecules with the Molinspiration Tool

The computational platform Molinspiration (https://www.molinspiration.com/ accessed on 8 April 2024) was used to calculate the physicochemical properties of the compounds synthesized and studied in this research.

4. Conclusions

In conclusion, the synthesis of dibenzalacetones was carried out via a double mixed aldol condensation between acetone and suitable substituted benzaldehyde in the presence of sodium hydroxide in ethanol. A total of 32 final dihydro-pyrazoles were synthesized 12 of which were novel in the literature. Compound 1f was a new one. Compounds 1a–f have been reported in the literature as neuroprotective and antiparasitic agents [42], and were further herein investigated for their antioxidant and lipoxygenase inhibitory activity. The structures of the compounds were identified by melting point measurement and spectroscopic techniques (IR, 1H NMR, 13C NMR, HRMS, EA). The lipophilicity of the compounds was determined experimentally. Compounds 2e and 3e show higher interaction with the DPPH free radical, 45–53% at 60 min. For most of the compounds, it appears that the interaction is time dependent. Lipophilicity does not contribute to the activity. It seems that the bulk of the compounds could prevent their interaction with the free radical. All the synthesized derivatives seem to exhibit very good inhibitory ability against lipid peroxidation. The most active inhibitors of lipid peroxidation are 4a (98%) and 4b (97%), whereas compounds 2d and 2e were the most potent lipoxygenase inhibitors with IC50 values 2.5 μM and 0.35 μM accordingly. Lipophilicity seems to favor lipid peroxidation inhibition but does not influence the lipoxygenase inhibitory activity. Molar refractivity of the substituents governs the lipoxygenase inhibitory activity. The drug likeness of the synthesized derivatives has been studied. Nine compounds have drug likeness properties, while the most potent one violates lipophilicity. Docking studies highlight the interactions with soybean lipoxygenase. Based on the above studies the novel derivatives possess antioxidant and anti-lipoxygenase inhibitory activities while some of them have been reported in the literature as anticancer and anti-inflammatory agents and thus can be considered as possible multitarget agents [42].

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/molecules30102224/s1, Table S1. Substituted dibenzalacetones (1a–f), dihydro-pyrazoles (2a–f, 3a–f, 4a–f), pyrazole-carboxamides (5a–e) and dihydro-pyrazol-ethanones (6a–e); 1H-NMR and 13C-NMR of the novel synthesized derivatives (Refs. [44,45,46,47,48,49,50,51,52,53,67]).

Author Contributions

Conceptualization, E.P.; methodology, docking studies, E.P.; writing—original draft preparation, S.-C.P. and E.P.; writing—review and editing, E.P.; supervision, E.P.; data curation, E.P., S.-C.P. and E.T.; validation, E.P. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable. The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author(s).

Acknowledgments

E. Pontiki would like to acknowledge D. Hadjipavlou-Litina, School of Pharmacy, Aristotle University of Thessaloniki for her guidance and useful advice and Alexandros Patsilinakos, Ioannis Fotopoulos and Eleftherios Charissopoulos for their valuable help and support.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Pratik, K.; Arun, K.; Neha, S.; Bhumika, Y.; Anshuman, S.; Kumar, G.S. Synthesis, Characterization of Ethyl 5-(Substituted)-1H-Pyrazole-3-Carboxylate Derivative as Potent Anti-Inflammatory Agents. Anti-Inflamm. Anti-Allergy Agents Med. Chem. 2018, 17, 32–38. [Google Scholar] [CrossRef] [PubMed]
  2. Gias, Z.T.; Afsana, F.; Debnath, P.; Alam, M.S.; Ena, T.N.; Hossain, M.H.; Jain, P.; Reza, H.M. A Mechanistic Approach to HPLC Analysis, Antinociceptive, Anti-Inflammatory and Postoperative Analgesic Activities of Panch Phoron in Mice. BMC Complement Med. Ther. 2020, 20, 102. [Google Scholar] [CrossRef]
  3. Benaroyo, L. How do we define inflammation? Praxis 1994, 83, 1343–1347. [Google Scholar]
  4. McCord, J.M. The Evolution of Free Radicals and Oxidative Stress. Am. J. Med. 2000, 108, 652–659. [Google Scholar] [CrossRef]
  5. Singh, R.; Devi, S.; Gollen, R. Role of Free Radical in Atherosclerosis, Diabetes and Dyslipidaemia: Larger-than-Life. Diabetes/Metab. Res. Rev. 2015, 31, 113–126. [Google Scholar] [CrossRef] [PubMed]
  6. Chung, W.-Y.; Jung, Y.-J.; Surh, Y.-J.; Lee, S.-S.; Park, K.-K. Antioxidative and Antitumor Promoting Effects of [6]-Paradol and Its Homologs. Mutat. Res./Genet. Toxicol. Environ. Mutagen. 2001, 496, 199–206. [Google Scholar] [CrossRef]
  7. Fiuza, S.M.; Gomes, C.; Teixeira, L.J.; Girão da Cruz, M.T.; Cordeiro, M.N.D.S.; Milhazes, N.; Borges, F.; Marques, M.P.M. Phenolic Acid Derivatives with Potential Anticancer Properties—A Structure–Activity Relationship Study. Part 1: Methyl, Propyl and Octyl Esters of Caffeic and Gallic Acids. Bioorganic Med. Chem. 2004, 12, 3581–3589. [Google Scholar] [CrossRef] [PubMed]
  8. Fresco, P.; Borges, F.; Diniz, C.; Marques, M.P. New Insights on the Anticancer Properties of Dietary Polyphenols. Med. Res. Rev. 2006, 26, 747–766. [Google Scholar] [CrossRef]
  9. Silva, F.A.M.; Borges, F.; Ferreira, M.A. Effects of Phenolic Propyl Esters on the Oxidative Stability of Refined Sunflower Oil. J. Agric. Food Chem. 2001, 49, 3936–3941. [Google Scholar] [CrossRef]
  10. Gomes, C.A.; Girão da Cruz, T.; Andrade, J.L.; Milhazes, N.; Borges, F.; Marques, M.P. Anticancer Activity of Phenolic Acids of Natural or Synthetic Origin:  A Structure—Activity Study. J. Med. Chem. 2003, 46, 5395–5401. [Google Scholar] [CrossRef]
  11. Caillon, A.; Schiffrin, E.L. Role of Inflammation and Immunity in Hypertension: Recent Epidemiological, Laboratory, and Clinical Evidence. Curr. Hypertens Rep. 2016, 18, 21. [Google Scholar] [CrossRef]
  12. Furman, D.; Campisi, J.; Verdin, E.; Carrera-Bastos, P.; Targ, S.; Franceschi, C.; Ferrucci, L.; Gilroy, D.W.; Fasano, A.; Miller, G.W.; et al. Chronic Inflammation in the Etiology of Disease across the Life Span. Nat. Med. 2019, 25, 1822–1832. [Google Scholar] [CrossRef] [PubMed]
  13. Todd, I.; Spickett, G.P.; Fairclough, L. Immunology; John Wiley & Sons: Hoboken, NJ, USA, 2015; ISBN 978-1-118-45166-3. [Google Scholar]
  14. Jacob P, J.; Manju, S.L.; Ethiraj, K.R.; Elias, G. Safer Anti-Inflammatory Therapy through Dual COX-2/5-LOX Inhibitors: A Structure-Based Approach. Eur. J. Pharm. Sci. 2018, 121, 356–381. [Google Scholar] [CrossRef]
  15. Baysal, T.; Demirdöven, A. Lipoxygenase in Fruits and Vegetables: A Review. Enzym. Microb. Technol. 2007, 40, 491–496. [Google Scholar] [CrossRef]
  16. Tuncer, S.; Banerjee, S. Eicosanoid Pathway in Colorectal Cancer: Recent Updates. World J. Gastroenterol. 2015, 21, 11748–11766. [Google Scholar] [CrossRef]
  17. Qu, T.; Uz, T.; Manev, H. Inflammatory 5-LOX mRNA and Protein Are Increased in Brain of Aging Rats. Neurobiol. Aging 2000, 21, 647–652. [Google Scholar] [CrossRef]
  18. Kulkarni, P.; Totre, G. Synthesis of Dibenzylidene Acetone via Aldol Condensation of Diacetone Alcohol with Substituted Benzaldehydes. Orbital Electron. J. Chem. 2019, 11, 292–296. [Google Scholar] [CrossRef]
  19. Ballesteros, J.F.; Sanz, M.J.; Ubeda, A.; Miranda, M.A.; Iborra, S.; Paya, M.; Alcaraz, M.J. Synthesis and Pharmacological Evaluation of 2′-Hydroxychalcones and Flavones as Inhibitors of Inflammatory Mediators Generation. J. Med. Chem. 1995, 38, 2794–2797. [Google Scholar] [CrossRef]
  20. Go, M.L.; Wu, X.; Liu, X.L. Chalcones: An Update on Cytotoxic and Chemoprotective Properties. Curr. Med. Chem. 2005, 12, 483–499. [Google Scholar] [CrossRef]
  21. Mukherjee, S.; Kumar, V.; Prasad, A.K.; Raj, H.G.; Bracke, M.E.; Olsen, C.E.; Jain, S.C.; Parmar, V.S. Synthetic and Biological Activity Evaluation Studies on Novel 1,3-Diarylpropenones. Bioorganic Med. Chem. 2001, 9, 337–345. [Google Scholar] [CrossRef]
  22. Liu, M.; Wilairat, P.; Croft, S.L.; Tan, A.L.-C.; Go, M.-L. Structure–Activity Relationships of Antileishmanial and Antimalarial Chalcones. Bioorganic Med. Chem. 2003, 11, 2729–2738. [Google Scholar] [CrossRef] [PubMed]
  23. Sivakumar, P.M.; Babu, S.K.G.; Mukesh, D. QSAR Studies on Chalcones and Flavonoids as Anti-Tuberculosis Agents Using Genetic Function Approximation (GFA) Method. Chem. Pharm. Bull. 2007, 55, 44–49. [Google Scholar] [CrossRef] [PubMed]
  24. Viana, G.S.B.; Bandeira, M.A.M.; Matos, F.J.A. Analgesic and Antiinflammatory Effects of Chalcones Isolated from Myracrodruon Urundeuva Allemão. Phytomedicine 2003, 10, 189–195. [Google Scholar] [CrossRef] [PubMed]
  25. Nakamura, C.; Kawasaki, N.; Miyataka, H.; Jayachandran, E.; Kim, I.H.; Kirk, K.L.; Taguchi, T.; Takeuchi, Y.; Hori, H.; Satoh, T. Synthesis and Biological Activities of Fluorinated Chalcone Derivatives. Bioorganic Med. Chem. 2002, 10, 699–706. [Google Scholar] [CrossRef]
  26. Perrin, D.D. Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution; Elsevier: Amsterdam, The Netherlands, 2016; ISBN 978-1-4832-8461-3. [Google Scholar]
  27. Fustero, S.; Sánchez-Roselló, M.; Barrio, P.; Simón-Fuentes, A. From 2000 to Mid-2010: A Fruitful Decade for the Synthesis of Pyrazoles. Chem. Rev. 2011, 111, 6984–7034. [Google Scholar] [CrossRef]
  28. Mykhailiuk, P.K. Fluorinated Pyrazoles: From Synthesis to Applications. Chem. Rev. 2021, 121, 1670–1715. [Google Scholar] [CrossRef]
  29. Neto, J.S.S.; Zeni, G. Alkynes and Nitrogen Compounds: Useful Substrates for the Synthesis of Pyrazoles. Chem. A Eur. J. 2020, 26, 8175–8189. [Google Scholar] [CrossRef]
  30. Janin, Y.L. Preparation and Chemistry of 3/5-Halogenopyrazoles. Chem. Rev. 2012, 112, 3924–3958. [Google Scholar] [CrossRef]
  31. Nájera, C.; Sydnes, L.K.; Yus, M. Conjugated Ynones in Organic Synthesis. Chem. Rev. 2019, 119, 11110–11244. [Google Scholar] [CrossRef]
  32. Keiko, N.A.; Vchislo, N.V. Synthesis of Diheteroatomic Five-Membered Heterocyclic Compounds from α,β-Unsaturated Aldehydes. Asian J. Org. Chem. 2016, 5, 1169–1197. [Google Scholar] [CrossRef]
  33. Zhang, Y.; Duan, D.; Zhong, Y.; Guo, X.-A.; Guo, J.; Gou, J.; Gao, Z.; Yu, B. Fe(III)-Catalyzed Aerobic Intramolecular N–N Coupling of Aliphatic Azides with Amines. Org. Lett. 2019, 21, 4960–4965. [Google Scholar] [CrossRef] [PubMed]
  34. Katz, A.M.; Pearson, C.M.; Kennedy, J.M. A Clinical Trial of Indomethacin in Rheumatoid Arthritis. Clin. Pharmacol. Ther. 1965, 6, 25–30. [Google Scholar] [CrossRef]
  35. Machado, V.; Cenci, A.R.; Teixeira, K.F.; Sens, L.; Tizziani, T.; Nunes, R.J.; Ferreira, L.L.G.; Yunes, R.A.; Sandjo, L.P.; Andricopulo, A.D.; et al. Pyrazolines as Potential Anti-Alzheimer’s Agents: DFT, Molecular Docking, Enzyme Inhibition and Pharmacokinetic Studies. RSC Med. Chem. 2022, 13, 1644–1656. [Google Scholar] [CrossRef]
  36. Ananikov, V.P.; Khemchyan, L.L.; Ivanova, Y.V.; Bukhtiyarov, V.I.; Sorokin, A.M.; Prosvirin, I.P.; Vatsadze, S.Z.; Medved’ko, A.V.; Nuriev, V.N.; Dilman, A.D.; et al. Development of New Methods in Modern Selective Organic Synthesis: Preparation of Functionalized Molecules with Atomic Precision. Russ. Chem. Rev. 2014, 83, 885–985. [Google Scholar] [CrossRef]
  37. Gulati, H.K.; Bhagat, K.; Singh, A.; Kumar, N.; Kaur, A.; Sharma, A.; Heer, S.; Singh, H.; Singh, J.V.; Bedi, P.M.S. Design, Synthesis and Biological Evaluation of Novel Indolinedione–Coumarin Hybrids as Xanthine Oxidase Inhibitors. Med. Chem. Res. 2020, 29, 1632–1642. [Google Scholar] [CrossRef]
  38. Singh, A.; Sharma, S.; Arora, S.; Attri, S.; Kaur, P.; Kaur Gulati, H.; Bhagat, K.; Kumar, N.; Singh, H.; Vir Singh, J.; et al. New Coumarin-Benzotriazole Based Hybrid Molecules as Inhibitors of Acetylcholinesterase and Amyloid Aggregation. Bioorganic Med. Chem. Lett. 2020, 30, 127477. [Google Scholar] [CrossRef]
  39. Bhagat, K.; Singh, J.V.; Sharma, A.; Kaur, A.; Kumar, N.; Gulati, H.K.; Singh, A.; Singh, H.; Bedi, P.M.S. Novel Series of Triazole Containing Coumarin and Isatin Based Hybrid Molecules as Acetylcholinesterase Inhibitors. J. Mol. Struct. 2021, 1245, 131085. [Google Scholar] [CrossRef]
  40. Mantzanidou, M.; Pontiki, E.; Hadjipavlou-Litina, D. Pyrazoles and Pyrazolines as Anti-Inflammatory Agents. Molecules 2021, 26, 3439. [Google Scholar] [CrossRef]
  41. Nurkenov, O.A.; Ibraev, M.K.; Schepetkin, I.A.; Khlebnikov, A.I.; Seilkhanov, T.M.; Arinova, A.E.; Isabaeva, M.B. Synthesis, Structure, and Anti-Inflammatory Activity of Functionally Substituted Chalcones and Their Derivatives. Russ. J. Gen. Chem. 2019, 89, 1360–1367. [Google Scholar] [CrossRef]
  42. Eid, N.M.; George, R.F. Facile Synthesis of Some Pyrazoline-Based Compounds with Promising Anti-Inflammatory Activity. Future Med. Chem. 2018, 10, 183–199. [Google Scholar] [CrossRef]
  43. Nauduri, D.; Reddy, G.B.S. Antibacetrials and Antimycotics: Part 1: Synthesis and Activity of 2-Pyrazoline Derivatives. Chem. Pharm. Bull. 1998, 46, 1254–1260. [Google Scholar] [CrossRef]
  44. Afonso, C.A.M.; Candeias, N.R.; Simão, D.P.; Trindade, A.F.; Coelho, J.A.S.; Tan, B.; Franzén, R. Comprehensive Organic Chemistry Experiments for the Laboratory Classroom; Royal Society of Chemistry: London, UK, 2016; ISBN 978-1-84973-963-4. [Google Scholar]
  45. Carapina da Silva, C.; Pacheco, B.S.; das Neves, R.N.; Dié Alves, M.S.; Sena-Lopes, Â.; Moura, S.; Borsuk, S.; de Pereira, C.M.P. Antiparasitic Activity of Synthetic Curcumin Monocarbonyl Analogues against Trichomonas Vaginalis. Biomed. Pharmacother. 2019, 111, 367–377. [Google Scholar] [CrossRef]
  46. da Silva, A.A.; Maia, P.I.d.S.; Lopes, C.D.; de Albuquerque, S.; Valle, M.S. Synthesis, Characterization and Antichagasic Evaluation of Thiosemicarbazones Prepared from Chalcones and Dibenzalacetones. J. Mol. Struct. 2021, 1232, 130014. [Google Scholar] [CrossRef]
  47. Hussain, H.; Ahmad, S.; Shah, S.W.A.; Ghias, M.; Ullah, A.; Rahman, S.U.; Kamal, Z.; Khan, F.A.; Khan, N.M.; Muhammad, J.; et al. Neuroprotective Potential of Synthetic Mono-Carbonyl Curcumin Analogs Assessed by Molecular Docking Studies. Molecules 2021, 26, 7168. [Google Scholar] [CrossRef]
  48. Daneshfar, Z.; Rostami, A. Cellulose Sulfonic Acid as a Green, Efficient, and Reusable Catalyst for Nazarov Cyclization of Unactivated Dienones and Pyrazoline Synthesis. RSC Adv. 2015, 5, 104695–104707. [Google Scholar] [CrossRef]
  49. Li, J.-T.; Zhai, X.-L.; Meng, X.-T. Synthesis of 1,5-Diaryl-3-Arylethenyl-2-Pyrazolines Under Ultrasound Irradiation. Asian J. Chem. 2010, 22, 589–592. [Google Scholar]
  50. George, R.F.; Kandeel, M.; El-Ansary, D.Y.; El Kerdawy, A.M. Some 1,3,5-Trisubstituted Pyrazoline Derivatives Targeting Breast Cancer: Design, Synthesis, Cytotoxic Activity, EGFR Inhibition and Molecular Docking. Bioorg. Chem. 2020, 99, 103780. [Google Scholar] [CrossRef]
  51. Vijayabaskar, V.; Perumal, S.; Selvaraj, S.; Lycka, A.; Murugan, R.; Balasubramanian, M. Synthesis and Multinuclear NMR Study of (E)-s-Trans -1-Acetyl-5-Aryl-3-Styryl-2-Pyrazolines. Magn. Reson. Chem. 1999, 37, 133–139. [Google Scholar] [CrossRef]
  52. Pathak, V.N.; Joshi, R.; Sharma, J.; Gupta, N.; Rao, V.M. Mild and Ecofriendly Tandem Synthesis, and Spectral and Antimicrobial Studies of N1-Acetyl-5-Aryl-3-(Substituted Styryl)Pyrazolines. Phosphorus Sulfur Silicon Relat. Elem. 2009, 184, 1854–1865. [Google Scholar] [CrossRef]
  53. Sehmi, A.; Ouici, H.B.; Guendouzi, A.; Ferhat, M.; Benali, O.; Boudjellal, F. Corrosion Inhibition of Mild Steel by Newly Synthesized Pyrazole Carboxamide Derivatives in HCl Acid Medium: Experimental and Theoretical Studies. J. Electrochem. Soc. 2020, 167, 155508. [Google Scholar] [CrossRef]
  54. Hansch, C.; Leo, A.; Taft, R.W. A Survey of Hammett Substituent Constants and Resonance and Field Parameters. Available online: https://pubs.acs.org/doi/pdf/10.1021/cr00002a004 (accessed on 15 February 2025).
  55. Hugo, K. QSAR: Hansch Analysis and Related Approaches; Methods and Principles in Medicinal Chemistry; Wiley: Hoboken, NJ, USA, 1993. [Google Scholar] [CrossRef]
  56. Claisen, L.; Claparède, A. Ueber Verbindungen Des Acetons Und Mesityloxyds Mit Benzaldehyd Und Über Die Constitution Des Acetophorons. Berichte Der Dtsch. Chem. Ges. 1881, 14, 349–353. [Google Scholar] [CrossRef]
  57. Kurland, B.F.; Peterson, L.M.; Lee, J.H.; Linden, H.M.; Schubert, E.K.; Dunnwald, L.K.; Link, J.M.; Krohn, K.A.; Mankoff, D.A. Between-Patient and Within-Patient (Site-to-Site) Variability in Estrogen Receptor Binding, Measured In Vivo by 18 F-Fluoroestradiol PET. J. Nucl. Med. 2011, 52, 1541–1549. [Google Scholar] [CrossRef]
  58. Peyrat-Maillard, M.N.; Cuvelier, M.E.; Berset, C. Antioxidant Activity of Phenolic Compounds in 2,2′-Azobis (2-Amidinopropane) Dihydrochloride (AAPH)-Induced Oxidation: Synergistic and Antagonistic Effects. J. Am. Oil Chem. Soc. 2003, 80, 1007. [Google Scholar] [CrossRef]
  59. Taraporewala, I.B.; Kauffman, J.M. Synthesis and Structure–Activity Relationships of Anti-Inflammatory 9,lO-Dihydro-9-Oxo-2-Acridine-Alkanoic Acids and 4-(2-Carboxyphenyl)Aminobenzenealkanoic Acids. J. Pharm. Sci. 1990, 79, 173–178. [Google Scholar] [CrossRef]
  60. Pontiki, E.; Hadjipavlou-Litina, D. Lipoxygenase Inhibitors: A Comparative QSAR Study Review and Evaluation of New QSARs. Med. Res. Rev. 2008, 28, 39–117. [Google Scholar] [CrossRef]
  61. Kostopoulou, I.; Tzani, A.; Polyzos, N.-I.; Karadendrou, M.-A.; Kritsi, E.; Pontiki, E.; Liargkova, T.; Hadjipavlou-Litina, D.; Zoumpoulakis, P.; Detsi, A. Exploring the 2′-Hydroxy-Chalcone Framework for the Development of Dual Antioxidant and Soybean Lipoxygenase Inhibitory Agents. Molecules 2021, 26, 2777. [Google Scholar] [CrossRef]
  62. El Khatabi, K.; El-Mernissi, R.; Aanouz, I.; Ajana, M.A.; Lakhlifi, T.; Khan, A.; Wei, D.-Q.; Bouachrine, M. Identification of Novel Acetylcholinesterase Inhibitors through 3D-QSAR, Molecular Docking, and Molecular Dynamics Simulation Targeting Alzheimer’s Disease. J. Mol. Model. 2021, 27, 302. [Google Scholar] [CrossRef]
  63. Mavridis, E.; Bermperoglou, E.; Pontiki, E.; Hadjipavlou-Litina, D. 5-(4H)-Oxazolones and Their Benzamides as Potential Bioactive Small Molecules. Molecules 2020, 25, 3173. [Google Scholar] [CrossRef]
  64. Kostopoulou, I.; Diassakou, A.; Kavetsou, E.; Kritsi, E.; Zoumpoulakis, P.; Pontiki, E.; Hadjipavlou-Litina, D.; Detsi, A. Novel Quinolinone-Pyrazoline Hybrids: Synthesis and Evaluation of Antioxidant and Lipoxygenase Inhibitory Activity. Mol. Divers. 2021, 25, 723–740. [Google Scholar] [CrossRef]
  65. Schrödinger Release Notes—Release 2023-4. Available online: https://www.schrodinger.com/life-science/download/release-notes/release-2023-4/ (accessed on 20 February 2025).
  66. Venkateswarlu, V.; Kour, J.; Kumar, K.A.A.; Verma, P.K.; Reddy, G.L.; Hussain, Y.; Tabassum, A.; Balgotra, S.; Gupta, S.; Hudwekar, A.D.; et al. Direct N-Heterocyclization of Hydrazines to Access Styrylated Pyrazoles: Synthesis of 1,3,5-Trisubstituted Pyrazoles and Dihydropyrazoles. RSC Adv. 2018, 8, 26523–26527. [Google Scholar] [CrossRef]
  67. Rekker, R.F.; Roelof, F. The Hydrophobic Fragmental Constant, Its Derivation and Application: A Means of Characterizing Membrane Systems; Elsevier Scientific Pub. Co.: Amsterdam, The Netherlands; New York, NY, USA, 1977. [Google Scholar]
  68. Myriagkou, M.; Papakonstantinou, E.; Deligiannidou, G.E.; Patsilinakos, A.; Kontogiorgis, C.; Pontiki, E. Novel Pyrimidine Derivatives as Antioxidant and Anticancer Agents: Design, Synthesis and Molecular Modeling Studies. Molecules 2023, 28, 3913. [Google Scholar] [CrossRef]
  69. Kouzi, O.; Pontiki, E.; Hadjipavlou-Litina, D. 2-Arylidene-1-Indandiones as Pleiotropic Agents with Antioxidant and Inhibitory Enzymes Activities. Molecules 2019, 24, 4411. [Google Scholar] [CrossRef]
  70. Ayala, A.; Muñoz, M.F.; Argüelles, S. Lipid Peroxidation: Production, Metabolism, and Signaling Mechanisms of Malondialdehyde and 4-Hydroxy-2-Nonenal. Oxidative Med. Cell. Longev. 2014, 2014, e360438. [Google Scholar] [CrossRef]
  71. Peperidou, A.; Kapoukranidou, D.; Kontogiorgis, C.; Hadjipavlou-Litina, D. Multitarget Molecular Hybrids of Cinnamic Acids. Molecules 2014, 19, 20197–20226. [Google Scholar] [CrossRef]
  72. Pontiki, E.; Hadjipavlou-Litina, D. Antioxidant and Anti-Inflammatory Activity of Aryl-Acetic and Hydroxamic Acids as Novel Lipoxygenase Inhibitors. Med. Chem. 2006, 2, 251–264. [Google Scholar] [CrossRef]
  73. Pettersen, E.F.; Goddard, T.D.; Huang, C.C.; Couch, G.S.; Greenblatt, D.M.; Meng, E.C.; Ferrin, T.E. UCSF Chimera—A Visualization System for Exploratory Research and Analysis. J. Comput. Chem. 2004, 25, 1605–1612. [Google Scholar] [CrossRef]
  74. Fiser, A.; Šali, A. Modeller: Generation and Refinement of Homology-Based Protein Structure Models. Methods Enzymol. 2003, 374, 461–491. [Google Scholar]
  75. Case, D.A.; Aktulga, H.M.; Belfon, K.; Cerutti, D.S.; Cisneros, G.A.; Cruzeiro, V.W.D.; Forouzesh, N.; Giese, T.J.; Götz, A.W.; Gohlke, H.; et al. AmberTools. J. Chem. Inf. Model. 2023, 63, 6183–6191. [Google Scholar] [CrossRef]
  76. Lindorff-Larsen, K.; Piana, S.; Palmo, K.; Maragakis, P.; Klepeis, J.L.; Dror, R.O.; Shaw, D.E. Improved Side-Chain Torsion Potentials for the Amber ff99SB Protein Force Field. Proteins Struct. Funct. Bioinform. 2010, 78, 1950–1958. [Google Scholar] [CrossRef]
  77. Li, P.; Roberts, B.P.; Chakravorty, D.K.; Merz, K.M., Jr. Rational Design of Particle Mesh Ewald Compatible Lennard-Jones Parameters for +2 Metal Cations in Explicit Solvent. J. Chem. Theory Comput. 2013, 9, 2733–2748. [Google Scholar] [CrossRef]
  78. O’Boyle, N.M.; Banck, M.; James, C.A.; Morley, C.; Vandermeersch, T.; Hutchison, G.R. Open Babel: An Open Chemical Toolbox. J. Cheminform. 2011, 3, 33. [Google Scholar] [CrossRef]
  79. Halgren, T.A. Merck Molecular Force Field. I. Basis, Form, Scope, Parameterization, and Performance of MMFF94. J. Comput. Chem. 1996, 17, 490–519. [Google Scholar] [CrossRef]
  80. Sousa da Silva, A.W.; Vranken, W.F. ACPYPE—AnteChamber PYthon Parser interfacE. BMC Res. Notes 2012, 5, 367. [Google Scholar] [CrossRef]
  81. Wang, J.; Wang, W.; Kollman, P.A.; Case, D.A. Automatic Atom Type and Bond Type Perception in Molecular Mechanical Calculations. J. Mol. Graph. Model. 2006, 25, 247–260. [Google Scholar] [CrossRef]
  82. Hess, B.; Kutzner, C.; van der Spoel, D.; Lindahl, E. GROMACS 4: Algorithms for Highly Efficient, Load-Balanced, and Scalable Molecular Simulation. J. Chem. Theory Comput. 2008, 4, 435–447. [Google Scholar] [CrossRef]
  83. Trott, O.; Olson, A.J. AutoDock Vina: Improving the Speed and Accuracy of Docking with a New Scoring Function, Efficient Optimization, and Multithreading. J. Comput. Chem. 2010, 31, 455–461. [Google Scholar] [CrossRef]
Molecules 30 02224 g001
Figure 1. General structure of dibenzalacetones.
Figure 1. General structure of dibenzalacetones.
Molecules 30 02224 g001
Molecules 30 02224 g002
Figure 2. Drugs bearing the pyrazole scaffold.
Figure 2. Drugs bearing the pyrazole scaffold.
Molecules 30 02224 g002
Molecules 30 02224 sch001
Scheme 1. General Synthetic Scheme: Synthesis of dibenzalacetones (1a–f) using: abs. EtOH, aqueous NaOH 10% w/v, 25 °C, 1–24 h. Synthesis of dihydro-pyrazoles (2a–f, 3a–f, 4a–f) using: 4-substituted hydrazines, EtOH, NaOH, MW, 100 W, 75 °C, 15–70 min. Synthesis of pyrazole-carboxamides (5a–e) using: H2NNHC(=O)NH2, EtOH, MW, 200 W, 100 °C, 20 min. Synthesis of dihydro-pyrazol-ethanones (6a–e) using: N2H4·H2O, CH3COOH, MW, 200 W, 100 °C, 20 min.
Scheme 1. General Synthetic Scheme: Synthesis of dibenzalacetones (1a–f) using: abs. EtOH, aqueous NaOH 10% w/v, 25 °C, 1–24 h. Synthesis of dihydro-pyrazoles (2a–f, 3a–f, 4a–f) using: 4-substituted hydrazines, EtOH, NaOH, MW, 100 W, 75 °C, 15–70 min. Synthesis of pyrazole-carboxamides (5a–e) using: H2NNHC(=O)NH2, EtOH, MW, 200 W, 100 °C, 20 min. Synthesis of dihydro-pyrazol-ethanones (6a–e) using: N2H4·H2O, CH3COOH, MW, 200 W, 100 °C, 20 min.
Molecules 30 02224 sch001
Molecules 30 02224 g003
Figure 3. 3D preferred docking pose of compound 2e (depicted in cyan) bound to soybean lipoxygenase. Iron appears as an orange sphere.
Figure 3. 3D preferred docking pose of compound 2e (depicted in cyan) bound to soybean lipoxygenase. Iron appears as an orange sphere.
Molecules 30 02224 g003
Molecules 30 02224 g004
Figure 4. Ligand interaction diagram of compound 2e with soybean lipoxygenase (ID: 3PZW). Hydrophobic residues are colored green, the polar ones cyan and the positive charged in blue. Figure made with free Maestro (Free Maestro academic license [65]).
Figure 4. Ligand interaction diagram of compound 2e with soybean lipoxygenase (ID: 3PZW). Hydrophobic residues are colored green, the polar ones cyan and the positive charged in blue. Figure made with free Maestro (Free Maestro academic license [65]).
Molecules 30 02224 g004
Table 1. Substituted dibenzalacetones (1a–f), dihydro-pyrazoles (2a–f, 3a–f, 4a–f), pyrazole-carboxamides (5a–e) and dihydro-pyrazol-ethanones (6a–e). Experimental RM lipophilicity values and theoretical clog P lipophilicity values. πx (lipophilic contribution of the X-substituent) and MRx (molar refractivity of the X substituent) [54,55,56,57].
Table 1. Substituted dibenzalacetones (1a–f), dihydro-pyrazoles (2a–f, 3a–f, 4a–f), pyrazole-carboxamides (5a–e) and dihydro-pyrazol-ethanones (6a–e). Experimental RM lipophilicity values and theoretical clog P lipophilicity values. πx (lipophilic contribution of the X-substituent) and MRx (molar refractivity of the X substituent) [54,55,56,57].
CompdGeneral StructureXYRM ± SDclog PπxMRx
1aMolecules 30 02224 i001H-0.10 ± 0.0034.6600.103
1bF-0.19 ± 0.0014.940.140.092
1cBr-0.65 ± 0.0346.380.860.888
1dCl-0.50 ± 0.0426.080.710.603
1eN(CH3)2-−0.14 ± 0.0094.990.181.555
1fCF3-0.57 ± 0.0316.470.880.502
2aMolecules 30 02224 i002HH1.00 ± 0.0846.9000.103
2bFH0.78 ± 0.0657.190.140.092
2cBrH2.1 ± 0.178.630.860.888
2dClH1.07 ± 0.0678.330.710.603
2eN(CH3)2H0.95 ± 0.0927.230.181.555
2fCF3H1.31 ± 0.0318.670.880.502
3aHBr1.11 ± 0.0687.7600.103
3bFBr1.03 ± 0.0578.050.140.092
3cBrBr1.46 ± 0.0499.490.860.888
3dClBr1.39 ± 0.0699.190.710.603
3eN(CH3)2Br1.25 ± 0.0868.090.181.555
3fCF3Br1.47 ± 0.0449.530.880.502
4aHCN−0.31 ± 0.0236.4300.103
4bFCN0.61 ± 0.0536.620.140.092
4cBrCN0.94 ± 0.0698.060.860.888
4dClCN0.85 ± 0.0687.760.710.603
4eN(CH3)2CN0.49 ± 0.0296.660.181.555
4fCF3CN0.8 ± 0.0318.100.880.502
5aMolecules 30 02224 i003H-0.06 ± 0.0053.2400.103
5bF-0.06 ± 0.0043.520.140.092
5cBr-0.60 ± 0.0554.960.860.888
5dCl-0.50 ± 0.0434.660.710.603
5eN(CH3)2-0.28 ± 0.0193.570.181.555
6aMolecules 30 02224 i004H-0.17 ± 0.0144.1100.103
6bF-0.24 ± 0.0214.400.140.092
6cBr-0.78 ± 0.0515.840.860.888
6dCl-0.65 ± 0.0485.540.710.603
6eN(CH3)2-0.47 ± 0.0364.450.181.555
SD standard deviation of the mean is less than 10%.
Table 2. Drug-likeness studies of synthesized compounds.
Table 2. Drug-likeness studies of synthesized compounds.
CompdmiLogPTPSANatomsMWnONnOHNHNviolationsNrotbVolume
1a4.1817.0718234.301004229.27
1b4.5117.0720270.281004239.13
1c5.8017.0720392.091014265.04
1d5.5417.0720303.191014256.34
1e4.3923.5524320.443006321.08
1f5.9717.0726370.291016291.86
2a6.0215.625324.432014313.11
2b6.3415.627360.412014322.97
2c7.6315.627482.222014348.88
2d7.3715.627393.322014340.18
2e6.2222.0831410.564016404.92
2f7.8115.633460.422016375.50
3a6.8315.626403.322014331.00
3b7.1515.628439.32014340.86
3c8.3715.628561.122024366.77
3d8.1715.628472.212014358.07
3e7.0322.0832489.464016422.81
3f8.4815.634539.322026393.59
4a5.7739.3927349.443014329.97
4b6.1039.3929385.423014339.83
4c7.3939.3929507.233024365.74
4d7.1339.3929418.333014357.04
4e5.9745.8733435.575016421.78
4f7.5639.3935485.433016392.56
5a3.5958.7022291.354203271.97
5b4.9558.7024360.244203299.05
5c5.2158.7024449.154213307.74
5d3.9258.7024327.334203281.84
5e3.8065.1728377.496205363.79
6a3.6832.6722290.373003277.25
6b5.0432.6724359.263013304.32
6c5.3032.6724448.163013313.02
6d4.0132.6724326.353003287.11
6e3.7739.1528376.505005369.06
Table 3. Interaction with DPPH at 20 and 60 min (RA%), AAPH-induced linoleic acid peroxidation inhibitory activity (AAPH%), soybean LOX in vitro inhibitory activity (% and IC50) of the synthesized compounds.
Table 3. Interaction with DPPH at 20 and 60 min (RA%), AAPH-induced linoleic acid peroxidation inhibitory activity (AAPH%), soybean LOX in vitro inhibitory activity (% and IC50) of the synthesized compounds.
Compd RA%, 100 μM,
20 min
(±SD) 		RA%, 100 μM,
60 min
(±SD) 		AAPH% Inhibition, 100 μM
(±SD) 		LOX% Inhibition,
100 μM
or IC50 (μM)
(±SD)
1a 5 ± 0.5 10 ± 0.5 69 ± 0.3 10 μΜ ± 0.4
1b 13 ± 0.6 100 ± 1.1 37 ± 0.1 30 ± 0.1
1c n.a. 44 ± 1.6 61 ± 0.5 28 ± 0.6
1d 86 ± 4.5 95 ± 4.8 53 ± 0.6 38 ± 0.7
1e n.a. 100 ± 8.7 50 ± 0.5 24 ± 0.6
1f 13 ± 0.8 26 ± 0.9 32 ± 1.4 24 ± 1.4
2a n.a. 17 ± 1.2 44 ± 0.7 42 ± 2.4
2b 2 ± 0.1 15 ± 0.6 39 ± 0.3 24 ± 1.9
2c 21 ± 0.6 n.a. 68 ± 0.6 n.a
2d 6 ± 0.4 10 ± 0.9 75 ± 0.1 2.5 μΜ ± 0.2
2e 24 ± 0.9 45 ± 1 78 ± 0.4 0.35 μΜ ± 0.02
2f 5 ± 0.2 n.a. 52 ± 2.5 14 ± 0.8
3a 10 ± 0.3 22 ± 0.9 75 ± 1.4 51 ± 2.2
3b 2 ± 0.1 6 ± 0.6 63 ± 2.6 17 ± 0.8
3c 2 ± 0.1 24 ± 0.9 40 ± 1.8 30 μΜ ± 2.9
3d 6 ± 0.5 11 ± 0.9 52 ± 2.5 11 ± 0.8
3e 30 ± 0.9 53 ± 0.9 80 ± 2.9 20 μΜ ± 0.1
3f 5 ± 0.4 14 ± 1.2 75 ± 2.7 38 ± 2.6
4a n.a. n.a. 98 ± 0.4 39 ± 0.4
4b 2 ± 0.1 n.a. 97 ± 0.6 n.a
4c 2 ± 0.1 n.a. 59 ± 0.2 17 ± 1.2
4d 23 ± 0.3 2 ± 0.1 51 ± 0.2 85 μΜ ± 4.1
4e 2 ± 0.1 2 ± 0.2 74 ± 0.9 6 ± 0.5
4f n.a. n.a. 12 ± 1.1 22 ± 1.8
5a n.a. n.a. 29 ± 2.2 4 ± 0.3
5b 19 ± 0.1 n.a. 8 ± 0.2 39 ± 0.7
5c n.a. n.a. 85 ± 0.6 37 ± 0.6
5d n.a. 34 ± 0.5 33 ± 0.5 80 μΜ ± 3.5
5e 20 ± 0.1 n.a. 61 ± 0.9 19 ± 0.4
6a 11 ± 0.6 n.a. 22 ± 1 24 ± 0.8
6b n.a. n.a. 46 ± 0.6 26± 0.3
6c n.a. n.a. 71 ± 0.4 1± 0.07
6d n.a. 8 ± 0.7 67 ± 0.4 42 ± 2.7
6e 7 ± 0.5 12 ± 1 56 ± 0.3 40 μΜ ± 0.6
NDGA 87 93 - 93 (0.45 μM)
Trolox - - 92 -
Standard deviation (±SD) of the mean is less than 10%. For the in vitro assays the mean value is derived from at least six independent experiments.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Peitzika, S.-C.; Tsiampakari, E.; Pontiki, E. Microwave Assisted Synthesis of Antioxidant Dihydro-Pyrazole Hybrids as Possible Lipoxygenase Inhibitors. Molecules 2025, 30, 2224. https://doi.org/10.3390/molecules30102224

AMA Style

Peitzika S-C, Tsiampakari E, Pontiki E. Microwave Assisted Synthesis of Antioxidant Dihydro-Pyrazole Hybrids as Possible Lipoxygenase Inhibitors. Molecules. 2025; 30(10):2224. https://doi.org/10.3390/molecules30102224

Chicago/Turabian Style

Peitzika, Stergiani-Chrysovalanti, Eirini Tsiampakari, and Eleni Pontiki. 2025. "Microwave Assisted Synthesis of Antioxidant Dihydro-Pyrazole Hybrids as Possible Lipoxygenase Inhibitors" Molecules 30, no. 10: 2224. https://doi.org/10.3390/molecules30102224

APA Style

Peitzika, S.-C., Tsiampakari, E., & Pontiki, E. (2025). Microwave Assisted Synthesis of Antioxidant Dihydro-Pyrazole Hybrids as Possible Lipoxygenase Inhibitors. Molecules, 30(10), 2224. https://doi.org/10.3390/molecules30102224

Article Metrics

Back to TopTop