European Journal of Chemistry
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    Synthesis of lactones from fatty acids by ring-closing metathesis and their biological evaluation

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    The present study involves the synthesis of macrocyclic lactones by the esterification of unsaturated fatty acids (oleic acid, undecenoic acid, and erucic acid) with unsaturated alcohols (allyl alcohol, prop-2-ene-1-ol, oleyl alcohol, and undecenol) followed by a ring closing metathesis reaction employing Grubbs' second generation catalyst (1.0-1.5 mmol). The structure of the compounds was confirmed by 1H NMR, 13C NMR, FT-IR, and ESI-Mass spectral studies. The antibacterial activity of the synthesised lactones was evaluated. The larger ring-sized lactone, namely, erucic acid lactone, exhibited excellent antibacterial activity against three bacterial cell lines, namely, Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis. Undecenoic acid-based lactones exhibited excellent antibacterial activity selectively against only Staphylococcus epidermidis. The assay of macrolactones for their in vitro anticancer activity was carried out by MTT for different cancer cell lines, namely, human prostate epithelial cancer cells (ATCC HTB-81), HepG2 derived from hepatic cancer cells (ATCC HB-8065), SKOV3 derived from human ovarian cancer cells (ATCC HTB-77), MDAMB-231 derived from human breast cancer cells (ATCC HTB-26) and Chinese hamster ovarian (CHO-K1) cell lines. The molecules selectively exhibited anticancer activity against Chinese hamster ovarian (CHO-K1) cell lines. Among macrolactones, (E)-oxacyclotridec-11-en-2-one (MALUN) was more active and its activity was much higher compared to others and on par with the reference standard Mitomycin C. This was followed by (E)-oxacyclotricos-14-en-2-one (MOLER) and (E)-oxacyclononadec-10-en-2-one (MOLOH). The fatty acid-based cyclic lactones with selective antibacterial and anticancer activities can be further explored for a variety of pharmaceutical formulations

    Molecular and crystal structure characteristics of 2-phenylaminotetrahydro-1,3-thiazepine hydrochloride and 2-phenyliminohexahydro-1,3-thiazepine

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    The current research includes the synthesis and crystallographic characterization of 2-phenylaminotetrahydro-1,3-thiazepine hydrochloride (HPAT) and 2-phenyliminohexa- hydro-1,3-thiazepine (PIT) compounds. 2-Phenylaminotetrahydro-1,3-thiazepine hydro-chloride was synthesized by cyclization of 1-(4-hydroxybutyl)-3-phenylthiourea in an acidic condition. The second compound, 2-phenyliminohexahydro-1,3-thiazepine, was obtained by neutralizing 2-phenylaminotetrahydro-1,3-thiazepine hydrochloride with sodium hydrocarbonate. Both compounds were characterized by the single-crystal X-ray diffraction method. Crystal data for C11H17N2OClS (HPAT): orthorhombic, space group P212121 (no. 19), a = 4.97183(14) Å, b = 15.1169(4) Å, c = 17.7376(5) Å, V = 1333.14(6) Å3, Z = 4, μ(CuKα) = 3.859 mm-1, Dcalc = 1.299 g/cm3, 9243 reflections measured (7.684° ≤ 2Θ ≤ 152.042°), 2749 unique (Rint = 0.0314, Rsigma = 0.0255) which were used in all calculations. The final R1 was 0.0351 (I > 2σ(I)) and wR2 was 0.0911 (all data). Crystal data for C11H14N2S (PIT): monoclinic, space group P21/n (no. 14), a = 9.6303(9) Å, b = 9.8938(6) Å, c = 11.5627(9) Å, β = 103.419(8)°, V = 1071.62(14) Å3, Z = 4, μ(CuKα) = 2.357 mm-1, Dcalc = 1.279 g/cm3, 3938 reflections measured (10.798° ≤ 2Θ ≤ 152.328°), 2172 unique (Rint = 0.0288, Rsigma = 0.0330) that were used in all calculations. The final R1 was 0.0431 (I > 2σ(I)) and wR2 was 0.1219 (all data). The asymmetric unit of HPAT contains one protonated amine, one chlorine anion, and one water molecule. Chlorine anion and water molecules play the role of the bridge in chain formation along the a- and b-axis through H-bonds with N-H hydrogen atoms. Furthermore, the Hirshfeld surface analyses are performed to determine the nature of the intermolecular contacts stabilizing the crystal structures of 2-phenylaminotetrahydro-1,3-thiazepine hydrochloride and 2-phenyliminohexahydro-1,3-thiazepine

    Newer chalcone scaffolds with reactive functional groups: Process, spectral and single crystal XRD studies

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    Chalcones are versatile scaffolds for the synthesis of various heterocyclic systems with commercial utility. This work describes the synthesis of five novel chalcone derivatives. Syntheses were performed by a simple one-pot, straightforward Claisen-Schmidt condensation catalyzed with pyrrolidine and KOH. The chalcones were prepared by condensation of 4-formylbenzonitrile with different aromatic ketones at room temperature. The structures of all compounds have been investigated by FT-IR, NMR, and HR-MS spectroscopy. In addition, one chalcone structure was characterized by single-crystal XRD study. Crystal data for C21H15NO2 (Ch2): monoclinic, space group P21/c (no. 14), a = 6.5694(3) Å, b = 33.2697(15) Å, c = 7.4516(4) Å, β = 97.563(2)°, V = 1614.47(14) Å3, Z = 4, T = 293(2) K, μ(MoKα) = 0.083 mm-1, Dcalc = 1.289 g/cm3, 16000 reflections measured (4.898° ≤ 2Θ ≤ 49.99°), 2822 unique (Rint = 0.0249, Rsigma = 0.0196) which were used in all calculations. The final R1 was 0.0484 (I > 2σ(I)) and wR2 was 0.1257 (all data). The absorption maxima of all novel products were evaluated by UV-visible spectroscopy. These well-established structures of all newly prepared chalcone scaffolds with reactive functional groups (i.e. nitrile and 2-propenone) can be exploited as a crucial intermediate in the synthesis of new heterocyclic scaffolds with fluorescence and other applications

    Comparison of the performance of an organic acid and an inorganic acid pretreatment by means of enzymatic hydrolysis of coffee husk

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    The study of different lignocellulosic materials for second-generation biofuels is one of the trending topics today because of the high demand for fuels for transportation and electricity generation. Coffee husk is presented as one study option considering that only 10% of the coffee fruit is used for coffee production. The pretreatment of the coffee husk with sulfuric acid (3 or 6%) and citric acid (6 or 12%) was compared using two methodologies. The first had reaction condition time (50, 70, 90, and 1440 min) and temperature (70 and 90 °C), while the second had autoclave conditions (121 °C, 14.696 psi, 60 min). The comparison was made to find the best methodology for acid pretreatment before enzymatic hydrolysis. The best result of the reduction of sugars (17.017%) and glucose yield (3.882%) was found with 6% C6H8O7 in autoclaving (121 °C, 14.696 psi, 60 min) with hydrolysis conditions of 72 h, 150 rpm, 50 °C, and using cellulases from Trichoderma reesei

    Antioxidant and antimicrobial activities of four medicinal plants from Algeria

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    Medicinal plants are used in folk medicine to cure several human diseases. This work was designed to evaluate the antioxidant and antimicrobial activities of different extracts of Globularia alypum, Dittrichia viscosa, Juniperus oxycedrus, and Retama sphaerocarpa. The total phenolic content (TPC), the total flavonoid content (TFC), and the condensed tannin content (CTC) were determined spectrophotometrically. The antioxidant activity was tested using TAC, DPPH and reducing power assays. The agar diffusion method was used to determine antimicrobial activity against four bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa) and one fungus (Candida albicans). J. oxycedrus acetone extract showed the highest extraction yield (35.56±0.45%), TPC (504.96±14.82 mg GAE/g DE) and TFC (43.91±0.87 mg QE/g DE). The same extract exhibited the highest TAC (350.67±6.05 mg GAE/g DE) and was the most effective against the DPPH free radical (IC50 = 0.21±0.01 mg/mL). In contrast, the J. oxycedrus methanol extract showed the highest reducing power (A0.5 = 0.39 ± 0.09 mg/mL). All extracts tested showed antibacterial and anticandidal activities at different concentrations. The best antimicrobial effect was also observed with the acetone extract of J. oxycedrus against P. aeruginosa (26.77±0.06 mm), B. cereus (17.16±0.08 mm), E. coli (15.84±0.04 mm), and C. albicans (21.36±0.11 mm), while the ethanol extract of D. viscosa was the most active against S. aureus (24.54±0.03 mm). The results of this study provide a scientific basis for the traditional use of these local plants and demonstrate their potential as sources of natural antioxidant and antimicrobial bioactive compounds

    Simultaneous determination of amlodipine and lisinopril dihydrate using fourth derivative spectroscopy

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    A new fast and simple selective method for the simultaneous determination of lisinopril dihydrate and amlodipine in combined drugs was developed using the fourth derivative spectrum method, based on the zero-crossing-point technique for the determination of compounds in drugs. The wavelength values for lisinopril dihydrate and amlodipine in solvent medium were found to be (203, 207, and 231 nm) and (215, 254, and 277 nm), respectively, with the average obeying Beer’s law in the range of lisinopril dihydrate 2.0 to 45.0 µg/mL and amlodipine 2.0 to 35.0 µg/mL. Lisinopril dihydrate has molar absorptivity regions (9227.76-11700.28 L/mol.cm, 203 nm), (15320.74-20795.59 L/mol.cm, 207 nm), and (2207.60-3311.40 L/mol.cm, 231 nm), while amlodipine (5886.72-10914.96 L/mol.cm, 215 nm), (5518.8-6418.16 L/mol.cm, 254 nm) and (1676.08-1921.36 L/mol.cm, 277 nm). The recovery rate of lisinopril dihydrate in the pharmaceutical dosage forms range was 95.13 to 102.60% and amlodipine 95.14 to 102.80%. The results of the relative error showed that the interferences did not affect the method of estimating these compounds. The proposed method has been successfully applied to estimate pharmaceutical dosage forms

    Coumarin-hydrazone-based fluorescence sensor for Al(III) detection in aqueous solution: DFT calculation and DNA interaction studies

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    A new 'turn on' fluorescence chemosensor derived from coumarin-based compounds was successfully synthesised. N'-(2-Oxo-2H-chromene-3-carbonyl)isonicotinohydrazide (H2L) was characterised by different spectroscopic techniques such as IR, UV-vis, and NMR spectroscopy. The electronic structures of H2L and Al@HL were calculated using the density functional theory method using Becke’s three parameter Lee-Yang-Parr (B3LYP) exchange functional with the 6-31G+(d,p) basis set. The detection limit of H2L for the Al (III) ion was found to be 2.6 µM, which is low enough to detect micromolar and is below the World Health Organisation guideline for drinking water

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    A quantum chemistry background of sickle cell anemia and gaps in antisickling drug development

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    Sickle cell anemia disease has been a great challenge for the world in the present situation. It occurs only due to the polymerization of sickle hemoglobin (HbS) having Pro-Val-Glu (PVG) typed mutation, while the polymerization does not occur in normal hemoglobin (HbA) having Pro-Glu-Glu (PGG) residues. According to data from the literature, Val-beta6 of Pro-Val-Glu is hydrophobic in nature, which appears to fit into a hydrophobic pocket in the adjacent HbS. After the insertion of Pro-Val-Glu into a hydrophobic pocket on the adjacent HbS, the polymerization is started. This is a questionable point on how the replacement of glutamic acid with valine in HbS makes it more reactive to fit into a hydrophobic pocket on adjacent HbS for polymerization. No data from the literature on the reactivity of HbS for polymerization was found yet. This is the first time that the theoretical calculation was done in both HbA and HbS where they were structurally different. After that, a comparative study between PVG and PGG was done at quantum level for the evaluation of the reactivity to fit into a hydrophobic pocket on adjacent HbS. At a quantum level, it was found that the HOMO-LUMO gap of Pro-Val-Glu was lower than that of Pro-Glu-Glu. According to the data from the literature, the lesser HOMO-LUMO gap promotes the initiation of the polymerization reaction. On the basis of the results, it was also shown how the mutation point (Pro-Val-Glu) in HbS becomes more reactive to polymerization, whereas Pro-Glu-Glu in HbA does not. The computational method developed for the first time will be very helpful not only for molecular biologists but also for computational and medicinal chemists. Additionally, the required modifications based on gaps in anti-sickling drug development are also suggested in the presented article

    Synthesis of coumarin-3-carboxylic acids in waste curd water: A green approach

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    An efficient and green protocol has been developed for the synthesis of derivatives of coumarin-3-carboxylic acid using waste curd water as a catalytic solvent. Curd water successfully catalyzes the reaction of 2-hydroxybenzaldehydes with dimethyl malonate under ultrasonic irradiation (40 °C) to construct different scaffolds of coumarin-3-carboxylic acid, with good to outstanding yields. The use of biodegradable solvents, sustainability, low reaction duration, mild reaction conditions without metals and Lewis acids, excellent yields, and compatibility with a wide range of electronically diverse substrates are all advantages of this synthesis process. Acidic curd water, which acts as a biological catalyst as well as a solvent for the reaction under ultrasonic irradiation, may be a better green alternative to some standard methods for synthesizing coumarin-3-carboxylic acids

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