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A green and efficient regioselective protocol was developed for the preparation of novel isoxazolines and isoxazoles of N-saccharin derivatives via the water-promoted cycloaddition reaction of nitrile oxides with alkenes and alkynes. It is noteworthy that KI/Oxone/water-promoted one-pot three-component reactions of aldehyde, hydroxylamine hydrochloride, and alkene or alkyne were observed to be very satisfactory. The synthesis of all adducts (4a-j/5a-j) has been carried out by this method with high to excellent yields (70-95%) at 25°C within 30 min, using ultrasonic probe. All the new compounds were thoroughly characterized by spectroscopic techniques and also 5b, 5c and 5f were structurally identified by single-crystal X-ray diffraction methods. X-ray crystallography structure analysis clearly supported the regioselectivity of the cycloaddition reaction.

In the present study, a series of thiazolidine-2,4-diones derivatives (3a–3e) and (4a–4e) were synthesized and characterized by 1H NMR, 13C NMR and ESI-MS spectrometry. All compounds were screened for their α-glucosidase and α-amylase inhibitory activities. In vitro biological investigations revealed that most of compounds were active against α-glucosidase with IC50 values in the range of 43.85 ± 1.06 to 380.10 ± 1.02 µM, and α-amylase with IC50 in the range of 18.19 ± 0.11 to 208.10 ± 1.80 µM. Some of the tested compounds were found to be more potent inhibitors than the clinical drug Acarbose (IC50glucosidase = 97.12 ± 0.35 µM and IC50amylase = 2.97 ± 0.004 μM). The lead compounds were evaluated for their acute toxicity on Swiss mice and found to be completely non-toxic with LD > 2000 mg/kg BW. Furthermore, the Structure–activity relationship (SAR) and the binding interactions of all compounds with the active site of α-glucosidase and α-amylase were confirmed through molecular docking and stabilizing energy calculations. This study has identified the inhibitory potential a new class of synthesized thiazolidine-2,4-diones in controlling both hyperglycemia and type 2 diabetes mellitus. Furthermore, the theoretical binding mode of the target molecules was evaluated by molecular docking studies against the 3D Crystal Structure of human pancreatic α-amylase (PDB ID: 1B2Y) and α-glucosidase (PDB ID: 3W37) Communicated by Ramaswamy H. Sarma

A rapid and green method for the synthesis of novel N-thiazolidine-2,4-dione isoxazoline derivatives 5 from N-allyl-5-arylidenethiazolidine-2,4-diones 3 as dipolarophiles with arylnitrile oxides via 1,3-dipolar cycloaddition reaction. The corresponding N-allyl substituted dipolarophiles were prepared by one-pot method from thiazolidine-2,4-dione with aldehydes using Knoevenagel condensation followed by N-allylation of thiazolidine-2,4-dione in NaOH aqueous solution under sonication. In addition, the isoxazoline derivatives 5 were synthesized by regioselective and chemoselective 1,3-dipolar cycloaddition using inexpensive and mild NaCl/Oxone/Na

A simple and green one-pot reaction has been proposed for the synthesis of novel 3,5-disubstituted isoxazole-sulfonates and -sulfonamides (5a-j) in water under ultrasound irradiation. The methodology is based on the use of safe and environmentally friendly reagents and allows, via in-situ 1,3-dipolar cycloaddition, an easy access to functionalized heterocycles with the creation of four new bonds (S O, C N, C O and C C). Comparison studies using classical magnetic stirring and ultrasound irradiation clearly showed that sonication promoted clean transformation, high yields (72–89%) and faster reactions (20–28 min). All the synthesized compounds were fully characterized by MS-ES, 1H NMR, 13C NMR spectroscopy and HPLC analysis.

The search for new effective and eco-friendly corrosion inhibitors seems to be a never-ending task for practical applications. Herein, the principal objective of this work is to investigate the corrosion inhibition effect of novel 1,2,3-triazolyl nucleosides namely, 2-(acetoxymethyl)-5-(3-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TBAc) and 2-(acetoxymethyl)-5-(3-((1-(naphthalen-2-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TNAc) for mild steel (MS) in HCl solution. Different amounts of TBAc and TNAc inhibitors were prepared in 1.0 mol/L HCl medium, and their inhibition effect was investigated via electrochemical measurements, X-ray photoelectron spectroscopy (XPS), quantum chemical calculations (DFT), and molecular dynamics (MD) modeling. Further, we have examined the effect of iodide ions on inhibition efficiency, and the obtained data were compared and discussed. Results showed that these green compounds exhibited high inhibition performances thanks to their excellent molecular and electronic properties. They indicated that TNAc and TBAc showed high corrosion inhibition efficiencies at 5x10-3 mol/L with 0.1 mmol/L of KI. The inhibition efficiency of TNAc and TBAc reached 85% and 79% at 5x10-3 mol/L, while it improved to 94% and 91% in the presence of KI, respectively. Electrochemical tests revealed that the studied molecules acted as mixed-type inhibitors and they had a significant effect on the polarization resistance of mild steel. Moreover, the surface morphology analysis was performed using a scanning electron microscope (SEM) and XPS. Besides, a systematic understanding of how these molecules are adsorbed on steel surface was theoretically investigated. Taken together, experimental and theoretical results suggested a significant role of molecular properties of studied derivatives along with intermediate species in promoting their adsorption behavior. A consistent association was found between electrochemical measurements and theoretical calculations.

To date, the corrosion of metal surfaces is one of challenging problems in the modern business (technology and industrial applications). So, corrosion control of metal at different stage of application is necessary. To avoid this problem, organic and inorganic corrosion inhibitors are widely used. For this purpose, the present study deals with the corrosion inhibition assessment of novel uridine- (Murmu et al., 2020; Dehghani et al., 2020; Li et al., 2020) [1,2,3]triazole nucleosides as green corrosion inhibitors, namely 2-(acetoxymethyl)-6-(4-((3-(3,4-diacetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-2,6-dioxo-3,6-dihydropyrimidin-1(2H)-yl)methyl)-1H-1,2,3-triazol-1-yl)tetrahydro-2H-pyran-3,4,5-triyl triacetate (TPTAc) and 2-(acetoxymethyl)-5-(3-((1-(3,4-diacetoxy-5-(acetoxymethyl)tetrahydrofuran-2-yl)-1H-1,2,3-triazol-4-yl)methyl)-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)tetrahydrofuran-3,4-diyl diacetate (TPDAc). After synthesis and characterization procedure, the corrosion inhibition performances of these compounds against the corrosion of mild steel (MS) are studied using both experimental and theoretical exploration. The effect and inhibition action of these inhibitors on the electrochemical behavior of MS corrosion was evaluated experimentally via electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and weight loss techniques. In addition, theoretical calculations are made to analyze adsorption properties and characteristics of synthesized molecules on MS surface. The results obtained from all electrochemical experiments confirmed that the inhibitors understudy exhibited high inhibition performances thanks to their adsorption capacity on MS surface. EIS data indicated that TPTAc is quite effective at 5 × 10−3 M than TPDAc at the same concentration. PDP results revealed that the studied molecules acted as mixed-type inhibitors and they had a strong influence on the protective layer formed. The corrosion rate (CR) values considerably fall down from 1.135 mg cm−2 h−1 to 0.090 and 0.158 mg cm−2 h−1 at 5 × 10−3 M of TPTAC and TPDAc, respectively. Moreover, the effect of KI ions was also evaluated, and the results suggest that the presence of iodide ions has significantly improved the inhibition performances (97% for TPTAc and 90% for TPDAc at 5 × 10−3 M). Also, the calculated values of Gibb's free energy ( Δ G ads 0 ) are −33.61 kJ/mol and −34.33 kJ/mol for TPTAC and TPDAc, respectively; lying between −21 and −40 kJ/mol, confirming both physisorption as well as chemisorption interactions. In addition, results indicated that the inhibition intensity of studied compounds was expected to happen by means of adsorption over the MS surface which obeys the Langmuir's adsorption isotherm. The surface characterizations confirmed previous findings and contributed additional evidence on the morphological changes of MS surface during corrosion. The anti-corrosive and adsorption properties of studied compounds were detailed by DFT and molecular dynamics (MD) simulations. The results of theoretical calculations demonstrate strong and consistent agreement with experimental outcomes.

A green and efficient synthesis of new sulfonamide-1,2,3-triazoles 5 in heterogeneous conditions has been developed. The procedure involved one-pot four-component tandem sulfonamidation/azidation/1,3-dipolar cycloaddition (1,3- DC ) reactions under a cooperative effect of ultrasound irradiation and Cu (II) supported on amorphous mesoporous silica [mSiO2-Cu (II)] catalysis at room temperature in aqueous medium. In addition, the 1,4-disubstituted 1,2,3-triazoles 5 were synthesized by regioselective and chemoselective methods to afford the pure products in excellent yields and short reaction times under ultrasonic irradiation. The supported catalyst has been prepared from copper (II) nitrate by simple method using ultrasound activation and characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method and Barrett-Joyner-Halenda (BJH) method. Also, the catalyst is easily prepared, stable, efficient, selective, and reusable under ultrasonic conditions.

International audience; A new, straightforward and eco-compatible route to C-(hetero)aryl nucleosides is reported. This ribosylation process consists of a one-step FeCl 3 catalyzed Friedel-Crafts b-C-glycosydation reaction. This reaction occurs through an oxonium intermediate from readily available protected sugars leading to functionalized C-nucleosides with high stereocontrol. The expected new C-nucleosides were obtained in good yields within a short reaction time (10 min). Moreover, this approach is compatible with the use of a range of bulky (poly)aromatics such as naphthalene, anthracene and pyrene, which are not easily accessible via classical routes. These new C-aryl-nucleosides exhibit interesting photophysical properties, underling their potential use for further nucleic acid labelling.

We report herein a simple and efficient synthesis of a new series of antibacterial uridine nucleosides. The strategy involved a sequential silylation/N-glycosylation/N-propargylation procedure of uracil 1 for preparing the dipolarophile 5 in good yield. A series of novel uridine-[1,2,3]triazole nucleosides 6a-j were efficiently synthesized via the copper-catalyzed azide-alkyne cycloaddition (CuAAC) from dipolarophile 5 with different selected azides. The reactions were carried out under both conventional and ultrasonic irradiation conditions. In general, improvements were observed when reactions were carried out under sonication. Their antibacterial potential has been evaluated by means of a micro-dilution assay against either Gram-positive or Gram-negative bacteria. Compounds 6i and 6j have shown significant bactericidal activity against Staphylococcus aureus (MIC = 10 and 6 μM, respectively), and 6h against Escherichia coli (MIC = 8 μM). Moreover, antibacterial kinetic assays showed that 6i and 6j significantly reduced the S. aureus growth rate at the MIC concentration, after 6 h, compared to their deprotected analogs, 6k and 6l, respectively. Compound 6h also significantly reduced the growth of E. coli. These antibacterial effects may be related to the penetrating properties of these compounds, as revealed by the leakage of nucleic acids from the sensitive strains.

The C-aryl-ribosyles are of utmost interest for the development of antiviral and anticancer agents. Even if several synthetic pathways have been disclosed for the preparation of these nucleosides, a direct, few steps and modular approaches are still lacking. In line with our previous efforts, we report herein a one step - eco-friendly β-ribosylation of aryles and heteroaryles through a direct Friedel-Craft ribosylation mediated by bismuth triflate, Bi(OTf)3. The resulting carbohydrates have been functionalized by cross-coupling reactions, leading to a series of new C-aryl-nucleosides (32 compounds). Among them, we observed that 5d exerts promising anti-proliferative effects against two human Chronic Myeloid Leukemia (CML) cell lines, both sensitive (K562-S) or resistant (K562-R) to imatinib, the “gold standard of care” used in this pathology. Moreover, we demonstrated that 5d kills CML cells by a non-conventional mechanism of cell death.

In the title compound, C15H15NO5S, the benzene and heterocyclic rings are close to being coplanar [dihedral angle = 1.49 (6)°]. In the crystal, pairwise C—H...O hydrogen bonds form dimers, which are arranged into `stair-step' rows by way of C=O–π interactions between a carbonyl group and the benzene ring [O...π = 3.3837 (12) Å].