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  • Open access
  • 100 Reads
Carbon Dots from Coffee Grounds by a One-Pot Microwave-Assisted Method

Carbon-based nanomaterials, particularly carbon dots (C-dots) have attracted the researchers interest due their excellent luminescence, photostability and biocompatibility, encouraging their use in several areas such as biomedicine, (bio)sensors, photocatalysis and optoelectronics.

C-dots could be prepared by a variety of methods (top-down and bottom-up approaches), using a great diversity of carbon sources. Bottom-up processes based on the use of waste materials for producing C-dots are particularly attractive since an effective reduction of environmental impacts of those wastes may be foreseen, while high-valued nanomaterials can be simultaneously obtained.

Coffee is one of the most consumed brews all over the world, generating large amounts of coffee waste, a source of a serious environmental problem due to the high content of organic matter such as caffeine, phenols, tannins, and sugars.

Herein, we explore the valorization of coffee grounds generated from automatic and vending machines for production of C-dots through a one-pot monomode microwave-assisted method.

Structural and photophysical characterization of the as-synthesized nanomaterials have been carried out, and their potential applications as sensing materials for pollutants and explosives (e.g. nitroanilines and nitroaromatics) were evaluated by fluorescence and absorption techniques.

  • Open access
  • 58 Reads
Isoxazoles via Cycloaddition of Terminal Alkynes and Nitrile Oxides (from Oximes)
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Conditions for the production of isoxazoles in a one-pot process are presented. Nitrile N-oxides are generated by the oxidation (using hypervalent iodine reagents) of oximes that subsequently undergo 1,3-dipolar cycloaddition with terminal alkynes affording the isoxazoles. From a collection of three terminal alkynes and four aldehydic oximes, 11 distinct isoxazoles were prepared. The effectiveness of various oxidants and solvent systems is discussed, as are side reactions.

  • Open access
  • 45 Reads
RESORUFIN BASED COLOROMETRIC AND FLUORESCENT PROBE FOR SELECTIVE DETECTION OF MERCURY.

Environmental pollution crisis, particularly mercury ions (Hg2+) contamination, seriously threatens health of all living organisms. Several researchers have explored that even extremely low concentration of Hg2+ can rigorously damage the living organisms. Therefore, it is very much needed for real-time detection of Hg2+. To tackle mercury contamination and for its detection We herewith tried an intelligent design of a new fluorescent “turn-on” probe which was prepared based on the mercury promoted hydrolysis of vinyl ether moiety. The probe rapidly reacted with mercury ions and showed good selectivity over other metal ions.

  • Open access
  • 60 Reads
IN SILICO SCREENING OF NATURAL PHYTOCOMPOUNDS TOWARDS IDENTIFICATION OF POTENTIAL LEAD COMPOUNDS FROM DIFFERENT VARIETIES OF CUMIN
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We probed into the effect of different varieties of cumin for the search of potential leadsbased on the phytochemical profiles and bioactivities In silico study were applied to relevant bioactive compounds in search of a lead compound through molinspiration cheminformatics software. Different lead compounds from different varieties of cumin were selected for bioactivity prediction and drug likeness score on the basis of Lipinski’s rule. All of the compounds fulfilled Lipinski’s rule as their Milog P score was below 5 suggesting these compounds are means these shows good permeability across cell membrane.All the screened compounds had minimum and no violations of Lipinski rule. Different lead compounds from different varieties of cumin showed good bioactivity score for drug targets including nuclear receptor ligand, protease inhibitor and enzyme inhibition and thus expected to have excellent pharmacological activity in vivo. The results of this study justify their topical application as immunomodulators action but some structural modifications in order to make the compound more polar will definitely improve oral bioavailability and thus the usefulness and therapeutic efficacy of different varieties of cumin. All the lead compounds from different varieties of cumin, are predicted to be orally active and is considered as a potential candidate for the further research as its bioactivity score due to high affinity for various drug targets was better than the standard as well as among other tested compounds. Evidence from the present study advocates the need for exploring different lead compounds from different varieties of cumin in an endeavor to discover unique bioactive lead compounds that could target specific ailments. The selected molecules were assessed for Pharmacodynamic parameters like mutagenicity, tumorigenicity, reproductive effect and ocular & skin irritancy and pharmacokinetic properties like solubility, human intestinal absorption and blood brain barrier permeability. Based on the results, each ligand was assigned with respective drug-likeness and drug score.

  • Open access
  • 69 Reads
Synthesis, characterization and preliminary antibacterial evaluation against Staphylococcus aureus of a new 2,4,5-tri(hetero)arylimidazole derivative based on azaindole heterocycle

Imidazole derivatives are known for their numerous biological applications, such as antibacterial, antifungal, antioxidant, antiviral, antiparasitic and anticancer, among others. Therefore, several imidazole derivatives have been synthesized and developed in recent years as potential drugs in the treatment of several diseases. In this communication, we report the synthesis of a new imidazole derivative, substituted at positions 2, 4 and 5 with heterocyclic groups, using a simple synthetic methodology and an easy purification procedure. The new compound was characterized by the usual spectroscopic techniques (NMR, UV-Vis absorption and emission). The evaluation of the novel imidazole derivative as a potential antibiotic drug was carried out against the Gram-positive bacterium Staphylococcus aureus, using disk test diffusion method. Results showed a dose-response effect against the bacteria under study, revealing that the rational design of this imidazole derivative is quite promising to improve antibacterial activity of imidazole derivatives.

  • Open access
  • 61 Reads
Comparative Study of Phytochemical Analysis and identification of drug lead compounds from some medicinal plants
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Secondary metabolites found in the medicinal plants play important role in curing different diseases and used as important raw materials for the manufacturing of traditional and modern medicine. These medicinal plants like Annona reticulata with Allium sativum, Allium fistolisum and Brassica oleraceae reduces various risk factors associated with several diseases. It has been shown to inhibit enzymes involved in lipid synthesis, decrease platelet aggregation, prevent lipid peroxidation of oxidized erythrocytes and LDL, increase antioxidant status, and inhibit angiotensin converting enzyme. It also reduces cholesterol, inhibits platelet aggregation, reduces blood pressure, and increases antioxidant status. Therefore, our aim was to compare the different secondary metabolites present in the crude extracts of aqueous and methanolic. Phytochemicals screening revealed the results that alkaloids, reducing sugar, flavonoids, glycosides, cardiac glycosides, tannin and phenolic compounds, saponins, amino acid & triterpenoids It indicated that bioactive components are present in these plants that could be accounted for its pharmacological effects. Thus, the results support the uses of these plant species in traditional medicine.

  • Open access
  • 59 Reads
Regiospecific bromination of (2е, 4е) -5-aryl-2- (4-arylthiazol-2-yl) penta-2,4-dienenitriles
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In the reaction of (2E, 4E) -5-phenyl-2-cyano-2,4-pentadientioamide or (E) -3- (2-nitrophenyl) acrolein and cyanothioacetamide with α-bromoketones received new (2E, 4E) -5-aryl-2- (4-arylthiazol-2-yl) penta-2,4-dienenitriles. Direct bromination of the latter by the action of Br2 in DMF proceeds regiospecifically at the C5 position of the thiazole ring without affecting the diene system and leads to the formation of previously undescribed (2E, 4E) -5-aryl-2- (5-bromo-4-arylthiazol-2-yl) penta-2,4-diennitriles. The structure of the reaction products was established using 2D NMR spectroscopy and X-ray diffraction analysis.

  • Open access
  • 33 Reads
Synthesis of light-harvesting antenna dyads as phototherapeutic agents

Photodynamic inactivation (PDI) has been proposed as an alternative therapy to combat bacterial infections. This therapy combines a photosensitizer, visible light, and oxygen to produce reactive oxygen species (ROS), which lead to cell death. In this sense, porphyrins are interesting photodynamic agents, however, they present low absorption in the phototherapeutic window. Therefore, the design of new dyads combining tetrapyrrolic macrocycles and light-harvesting antennas can be useful to increase the absorption in visible region.

In this study, two dyads, P-BDP and ZnP-BDP, were synthesized containing a BODIPY unit linked to a free-base porphyrin and its complex with Zn(II) via a 1,3,5-triazine group. First, an amino-porphyrin was bound to 1,3,5-triazine in 80% yield. In a second step, this structure was reacted with an amino-BODIPY to obtain a dyad (25%). Finally, the third chlorine atom of the triazine unit was substituted by N,N-dimethylethylenediamine in THF (98%). The BODIPY moiety in the dyads acts as a light-harvesting antenna, which produces an intramolecular energy transfer to the porphyrin unit. In addition, the Zn(II) in the tetrapyrrolic macrocycle increases the intersystem crossing, favoring the generation of ROS. In turn, the tertiary amine in the triazine structure can acquire a positive charge at physiological pH by increasing binding to microbial cells. The absorption spectrum of P-BDP and ZnP-BDP resulted in a linear combination of the spectra of the corresponding monomers. The fluorescence spectra showed a strong decrease in the BODIPY emission along with the increase in the porphyrin unit emission, indicating a deactivation (>99%) of the BODIPY singlet state by porphyrin. The photodynamic activity of both dyads is enhanced with respect to that of their porphyrin monomers. Thus, the new dyads present interesting properties to act as phototherapeutic agents.

  • Open access
  • 73 Reads
Synthesis of triterpenoid-derived α-acyloxycarboxamides via Passerini reaction

Herein we describe the synthesis of a small series of α-acyloxycarboxamides via a facile and efficient one-pot procedure, employing a plant-derived triterpenoid as carboxylic acid component. The products were obtained in overall yields of 25 to 79%, while we scoped the effect of the nature of the aldehyde component on the reaction yields.

  • Open access
  • 143 Reads
An Efficient Synthesis of Novel Hydrazine-Carboxamides In Water-Ethanol Solvent System as anticancer agents.
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Hydrazine-carboxamide has shown a promising anticancer activity. A series of novel Hydrazine-carboxamide derivatives were synthesised in three step process, in first step substituted phenyl urea was synthesised, followed by synthesis of substituted phenyl semicarbazide, finally the substituted phenyl semicarbazide and substituted aromatic aldehydes/ketones were condensed using water-ethanol (2:1) solvent system to obtain final novel series of Hydrazine-carboxamides. The method reported is efficient as it is less time consuming with good yields. Overall anticancer activity, with the synthesised compounds was carried out. Some Hydrazine-carboxamides compounds were found to possess significant anticancer efficacy.

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