A metal-free visible light promoted three-component facile synthesis of 4-oxo-tetrahydroindoles in ethanol–water

A mild and efficient visible light–mediated one-pot multicomponent tandem approach to construct 4-oxo-tetrahydroindoles in ethanol–water medium at room temperature has been described. The characteristics of reported methodology are the utilization of visible light, an ideal source of energy to generate C C and C N bonds from commercially available substrates namely dimedone, phenacyl bromides, and amines. The presented protocol is highly compatible for developing 4-oxo-tetrahydroindole derivatives with improved selectivity and high yields. Moreover, metal-free synthesis, environmental friendly solvent, easy workup process, high atom economy, cost-effectiveness, short reaction time, and broad substratescope are the major advantages of reported protocol.     

A Novel Molecular Imprint Polymer Quartz Crystal Microbalance Nanosensor for the Detection of Andrographolide in the Medicinal Plant Extract

Russian Journal of Electrochemistry - A novel quartz crystal microbalance (QCM) sensor based on molecular imprint polymer (MIP) has been developed for the detection of andrographolide in the...     

Effects of Essential Oils of Elettaria cardamomum Grown in India and Guatemala on Gram-Negative Bacteria and Gastrointestinal Disorders

The present study examined the chemical composition and antimicrobial and gastrointestinal activity of the essential oils of Elettaria cardamomum (L.) Maton harvested in India (EC-I) and Guatemala (EC-G). Monoterpenes were present in higher concentration in EC-I (83.24%) than in EC-G (73.03%), whereas sesquiterpenes were present in a higher concentration in EC-G (18.35%) than in EC-I (9.27%). Minimum inhibitory concentrations (MICs) of 0.5 and 0.25 mg/mL were demonstrated against Pseudomonas aeruginosa in EC-G and EC-I, respectively, whereas MICs of 1 and 0.5 mg/mL were demonstrated against Escherichia coli in EC-G and EC-I, respectively. The treatment with control had the highest kill-time potential, whereas the treatment with oils had shorter kill-time. EC-I was observed to be more potent in the castor oil-induced diarrhea model than EC-G. At 100 and 200 mg/kg, P.O., EC-I exhibited 40% and 80% protection, respectively, and EC-G exhibited 20% and 60% protection, respectively, in mice, whereas loperamide (10 mg/kg, i.p., positive control) exhibited 100% protection. In the in vitro experiments, EC-I inhibited both carbachol (CCh, 1 µM) and high K⁺ (80 mM)-induced contractions at significantly lower concentrations than EC-G. Thus, EC-I significantly inhibited P. aeruginosa and E. coli and exhibited more potent antidiarrheal and antispasmodic effects than EC-G.     

Application of nitrogen-rich porous organic polymer for the solid-phase synthesis of 2-amino-4H-benzo[b]pyran scaffolds using ball milling process

Molecular Diversity - This paper presents the efficient synthesis of 2-amino-4H-benzo[b]pyrans using mesoporous poly-melamine-formaldehyde as a polymeric heterogeneous catalyst. According to the...     

New protocols for the synthesis of 5-amino-7-(4-phenyl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate esters using an efficient additive

This work introduces a new additive named 4,4’-trimethylenedipiperidine for the practical and ecofriendly preparation of ethyl 5-amino-7-(4-phenyl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate derivatives. This chemical is commercially available and easy to handle. It also possesses a low melting point and a broad liquid range temperature, high thermal stability, and good solubility in water. Based on green chemistry principles, the reaction was performed in a) a mixture of green solvents i.e. water and ethanol (1:1 v/v) at reflux temperature, and b) the additive was liquefied at 65 °C and the reaction was conducted in the liquid state of the additive. High yields of the desired triazolo-pyrimidines were obtained under both aforementioned conditions. Our results demonstrated that this additive, containing 2 Lewis base sites and able to act as an acceptor-donor hydrogen bonding group, is a novel and efficient alternative to piperidine, owing to its unique properties such as its reduced toxicity, nonflammable nature, nonvolatile state, broad liquid range temperature, high thermal stability, and ability to be safely handled. Furthermore, this additive could be completely recovered and exhibited high recyclability without any change in its chemical structure and no significant reduction in its activity. The current methodology has several advantages: (a) it avoids the use of hazardous materials, as well as toxic, volatile, and flammable solvents, (b) it does not entail tedious processes, harsh conditions, and the multistep preparation of catalysts, (c) it uses a metal-free and noncorrosive catalyst, and (d) reduces the generation of hazardous waste and simple work-up processes. The most important result of this study is that 4,4’-trimethylenedipiperidine can be a promising alternative for toxic, volatile, and flammable base reagents in organic synthesis owing to its unique properties.     

Characterization of Volatile Components of Chassalia chartacea and Its Acetylcholinesterase Inhibitory Activity

Chemistry of Natural Compounds -     

An artificial neural network approach for the prediction of dynamic viscosity of MXene-palm oil nanofluid using experimental data

Journal of Thermal Analysis and Calorimetry - Given the excellent thermal properties of MXene, MXene nanomaterials-based nanofluids may have the potential of being used as heat transfer fluids. In...     

Impact of polyvinylpyrrolidone and quantity of silver nitrate on silver nanoparticles sizing via solvothermal method for dye-sensitized solar cells

The multiple sizing of silver nanoparticles (AgNPs) were synthesized from the miscible compound of ethylene glycol (EG), polyvinylpyrrolidone (PVP) and silver nitrate (AgNO3) via the solvothermal method. During the synthesis, the PVP-AgNO3 was contemplated as a paramount parameter. Using the simple method of solvothermal, the sizing of AgNPs was easily controlled in accord with the augmentation of PVP-AgNO3 at secured and moderate temperature. In regards to the sizing of AgNPs, the presence of minimum agglomeration, the absorption capability and chemical structures were highlighted through a series of verification includes ultraviolet–visible (UV–Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) analysis. The effectiveness of the synthesized AgNPs was further investigated and compared with the commercial AgNPs by incorporating the AgNPs into titanium dioxide (TiO2) semiconductor film-based dye-sensitized solar cells (DSSCs). Results signified that the spherical AgNPs with produced sizing within the range of 19.6 to 45.2 nm were greatly impacting by tunable quantities of PVP-AgNO3, which was validated in the forms of linear equations. A larger size promotes a slower nucleation rate that conduces agglomeration. In opposition to this, the smallest size of AgNPs develops a faster formation rate of Ag ions into AgNPs, inducing the deterrent of agglomeration in light of notable particle dispersion. The power conversion efficiency (PCE) contributed by the incorporation of synthesized AgNPs into TiO2 is also 41.2% higher than that of the commercial AgNPs-TiO2. This is because the synthesized AgNPs provides less agglomeration which led to a better surface plasmonic effect towards the nanoparticles.     

Interplay of H‐Bonds with Aromatics in Isolated Complexes Identifies Isomeric Carbohydrates

The tremendous isomeric diversity of carbohydrates enables a wide range of their biological functions but makes the identification and study of these molecules difficult. We investigated the ability of intermolecular interactions to communicate structural specificity of carbohydrates to protonated aromatic molecules in non‐covalent complexes, isolated and cooled in the gas phase. Our study revealed that small structural differences between carbohydrate isomers of any type, including enantiomers, are accurately communicated by these interactions to aromatic molecules as detectable changes in their electronic excitation spectra. The specific response of the aromatics to the isomers of carbohydrates is fine‐tuned by the interplay of the various involved non‐covalent bonds. These findings enable the gas‐phase identification and relative quantification of any isomers of oligosaccharides in their solution mixtures using the 2D UV‐MS fingerprinting technique.