New silica-supported yttrium trinitrate was prepared, characterized, and used as a reusable catalyst for the three-component synthesis of quinazolinones/thiones via the Biginelli condensation under solvent-free conditions. Non-toxic reagent, short reaction times, simple work-up procedure, and high yield of the products are some of the important advantages of present method.
Evaluating the capability of electrospinning method as an efficient versatile approach for fabrication of fibers, a central composite design (CCD) model was used to design an experimental program for investigation of effective in production of poly (vinyl alcohol) (PVA) fibers fabricated from aqueous solutions of PVA. The studied variables were polymer solution concentration, applied voltage, distance between nozzle and collector plate and flow rate of solution injection. The influence of these parameters on diameter and morphology of obtained PVA fibers was studied by SEM analysis. Among all factors, concentration would strongly affect the fiber diameter.
Optimal method were developed for the green synthesis of quinoxaline derivatives based on the highly efficient and simple condensation reaction of various aromatic 1,2-diketones and 1,2-diamines in nearly quantitative yields in water. In this method we did not use any catalyst. The very mild reaction conditions, the high yields of the products, and the absence of any catalyst make this methodology an efficient and green route for synthesis of quinoxalines.
A tautomeric equilibrium exists for quinoline-2-thiol and quinoline-2(1H)-thione. Quantum mechanical calculations predict the thione is the major tautomer and this is confirmed by the absorption spectra. The utility of quinolone-2-thiol/quinoline-2(1H)-thione as a chromophore for developing fluorescent sensors is explored. No fluorescence is observed when excited at absorption maxima, however a fluorescence increase is observed when exposed to HNO, a molecule of import as a cardiovascular therapeutic. Alkylated quinoline-2-thiol derivatives are found to be fluorescent and show a reduction in fluorescence when exposed to metals and changes in pH.
The condensation of several aromatic/heteroaromatic aldehydes with 2-aminothiophenol under melt reaction conditions afforded 2-arylbenzothiazoles under solvent-free conditions. The major advantages of the present method are high yields, short reaction times, and eco-friendly conditions.
An ionic liquid 1-Butyl-3-methylimidazoliumchloride[BMIm]Cl/sodium hydroxide system, was employed as a catalyst for the fast and one-pot crossed aldol-condensation of various aromatic aldehydes and cyclic ketones, to produce a variety of substituted ?,? & apos; -bis(benzylidene)-cycloalkanones under neat conditions. This process is simple, efficient and environmentally benign and proceeds in high yield and short reaction times. The ionic liquid can be recycled for subsequent reactions without any appreciable loss of efficiency.
An efficient and simple synthesis of some 2-amino-3-cyano-4H-pyran derivatives was developed by the one-pot and three-component reaction of aldehydes, ethyl acetoacetate, and malononitrile in the presence of ammonia as catalyst at room temperature. The reaction is rapid and clean, and gives the products in high yields.
In this article, an efficient, environmentally benign, solvent-free synthesis of diethyl-2,6-dimethyl-4-(1-phenyl-3-aryl-1H-pyrazol-4-yl)-1,4-dihydropyridine-3,5-dicarboxylates and their simple oxidative aromatization in presence of selected hypervalent iodine (III) reagents under solvent-free condition at room temperature is demonstrated. All reactions were carried out by grinding the reactant pyrazole substituted Hantzch-1,4-dihydropyridines and hypervalent iodine (III) reagent in a mortar with pestle. [Hydroxy(tosyloxy)iodo]benzene act as an more efficient oxidizing reagent in comparison to phenyliodine bistrifluoroacetate and iodobenzene diacetate in terms of reaction time and yields. The advantages of present protocol are the environment friendly, short reaction time, mild reaction conditions, and high yields of the products.
The predominant tautomeric forms of N1–H, N2–H of 5-(2,6-dimethyl- and 5-(2,6-diisopropylphenoxy)-(1H)-tetrazoles were analyzed at B3LYP method using 6-311G(d,p) basis set in the gas phase. The N1–H form of tetrazoles was found to be more stable than N2–H form in both solid and gas phases. Crystal structures of both tetrazoles show an intermolecular H-bond between N1-H and N4 atom of other tetrazole space. The hydrogen bonds between each tautomer of tetrazoles were evaluated at B3LYP/6-311G(d,p) level. The geometrical parameters and spectral data of tetrazoles and their variation were studied in both solid and gas phases.
A simple and efficient procedure for the synthesis of 3, 4-dihydropyrimidin-2(1H)-ones under solvent-free condition using non-toxic and mild acid mesoporous SBA-15 nanoparticles as a catalyst has been investigated. This method has the advantages of the excellent yield, short reaction time, environmentally friendly conditions and simple experimental procedure.