Green chemical synthesis of fluorinated 1,3,5-triaryl-s-triazines in aqueous medium under microwaves as potential antifungal agents

Reasonable pure fluorinated s-triazines were synthesized in quantitative yield (96-99%) in 2-3 min in aqueous medium under microwaves, by reaction of fluorinated anilines and aqueous formaldehyde. All synthesized compounds have been screened in vitro for their antifungal activity against Rhizoctonia solani, Fusarium oxysporum, and Collectotrichum capsici.     

Microwave assisted green chemical synthesis of novel spiro[indole-pyrido thiazines]: a system reluctant to be formed under thermal conditions

Spiro [3H-indole-3,2′-[4H] pyrido [3,2-e]-1,3-thiazine]-2,4′ (1H) diones, a class of previously unknown compound which does not form under conventional conditions, can be prepared by treatment of ‘in situ’ generated 3-indolylimine derivatives with 2-mercaptonicotinic acid under microwave irradiation in absence of any solvent or solid support in 85-92% yields in 3-8 min. The facile one pot reaction is generalized for a variety of ketones and amines to give pure pyrido [3,2-e] thiazine derivatives, which do not require further purification processes.     

Bifunctional Lewis acid-nucleophile-based asymmetric catalysis: mechanistic evidence for imine activation working in tandem with chiral enolate formation in the synthesis of beta-lactams

We report a mechanistically based study of bifunctional catalyst systems in which chiral nucleophiles work in conjunction with Lewis acids to produce beta-lactams in high chemical yield, diastereoselectivity, and enantioselectivity. Chiral cinchona alkaloid derivatives work best when paired with Lewis acids based on Al(III), Zn(II), Sc(III), and, most notably, In(III). Homogeneous bifunctional catalysts, in which the catalyst contains both Lewis acidic and Lewis basic sites, were also studied in detail. Mechanistic evidence allows us to conclude that the chiral nucleophiles form zwitterionic enolates that react with metal-coordinated imines. Alternative scenarios, which postulated metal-bound enolates, were disfavored on the basis of our observations.     

Kinetics of non-isothermal decomposition of acid maleato complexes of some bivalent metals

McGinn et al. [1] and Misra and Naik [2] studied the complexing capacity of maleic acid with metals. Edge [3] reported his findings on the pyrolysis of normal nickel maleato. This note is concerned with the estimation of kinetic parameters of the non-isothermal decomposition of acid maleato complexes of Co(II), Cu(II), Ni(II) and Cd(II).     

Antiferromagnetic interactions in single crystalline Zn1-xCoxO thin films

In a rather contradictory situation regarding magnetic data on Co-doped ZnO, we have succeeded in fabricating high-quality single crystalline Zn(1-x)Co(x)O (x=0.003-0.07) thin films. This gives us the possibility, for the first time, to examine the intrinsic magnetic properties of ZnO:Co at a quantitative level and therefore to address several unsolved problems, the major one being the nature of the Co-Co interaction in the ZnO structure.     

Antimicrobial activities of essential oil and methanol extract of Coriaria nepalensis

Plant extracts and products have been used for centuries in traditional medicine; for most of them, in addition to the scant scientific credibility, the chemical composition and spectrum of activity are yet to be explored. To put forward this effort and to identify novel antimicrobial agents, the inhibitory activities of methanolic extract and essential oil from Coriaria nepalensis against various microorganisms including pathogenic yeast, and Gram-positive and negative bacteria were evaluated. Chemical compositions of C. nepalensis methanolic extract and essential oil were analysed by gas chromatography-mass spectrometry. In vitro susceptibility tests against all the tested isolates were performed in terms of minimum inhibitory concentration (MIC), and well diffusion assay using standard protocols. All microorganisms tested were profoundly found susceptible to both the C. nepalensis extract and oil with MIC values of 1.3-2.1?mg?mL?1 (Gram-positive bacteria), 1.4-2.2?mg?mL?1 (Gram-negative bacteria) and 0.9-1.6?mg?mL?1 (yeasts). The extent of inhibition was shown more by methanolic extract than by essential oil. This study is the first to report the antimicrobial activity of extracts obtained from the C. nepalensis. It can be concluded that the observed antimicrobial characteristics of C. nepalensis indicate that it might be a promising antimicrobial agent.     

Dielectric properties of Pb(Mg1/4Zn1/4Nb1/2)O11/4

Polycrystalline samples of Pb(Mg_1/4Zn_1/4Nb_1/2)O_11/4 have been synthesized by high temperature columbite precursor solid state reaction technique. Using X-ray diffraction (XRD) technique, compound formation in single phase cubic structure was observed and XRD analysis provided preliminary structural data. Detailed studies of dielectric properties of the compound reveal that this compound has high dielectric constant and diffuse phase transition in a wide range of temperatures around the Curie temperature. The charge deficiency of the compound presumably gets compensated in the high temperature columbite precursor process of sample preparation which is supported by single phasic form of the material.     

Structure determination and infrared spectroscopy of K(UO2)(SO4)(OH)(H2O) and K(UO2)(SO4)(OH)

Two potassium uranyl sulfate compounds were synthesized, and their crystal structures were determined by single-crystal X-ray diffraction. K(UO2)(SO4)(OH)(H2O) (KUS1) crystallizes in space group P21/c, a = 8.0521(4) A, b = 7.9354(4) A, c = 11.3177(6) A, beta = 107.6780(10) degrees , V = 689.01(6) A3, and Z = 4. K(UO2)(SO4)(OH) (KUS2) is orthorhombic Pbca, a = 8.4451(2) A, b = 10.8058(4) A, c = 13.5406(5)A, V = 1235.66(7)A3, and Z = 8. Both structures were refined on the basis of F2 for all unique data collected with Mo Kalpha radiation and a CCD-based detector to agreement indices R1 = 0.0251 and 0.0206 calculated for 2856 and 2616 reflections for KUS1 and KUS2, respectively. The structures contain vertex-sharing uranyl pentagonal bipyramids and sulfate tetrahedra linked into new chains and sheet topologies. Infrared spectroscopy provides additional information about the linkages between the sulfate and uranyl polyhedra, as well as the hydrogen bonding present in the structures. The U-O-S connectivity is examined in detail, and the local bond angle is impacted by the steric constraints of the crystal structure.