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A method for the determination of nitrite in soil and vegetable samples by UV-Vis spectroscopy was proposed. The kinetic UV-Vis data were collected during the reaction between nitrite and 4-amino-3-hydroxynaphthalene-1-sulfonic acid with concentration of 0.001 M and pH 1.6. Data were collected by standard addition method. Multivariate curve resolution-alternating least squares was employed to analyze data with non-negativity and three-way data structure constraints. The method can be used to solve matrix effect and unknown interferents in the determination of nitrite in complex samples. The proposed method was used to determine nitrite at low mg/L levels with satisfactory results in soil, lettuce, cabbage and cucumber samples. Keywords: nitrite, kinetic, multivariate curve resolution-alternating least squares, unknown interferents, Nitrite is commonly monitored in water, agriculture and food [1]. Nitrite is an important water pollutant and excess concentration of nitrite in drinking water is hazardous to health, especially to [...]

Sequential injection chromatography (SIC) is based on a stopped-flow approach utilizing microscale low-pressure pump and selection valves coupled with micro-scale fiber optic spectrometric devices. In the current communication, a new method for the estimation of furosemide (FSD) and amiloride (AMD) in tablet formulation exploiting SIC is reported. The method was reverse-phase liquid chromatographic-based. The separation was carried out onto C18 monolithic column (4.6 x 50 mm) with a mobile phase composition of 25 mM phosphate buffer (pH 4.0)-acetonitrile (65 : 35, v/v). Other conditions were: sample volume 30 µL, flow rate 30 µL/s and UV detection at 283 nm. The SIC method is eco-friendly and cost-effective. The volume of consumed mobile phase was 3.25 mL. The sample frequency was 24 samples/h. The assay also exhibited linear dynamic ranges of 10-100 µg/mL for FSD and 5-80 µg/mL for AMD. Acceptable intraand inter-day precision (the RSD values were less than 2.2%) as well as accuracy (the recovery range was 97.5-98.4%) were obtained for concentrations over the range of the standard curves. The procedure was established for the purpose of quality control at a pharmaceutical laboratory. Keywords: amiloride, furosemide, method validation, pharmaceutical analysis, sequential injection chromatography DOI: 10.1134/S1061934814100025, Sequential injection chromatography is the most recent version in the family of flow injection techniques [1-3]. For its wide range of applications, the common approach in SIC is liquid chromatography [...]

Reversed phase HPLC separation and isolation of isomers of 3-chloro-2-hydroxy-4-naphthoquinone-1-oxime was investigated. At pH 7 with acetonitrile as a mobile phase, no separation occurs. Using various buffer solutions the pH of the mobile phase was maintained and the effect was studied between pH ~2.5 and ~10.5. Two distinct peaks are observed in chromatograms in the pH range studied. These peaks are assigned to para-tautomer 3,3-chloro-2-hydroxy-4-naphthoquinone-1-oxime and ortho-tautomer 4,3-chloro-4-hydroxy-2-naphthoquinone-1-oxime. Tautomeric equilibrium was found in acidic pH of mobile phase, whereas at pH 6.8 and basic pH of mobile phase the tautomers are well separated from each other. Isolation of the tautomers was carried out by preparative HPLC technique. The solids of tautomers 3 and 4 were obtained as ammonium acetate adducts. Keywords: naphthoquinoneoxime, keto-enol tautomerism, separation of isomers, pH effect, HPLC, 3-chloro-2-hydroxy-4-naphthoquione-1-oxime DOI: 10.1134/S1061934814120144, Naphthoquinones are important constituents of plant families such as Plumbaginaceae, Juglandaceae, Ebenaceae and many commercially important tropical hardwood species. The first report of HPLC separation of non-isoprenoid naphthoquinones was published [...]

Multicage fullerene cycloadducts have been detected by MALDI mass spectrometry; they have been found as admixtures in the products of reactions of the trifluoromethylation of fullerene samples doped with metallic sodium, the reaction between fullerenes and a mixture of trifluoromethylfullerenes, and the synthesis of fulleroproline esters. As a result, over 75 new compounds of this type have been identified. The optimization of the synthesis procedures and chromatographic fractionation allowed us to extract five compounds in the pure form: [(C.sub.60]).sub.2][(C[F.sub.2]).sub.2][(C[F.sub.3]).sub.8], [([C.sub.60)].sub.2][(C[F.sub.2]).sub.2][(C[F.sub.3]).sub.3][C.sub.2][F.sub.5], [([C.sub.60]).sub.2][(C[F.sub.2]).sub.2][(C[F.sub.3]).sub.5][C.sub.2][F.sub.5] [([C.sub.60]).sub.2][(C[F.sub.2]).sub.2][(C[F.sub.3])2]O, and [C.sub.60]C[H.sub.2]N(C[H.sub.2][C.sub.60])CCOOtBu. Chemical structures of two of them, proposed on the basis of post source decay mass spectra, have been further confirmed by NMR spectra. Keywords: multicage fullerene cycloadduct, MALDI, trans-2-[3-(4-tert- butylphenyl)-3-methyl-3-propenylidene]malononitrile, post source decay DOI: 10.1134/S1061934810140091, INTRODUCTION Among the great number of fullerene derivatives, a special place is occupied by the derivatives whose molecules consist of several fullerene cages. The increased interest in such compounds is [...]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.icarus.2010.07.023 Byline: M.L. Moriconi (a), J.I. Lunine (b)(e), A. Adriani (b), E. D'Aversa (b), A. Negrao (b)(c), G. Filacchione (d), A. Coradini (b) Keywords: Titan; Satellites, Surfaces; Infrared observations; Image processing Abstract: Liquid hydrocarbons were long predicted on Titan's surface before the RADAR instrument onboard Cassini detected lakes poleward of 70[degrees]N in July 2006. Before that the Cassini Imaging Science Subsystem (ISS) observed a lake-like feature in the South Pole, named Ontario Lacus, in July 2004. Here we analyze one observation of Ontario Lacus taken by the Visual and Infrared Mapping Spectrometer (VIMS) on 2007 December 5, during the T 38 flyby. This is the best spatially resolved image of a Titan lake to date by an imaging spectrometer, and has been previously reported in Brown et al. (Brown, R.H., Soderblom, L.A., Soderblom, J.M., Clark, R.N., Jaumann, R., Barnes, J.W., Sotin, C., Buratti, B., Baines, K.H., Nicholson, P.D. [2008]. Nature 454, 607-610) and in Barnes et al. (Barnes, J.W. et al. [2009]. Icarus 201, 217-225). The observing geometry and our data processing will be explained, followed by a discussion of the main characteristics of the image. The analyzed image covers a small portion of Ontario Lacus and shows what appears from RADAR data to be a region of modest slope ('ramp') adjacent to the dark lake itself. Our analysis of 5.0[mu]m spectral data suggests that the previously reported absorption feature of ethane seen at shorter wavelengths may be produced by damp sediments adjacent to the main liquid basin. The latter appears to be absorbing all of the photons incident upon it in the 5[mu]m spectral region and shows no discernible absorption features. A characterization of the basin composition and morphology is developed with the help of ISS and RADAR observations. The simplest model consistent with the data is an optically deep lake surrounded by a region in which ethane, propane, possibly methane, and other, less volatile hydrocarbons and nitriles are present mixed into spectroscopically neutral sediments. The dominance of relatively low vapor pressure organics outside the lake itself suggests a retreat of Ontario Lacus associated with evaporation on seasonal or longer timescales, consistent with analysis of RADAR and ISS images. Author Affiliation: (a) Institute of Atmospheric Science and Climate-CNR, Via Fosso del Cavaliere 100, I-00133 Rome, Italy (b) IFSI-INAF, Via Fosso del Cavaliere 100, I-00133 Rome, Italy (c) Escola Superior de Tecnologia e Gestao de Leiria, Campus 2, Morro do Lena-Alto do Vieiro, P-2411 Leiria, Portugal (d) IASF-INAF, Via Fosso del Cavaliere 100, I-00133 Rome, Italy (e) Department of Physics, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Roma, Italy Article History: Received 15 October 2009; Revised 22 July 2010; Accepted 27 July 2010

The C-C coupling of the new tricyclic hydrazones 3-7 with aryl and heteroaryl halides gave under reductive Heck conditions the tricyclic 1-(arylideneamino)pyrolidine-2,5-diones 8-11a, 9-11b, 10c, and 12. The [3+2] cycloadditions of 3-7 with p-chlorophenyl nitrile oxide (13) yielded the bridged isoxazoline derivatives 14-18 with potential biological activity. Key words: tricyclic hydrazone, reductive Heck reactions, C-C coupling, nitrile oxides, isoxazolines. Le couplage C-C des nouvelles hydrazones tricycliques 3-7 avec des halogenures d'aryles et d'heteroaryles, dans les conditions reductrices de Heck, conduisent a la formation des 1-(arylideneamino)pyrolidine-2,5-diones tricycles 8-11a, 9-11b, 10c et 12. Les cycloadditions [3+2] des composes 3-7 avec l'oxyde du p-chlorophenylnitrile (13) conduisent a la formation des derives isoxazolines pontees 14-18 qui peuvent presenter une activite biologique. Mots-cles : hydrazone tricyclique, reactions reductrices de Heck, couplage C-C, oxydes de nitriles, isoxazolines., Introduction In a collaborative effort with Kaufmann and co-workers, (1-3) we reported palladium(II) acetate catalyzed asymmetric Heck-type hydroarylations of bicyclic and tricyclic alkenes, such as epibatidine analogs, and their domino-Heck [...]

An Fe[Cl.sub.3]-mediated intramolecular heterocyclization of 3-alkoxyimino-2-arylalkylnitriles is applied to prepare a series of functionalized N-alkoxyindole-3-carbonitrile derivatives. The novel synthetic method allows the N-moiety on the side chain to be annulated to the benzene ring as the final synthetic step which in turn facilitates the functionalization of the benzenoid portion of the indole at an early stage of the synthesis.

A detailed study of the reaction of salicylic aldehydes and malononitrile was carried out to understand reaction pathway, the structure of the isolated products, and the corresponding reaction conditions. The complex was observed to show significant antifungal activity, when tested on various strains of Aspergillus species.

The pump-probe photoionization of isolated benzonitrile (BN) and phenylacetylene (PA) in a supersonic beam is discussed. Results suggest the production of a low-ionization-potential species, which lasts more than hundreds of microseconds after excitation to the [S.sub.1] states.

A five step synthesis of 8,16-dicyano-anti-[2.2]metacyclophane -1,9-diene from 1,3-bis(bromomethyl)benzonitrile is demonstrated.

A new silica-supported zinc-copper matrix reagent has promoted the conjugate addition of alkyl iodides to cyclic and acyclic alkenenitriles in water. Conjugate additions to acyclic and cyclic 5-7 membered alkenenitriles are found to be more effective for primary alkyliodides, although secondary and tertiary alkyliodides are viable reaction partners.

The synthesis of five new meso-tetraarylporphyrins having pyridine, pyrimidine or nitrile groups extending tetragonally via alkynyl linkages from the para positions is presented. The radial extension is nearly double that of common porphyrins such as tetra-p-pyridylporphyrin and these extended porphyrins are used in the area of porous metal-organic frameworks.

1-Arylmethyl-2-(cyanomethyl)aziridines are transformed into 4-(N,N-bis(arylmethyl)amino)-3-(pyrrolidin-1-yl)butanenitriles and 4-(N,N-bis(arylmethyl)amino)-2-butenenitriles through 4-(N,N-bis(arylmethyl)amino)-3-bromobutanenitriles in high yields. The main steps have involved the unprecedented regiospecific ring opening of intermediate 2-(cyanomethyl)aziridinium salts by bromide and pyrrolidine in acetonitrile at the substituted aziridine carbon atom.

The sulfur K-edge X-ray absorption spectroscopy (XAS) which was used to study a series of [Ni.sup.II] complexes based on the N,N'-bis(2-mercaptoethyl)-1,5-diazacyclootanato (DACO) ligand system revealed that RS[O.sub.2.sup.-] is comparable to R[S.sup.-] in [sigma] donation but is a worse [pi] donor.

The reactivity and the intramolecular cyclizations of the bicyclic [delta]-hydroxynitriles are investigated. The analogues derived from such reactions after further reactions give various annulated enones, which is found to be a result of an initial elimination reaction to form alkenes, followed by the formation of the activated cyano group.

The covalent functionalization of short single wall carbon nanotubes (s-SWNTs) with strong electron acceptor photosensitizer pyrylium moieties and the observation of a photoinduced solubility increase in the resulting compound are reported. The photoinduced solubility could be attributed to the debundling of the nanotubes due to photoinduced charge separation through the nanotube walls and the photoinduced solubility could serve to develop SWNT layers suitable for photolithography patterning.

The synthesis and liquid crystalline properties of four substituted 4H-benzo [1,2,4]-thiadiazines by condensation of the proper anilines and benzonitriles followed by oxidative cyclization is presented. The first observations have shown that some persistent radicals can be efficiently generated from 4H-benzo [1,2, 4]-thiadiazines and purified in a strictly anerobic atmosphere.

The Rh-catalyzed intermolecular hydroacylation between salicylaldehyde and alkenylnitriles have produced normal-hydroacylated products at room temperature. The addition of C[H.sub.3]CN and NaOAc has accelerated the Rh-catalyzed hydroacylation of monoolefins to produce the normal-hydroacylated products under mild conditions.

The preparation and characterization of a series of ionic liquids (ILs) based on nitrile-functionalized imidazolium, pyridinium and quaternary ammonium as cations and chloride and tetrafluoroborate, hexafluorophosphate, dicyanamide, and bis(trifluoromethanesulfonyl)imide as anions is presented. The physicochemical properties are comparatively studied and the results have shown that the incorporation of a CN group to a cation result in remarkable changes in these properties.

The reaction of N-tosylaziridines with nitriles and carbonyls to produce imidazolines and oxazolidines is studied in the presence of a variety of Lewis acids. The results have shown that the reaction can proceed through either 2-aryl-N-sulfonylaziridines ([S.sub.N]1) or alkyl-N-tosylazidines ([S.sub.N]2) fashion.

Racemic 1-arylaaziridine-2-carbonitriles were catalyzed by the Rhodococcus erythropolis. It was found that 1-phenylaziridine-2carboxamide undergoes readily the Lewis acid catalyzed ring opening reaction with an azide.

The synthesis of [alpha]-aminonitriles and their fluorinated analogs has been carried out in high yield and purity by the Strecker reaction from the corresponding ketones and amines with trimethylsilyl cyanide using gallium triflate in dichloromethane. Monofluoro-, difluro-, or trifluoromethyl groups can be incorporated into the [alpha]-aminonitrile product by varying the nature of the fluorinated ketones. Study with various fluorinated and nonfluorinated ketones reveals that the choice of proper catalyst and the solvent system (suitable metal triflates as a catalyst and dichloromethane as a solvent) plays the key role in the direct Strecker reactions of ketones. three-component reaction | [alpha]-aminonitriles

The reactions between platinum-bound RCN species and HN-E[R.sub.pi] to specific imines as guanidines are studied to perform and apply nitrile-guanidine coupling to the formation of 1,3-diaza-1,3-dienes. The results have ascertained that it constitutes a novel synthetic approach to a useful class of heterocyclic species like 1,6-dihydro-1,3,5-triazines.

Chelation can be used as a means of stereocontrol in alkylations of metalated nitriles. Chemaltion-controlled metalated nitrile geometry has permitted the selective cyclizations to cis and trans hydrindanes and decalins, while also helping in understanding the geometrical requirements of the cyclizations.

A new approach is developed based on fluorescence quenching of a chromophore, pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt, POH) for monitoring the synthesis of the pyranine-substituted phthalonitrile derivative PoPht. The new material can be used for synthesizing the phthalocyanine having an increased fluorescence property and solubility in an aqua medium, which would result in a desired candidate molecule in many applications of phthalocyanines.

The specific rotations of several substituted oxiranes, 2-chloropropionitrile and 30 degree-rotated ethane are calculated by using a sum-over-states approach. The first few excited states proved to have only a relatively small effect on the calculated specific rotation, in each case, and hence the need to use a large number of excited states was observed, in order to achieve convergence wit the results of the more direct linear response method.

The first example of the use of cyanohydrins as a C[N.sup.minus] source in a organocatalyzed Strecker reaction performed under phase transfer conditions and employing N-Boc protected [alpha]-amido sulfones as imine precursors is described. N-Boc has proved to be the most suitable protection since the reaction run with N-Cbz [alpha]-amido sulfone led to a sizable decrease of the enantioselection.

A simple and efficient methodology for the synthesis of a small library of substituted indolizines with different degrees of saturation starting from the racemic 2-formyl-1,4-DHP reagent is presented. The main step of the sequential reaction was based on the highly diastereoselective tandem Michael addition/intramolecular amino-nitrile cyclization catalyzed by an organic base, which produced 1,7-dihydroindolizines in a diastereoselective manner.

The isomerization and decomposition of 1,2-benzisoxazole are analyzed behind reflected shock waves in a pressurized driver, single-pulse shock tube. The rate constants are estimated on the basis of the potential energy surfaces by using transition-state theory and are compared to the experimental results obtained by the single-pulse shock-tube method.

The generation of gas-phase vanadyl (V[O.sup.2+]), vanadyl hydroxide (VOO[H.sup.+]) and vanadium(V) dioxo (V[O.sub.2.sup.+]) cations complexed with nitrile ligands by using electrospray ionization (ESI) is described. The results have shown that the [[V[O.sub.2][(L).sub.2]].sup.+] species requires higher collision energies to liberate the nitrile ligand, indicating that they are strongly bound than the [[VOOH[(L).sub.2]].sup.+] counterparts.

The electric deflections of p- and m-aminobenzonitrile (PABM and MABN) and of p- and m-(dimethylamino)benzonitrile (PDMABN and MDMABN) molecules are presented. The change in symmetry and the introduction of methyl groups have led to a transition from the rigid response to the linear response.

The charge transfer (CT) state formation of trans-4-dimethylamino,4'-cyanostilbene (DCS) is examined in a solvent using ab initio complete active space self-consistent field calculations combined with polarized continuum model. The DCS as well as 4-dimethylaminobenzonitrile studies confirms that skeletal relaxation where the benzene ring loses its aromaticity is essential to stabilize the CT state in a solvent besides the torsional motion.

Coupled-cluster and density functional methods are used to determine specific rotations and electronic circular dichroism (ECD) rotational strengths for (S)-2-chloropropionitrile. Density functional specific rotations using the B3LYP functional with basis sets of quadruple-zeta quality containing up to 588 functions are found to be too large compared to experiment by almost a factor of 2.

A comprehensive study of the synthetic potential of the enantioenriched cyanohydrin-O-carbonates and cyanohydrin-O-phosphates to provide the corresponding gamma-substituted alpha,beta-unsaturated nitriles using heteronucleophiles and malonate as nucleophiles in the presence of palladium or iridium complexes as catalysts. The optimal conditions foe each nucleophile and substrate, concerning the stereoselectivity and enantioselectivity, as well as the comparison between the carbonate and the phosphate as leaving groups are evaluated.

The unprecedented palladium-catalyzed C-H addition of arenes to nitriles yields aryl ketones or the corresponding hindered imines, where the addition of a small amount of DMSO increases the yields dramatically. A concise route to xanthones starting from cheap starting materials is developed by using this synthetic protocol.

The synthesis of a second-generation macromonomer with peripheral tert-butyl-protected carboxylates and a methacrylate polymerizing unit, as well as its free radical polymerization using azobisisobutyronitrile (AIBN) as initiater precursor is described. Scanning force microscopy (SFM) imaging of both protected (noncharged) and unprotected (charged) dendronized polymers on solid substrates reveals mostly linear chains but also some with main-chain branches.

The kinetic and thermodynamic properties of the regioselective addition of bifunctional hydroxylaminooxime-type HO-nucleophiles to form Pt-complexed nitriles are described. The results of the synthetic, kinetic and theoretical studies have shown that the high regioselectivity of the reactions of the 1,2-hydroxylaminooximes with ligated nitriles is both kinetically and thermodynamically controlled.

Two polymorphs of a compound [H2DABCO][Ni-(mnt)(sub 2)](sub 2) (where (H2DABCO](sub 2+) = diprotonated 1,4-diazabicyclo-[2.2.2]octane and mnt(sub 2-)= maleonitriledithiolate), are presented, each of which exhibits a spin transition with a clear hysteresis loop. The results have shown that H-bonding interactions exist between cations and anions and pi...pi, S...S and S...Ni interactions between anions.

The transformation of acid chlorides (RC(O)Cl) to organic nitriles by the terminal niobium nitride anion through isovalent N for O(CI) metathetical exchange is presented. This establishes a firm connection between dinitrogen cleavage chemistry and nitrogen atom transfer reactivity.

Cross-nucleation between polymorphs is studied in the spontaneous and melt crystallization of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrite (ROY) and extensive and selective cross-nucleation between ROY polymorphs is observed. Results show that the pathway of crystallization in systems is not determined only by the initial nucleation, but also by cross-nucleation between polymorphs and their different growth rates.

A strategy for synthesizing Fe(III)complexes of ligands cointaning carboxamido-N and thiolato-S donors are described. The ligands in which the carboxamide and thiolate functionalaties are kept in conjugation could be used to isolate Fe(III) complexes with carboxamido-N and thiolato-S coordinates.

Highly enantioselective intermolecular hydro phosphination reaction is described. Focus is laid on additions of secondary phosphines to methacrylonitrile, while strategies for new catalytic enantioselective hydrophosphinations is based on several of the concepts.

A mild and transition-metal-free method for the alpha-arylation of aliphatic nitriles with activated heteroaryl halides that were developed at ambient temperature was described. Generation of the nitrile anion in the presence of the heteroaryl halide was the success of the process.

Palladium-catalyzed procedures for the selective monoarylation of acetonitrile and primary nitriles are achieved using alpha-silyl nitriles in the presence of ZnF2. This procedure is compatible with a variety of functional groups, including cyano, keto, nitro and ester groups, on the aryl bromide.

The scope and stereoselectivity of the acid-promoted cyclization of new tryptophan-based alpha-amino nitriles derived from either ketones or aldehydes to novel hexahydropyrrolo[1',2',3':1,9a,9]imidazo-[1,2-a]indoles is described. The time and stereoselectivity of the reaction mostly depended on both the steric volume of the substituents at the amino nitrile and its stereochemistry.