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Thermal paper poses a significant challenge to latent print development as it tends to change color when traditional fingerprint development formulations are applied to it. In this study, the optimal components of ninhydrin, 1,2-indanedione, 1,8-diazafluoren-9-one ( DFO), and 5-methylthioninhydrin (5- MTN) for yielding clear fingerprints on thermal paper were determined by systematically adjusting the relative amounts of the reagents, polar solvents, and the nonpolar diluent petroleum ether, followed by validation on text-printed thermal paper. Specifically, 3.0% ethyl acetate as the polar solvent in petroleum ether was found to be the optimal combination; the optimal dilution ratios of ninhydrin, DFO, and 5- MTN original solutions with petroleum ether were 1 to 2, 11, and 7, respectively. The optimal concentration of 1,2-indanedione in petroleum ether was 0.125 g/L, with a string of 0.5% ethyl acetate in petroleum ether. [ABSTRACT FROM AUTHOR]

From 15 May to 15 December 1994, 2943 patients suspected of having contact dermatitis (1955 women, 988 men) were patch tested with methyldibromoglutaronitrile 0.3%, 0.1% and .05% pet. 119 patients (4.0% women, 4.1% men, 3.8%) proved to be allergic. 71% of the reactions were considered to be relevant. In 2/3 of the patients, causative products were cosmetics, in 1/3 moistened toilet tissues. Testing with methyldibromoglutaronitrile at lower concentrations 0.05% and 0.1%) and with commercial allergens (Euxyl® K 400 and methyldibromoglutaronitrile, both containing methyldibromoglutaronitrile 0.1%), resulted in a number of false-negative reactions. All preservatives in the European standard series had lower scores than the 4% positive reactions to methyldibromoglutaronitrile (formaldehyde 2.0%. MCI/MI (Kathon® CG) 3.2% parabens, 1.0% quaternium-15 1.3%). It is concluded that methydibromoglutaronitrile (present in the commercial preservative Euxyl® K 400) is an important contact allergen in the Netherlands in cosmetics and moistened toilet tissues. It should be added to cosmetics series and to proctological series. The optimal test concentration is unknow, but may be 0.3%. pet. Th concentration of 0.1% methyldibromoglutaronitrile in the currently available commercial allergens appears to be too low, resulting in a number of false-negative reactions. [ABSTRACT FROM AUTHOR]

Three relatively new reagents for developing latent fingermarks on porous substrates, 1,2-indandione (IND), 5-methylthioninhydrin (5-MTN), and lawsone, are compared with the more widely used ninhydrin and 1,8-diazofluoren (DFO). Developed latent fingermark visualization on 10 different substrates comprising colored papers, cardboard, and cellophane rather than conventional printer and writing/notepad paper is assessed using latent fingermark deposits from 48 donors. Results show improved fluorescent fingermark visualization using IND compared with DFO on a range of colored cardboards and thick white paper, thus extending the range of substrates known to yield improved visualization with IND. Adding zinc chloride to IND failed to yield any further improvement in fluorescent fingermark visualization. 5-MTN (with and without zinc chloride posttreatment) showed no improvement in visualization compared with ninhydrin and DFO although visible fingermarks were developed. Lawsone produced fluorescent visible fingermarks only with white substrates, which were inferior to those produced with DFO. [ABSTRACT FROM AUTHOR]

A thin film of poly-([IrCl(cod)(NHC-onbe)] n-(propyl-onbe) m) (onbe=oxanorbornene) coated on filter paper reacts quantitatively with CO to yield 1,5-cyclooctadiene, the unpleasant smell of which can be detected by the human olfactory system with very high sensitivity. Odorless, but toxic CO is thus 'translated' into the distinct smell of 1,5-cyclooctadiene. Based on malodorogenic sensing it is possible to smell the presence of CO. [ABSTRACT FROM AUTHOR]

Occupational contact allergy to 1,2-benzisothiazolin-3-one (1,2-BIT. Proxel®) is analysed. This compound is widely used in industry as a preservative in water-based solutions such as pastes, paints and cutting oils. The optimal concentration for patch testing proved to be 0.4 g/1 (0.04%) in water. In 4 out of 17 patients (23%) at occupational risk (painters, paper-hangers), contact allergy to 1,2-BIT was found. Of 556 consecutive dermatological patients without clear occupational risk, 10 (1.8%) showed positive patch tests to 1.2-BIT in 3 patients 1,2-BIT contact allergy was related to domestic paper-hanging. Although the chemical structure of 1,2-BIT shows some analogy with the preservative Kathon® CG, true cross-sensitivity was found to be unlikely. [ABSTRACT FROM AUTHOR]

This paper investigates the optimal tracking performance based on the codec, colored noise, and bandwidth constraints in the network time‐delay systems. Choosing the optimal two‐degree‐of‐freedom compensator and the dominant expression of the system optimal tracking performance is obtained after Youla parameterization by using the coprime factorizations method and spectral decomposition technology. The result shows that the tracking performance of the system is determined by the nonminimum phase zero and unstable pole of the controlled plant. Moreover, codec, colored noise, and bandwidth constraints can also significantly impact the performance. Finally, two simulation examples prove the accuracy of the theory. [ABSTRACT FROM AUTHOR]

It is a well-known fact that by changing the 1,3-dipolar cycloaddition (1,3- DC) reaction mechanism from concerted to stepwise, the stereospecificity is lost; since in synthesizing the required heterocyclic molecules that reaction is a requisite, it is important to study the concertedness of that reaction. Several papers on this subject have already stated that the existence of electron withdrawing groups ( EWG) or electron donor groups ( EDG) on dipole or dipolarophile leads to a high-energy differentiation between the dipole HOMO and dipolarophile LUMO (or vice versa) as well as the emergence of an intermediate in the reaction pathway. This paper seeks answering the question of when an EWG on dipole and an EDG on dipolarophile could be a factor in making the reaction mechanism stepwise, and does repositioning of functional groups in replacing dipole and dipolarophile switches the reaction mechanism from stepwise into concerted or vice versa? [ABSTRACT FROM AUTHOR]

The paper describes a comprehensive investigation to establish the heterophase acid-catalyzed 1, 2 Michael addition reaction between fullerenol (nucleophile) and substituted acrylates (R = H, CH3, Ph)/vinyl acrylates (electron deficient olefins). The main emphasis is to evaluate structure–property relationship and establish a mechanism for tuning the structure in different operating conditions, which could be useful while adapting this reaction in designing of fullerene core starlike macromolecules. The effect of substituents on the rate of formation of the product is another important aspect covered in the present paper. The most significant outcome of the present investigation are (i) the nature of the product formed has direct bearing with operating process, whereas, (ii) rate of reaction and the properties of the end-products depends on the nature and position of substituents attached to olefins. Adopting heterogeneous phase reaction scheme, the reaction can be easily controlled at 1, 2 Michael addition stage which otherwise proceeds further to provide cyclic product in single-phase reaction. The nature of the substituent at β-carbon of the olefins have the inverse effect on the rate of the reaction. The steric rather than electronic effect of substituents governs the rate of reaction. However, the significant influence of β-substituents on the properties of the Michael addition products are observed in a more classical manner. The phenyl substituent at the β-position measured the slowest rate of reaction but imparts highest thermal stability. In such systems, the vinyl substitution on esteric carbon further reduces both the reaction rate and the thermal stability. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The demand for the efficient utilization of biomass ‐ derived sugars has increased in the field of green and sustainable chemistry. In this paper, Sho Yamaguchi, Toshihide Baba et al. report a new route to the cascade synthesis of five ‐ membered lactones, which can be utilized not only as fine chemicals but also as chemical starting materials, using a biomass ‐ derived sugar (1,3 ‐ dihydroxyacetone, DHA) as a carbon nucleophile and various aldehydes. This achievement provides a new synthetic strategy to generate a wide range of valuable compounds from a single biomass ‐ derived sugar and electrophiles. More information can be found in the Full Paper by Sho Yamaguchi, Toshihide Baba et al. on page   1731 in Issue 11, 2016 (DOI: 10.1002/asia.201600307). [ABSTRACT FROM AUTHOR]

The paper is mainly focused on the induced circular dichroism (ICD) based on central-to-axial chirality transfer for direct chiral recognition and ee value detection of 1,2-diaminocyclohexane (1,2-DACH) enantiomers. A novel achiral polymer sensor with potential axial chirality feature is designed and synthesized. This conjugated polymer incorporating biphenol moiety can bind chiral 1,2-DACH substrates via intramolecular hydrogen-bonding interactions, which could result in the detectable exciton-coupled circular dichroism (CD) spectrum due to the chirality transfer from an enantiopure building block to a dynamically racemic 1,1′-biphenyl-2,2′-diol moiety in the polymer chain backbone. The linear regression analysis of ICD sensing shows an excellent agreement between CD intensity and concentration of chiral 1,2-DACH, which indicates this biphenol-based achiral polymer can be used as a chiral sensor for direct recognition and ee value detection of 1,2-DACH enantiomers by using ICD spectra of achiral polymer sensor. [ABSTRACT FROM AUTHOR]

The relationship between phosphorus and carbon chemistry has been realized for many years. Phosphorus relatives of classical organic ligands (like cyclopentadienide, Cp-) in which carbon atoms have been substituted for phosphorus atoms are important classes of organometallic ligands, which are relevant to catalysis. Often, however, a limit to applying the phosphorus counterparts is the low-yielding and circuitous nature of their synthesis. A case in point is the 1,2-diphospholide ligand framework, an important analogue of the cyclopentadienyl ligand, which has only been obtained from multistep syntheses. We report in this paper a high-yielding and direct route to this type of framework using a very simple approach. Treatment of MesPHLi (Mes = 2,4,6-trimethylphenyl) with Sb(NMe2)3 generates the 5,7-dimethyl-1,2-benzodiphosphol-1-ide anion ( 1), the first 1,2-diphospholide analogue of indenyl. Structural and NMR spectroscopic investigations suggest that this unique reaction, involving double C-H deprotonation of a CH3 group of the Mes ligand, occurs through the rearrangement of a tetraphospha-1,4-diide anion. [ABSTRACT FROM AUTHOR]

This paper describes an efficient method for the synthesis of α-methylidene-γ-amino acid esters from readily available aldehydes by using aminative umpolung strategy. Electrophilic aromatic aldehydes were converted to α-imino anions via amination with 2,2-diphenylglycine in methanol and subsequent decarboxylation in acetonitrile. The in situ generated α-imino anions displayed high activity in the reaction with Morita-Baylis-Hillman adducts in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as catalyst, to give a variety of substituted α-methylidene-γ-amino acid esters in 54-96% yields with 3.2-7.1:1 diastereoselectivity. The resulting α-methylidene-γ-amino acid esters can be efficiently converted into biologically important α- exo-methylidene-γ-lactams under mild conditions. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and structural characterization of two new one-dimensional coordination polymers involving 1,3-bis(4-pyridyl)propane ligand named {(μ-NCS)2[Cu(bpp)] ·dmf} n ( 1) and {[Cu(mebpy)(bpp)(dmso)](ClO4)2 ·dmso} n ( 2) (bpp = 1,3-bis(4-pyridyl)propane and mebpy = 4,4'-dimethyl-2,2'-bipyridine). These compounds were characterized by means of elemental analysis, thermal analysis (TG/DTA), vibrational spectroscopy (IR and Raman) and had their structures determined by single-crystal X-ray diffraction analysis. Compound 1 consists of CuN4 coordination spheres with bpp ligands in the unusual GG conformation coordinated in bridges between CuII centers to form a wavelike 1-D coordination polymer. On the other hand, in compound 2 the bpp ligand adopts the TT conformation in bridging mode extending the 1D cationic polymeric chain. [ABSTRACT FROM AUTHOR]

In the “chemical billiard” reaction shown on the front cover, a counter ion directs the attack of the azide anion to one or another electrophilic center of the organic substrate. Covalently bonded metal azides transfer N3− to the β ‐ carbon atom through a Lewis ‐ acid ‐ promoted SN’ process, while ionic azides react through SN2 attack on the silicon. These two pathways lead to entirely different products. More information can be found in the Full Paper by A. Yu. Sukhorukov et al. on page 4570 ff. [ABSTRACT FROM AUTHOR]

Copolymerization of propylene with styrenic α-olefin monomers is rare with C2-symmetric ansa-metallocene-type catalysts, which are the dominant single-site catalysts for isospecific propylene polymerization. This makes it difficult to obtain compositionally narrow-distributed reactive polypropylene with isotactic stereoregularity ( iPP) bearing benzyl and styryl moieties, which are important precursors for iPP functionalization. In this paper, rac-CH2(3- t-Bu-1-Ind)2ZrCl2 is paired with methylaluminoxane (MAO) and used in copolymerization of propylene with p-methyl­styrene ( p-MS) and 1,4-divinylbenzene (DVB). Due to the unified primary regiochemistry of the catalyst toward both propylene and the styrenic monomers, both copolymerizations are viable, with the incorporation of the styrenic monomers not disastrously decreasing the catalyst activity. The fingerprint primary-primary consecutive sequences of propylene and p-MS/DVB are clearly identified by 13C NMR. As high as 1.37 mol% of p-MS and 0.93 mol% of DVB are incorporated into iPP at fairly high catalyst activities. It is noteworthy that DVB is incorporated with a selective mono-enchainment mode, leaving iPP with pendant styryl groups on the linear backbone. Both the iPP/ p-MS and iPP/DVB copolymers show narrow molecular weight distributions (<3), indicating a single-site characteristic of the copolymerizations. Overall, copolymerization of propylene with p-MS and DVB with a C2-symmetric ansa-metallocene catalyst is made possible by unification of the insertion regiochemistry of the comonomers. [ABSTRACT FROM AUTHOR]

This paper discusses a design of experiments (DoE) assisted optimization and robustness testing of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method development for the trace analysis of the potentially genotoxic 1,3-diisopropylurea (IPU) impurity in mometasone furoate glucocorticosteroid. Compared to the conventional trial-and-error method development, DoE is a cost-effective and systematic approach to system optimization by which the effects of multiple parameters and parameter interactions on a given response are considered. The LC and MS factors were studied simultaneously: flow (F), gradient (G), injection volume (Vinj), cone voltage (Econ), and collision energy (Ecol). The optimization was carried out with respect to four responses: separation of peaks (Sep), peak area (Ap), length of the analysis (T), and the signal-to-noise ratio (S/N). An optimization central composite face (CCF) DoE was conducted leading to the early discovery of carry-over effect which was further investigated in order to establish the maximum injectable sample load. A second DoE was conducted in order to obtain the optimal LC-MS/MS method. As part of the validation of the obtained method, its robustness was determined by conducting a fractional factorial of resolution III DoE, wherein column temperature and quadrupole resolution were considered as additional factors. The method utilizes a common Phenomenex Gemini NX C-18 HPLC analytical column with electrospray ionization and a triple quadrupole mass detector in multiple reaction monitoring (MRM) mode, resulting in short analyses with a 10-min runtime. The high sensitivity and low limit of quantification (LOQ) was achieved by (1) MRM mode (instead of single ion monitoring) and (2) avoiding the drawbacks of derivatization (incomplete reaction and time-consuming sample preparation). Quantitatively, the DoE method development strategy resulted in the robust trace analysis of IPU at 1.25 ng/mL absolute concentration corresponding to 0.25 ppm LOQ in 5 g/l mometasone furoate glucocorticosteroid. Validation was carried out in a linear range of 0.25-10 ppm and presented a relative standard deviation (RSD) of 1.08% for system precision. Regarding IPU recovery in mometasone furoate, spiked samples produced recoveries between 96 and 109 % in the range of 0.25 to 2 ppm. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper describes an efficient approach for the synthesis of a new series of 6-[3-alkyl(aryl/heteroaryl)-5-trifluoromethyl-1 H-pyrazol-1-yl]nicotinic acids (where alkyl = CH3; aryl = Ph, 4-OCH3Ph, 4,4′-BiPh; and heteroaryl = 2-Furyl) from the reaction of alkyl(aryl/heteroaryl)substituted 2-(5-trifluoromethyl-5-hydroxy-4,5-dihydro-1 H-pyrazol-1-yl)-5-(5-trifluoromethyl-5-hydroxy-4,5-dihydro-1 H-1-carbonylpyrazol-1-yl)pyridines, under basic conditions and at 70-95% yields. In a subsequent step, the of pyrazolyl-nicotinic acids done in thionyl chloride and methanol led to the isolation of a series of methyl 6-[alkyl(aryl/heteroaryl)-5-trifluoromethyl-1 H-pyrazol-1-yl] nicotinates as stable hydrochloride salts at 64-84% yields, which could be easily converted to hydrazides to give new oxadiazolyl-pyrazolyl-pyridine tricyclic scaffolds at good yields from a [4 + 1] reaction with 1,1,1-triethoxyethane and 1-(triethoxymethyl)benzene as the reagent/solvent. [ABSTRACT FROM AUTHOR]

2,3-Butanediol (2,3- BD) is a major by-product of 1,3-propanediol (1,3- PDO) fermentation by Klebsiella pneumoniae ZG25. It not only consumes large amounts of its carbon source and nicotinamide adenine dinucleotide to diminish synthesis of 1,3- PDO, but also serves as an obstacle to high-purity 1,3- PDO in downstream processes. To decrease the formation of 2,3- BD and make an intrinsic improvement in 1,3- PDO production, the budC gene in K. pneumoniae, coding 2,3- BD dehydrogenase, which is a key gene of the 2,3- BD pathway, was successfully knocked out using the Red recombination system described in this paper. The results of the mutant fed-batch fermentation showed that the 1,3- PDO concentration, productivity per cell dry weight, and conversion rate increased to 880 mmol L−1, 22.0 mmol L−1 h−1, and 0.700 mol mol−1, respectively, increasing by 10%, 15%, and 11% compared with the parent strain. Meanwhile, 2,3- BD was still found in fermentation broth with the 2,3- BD metabolic pathway blocked, which implies that K. pneumoniae possesses a pathway of the 2,3- BD cycle as a replenishment pathway. [ABSTRACT FROM AUTHOR]

The crystallization of shea stearin was investigated both before and after pre-treatment with silica to remove a small amount (0.7 wt%) of diacylglycerols (DAGs) and oxidized material. NMR (for solid fat content), X-ray diffraction (XRD), polarized light microscopy, confocal Raman microscopy, and non-isothermal, isothermal and 'stop-and-return' differential scanning calorimetry (DSC) techniques were used. Four major polymorphs previously found with 1,3-distearoyl-2-oleoyl-sn-glycerol (StOSt) were detected: α, γ, β′, and β; whilst evidence for a further (δ) polymorph was found by DSC and possibly XRD but not Raman spectroscopy. Isothermal crystallization of shea stearins by DSC at 20°C produced α and δ forms within 5 min which then transformed to γ. Microscope images showed that after 1 day these had transformed into β′ with a few crystals of β, with further conversion to β after one week. Silica treated samples showed a faster initial crystallization, with faster transformation or direct crystallization into δ and then γ and β′ forms. Non-isothermal DSC also showed a faster transformation into γ from α on the subsequent remelt. However, further transformation into β appeared to occur at reasonably similar rates for both types, suggesting that DAGs have less influence on this transformation and may be excluded from higher forms. Practical applications: This paper has two main practical applications: (i) Provides knowledge and understanding of the crystallization and polymorphic behavior of commercial shea stearin, which is a widely used fat in the confectionery, cosmetic, and pharmaceutical industries. (ii) The presence of small amounts of DAGs significantly delays the crystallization process of shea stearin, particularly of the lower polymorphs. [ABSTRACT FROM AUTHOR]

In the field of aliphatic polyesters there is a great interest in building novel macromolecular structures that may effectively feature the required properties for specific applications. For this reason, it is extremely important to understand the correlations between chemical structure and final performance. Monomers based on the 1,4-cyclohexylene unit are interesting as they are potentially bio-based and rigid enough to improve glass transition and melting temperatures. The present paper describes the preparation of samples of poly(1,4-cyclohexylenedimethylene adipate), characterized by different cis/trans isomeric ratio of the cyclic units, the analysis of their thermal properties and the comparison with the properties of similar polymers such as poly(butylene adipate), poly(butylene-1,4-cyclohexanedicarboxylate) and poly(1,4-cyclohexylenedimethylene-1,4-cyclohexanedicarboxylate). The effect of the rigidity and of the stereochemistry of the 1,4-cyclohexylene unit on the thermal properties was analysed. Such an effect reaches its maximum level when the cyclic-containing monomers are the diacid or the diester and when the trans isomers predominate. Starting from such a result, the combination of specific cyclic building blocks with the correct cis/trans ratio makes it possible to build macromolecular structures with the required final properties. [ABSTRACT FROM AUTHOR]

Examines the capability of genipin, a hydrolytic product of geniposide extracted from gardenia fruit, as a fingerprint reagent. Determination of the optimal conditions for fingerprint development; Comparison of genipin with classical reagents such as ninhydrin; Identification of genipin as harmless and environmentally friendly reagent; Visibility of genipin on brown wrapping paper and on papers with highly luminescent backgrounds.

An amidine base-containing polymer, polystyrene-bound 1,8-diazabicyclo[5.4.0]undec-7-ene (PS-DBU), proved to serve as a prominent catalyst support. The combined use of selected copper salts with PS-DBU in the catalytic hydrogenation of acetophenone qualifies DBU as beneficial to generate catalytically active species and stabilize them on the polymer. Catalyst preparation and characterization reveal that the active copper species is in a low-valent state and the nanosized particles possibly grow on the amidine structure. The high immobilization ability of PS-DBU almost entirely prohibited copper leaching to the product over six cycles of hydrogenation and catalyst recovery. The copper catalyst attached to PS-DBU specifically promotes the hydrogenation of various ketones and aldehydes under 10 atm of H2 at 90 °C to afford alcoholic products in satisfactory yields. [ABSTRACT FROM AUTHOR]

The methods available for the synthesis of chalcogenophenes, in general, are associated with drawbacks of harsh conditions, use of costly metals, broad applicability, tedious purification process and low yield. To avoid these drawbacks a transition metal-free iodine-catalyzed reaction of aryl-susbstituted 1,3-dienyl bromides with potassium selenocyanate/potassium sulfide (KSeCN/K2S) leading to the corresponding selenophenes and thiophenes has been developed. Iodine is relatively benign, less expensive and readily available. Several diversely substituted selenophenes and thiophenes have been obtained by this procedure in high yields. Using this procedure 2-(4-chlorophenyl)thiophene, a key intermediate for the synthesis of a melanin concentrating hormone receptor ligand involved in the treatment of eating disorders, weight gain, obesity, depression and anxiety has been synthesized. Although the reaction is one-pot essentially it proceeds in two steps involving a selenocyanate/thiolate intermediate leading to the selenophene/thiophene. The simple operation, use of inexpensive reagents and a metal-free process make this procedure more attractive for an easy access to substituted selenophenes and thiophenes. [ABSTRACT FROM AUTHOR]

A novel three-component selenosulfonation of 1,7-enynes with sulfinic acids and diphenyl diselenides for the formation of multifunctional 3,4-dihydroquinolin-2(1 H)-ones was developed in batch and flow. This room-temperature protocol provides a highly efficient approach to diverse selenosulfones in moderate to excellent yields and with a broad scope of substrates. It should provide a potential synthesis method for the construction of diverse and meaningful 3,4-dihydroquinolin-2(1 H)-ones derivatives in the fields of pharmaceutical and biological chemistry. Additionally, an obvious acceleration (20 h to 43 s) was obtained under micro flow conditions. [ABSTRACT FROM AUTHOR]

Novel organophilic nanohybrid materials (K-TDD) were obtained by the grafting of 1,2-tetradecanediol (TDD) onto the surface of kaolinite (K). XRD, IR, TGA-DTG, and SEM characterization showed that TDD grafting results in a partial exfoliation of kaolinite layers. This material was used to modify a glassy carbon electrode (GCE/K-TDD) and applied for the trace analysis of methyl parathion (MP). The signal of MP recorded on GCE/K-TDD was more intense compared to the unmodified GCE or to one modified with a film of natural kaolinite. Several parameters that can affect the stripping response were systematically investigated to optimize the sensitivity of the organokaolinite-modified electrode. A linear calibration curve for MP was obtained in the concentration range from 2×10−6 to 14×10−6 mol .L−1 in acetate buffer (pH 6), giving a detection limit of 9×10−8 mol .L−1. The sensitivity of the method was found to be 2.42 μA/μM for the range of concentrations that gives a linear calibration curve. The electrode was shown to be very stable, with the electrochemical response of MP decreasing by only 1.5 % after a series of nine measurements. The interference of various inorganic ions and organic compounds likely to influence the stripping determination of the MP were also examined. The results showed that the GCE/K-TDD electrode was effective in solutions containing interfering species and could be applied for the quantification of MP pesticide in natural water. [ABSTRACT FROM AUTHOR]

A label free impedimetric aptasensor for simple, fast and reusable picomolar detections of Ochratoxin A (OTA) in grape juices was designed. Two main factors were observed to affect the accurate detections of the toxin: i-lateral interactions between self-assembled aptamers ii- adsorption of large molecules present in complex matrixes like grape juices. Lateral interactions between aptamers were minimized by constructing the aptasensor in a Layer-by-Layer procedure. The interferences associated to the unspecific and irreversible adsorption of large molecules present in grape juice, were reduced by submitting samples to ultrafiltration prior to analysis. With this protocol, a 0.12 pM limit of detection and 0.24 pM limit of quantification in spiked grape juices were achieved after only 5-7 mins of interaction with the samples. The presented aptasensor can be recovered after a simple immersion in hot water (90 °C) for ten minutes. [ABSTRACT FROM AUTHOR]

A thiolated catechol (CA) consisting of 1,6-Hexanedithiol (HDT) and CA was modified on a gold (Au) electrode to obtain an amperometric L-cysteine sensor with detection limit of 60.6 nM. The preparation of thiolated CA was conducted via a thiol addition between HDT and electro-oxidized CA (EOCA). Briefly, the thiol addition reaction was accomplished by potential cycling of HDT/Au electrode in 0.1 M phosphate buffer (PB, pH 7.2) containing CA, and an EOCA-HDT/Au electrode was produced. The obtained EOCA-HDT/Au electrode exhibits a pair of well-defined redox peaks (at 0.22/0.10 V) of o-quinone moiety, which effectively mediates the oxidation of L-cysteine in a 0.1 M PB (pH 7.2), with an over-potential decrease by ca. 0.12 V (versus bare Au electrode). Electrochemical quartz crystal microbalance, cyclic voltammetry and surface-enhanced Raman spectra were used to study relevant processes and/or film properties. The amperometric L-cysteine sensor has good anti-interferent ability and reproducibility. It also has acceptable recovery for detection of L-cysteine in urine samples. [ABSTRACT FROM AUTHOR]

In the present study we describe a simple method to immobilize the redox mediator anthraquinone-2,6-disulfonate (AQDS) at the surface of graphite electrodes, by means of a commercial anion exchange membrane. Cyclic voltammetry experiments confirmed the efficacy of the immobilization protocol and the long-term (over 70 days) electrochemical stability of the AQDS-functionalized electrode. Potentiostatic (-300 mV vs. SHE) batch experiments proved the capability of the electrode in accelerating the bioelectrochemical reductive dechlorination of the groundwater contaminant 1,2-dichloroethane (1,2-DCA) to harmless ethene by a mixed microbial culture, by serving as electron donor in the process. Considering the reported broad range of anodic and cathodic reactions catalyzed by AQDS, the herein described functionalized electrode has a remarkable potential for application in the environmental and industrial sector. [ABSTRACT FROM AUTHOR]

This paper considers the high-speed, low-power consumption BiCMOS ECL RAM and discusses the input buffer circuit, including the level conversion circuit which transforms the ECL level to MOS level. It is seen that the following circuit is the optimal from the viewpoints of the delay time and the power consumption. The address buffer circuit is composed of the ECL circuit and the emitter follower, the level conversion circuit is a CMOS cross-coupled circuit, and the driver circuit is composed of the Si-nMOS driver. The high speed and low current dissipation performances are obtained with the delay time of 1.6 its, current dissipation of 2.32 The sense amplifier is constructed using ECL circuit with the constant-current source with small dependencies on the temperature and the source voltage. A high speed is realized by producing the output from the wired-OR of the emitter-follower transistors of the blocks, with the time from the common data line to the output being 1.6 ns. Based on the obtained circuit structure, a 64 K × l bit BiCMOS ECL RAM is realized using the 1-μm BiCMOS, with the access time of 7 ns and the power consumption of 800 mW[1]. [ABSTRACT FROM AUTHOR]

The kinetics of carbon flow through various metabolites of Caulerpa simpliciuscula C. Ag., a siphonaceous green alga, are described. The pattern of C fixation in this alga differs from those observed in higher plants and other green algae in a number of respects. After 40 min incubation, soluble β-linked polyglucans are the most important labelled carbohydrates. Sucrose, although detectable, is never a major recipient of label and does not label until after other oligosaccharide fractions. The sugar monophosphates contain a large proportion of the [SUP14]C assimilated intermediates, but also as storage pools. The pattern of amino acid labelling resembles that reported for other species of green algae in that alanine becomes labelled most rapidly, followed by glycine, and much later by glutamate, glutamine and asparagine. These labelling patterns are discussed in the light of what is known of patterns of C flow in other algae. [ABSTRACT FROM AUTHOR]

A series of novel cationic and neutral Rh complexes with an N-donor-functionalized 1,2,3-triazol-5-ylidene (TRZ) ligand (in which the pendant N donor is NHBoc, NH2, or NMe2) is described. The catalytic activity of these complexes was evaluated in the hydrothiolation of alkynes. Among the catalysts, a neutral dicarbonyl complex featuring the tethered-NBoc amido-TRZ ligand proved very selective for alkyne hydrothiolation with an aryl thiol. Remarkably, the reaction could be carried out in the absence of pyridine or base additive. In addition, during the reaction, no evidence for oxidative addition of the thiol S−H bond was observed, strongly suggesting a reaction pathway in which a bifunctional ligand is involved. Experimental and theoretical mechanistic investigations suggest a ligand-assisted deprotonation of thiol, hemilabile dissociation of amine from the metal, and thiolate coordination, which is indicative of a different reaction mechanism to those previously reported for related alkyne hydrothiolation reactions. [ABSTRACT FROM AUTHOR]

The crystalline structures of four homologues of the 1,2-dibromo-4,5-dialkoxybenzene series [Br2C6H2(OCnH2n + 1)2 for n = 2, 12, 14 and 18] have been solved by means of single-crystal crystallography. Comparison along the series, including the previously reported n = 10 and n = 16 derivatives, shows a clear metric trend (b and c essentially fixed along the series and a growing linearly with n), in spite of some subtle differences in space groups and/or packing modes. A uniform packing pattern for the aliphatic chains has been found for the n = 12 to 18 homologues, which slightly differs from that of the n = 10 derivative. The crystalline structures of all the higher homologues (n = 10-18) seem to arise from van der Waals interchain interactions and, to a lesser extent, type II Br· · ·Br interactions. The dominant role of interchain interactions provides direct structural support for the usual interpretation of melting point trends like that found along this series. Atoms in Molecules (AIM) analysis allows a comparison of the relative magnitude of the interchain and Br· · ·Br interactions, an analysis validated by the measured melting enthalpies. [ABSTRACT FROM AUTHOR]

A series of spiro[indoline-3,2′-[1,3,4]oxadiazol]-2-ones were prepared from the reaction of isatin derivatives and hydrazonoyl chlorides through the 1,3-dipolar cycloaddition reaction. This method has some important aspects, such as mild reaction condition, easy purification, and high yield of products. Also, the synthesis of spiro[acenaphthylene-1,2′-[1,3,4]oxadiazol]-2-one and spiro[[1,3,4]oxadiazole-2,9′-phenanthren]-10′-one were studied under the same condition. The structures were confirmed spectroscopically (IR, 1H- and 13C-NMR, and EI-MS) and by elemental analyses. A plausible mechanism for this reaction is proposed. [ABSTRACT FROM AUTHOR]

Mn concentrations were determined using square-wave cathodic stripping voltammetry (CSV) with inexpensive, stencil-printed carbon ink electrodes generated on polypropylene transparency films. Using an optimized pH 5 ammonium acetate buffer and addition of 1,4-benzoquinone, a detection limit as low as 500 nM (30 ppb) was achieved. Addition of 1,4-benzoquinone improved peak potential reproducibility and height, while addition of 3.5 % w/w sodium chloride to the background solution approximately doubled the sensitivity (μA/ppm). Tolerance tests with interfering metals were conducted and the method was found to be resilient to chromium(VI), iron(III), magnesium(II), nickel(II), and zinc(II), but susceptible to aluminum(III), copper(II), iron(II), and lead(II) at concentration ratios at or below one. This technique was successfully used to measure Mn levels in yerba mate and green tea samples as an example application. [ABSTRACT FROM AUTHOR]

We present a quantum chemical investigation of benzofuran and cholorobenzofuran formation mechanisms during the combustion of 1,3-dichloropropene. Density functional theory and Gaussian- n thermochemical methods are used to propose detailed mechanistic reaction pathways. These calculations indicate that oxidation of phenylvinyl radical intermediates and subsequent ring closure are key mechanistic pathways in the formation of benzofuran and chlorobenzofuran. Thermochemical and kinetic parameters presented herein will assist in further elucidation of dioxin formation mechanisms from thermolyses of hydrocarbon moieties. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The direct α-Csp2--H functionalization and thiomethylation of α-oxoketene dithioacetals (DTAs) has been accomplished with dimethyl sulfoxide (DMSO) in the presence of iodine and a copper(I) salt for the first time. A prerequisite is the in situ iodination of the α-Csp2 atom of dithioacetals that could offer other reaction channels. The operationally simple one-pot protocol includes region-defined consecutive iodination and sulfenylation of the challenging α-Csp2--H bond of dithioacetals employing cheap and readily available reagents. DMSO here plays a dual role as thiomethyl source and solvent. [ABSTRACT FROM AUTHOR]

The front cover picture, provided by Bo Wang, Xinyan Wang, and Yuefei Hu, illustrates the characteristics of 1 ‐ copper(I) ‐ 2 ‐ phenylethyne in its preparation, properties and structure. By using its polymeric structure, the tandem reaction sequence of 1 ‐ Cu(I) ‐ alkyne with an azide (cycloaddition) and then an electrophile E+ (electrophilic substitution) can be controlled efficiently. Thus, a general method for the synthesis of 1,4,5 ‐ trisubstituted 1,2,3 ‐ triazoles was developed by simply stirring the mixture of a 1 ‐ copper(I) ‐ alkyne, an azide and an electroplile E+. Details can be found in the full paper on pages 401 – 407 (B. Wang, N. Liu, W. Chen, D. Huang, X. Wang, Y. Hu, Adv. Synth. Catal. 2015, 357, 401 – 407; DOI: 10.1002/adsc.201400471). [ABSTRACT FROM AUTHOR]

NHC-B,N-heterocyclic compounds have been found to act as convenient precursors for obtaining either 1,3-azaborinine or 1 H-imidazo[1,2-a]indole derivatives, which are two different and rare classes of compounds. The formation of these two classes of compounds from the NHC-B,N-heterocycles is highly selective depending on the external stimuli employed, and the resulting products have been studied for their interesting chemical and photophysical properties. The mechanism and possible reaction pathways of the unusual transformation are established by computational studies. [ABSTRACT FROM AUTHOR]

Sulfamethoxazole (SMZ), an antibacterial sulfonamide drug, has been selectively determined using poly-1,5-diaminonaphthalene (p-DAN) modified glassy carbon electrode (GCE). The modified sensor was characterized by field emission scanning electron microscopy (FE-SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). SMZ showed linear response in the concentration range of 0.5-150 µM by using square wave voltammetry (SWV) and the detection limit was found to be 0.05 nM with sensitivity of 0.085 µA µM-1. The proposed sensor has been successfully employed to determine SMZ in the pharmaceutical tablets and human urine samples. [ABSTRACT FROM AUTHOR]

The treatment of 2-phenyl-1H-1,3-benzazaphosphole (H[2- ph-bp], 1) with free 1,3-bis(2,4,6-trimethylphenyl)imidazol-2- ylidene (IMes, 2) and 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol- 2-ylidene (SIMes, 3) afforded two imidazolium 1,3-benzazaphospholides, [1,3-bis(2,4,6-trimethylphenyl) imidazolium 2-phenyl-1,3-benzazaphospholide [(IMesH)+(2-ph-bp)-, 4] and 1,3-bis(2,4,6-trimethylphenyl)- 4,5-dihydroimidazolium 2-phenyl-1,3-benzazaphospholide [(SIMesH)+(2-ph-bp)-, 5], which further reacted with carbo- diimide to give 2-(N,N=-diisopropylcarbamimidoyl)-1,3-bis- (2,4,6-trimethylphenyl)imidazolium 2-phenyl-1,3-benzazaphospholide (6) and 2-(N,N=-diisopropylcarbamimidoyl)-1,3- bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazolium 2-phenyl- 1,3-benzazaphospholide (7), respectively. These compounds were characterized by multinuclear (1H, 13C{1H}, and 31P{1H}) NMR and IR spectroscopy, and X-ray diffraction analysis. The structures feature ion pair conformation in the solid state with strong charge-assisted C-H···N or N-H···N interaction. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations were carried out to investigate the 1,2-migration in metallasilabenzenes. The results suggested that the chloride migration of metallabenzenes is unfavorable due to the loss of aromaticity in the nonaromatic analogues. In sharp contrast, such a migration in metallasilabenzenes is favorable due to the reluctance of silicon to participate in π bonding. The migration of hydride and methyl group from the metal center to the silicon atom in metallasilabenzenes is computed to be also feasible. In addition, the π donor ligand and the third row transition metal can stabilize metallasilabenzenes. Thus, such a migration becomes less favorable thermodynamically and kinetically. These findings could be very helpful for synthetic chemists to realize the first metallasilabenzene. [ABSTRACT FROM AUTHOR]

The recent negative publicity about the widely used preservative methylisothiazolinone and methylchloroisothiazolinone has made many cosmetic manufacturers look for safety alternatives. Several cases of contact allergy to methyldibromoglutaronitrile in euxyl k 400 have been described. Of 107 cosmetic products including shampoos, shower gels, bath foams, body milks and creams, analyzed for the presence of methyldibromoglutaronitrile, 14 that is 13% proved to contain the preservative. Of 1142 patients tested, 6 had a positive reaction to methyldibromoglutaronitrile.

The simultaneous electrochemical detection of homocysteine and cysteine using an absorbed ortho-quinone species, catechol, at the nanocarbon modified glassy carbon electrode was achieved via 1,4-Michael addition reaction. The detection was done in the presence and the absence of each other as well as with both glutathione and ascorbic acid present in order to investigate the selectivity of homocysteine and cysteine. A determination of homocysteine sensitivity is (0.882±0.296) nA nM−1 with a LOD of ca. 11 nM and cysteine sensitivity is (7.501±0.202) mA µM−1 with a LOD of ca. 5.0 µM within a range of 0-0.1 mM. [ABSTRACT FROM AUTHOR]

Two new Co(II) coordination polymers, [Co(Hnbta)(bth)]n ( 1) and {[Co3(nbta)2(bth)3(H2O)]·H2O}n ( 2), (H3nbta = 5-nitro-1,2,3-benzenetricarboxylic acid and bth = 1,6-bis(1,2,4-triazole-1-yl)hexane), have been synthesized under different pH values through hydrothermal reactions. Both complexes were characterized by elemental analysis, IR spectra, thermogravimetric analysis (TGA), and single-crystal X-ray crystallography. Complex 1 exhibits a 3D polythreaded network based on 4-connected sql 2D layer. Complex 2 has a (4,4,5)-connected trinodal 3D pillar-layered network with a (42·64)2(42·67·8)2(64·82) topology. Magnetic susceptibility measurements indicate that complexes 1 and 2 show weak antiferromagnetic interactions between the adjacent Co(II) ions. [ABSTRACT FROM AUTHOR]

The Cover Feature shows that copper nanoparticles grown on polystyrene‐bound 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (PS‐DBU) can catalyze the hydrogenation of ketones and aldehydes. In their Full Paper, R. Watari et al. demonstrate that the PS‐DBU provides a suitable environment for the formation and stabilization of catalytically active Cu species. The prepared Cu nanoparticles on PS‐DBU exhibit high catalytic activity with negligible Cu leaching, robustness, good recyclability, and broad functionality tolerance. These results demonstrate the potential of PS‐DBU as an immobilizing support for transition‐metal catalysts for the first time. More information can be found in the Full Paper by R. Watari et al. on page 4501 in Issue 24, 2017 (DOI: 10.1002/cctc.201701316). [ABSTRACT FROM AUTHOR]

An unexpected copper-catalyzed sequential C-arylation and denitrogenation of tetrazoles leading to 1,3-diaminoisoquinoline derivatives has been developed, and the corresponding 1,3-diaminoisoquinoline derivatives were obtained in moderate to good yields. The method provides a novel strategy for the synthesis of isoquinoline derivatives containing various functional groups. [ABSTRACT FROM AUTHOR]

The dipole moments of cis and trans-1,3-dichloro-, 1,3-dibromo-, and 1,3-diiodocyclobutanes were obtained. The deviation from planarity (angle of puckering) was calculated from the dipole moments. In all cases, the compounds were found to be non-planar (puckered). Although the angle strain increases slightly for a non-planar ring, the decrease in torsional strain becomes more important. For the cis-series, it was found that the angle of puckering was largest for the 1,3-diiodocyclobutane. For the trans-series the angle of puckering was the least for the 1,3-diiodocyclobutane. trans-1,3-Dibromo-1,3-dimethylcyclobutane has the least amount of puckering of all the compounds studied. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [ABSTRACT FROM AUTHOR]

Gibberellic acid (GA3) and β-indolylacetic acid (IAA), two of the well known growth hormones, induce four fold the activity of ornithine decarboxylase (ODC) during the germination of barley seeds (Hordeum vulgare L. var. Beca).. The optimal concentration for induction of ODC was 10-5 M for GA3 and 10-3 M for IAA. When 10-3 M of a polyamine, putrescine or spermidine, is added to the growth medium, ODC activity is significantly inhibited. This inhibition is due to the induction of a protein inhibitor of ODC (antizyme), whose apparent molecular weight is 16 000 ± 2 000 daltons. Addition of GA3 to cultures which have been grown for 50 or 98 h in the presence of polyamines, abolishes the observed inhibition of ODC activity, while in the reverse experiment, addition of polyamines at 50 or 98 h does not affect the ODC activity induced by GA3. Cadaverine, a physiological plant diamine, enhances ODC activity; whereas 1,8-diaminooctane (the alkyl analogue of spermidine) does not have any effect. [ABSTRACT FROM AUTHOR]

Benzisothiazollin-3-one is a preservative widely used in industry. The manufacturer states that it is a known skin irritant and sensitiser, but these facts are not well-known. A case is described of contact allergy in a lithoprinter caused by it when used as a preservative in gum arabic. The literature is reviewed and a suitable patch-test concentration is suggested. It should be included in the patch-test battery for lithoprinters. [ABSTRACT FROM AUTHOR]

During the investigation of an outbreak of dermatitis in a medium-sized engineering works, the authors discovered four patients with allergic contact sensitivity to hexahydro,1,3,5, tris (2-hydroxyethyl) triazine, (Grotan), a new bacteriocidal agent used in coolant liquids. The authors failed to find any published report on this subject and would like to draw attention to Grotan as a new potential sensitizer. [ABSTRACT FROM AUTHOR]