Palladium-assisted multicomponent synthesis of 2-aryl-4-aminoquinolines and 2-aryl-4-amino[1,8]naphthyridines

A palladium-mediated multicomponent domino reaction leading to 2-aryl-4-amino-quinolines and 2-aryl-4-amino[1,8]naphthyridines is reported. The scope of the reaction was examined using carbon monoxide, two 2-ethynyl-arylamines, four aryl iodides, and 10 primary amines as substrates. The selection of the appropriate catalytic system was achieved testing several palladium/phosphine systems and overrides previously reported drawbacks associated with the use of primary amines in related reactions. Moreover several features concerning the role of both palladium [(0) and (II)] and phosphines are reported.     

Reaction of enaminonitriles with isocyanates. Synthesis of new 2-oxo- and 6-oxopyrimidines

The reaction of enaminonitriles 1 with aryl or benzyl isocyanates afforded C- 3–5 or N-adducts 6–8 or a mixture of both depending on the substitution pattern of the considered enaminonitrile. The one-step synthesis of 6-oxopyrimidines 9–11 and 2-oxopyrimidines 12–14 by cyclization of compounds 3–5 and 6–8 respectively is also described.     

Monitoring of an industrial process by multivariate control charts based on principal component analysis

The control and monitoring of an industrial process is performed in this paper by the multivariate control charts. The process analysed consists of the bottling of the entire production of 1999 of the sparkling wine "Asti Spumante". This process is characterised by a great number of variables that can be treated with multivariate techniques. The monitoring of the process performed with classical Shewhart charts is very dangerous because they do not take into account the presence of functional relationships between the variables. The industrial process was firstly analysed by multivariate control charts based on Principal Component Analysis. This approach allowed the identification of problems in the process and of their causes. Successively, the SMART Charts (Simultaneous Scores Monitoring And Residual Tracking) were built in order to study the process in its whole. In spite of the successful identification of the presence of problems in the monitored process, the Smart chart did not allow an easy identification of the special causes of variation which casued the problems themselves.     

New synthesis of 2(1H)-pyridone derivatives

The reaction of N¹-acyl-2-ethoxycarbonylacetamidrazones 1 with diethyl ethoxymethylenemalonate (EMME) is reported. By refluxing equimolecular amounts of 1 and EMME in DMSO/toluene (or ethanol) solution, the 1-acylamino-2(1H)-pyridones 2 were obtained in good yield. When the reaction was performed in ethanolic solution in the presence of triethylamine, the 6-acylhydrazino-2(1H)-pyridones 3 were obtained.     

Variable-temperature NMR study of the enol forms of benzoylacetones

The enol forms of the beta-diketones, benzoylacetones, have been studied using long-range carbon-hydrogen couplings involving the chelate OH proton, O1H chemical shifts, 13C chemical shifts and deuterium isotope effects on 13C chemical shifts. Studies were done in the temperature range from 268 to 181 K. The compounds are shown to be tautomeric, in opposition to a more symmetrical, delocalised, close to one-potential well structure as found in the solid at very low temperature. The same is true for dibenzoylmethane. The isotope effects on chemical shifts are very sensitive gauges of structure in these almost symmetrical systems. Equilibrium constants are determined and related to other similar compounds.     

Chelation with metal is not essential for antitumor photodynamic activity of sulfonated phthalocyanines

It is generally assumed that a central metal is essential for the efficiency of phthalocyanines in photodynamic therapy (PDT) of cancer. Contrary to the set opinion, the results of the present study indicate that the metal-free sulfonated phthalocyanines (H2PcSn, where n is the number of sulfonate groups per molecule) possess a considerable photoactivity. The relative phototoxicities of H2PcS1.5, H2PcS2.4, H2PcS3.1 and H2PcS3.8 on HEp2 human epidermoid carcinoma cells were 3.3, 20, 3.3 and 1, respectively, thus demonstrating dependence of the activity on the sulfonation degree, known for metallo-PcSn. A significant delay in tumor growth and a decrease in tumor regrowth rate were observed in mice after PDT with H2PcS2.4. The antitumor effect declined in the order H2PcS2.4 > H2PcS3.1 > H2PcS1.5 and vanished for H2PcS3.8. We demonstrate here that the high photodynamic activity of H2PcS2.4 can be explained by its physicochemical properties in living cells and tissues. Thus, H2PcSn (n is about 2) can be considered as a new alternative in PDT of light-accessible neoplasms and further clinic-oriented studies are warranted.     

Effect of the Magnetic Field on the Supramolecular Structure of Chiral Smectic C Phases: 2H NMR Studies

We present a theoretical and experimental ²H NMR study of the effect of external magnetic fields on the supramolecular organization of chiral smectic liquid‐crystalline mesophases, such as SmC* and re‐entrant SmC*. Three experimental cases in which the supramolecular helical structure of the smectic C* phase is unwound by a magnetic field (H), parallel to the helical axes of this phase, are discussed in detail. Unwinding of the helical structure is described by using a theoretical model based on the Landau‐de Gennes theory, which allows us to explain the transition temperatures among the SmA, SmC*, and uSmC* phases. The energy‐density behavior in the vicinity of the transitions and the value of the critical magnetic field H_C for unwinding the helical structure are discussed by applying this model to three ferroelectric smectogens ( MBHB , 11EB1M7 , ZLL7/* ), which are studied by ²H NMR spectroscopy at different magnetic fields (from 2.4 to 9.4 Tesla). Furthermore, the tilt angle of the three smectogens in the SmC* phase has been directly evaluated, for the first time, by comparing the quadrupolar splittings at different magnetic fields. In one case, ²H NMR angular measurements are used to obtain the tilt angle in the re‐entrant smectic C phase.     

Microstructural Evolution of Titanium Carbonitride Based Materials During Oxidation

 Ti(C, N) based materials represent a new class of hard and wear resistant structural materials. Nowadays, the main field of applications is focused on metal cutting and finishing operations. For these kinds of applications usually the mentioned materials work in oxidizing environments at high temperatures. The thermophysical stability under these conditions represents therefore a key factor that influences the material’s performance, and consequently the tool life of the component in service. The present study aimed to investigate the oxidation behaviour of two different Ti(C, N)-WC based materials, the first containing 0.9 wt% of Co and the second 6.2 wt% of Ni and 2.9 wt% of Co. Cycled oxidation tests (20 hours each) were conducted with a muffle furnace in laboratory static air at 1000 °C up to 100 hours. During the initial transitory stage the competition between the mass gain due to the formation of solid TiO₂ (rutile) and the mass loss due to released volatile W oxides controlled the mass change; thereafter the oxidation process obeyed a linear law. Great microstructural modifications occurred on the (sub)surfaces of the oxidized samples: multiphase TiO₂ based scales grew upon the external surfaces of the oxidized specimens. Kinetics and oxidation mechanisms were proposed and discussed.     

Confined space design by nanoparticle self-assembly

Nanoparticle (NP) self-assembly has led to the fabrication of an array of functional nanoscale systems, having diverse architectures and functionalities. In this perspective, we discuss the design and application of NP suprastructures (SPs) characterized by nanoconfined compartments in their self-assembled framework, providing an overview about SP synthetic strategies reported to date and the role of their confined nanocavities in applications in several high-end fields. We also set to give our contribution towards the formation of more advanced nanocompartmentalized SPs able to work in dynamic manners, discussing the opportunities of further advances in NP self-assembly and SP research.

This perspective gives an outlook on the design of interparticle confined nanocavities in self-assembled NP systems and their functional relevance.     

Analysis of yttrium aluminium borate crystals by solution-based methods: inductively coupled plasma atomic emission spectrometry and flame atomic absorption spectrometry

Comparative analysis of yttrium aluminium borate (YAB) /YAl₃(BO₃)₄/ optical single crystals was performed by flame atomic absorption spectrometry (FAAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) methods for Cr, Dy, Er, Yb, Y, Al, B and Mo. The dopant element, Ce, could be determined only by the ICP-AES method at the required concentration level. The powdered crystal samples were fused with lithium metaborate (LiBO₂) at 950 °C in a platinum crucible and then dissolved in 6 mol l⁻¹ HCl. Although this fusion-dissolution procedure proved to be simple and effective, the quantitative determination of B—as the matrix element in samples—was handicapped by the B content of the fusing reagent. For the FAAS method, with the use of nitrous oxide–acetylene flame, cesium chloride ionization buffer and lanthanum chloride releasing agent [0.1+0.2% (m/v), respectively] were applied. These agents enhanced the atomic absorption signals of Cr, Dy, Er, Mo, Yb and Y, whereas no change of sensitivity was resulted in for Al and B. A fairly good agreement was found between the results of the two alternative spectrochemical methods. The predicted stoichiometry of the crystals was also well approximated indicating the reliability of the crystal growth technology applied.