We report the complete GNO solar neutrino results for the measuring periods GNO III, GNO II, and GNO I. The result for GNO III (last 15 solar runs) is View the MathML source[54.3−9.3+9.9(stat)±2.3(syst)]SNU(1σ)(1σ) or View the MathML source[54.3−9.6+10.2(incl. syst)] SNU (1σ ) with errors combined. The GNO experiment is now terminated after altogether 58 solar exposure runs that were performed between 20 May 1998 and 9 April 2003. The combined result for GNO (I + II + III) is View the MathML source[62.9−5.3+5.5(stat)±2.5(syst)] SNU (1σ ) or View the MathML source[62.9−5.9+6.0] SNU (1σ ) with errors combined in quadrature. Overall, gallium based solar observations at LNGS (first in GALLEX, later in GNO) lasted from 14 May 1991 through 9 April 2003. The joint result from 123 runs in GNO and GALLEX is [69.3±5.5(incl. syst)] SNU[69.3±5.5(incl. syst)] SNU (1σ). The distribution of the individual run results is consistent with the hypothesis of a neutrino flux that is constant in time. Implications from the data in particle- and astrophysics are reiterated
We report the first GNO solar neutrino results for the measuring period GNO I, solar exposure time May 20, 1998 till January 12, 2000. In the present analysis, counting results for solar runs SR1–SR19 were used till April 4, 2000. With counting completed for all but the last 3 runs (SR17–SR19), the GNO I result is [65.8 ± 10.29.6 (stat.) ± 3.43.6 (syst.)] SNU (1σ) or [65.8 ± 10.710.2 (incl. syst.)] SNU (1σ) with errors combined. This may be compared to the result for Gallex (I–IV), which is [77.5 ± 7.67.8 (incl. syst.)] SNU (1σ). A combined result from both GNO I and Gallex (I–IV) together is [74.1 ± 6.76.8 (incl. syst.)] SNU (1σ)
Various aqueous surfactants proved to be excellent media for carrying out palladium-catalyzed Suzuki−Miyaura cross-coupling reactions under mild conditions. The dehalogenation side reaction, which is usually a drawback with the aqueous protocol, was not observed. The concentration of the surfactant in water played a pivotal role for the reaction outcome. Smooth cross-coupling of iodoanisole and a variety of aryl bromides, including electron-rich derivatives, with aryl boronic acids occurred at room temperature in high yields either with [Pd(PPh3)4] or Pd/C as catalyst. The water-surfactant Pd/C system combines high activity under ambient conditions (air), easy separation and recyclability. Palladium acetate was found to be effective in cross-coupling of the less reactive aryl chlorides at 100 °C
A new approach to the Friedländer synthesis of quinolines is described. Polysubstituted quinolines are readily prepared under milder conditions than in other existing methods through a gold(III)-catalysed sequential condensation/annulation reaction of o-amino aromatic carbonyls and ketones containing active methylene groups.The presence of the quinoline scaffold in the framework of various pharmacologically active compounds with antiasthmatic, 1 antiinflamatory 2 and tyrosine kinase PDGF-RTK inhibiting properties 3 continues to spur synthetic efforts regarding their acquisition. 4Most of the classical synthetic protocols for quinolines suffer from harsh conditions, poor yields and the use of hazardous acid or basic catalysts. In particular, since 1882 the synthesis of the quinoline nucleus by the Friedländer procedure has been extensively explored. 5 Hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, and polyphosphoric acid were widely employed as catalysts. In the cases in which acetic acid was used alone, it probably functioned as a convenient solvent and not as a catalyst. Uncatalysed Friedländer syntheses required more drastic reaction conditions, with temperatures in the range 150-220°C. The reaction path suggested for the Friedländer procedure may involve sequential formation of Ν-(o-acylphenyl)-β-enaminones/cyclodehydration reaction.During our studies towards the development of new environmentally friendly syntheses of heterocycles through transition metal catalysed domino reactions we observed the high efficiency of gold(III) catalysis 6 in sequential amination/annulation reaction of α-propargyl dicarbonyls with amine, aminoalcohols and α-aminoesters. 7 Moreover, we developed a simple and clean gold-catalysed synthesis of β-enaminones from 1,3-dicarbonyls and ammonia/amines that requires neither a corrosive acid catalyst nor azeotropic conditions using a large excess of aromatic solvents like benzene. 8 Consequently, since we were interested in the synthesis of functionalized quinolines, 9 we were driven to investigate the extension of the gold(III) catalysis to the development of a mild version of the Friedländer synthesis of quinolines. Indeed, by choosing as the model system the reaction of ethyl acetoacetate (1a) with 2-aminobenzophenone (2a) (Scheme 1), we failed to obtain the corresponding quinoline derivative 3a without adding any catalyst; the starting 2-aminobenzophenone (2a) was recovered (90%) after reacting at 40°C in ethanol for 6 hours. By contrast, in the presence of a catalytic amount of NaAuCl 4 ⋅2H 2 O (Aldrich) the quinoline 3a was isolated in 83% yield under the same reaction conditions. Furthermore, the reaction can be run very efficiently at room temperature (Table 1, entry 1). Scheme 1A screening of the efficiency of other transition metal salts revealed that palladium(II)-, copper(I)-, and silver(I) salts were ineffective as catalysts; ZnCl 2 can lead to the formation of 3a (43% yield), even if its efficiency is lower 10 than that of gold(III). Recently, Kobayashi and co-wor...
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