Synthesis of 2-Acetylbenzonitriles and Their Reactivity in Tandem Reactions with Carbon and Hetero Nucleophiles: Easy Access to 3,3-Disubstituted Isoindolinones

2-Acetylbenzonitriles have been conveniently synthesized by the oxidation of the respective 2-ethylbenzonitriles, combining in a one-pot procedure radical bromination and hydrolysis reactions. The obtained ketones reacted under very mild conditions with carbon and hetero nucleophiles to give a wide range of 3,3-disubstituted isoindolinones in yields of 80–99 % by a tandem process consisting of an addition step and a subsequent Dimroth-type rearrangement. Among the tested nucleophiles, the addition of water in the presence of a catalytic amount of KOH allowed a convenient access to an unprecedented variety of novel 3-hydroxy-3-methylisoindolinones

Search for Theta(++) Pentaquarks in the Exclusive Reaction gamma p -\u3e K(+)K(-)p

The exclusive reaction gamma p -\u3e(K) over bar (0)K(+)n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of the exotic baryon Theta(+)(1540)-\u3e nK(+). The decay to nK(+) requires the assignment of strangeness S=+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 pb(-1). No evidence for the Theta(+) pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK(+) mass. The 95% C.L. upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb

Search for Theta(+)(1540) pentaquark in high-statistics measurement of gamma p -\u3e(K)over-bar(0)K(+)n at CLAS

The exclusive reaction gamma p -\u3e(K) over bar (0)K(+)n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of the exotic baryon Theta(+)(1540)-\u3e nK(+). The decay to nK(+) requires the assignment of strangeness S=+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 pb(-1). No evidence for the Theta(+) pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK(+) mass. The 95% C.L. upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb

Search for the Theta(+) pentaquark in the reactions gamma p -\u3e(K)over-bar(0)K(+)n and gamma p -\u3e(K)over-bar(0)K(0)p

The exclusive reactions gamma p -\u3e(K) over bar (0)K(+)n and gamma p -\u3e(K) over bar (0)K(0)p have been studied in the photon energy range 1.6-3.8 GeV, searching for evidence of the exotic baryon Theta(+)(1540) in the decays Theta(+)-\u3e nK(+) and Theta(+)-\u3e pK(0). Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The integrated luminosity was about 70 pb(-1). The reactions have been isolated by detecting the K+ and proton directly, the neutral kaon via its decay to K-S -\u3epi(+)pi(-) and the neutron or neutral kaon via the missing mass technique. The mass and width of known hyperons such as Sigma(+), Sigma(-) and Lambda(1116) were used as a check of the mass determination accuracy and experimental resolution. Approximately 100 000 Lambda(*)(1520)\u27s and 150 000 phi\u27s were observed in the (K) over bar (0)K(+)n and (K) over bar (0)K(0)p final state, respectively. No evidence for the Theta(+) pentaquark was found in the nK(+) or pK(S) invariant mass spectra. Upper limits were set on the production cross section of the reaction gamma p -\u3e(K) over bar (0)Theta(+) as functions of center-of-mass angle, nK(+) and pK(S) masses. Combining the results of the two reactions, the 95% C.L. upper limit on the total cross section for a resonance peaked at 1540 MeV was found to be 0.7 nb. Within most of the available theoretical models, this corresponds to an upper limit on the Theta(+) width, Gamma(+)(Theta), ranging between 0.01 and 7 MeV