Study of the reactione + e −→K + K − in the energy range1350 \leqq \sqrt s \leqq 2400 MeV

Thee ⁺ e ^?→K ⁺ K ^? cross section has been measured from about 750 events in the energy interval \(1350 \leqq \sqrt s \leqq 2400 MeV\) with the DM2 detector at DCI. TheK ^± form factor |F _F ^±| cannot be explained by the ρ, ω, ? and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment.     

The Stereochemistry of simple enols in solution

On the basis of their ¹H n.m.r. spectra it is concluded that vinyl alcohol and $\text{trans}$-1-propenol exist mainly in the $\text{syn}$-conformation and that $\text{cis}$-1-propenol and 2-methyl-1-propenyl exist mainly in the $\text{anti}$ conformation.     

Esmodil: an acetylcholine mimetic resurfaces in a Southern Australian marine sponge Raspailia (Raspailia) sp

Bioassay directed fractionation of a Raspailia (Raspailia) sp. (Order Poecilosclerida; Family Raspailiidae) collected during scientific trawling operations off the Northern Rottnest Shelf yielded as nematocidal agents the known metabolites, phorboxazoles A (1) and B (2). Further examination revealed the new natural product but known synthetic compound, esmodil (3). The structure for 3 was confirmed by spectroscopic analysis and total synthesis.     

Tetrahedral intermediates 4. The effect of chloro-substituents on the kinetics of the breakdown of hemiorthoesters

1-Hydroxy-2-chloromethyl-1,3-dioxolane (4) and 1-hydroxy-2-dichloromethyl-1, 3-dioxolane (5) have been detected as intermediates by¹H NMR spectroscopy in the hydration of respectively 2-chloromethylene-1, 3-dioxolane and 2-dichloromethylene-1, 3-dioxolane in aqueous acetonitrile. The kinetics of the breakdown of (4) and (5) into ethylene glycol monochloroacetate and monodichloroacetate have been studied by uv spectroscopy and values ofk_H+,k_HO-, andk_H2O evaluated. It was found that the introduction of chlorosubstituents into 2-hydroxy-2-methyl-1, 3-dioxolane caused a decrease ink_H+ and increase ink_H2O- and little change ink_H2Ofor its breakdown. The mechanisms of these reactions are discussed. Present     

Radiative decay ofJ/ψ into γ π+ π−

The radiative decayJ/ψ → γ π⁺ π^? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe ⁺e^? storage rings at Orsay. The π⁺ π^? mass spectrum shows a cleanf ₂ (1270) signal, and the possible presence of two other states at thef ₂ (1720) andf ₄ (2030) masses. For thef ₂ (1270), the branching ratio BR(J/ψ →γf)xBR(f→π⁺ π^?) is measured to be (7.50±0.30±1.12)×10^?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed.     

Heronapyrroles A-C: farnesylated 2-nitropyrroles from an Australian marine-derived Streptomyces sp

Chemical analysis of a marine-derived Streptomyces sp. (CMB-M0423) isolated from beach sand off Heron Island, Australia, yielded three new members of the rare pyrroloterpene biosynthetic structure class. Identified by detailed spectroscopic analysis as the first reported examples of naturally occurring 2-nitropyrroles, heronapyrroles A-C (1-3) displayed promising biological activity-with low to submicromolar IC(50) activity against Gram-positive bacteria but no cytotoxicity toward mammalian cell lines.