Reaction of 2-acetyl-5-methyl-1, 2, 3-diazaphosphole with diazoacetic ester

Independent of the nature of the solvent, the reaction of 2-acetyl-5-methyl-1,2,3-diazaphosphole with diazoacetic ester proceeds without the evolution of nitrogen to give Δ2-phosphapyrazoline derivatives. The latter in CH2Cl2, CH3CN, or alcohols are isomerized to compounds with two NH groups. © 1984 Plenum Publishing Corporation

Interaction of 2,5-diphenyl-3,4-diazacyclopentadienone 3,4-dioxide with vinylphosphonic acid dimethyl ester

The interaction of 2,5-diphenyl-3,4-diazacyclopentadienone 3,4-dioxide and vinylphosphonic acid dimethyl ester, irrespective of the ratio of reagents, occurred at one nitrone system of the dioxide and led to the formation of the 1:1 addition product. © 1983 Plenum Publishing Corporation

Reaction of 1-phenyl-3-methyl-4-(p-dimethylamidoanil)-5-pyrazolone and 5-benzylidene-3-phenyl-2,4-thiazolidinedione with dimethylphosphorous acid and tri(dimethylamino)phosphine

1. The reaction of dimethylphosphorous acid with l-phenyl-3-methyl-4-(p-dimethylamidoanil)-5-pyrazolone (I) gives the dimethyl ester of (1-phenyl-3-methyl-5-hydroxy-4-pyrazolyl)-p-dimethylamidoanilphosphonic acid (III), while reaction with 5-benzylidene-3-phenyl-2,4-thiazolidinedione (II) gives the dimethyl ester of (3-phenyl-2,4-thiazolidinedion-5-yl)benzylphosphonic acid (V). 2. The corresponding salt is formed when thiazolidinedione (II) is reacted with dimethylphosphorous acid in the presence of diethylamine or triethylamine. 3. Pyrazolone (I) and thiazolidinedione (II) form the 1:1 bipolar adducts with tri(dimethylamino)phosphine. © 1976 Plenum Publishing Corporation

Stereochemistry of organophosphorus compounds - Communication 10. Structure of 2,3-diphenyl-4-diethoxyphosphono-5-cyano(and carbomethoxy)-isoxazolidines

The 1, 3-dipolar cycloaddition reaction of diethyl β-cyanovinylphosphonate and methyl 3-(diethylphosphono) acrylate with C,N-diphenylnitrone respectively gave trans-2,3-diphenyl-4-diethoxyphosphono-5-cyanoisoxazolidine and trans-2,3-diphenyl-4-diethoxyphosphono-5-carbomethoxyisoxazolidine. © 1976 Plenum Publishing Corporation

Reaction of trimethyl phosphite and tri(dimethylamino)phosphine with C,N-diphenylnitrone and 2,5-diphenyl-3,4-diazacyclopentadien-l-one-3,4-dioxide

1. C,N-Diphenylnitrone reacts with trimethyl phosphite to give trimethyl phosphate and benzalaniline. 2. C,N-Diphenylnitrone and 2,5-diphenyl-3,4-diazacyclopentadien-1-one-3,4-dioxide react with tri-(dimethylamino)phosphine in two directions: with the transfer of oxygen from the nitrone to the tri(dimethylamino)phosphine, and with the formation of bipolar ions, which were isolated as the sodium salts by reaction with sodium tetraphenylboronate. © 1975 Plenum Publishing Corporation

1,3 Dipolar cycloaddition of C-benzoyl-N-phenylnitrone to esters of vinyl-, β-cyanovinyl, and allylphosphosphonic acids and of C,N-diphenylnitrone to an allylphosphonic acid ester

1. The reaction of 1,3 dipolar cycloaddition of C-benzoyl-N-phenylnitrone to dimethyl vinylphosphonate at 20° gave isomeric trans-2-phenyl-3-benzoyl-4-dimethylphosphono- and trans-2-phenyl-3-benzoyl-5-dimethylphosphonoixoxazolidines. Only the first isomer is obtained in the reaction in boiling benzene. 2. The 1,3 dipolar addition of C-benzoyl-N-phenylnitrone to the diethyl ester of β-cyanovinylphosphonic acid leads to trans-2-phenyl-3-benzoyl-4-diethylphosphono-5-cyanoisoxazolidine. 3. The cycloaddition of C,N-diphenylnitrone to the dimethyl ester of allylphosphonic acid leads to the formation of trans-2,3-diphenyl-5-dimethylphosphonomethyleneisoxazolidine, while the cycloaddition of C-benzoyl-N-phenylnitrone to this diester gives trans-2-phenyl-3-benzoyl-5-dimethylphosphonomethyleneisoxazolidine. © 1977 Plenum Publishing Corporation

An observation of the f0(1710)f_0(1710) meson in the ωϕ\omega\phi system in the Pion-BeBe Interaction at Momentum of 29 GeV

The charge-exchange reaction $\pi^-p \rightarrow n\,\omega(783)\phi(1020)$, $\omega \rightarrow \pi^+\pi^-\pi^0$, $\phi \rightarrow K^+K^-$ is studied with the upgraded VES facility (U-70, Protvino) in the interaction of a 29 GeV pion beam with a beryllium target. The distribution over the invariant mass of the system $M_{\omega\phi}$ shows a near-threshold signal. A partial wave analysis reveals that the scalar state ($J^{PC}=0^{++}$) dominates in this mass region. The observed signal can be described with a contribution of the known resonance $f_0(1710)$. Using OPE approximation for the reaction $\pi^-p \rightarrow n\, f_0(1710)$ the product of branching fractions is found to be: $Br(f_0(1710)\rightarrow \pi\pi)\cdot Br(f_0(1710)\rightarrow \omega\phi) = (4.8 \pm 1.2) \cdot 10^{-3}$

Measurement of the transverse target and beam-target asymmetries in η\eta meson photoproduction at MAMI

We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the $\vec \gamma \vec p\to\eta p$ reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of $\eta$ meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed.Comment: 5 pages, 3 figures, accepted for publication in PR

K+ΛK^+\Lambda and K+Σ0K^+\Sigma^0 photoproduction with fine center-of-mass energy resolution

Measurements of $\gamma p \rightarrow K^{+} \Lambda$ and $\gamma p \rightarrow K^{+} \Sigma^0$ cross-sections have been obtained with the photon tagging facility and the Crystal Ball calorimeter at MAMI-C. The measurement uses a novel $K^+$ meson identification technique in which the weak decay products are characterized using the energy and timing characteristics of the energy deposit in the calorimeter, a method that has the potential to be applied at many other facilities. The fine center-of-mass energy ($W$) resolution and statistical accuracy of the new data results in a significant impact on partial wave analyses aiming to better establish the excitation spectrum of the nucleon. The new analyses disfavor a strong role for quark-diquark dynamics in the nucleon.Comment: 7 pages, 8 figure

T and F asymmetries in π0 photoproduction on the proton

The γp→π0p reaction was studied at laboratory photon energies from 425 to 1445 MeV with a transversely polarized target and a longitudinally polarized beam. The beam-target asymmetry F was measured for the first time and new high precision data for the target asymmetry T were obtained. The experiment was performed at the photon tagging facility of the Mainz Microtron (MAMI) using the Crystal Ball and TAPS photon spectrometers. The polarized cross sections were expanded in terms of associated Legendre functions and compared to recent predictions from several partial-wave analyses. The impact of the new data on our understanding of the underlying partial-wave amplitudes and baryon resonance contributions is discussed