First measurement of inclusive B→Xsη decays

We report a first measurement of inclusive B→Xsη decays, where Xs is a charmless state with unit strangeness. The measurement is based on a pseudoinclusive reconstruction technique and uses a sample of 657×10(6)BB pairs accumulated with the Belle detector at the KEKB e+e- collider. For MXs < 2.6 GeV/c2, we measure a branching fraction of [26.1±3.0(stat)-2.1+1.9(syst)-7.1+4.0(model)]×10(-5) and a direct CP asymmetry of ACP=-0.13±0.04-0.03+0.02. Over half of the signal occurs in the range MXs > 1.8 GeV/c2.     

Observation of B(s)(0) → D(s)(*)+ D(s)(*)- using e+ e- collisions and a determination of the B(s)-B(s) width difference ΔΓ(s)

We have made the first observation of B(s)(0)→D(s)(*)+ D(s)(*)- decays using 23.6 fb(-1) of data recorded by the Belle experiment running on the Υ(5S) resonance. The branching fractions are measured to be B(B(s)(0)→D(s)+ D(s)-)=(1.03(-0.32-0.25)(+0.39+0.26))%, B(B(s)(0)→D(s)(*±) D(s)(?))=(2.75(-0.71)(+0.83)±0.69)%, and B(B(s)(0)→D(s)*+ D(s)*-)=(3.08(-1.04-0.86)(+1.22+0.85))%; the sum is B[B(s)(0)→D(s)(*)+ D(s)(*)-]=(6.85(-1.30-1.80)(+1.53+1.79))%. Assuming B(s)(0)→D(s)(*)+ D(s)(*)- saturates decays to CP-even final states, the branching fraction determines the ratio ΔΓ(s)/cosφ, where ΔΓ(s) is the difference in widths between the two B(s)-B(s) mass eigenstates, and φ is a CP-violating weak phase. Taking CP violation to be negligibly small, we obtain ΔΓ(s)/Γ(s)=0.147(-0.030)(+0.036)(stat)(-0.041)(+0.042)(syst), where Γ(s) is the mean decay width.     

3-(5-Amino-1,2,4-triazole)-1,2,4-oxadiazole: A new biheterocyclic scaffold for the synthesis of energetic materials

Nitrogen-rich heterocycles are increasingly used in energetic chemistry with the aim to achieve superior performance of the new energetic materials. Combining such building blocks into biheterocycles increases energy output while at the same time retains low sensitivity. Herein, we report the synthesis and characterization of a compound containing a 5-amino-1,2,4-triazole moiety connected with a 1,2,4-oxadiazole ring. The trichloromethyl group attached to the oxadiazole ring offers an attractive point for further transformations into potentially energetic compounds.     

Modular access to heterocycles: methyl 3-aminobenzo[<Emphasis Type="Italic">b</Emphasis>]thiophene-2-carboxylate–thiourea linkage or pyrimidine-4-one-2-thione formation

Abstract  Modular conditions for the formation of thioureas or pyrimidine-4-one-2-thiones connected to the benzo[b]thiophene, benzene and indole structures were performed. A benzo[b]thiophene isothiocyanate derivative was used as a model to study the condensation with simple aromatic amines and amino-l-sorbose derivative. The construction of pyrimidine-4-one-2-thiones using basic conditions afforded efficiently new heterocyclic aromatics, which were further transformed using the alkylated sulfur as a leaving group in palladium-catalyzed cross-coupling reactions. Graphical abstract        

Synthesis and Crystal Structures of Methyl 3-(Benzoylamino)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-5-carboxylate and <Emphasis Type="Italic">N</Emphasis>-[5-(3,4-Dimethoxyphenyl)-6-methyl-2-oxo-2<Emphasis Type="Italic">H</Emphasis>-pyran-3-yl]benzamide

Abstract  

The compounds methyl 3-(benzoylamino)-6-methyl-2-oxo-2H-pyran-5-carboxylate (1), C₁₅H₁₃NO₅, and N-[5-(3,4-dimethoxyphenyl)-6-methyl-2-oxo-2H-pyran-3-yl]benzamide (2), C₂₁H₁₉NO₅, crystallize as a centrosymmetric hydrogen-bonded dimer facilitated by N–H···O interactions involving the amide and carbonyl moiety of the lactone group of adjacent molecules. Supramolecular aggregation in 1 is controlled by a combination of π–π interactions [centroid–centroid distance = 4.0745(11) ?] and weak C–H···O hydrogen bonding between the phenyl ring of the benzoylamino group and the carbonyl atom of the methoxycarbonyl group and in 2 by a combination of π–π interactions [centroid–centroid distance = 4.0699(8) and 4.1556(10) ?], weak C–H···O interactions between the methoxy substituents of the adjacent dimethoxyphenyl group and weak C–H··· π interactions.     

Prediction of diesel fuel properties by vibrational spectroscopy using multivariate analysis

Partial least squares regression (PLS) calibration models based on Fourier transform infrared (FTIR-ATR) and Raman spectra (FT-Raman) were applied to the rapid and accurate simultaneous determination of the main properties of diesel fuels. Training sets were composed of over ninety commercial diesel fuel samples. The methods use baseline-uncorrected, raw FTIR-ATR and FT-Raman spectra. Two spectral regions were studied: full spectral region and “fingerprint” region. The models were validated using the cross-validation process. Based on the correlation coefficient and root mean square error of cross validation (RMSECV) values the both developed calibration models, PLS/FTIR-ATR and PLS/FT-Raman, were very accurate and comparable with standard testing methods. The following diesel fuel properties may be confidently estimated: cetane number, cetane index, density, viscosity, distillation temperatures at 10% (T10), 50% (T50) and 90% (T90) recovery, as well as the contents of total aromatics and polycyclic aromatic hydrocarbons. As compared to the “fingerprint” spectral region, the PLS/FTIR-ATR model using full spectral region displayed slightly better performances with the most of the correlation coefficient values above 0.98.     

Neutron activation cross section for Ni isotopes at 14·8 MeV

Neutron activation cross sections for Ni isotopes were measured using Ge(Li)γ-ray spectroscopy of the reaction products. The linear least-squares method was used to resolve the interfering reactions. The results obtained are compared with recent experimental and evaluated data, statistical model and semiempirical calculations.     

Neutron diffraction study of Fe83B17 metallic glass

The structure factorS(Q) was measured up to high momentum transfer,_max720 nm^–1 for Fe₈₃B₁₇ metallic glass sample. A ribbon sample was prepared by rapid quenching of the melt. In the alloy boron enriched with¹¹B isotope was used. The scattering neutron spectra were measured by the time-of-flight method at the IBR-30 facility of JINR in Dubna. The scattering angles of 30°, 60° and 150° were chosen to cover the scattering vector,Q, from 10nm^–1 up to 720nm^–1. The scattered spectra of vanadium were measured for the detector efficiency determination and those of molybdenum for the calibration. The reduced pair distribution functionG(r) was obtained using the Fourier transform ofS(Q). The atomic distances and the partial coordination numbers were calculated. It was found that the fluctuation of the Fe-B distance is larger than that of the Fe-Fe atomic pair. The chemical short-range parameter is equal to 44% of the maximum possible value.Dedicated to the memory of M. Gmitro.The sample of amorphous metallic material was kindly prepared by Dr. P. Duhaj. We would like to thank Dr. P. vec for microscoping our sample and for stimulating discussions.