Palladium-catalyzed benzylic arylation of N-benzylxanthone imine

The direct benzylic arylation of N-benzylxanthone imine with aryl chloride proceeds under palladium catalysis, yielding the corresponding coupling product. The product is readily transformed to benzhydrylamine. Taking into consideration that the imine is readily available from benzylic amine, the overall transformation represents a formal cross-coupling reaction of aryl halide with alpha-aminobenzyl metal.     

Nickel-catalyzed carboxylation of organozinc reagents with CO2

An efficient nickel catalyst system for the carboxylation of organozinc reagents with CO(2) under very mild conditions has been developed. The catalyst system complements the conventional methods and enables the direct synthesis of various saturated carboxylic acid derivatives from the corresponding alkylzinc reagents and CO(2).     

Comparative study on syntheses of 1,3,5-trimethoxy-1,3,5-triisopropylcyclotrisiloxane

1,3,5-Trimethoxy-1,3,5-triisopropylcyclotrisiloxane (2) was prepared from 1,3,5-triisopropyl-1,3,5-tri-o-tolylcyclotrisiloxane—(1) according to three kinds of methods as follows: the dearylchlorination of 1 using HCl/AlCl₃, which led to prepare 2 includes a very slight amount of aluminum species as impurities, the dearylbromination using Br₂, which simultaneously brought unnecessary bromination without isolated 2, and the dearylation using TfOH, which efficiently gave 2 of a high purity without metals of contamination.     

The amalgamation of high distance Heegaard splittings is always efficient

Let M be a compact orientable manifold, and F be an essential closed surface which cuts M into two 3-manifolds M ₁ and M ₂. Let be a Heegaard splitting for i = 1, 2. We denote by d(S _i ) the distance of . If d(S ₁), d(S ₂) ≥ 2(g(M ₁) + g(M ₂) − g(F)), then M has a unique minimal Heegaard splitting up to isotopy, i.e. the amalgamation of and . Ruifeng Qiu is supported by NSFC(10625102).     

Norm Estimates of the Partial Transpose Map on the Tensor Products of Matrices

We present a norm estimate for the partial transpose map Θ on the tensor product

Bacilosarcins A and B, novel bioactive isocoumarins with unusual heterocyclic cores from the marine-derived bacterium Bacillus subtilis

Two novel isocoumarins, bacilosarcins A (1) and B (2) were isolated from a culture broth of the marine-derived bacterium Bacillus subtilis TP-B0611. The structures and absolute configurations of 1 and 2 were determined on the basis of spectroscopic analyses and chemical conversions. Compound 1 possesses an unprecedented 3-oxa-6,9-diazabicyclo[3.3.1]nonane ring system while 2 has a 2-hydroxymorpholine moiety that is rare in nature. These compounds showed growth inhibition against barnyard millet.     

Convenient synthesis of Z-monoacetates of 2-alkylidene-1,3-propanediols

Various kinds of 3-substituted (Z)-hydroxymethyl-2-propenyl acetates were conveniently obtained in excellent yields by highly regioselective hydrolysis of 2-alkylidene-1,3-propylene diacetates in the presence of 100 w/w % of porcine pancreas lipase (PPL) Type II.     

Development of multiple prompt gamma-ray analysis

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M⁺(aq)+NaL⁺(nb)⇔ML⁺(nb)+Na⁺(aq) taking place in the two-phase water-nitrobenzene system [M⁺=Li⁺, K⁺, Rb⁺, Cs⁺; L = p-tert-butylcalix[4]arene-tetrakis (N, N-dimethylthioacetamide); aq = aqueous phase, nb = nitrobenzene phase] were evaluated. Furthermore, the stability constants of the ML⁺ complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Cs⁺<Rb⁺<K⁺<Li⁺<Na⁺.     

Reduction of Compton background from hydrogen in prompt gamma-ray analysis by multiple photon detection

Low-energy photons produced by the Compton scattering from hydrogen increase the background in the lower-energy region of the gamma-ray spectrum. This results in an increase in the detection limit for trace elements. In multiple photon detection prompt gamma-ray analysis (MPGA), only those elements that simultaneously emit two or more prompt gamma-rays, which have cascade relation and are emitted within a short interval, can be measured. Therefore, the influence of hydrogen can be reduced. In this study, standard polymer and food samples are measured. The hydrogen background is reduced in MPGA.     

Liquid chromatography-electrospray tandem mass spectrometric assay suitable for quantitation of YM155, a novel small-molecule survivin suppressant, in dog plasma

This paper describes a sensitive and selective liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for determination of the novel survivin suppressant YM155, 1-(2-methoxyethyl)-2-methyl-4,9-dioxo-3-(pyrazin-2-ylmethyl)-4,9-dihydro-1H-naphtho[2,3-d]imidazolium, which is developed for the treatment of solid tumors. This method uses a liquid-liquid extraction from 0.25 mL of dog plasma. LC separation was carried out on a Genesis Silica column (50 mm x 3.0 mm i.d.) at a flow-rate of 0.5 mL/min. Compounds were eluted using a mobile phase of 5 mm ammonium acetate and 0.1% formic acid in water-0.1% formic acid in acetonitrile, 17:83 (v/v). MS/MS detection was carried out with an MDS-Sciex API3000 triple quadrupole mass spectrometer in positive electrospray ionization mode. The standard curve was linear from 0.05 to 50 ng/mL (r > or = 0.9968). The lower limit of quantitation was 0.05 ng/mL. Good intra- and inter-day assay precision (within 7.4% RSD) and accuracy (within +/-12.3%) were obtained. The extraction recovery was 66.2%. The method was successfully applied to preclinical pharmacokinetic studies in dogs.