Preparation of primary arylamines via arylzinc chlorides in good yields

Primary arylamines can be prepared easily by electrophilic amination of arylzinc chlorides with acetone O-(2,4,6-trimethylphenylsulfonyl)oxime in the presence of DMPU as additive and CuCN as catalyst in good yields.     

A Pizzetti-type formula for the heat operator

We provide an asymptotic expansion of the integral mean of a smooth function over the Heat ball. Namely we generalize to the Heat operator the so-called Pizzetti’s Formula, which expresses the integral mean of a smooth function over an Euclidean ball in terms of a power series with respect to the radius of the ball having the iterated of the ordinary Laplace operator as coefficients. Similarly here, we express the heat integral mean as a power series with respect to the radius of the heat ball, whose coefficients are powers of a distorted heat operator. We also discuss sufficient conditions to have a finite sum. Received: 27 May 2005     

The Synthesis of α-DDB, β-DDB and Theoretical Study with AM1

Biphenyl units are present in a wide range of compounds both natural and synthetic, and many of them have pharmacological activity1. Xie Jingxi et al. found that dimethyl 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxybiphenyl-2,2'-dicarboxylate((-DDB) as an important intermediate for the synthesis of Schizandrin C analogue which is effective in lowering elevated SGPT level2-3. Two isomers dimethyl 6,6'-dimethoxy-4,5,4',5'-dimethylenedioxybiphenyl-2,2'-dicarboxylate ((-DDB) and 6,4,-dimethoxy-4…     

负载型过渡金属氧化物催化剂上SO_2的还原

研究了γ Al2 O3负载过渡金属氧化物催化剂上CO还原SO2 的反应 ,考察了系列过渡金属对该反应的催化活性 ,发现Fe系催化剂的性能最好。同时对还原反应的条件进行了选择 ,发现在较低温度下 ,大空速不利于SO2 的还原 ,而在较高温度下 ,气体空速对反应影响不大 ,不同的物料配比对反应结果有很大影响 ,当CO∶SO2 =2时 ,最有利于单质硫生成。研究证明 ,金属硫化物是催化SO2 还原反应的活性相 ,该活性相的形成与催化剂的氧化还原能力有关 ,整个还原反应的机理应为中间产物机理     

Robust and recoverable dual cross-linking networks in pressure-sensitive adhesives

Pressure-sensitive adhesives (PSAs) demand the ability to simultaneously improve toughness and adhesion. However, these requirements of PSAs have remained a great challenge because robust and recoverable characteristics are usually contradictory properties of PSAs. Dual cross-linking networks developed by incorporating dynamic noncovalent bonds into chemical cross-linking networks have the potential to mitigate these requirements in a wide variety of applications including adhesives, hydrogels, and elastomers. Herein, a facile approach to achieve dual cross-linking networks of acrylic PSAs with excellent mechanical properties and high-adhesive performance that integrate physically cross-linked networks into chemically cross-linked networks is proposed. Diurethane acrylic monomer-pentaerythritol ethoxylate (DAM-PEEL) groups were introduced into the acrylic PSA system through photopolymerization. The PSA/DAM-PEEL dual cross-linking networks led to the development of the chemically cross-linked networks for both PSA and DAM via covalent bonds and the physically cross-linked networks between the amide groups of DAM and the hydroxyl groups of PEEL via hydrogen bonds. Consequently, the PSA/DAM-PEEL dual cross-linking networks were able to simultaneously improve the modulus and stretchability. This design strategy for developing dual cross-linking networks of materials could offer potential applications for various adhesive-related applications.     

Residual detection of naproxen,methyltestosterone and 17α‐hydroxyprogesterone caproate in aquatic products by simple liquid–liquid extraction method coupled with liquid chromatography–tandem mass spectrometry

In the present study, we aimed to develop a reliable screening method based on liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) for the detection and quantification of naproxen, methyltestosterone and 17α‐hydroxyprogesterone caproate residues. The target analytes were extracted from samples of eel, flatfish and shrimp using acetonitrile with 1% acetic acid, followed by liquid–liquid purification with n‐hexane. Chromatographic separation was achieved on a reversed‐phase analytical column using 0.1% formic acid containing 10 mm ammonium formate in distilled water (A) and methanol (B) as mobile phases. All the matrix‐matched calibration curves were linear (R² ≥ 0.99) over the concentration range of the tested analytes. Recovery at three spiking levels (0.005, 0.01 and 0.02 mg/kg) ranged from 68 to 117% with intra‐ and inter‐day precisions <10%. Five market samples for each matrix (eel, flatfish and shrimp) were collected and tested for method application. In summary, the proposed method is feasible to screen and quantify the analytes with high selectivity in aquatic food products meant for human consumption.     

An Alkynyl-Dangling Ru(II) Polypyridine Complex for Targeted Antimicrobial Photodynamic Therapy

To realize clinical application of antibacterial photodynamic therapy (aPDT), one of the most arduous challenges is how to render aPDT agents high selectivity against bacterial pathogens. In light of the fact that amino group-containing lipids are rich on the outer surfaces of Gram-positive bacteria, we herein constructed an alkynyl-dangling ruthenium(II) polypyridine complex (Ru2) to preferentially label Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA) over mammalian cells via the amino-yne bio-orthogonal click reaction. Thanks to the strong singlet oxygen generation ability, Ru2 could photo-inactivate S. aureus and MRSA effectively and specifically. Phosphatidylethanolamine (PE) molecules also exist in mammalian cells but are not accessible for Ru2, leading to its poor binding/uptake and negligible cytotoxicity in the dark and upon irradiation towards mammalian cells as well as low hemolysis, all favorable for aPDT application.     

Novel aluminium compounds derived from Schiff bases: Synthesis,characterization and catalytic performance in hydroboration

Seven novel aluminium complexes supported by Schiff base ligands derived from o‐diaminobenzene or o‐aminothiophenol were synthesized and characterized. The reactions of AlMe₃ with L¹ (N,N′‐bis(benzylidine)‐o‐phenylenediamine) and L² (N,N′‐bis(2‐thienylmethylene)‐o‐phenylenediamine) gave the complexes L¹AlMe₃ ( 1 ) and L²AlMe₂ ( 2 ), respectively, which involved two types of reaction mechanisms: one was proton transfer and ring closure, and the other was alkyl transfer. Complexes L³AlMe₂ (HL³ = 4‐chlorobenzylidene‐o‐aminothiophenol) ( 3 ), L⁴AlMe₂ (HL⁴ = 2‐thiophenecarboxaldehyde‐o‐aminothiophenol) ( 4 ), L³AlH(NMe₃) ( 5 ), L⁴AlH(NMe₃) ( 6 ) and L⁵AlH(NMe₃) (HL⁵ = 4‐methylbenzylidene‐o‐aminothiophenol) ( 7 ) were prepared by reacting HL^3–5 with equimolar AlMe₃ or H₃Al?NMe₃, respectively. Compounds 3 – 7 feature an organic–inorganic hybrid containing CNAlSC five‐membered ring. All complexes were characterized using ¹H NMR and ¹³C NMR spectroscopy, X‐ray crystal structure analysis and elemental analysis. The efficient catalytic performances of 1 – 7 for the hydroboration of carbonyl groups were investigated, with compound 4 exhibiting the highest catalytic activity among all the complexes.     

Simultaneous determination of spinosad,temephos, and piperonyl butoxide in animal‐derived foods using LC–MS/MS

Pesticides, which are used as plant protection products, can enter the food chain, and exposure to these xenobiotics can cause a wide array of health problems in humans. Therefore, the objective of the present study was to develop an analytical method for the simultaneous determination of residual spinosad (sum of spinosyn A and D), temephos and piperonyl butoxide in porcine muscle, egg, milk, eel, flatfish and shrimp (sampling period: February to June 2018) using liquid chromatography–triple quadrupole tandem mass spectrometry (LC–MS/MS). The target analytes were extracted with a combination of acidified acetonitrile and ethyl acetate and subsequently purified with original QuEChERS kits (composed of magnesium sulfate and sodium chloride) as well as n‐hexane. All analytes were separated on a reversed‐phase analytical column using a mobile phase of (A) 0.1% formic acid containing 10 mm ammonium formate in distilled water and (B) methanol. Good linearity (R² ≥ 0.980) was achieved over the tested concentration range (3.5–35 μg/kg for spinosyn A; 1.5–15 μg/kg for spinosyn D; 5–50 μg/kg for temephos and piperonyl butoxide) in matrix‐matched standard calibrations. Fortified samples at three spiking levels yielded recoveries in the range of 71–105% with relative standard deviations ≤9.2%. The applicability of the method was evaluated via evaluating samples collected from a large wholesale market located in Seoul, and none of the samples contained any of the target analytes. In conclusion, the current approach is simple, efficient and reliable and can successfully determine the residual levels of spinosad, temephos and piperonyl butoxide in complex animal‐derived food products.