Synthesis of functionalized arylalkyl and diaryl ethers by [3+3] cyclization of 3-alkoxy- and 3-aryloxy-1-siloxy-1,3-butadienes with 3-(silyloxy)alk-2-en-1-ones

Functionalized diaryl ethers were prepared by [3+3] cyclization of 3-aryloxy-1-siloxy-1,3-butadienes with 3-(silyloxy)alk-2-en-1-ones.     

One-pot synthesis of aryl fluorides by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-fluoro-3-silyloxy-2-en-1-ones

Functionalized aryl fluorides were regioselectively prepared by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-fluoro-3-silyloxy-2-en-1-ones.     

Inclusions between large flat organic molecules; the induction of columns and mesophases

We describe here an overview on the formation of mesophases by the interaction between large flat aromatic cored molecules and relatively small organic electron acceptors which form stacked, sandwich-like columnar - electron donor-acceptor complexes. The inclusion of suitable donor and acceptor components may be used to induce columnar mesophases in mixtures of compounds which can be either mesomorphic or non-mesomorphic in the pure state. With judicious choice of donor and acceptor partners, induced mesophases of remarkable range and thermal stability can be prepared.See Ref. [1].Presented at the Sixth International Seminar on Inclusion Compounds, Istanbul, Turkey, 27–31 August, 1995.     

Highly effi cient and regioselective thiocyanation of aromatic amines,anisols and activated phenols with H2O2/NH4SCN catalyzed by nanomagnetic Fe3O4

A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild reaction conditions. The catalyst could be easily recovered from the reaction mixture using an external magnet and reused in several reaction cycles without loss of activity.     

Dinuclear palladium(I) sandwich complexes of furan and toluene

The reaction of a dinuclear palladium complex [Pd₂(CH₃CN)₆][X]₂ (X = BF₄, PF₆) with excess furan afforded the sandwich-type bis-furan dinuclear palladium(I) complex [Pd₂(μ-furan)₂(CH₃CN)₂][X]₂. The substitutionally labile bridging furan ligands in the dipalladium sandwich complex can be readily replaced with toluene to give the bis-toluene dipalladium(I) sandwich complex [Pd₂(μ-toluene)₂(CH₃CN)₂][X]₂.     

室内刷漆现场空气中的有机挥发物鉴定及苯系物测定

气相色谱及电子轰击源质谱联用应用于油漆施工中室内空气中有机挥发物及芳烃(主要是苯,甲苯及二甲苯)的监测及分析,从室内现场空气中取样用于测定其中的芳烃。从油漆稀释剂上方的挥发气体中取样用于有机挥发物的分析。气相色谱中采用INNWAX弹性石英毛细管色谱柱(30m×0.32mm,0.25μm),对色谱参数及条件作了详细叙述。通过在NIST色谱库检索,检出了30种化合物,定性测定毋需标准物质。有机挥发物中各组分的相对百分含量及空气中芳烃的含量通过面积百分率法并应用外标法可计算得到,测定空气中苯,甲苯及二甲苯的检出限在0.1~0.2ng间,上述三组分的工作曲线有良好的线性关系,相关系数在0.9995~0.9999之间。对浓度水平在10.0ng.L-1空气试样进行7次分析,得到相对标准偏差为10.8%。     

The Search for New Environmentally Friendly Chemical Processes

Minimization of the hazards in chemical industry processes and the avoidance of the production of toxic substances—these are the goals of environmentally friendly processes. These technologies can also be economically advantageous. This approach is exemplified by a new, almost ideal atom-efficient oxidative route to adipic acid ( 1 , see scheme), which offers several environmentally improved features compared to the traditional manufacture. [W]=tungsten catalyst.     

Direct carboxylation of aromatic compounds using the sodium hydrogen carbonate/triphenylphosphine ditriflate system

A new procedure was developed for the highly regioselective synthesis of aromatic carboxylic acids using the sodium hydrogen carbonate/triphenylphosphine ditriflate system in ethanol at room temperature. This metal-free system was used for the carboxylation of thiophenol with unexpected products in terms of selectivity. The simplicity of the procedure, readily available aromatic compounds, short reaction times, and mild reaction conditions are other advantages of this protocol.     

Cyclodehydrogenation of hetero-oligophenylenes

Pyrimidyl-penta-phenylbenzenes have been synthesized by Diels-Alder addition of phenylethynylpyrimidines and tetraphenylcyclopentadienones under microwave irradiation. Scholl reactions of these compounds led to two types of hetero polyaromatic hydrocarbons: (a) partial cyclization by creation of two C-C bonds ortho to the pyrimidine nitrogen atoms gave substituted tribenzo[e,gh,j]perimidine (N-1/3HSB) in high yields; (b) when the position 2 of the pyrimidine ring was substituted by a tert-butyl group, the Scholl reaction was complete and provided the first example of a diaza-hexa-peri-benzocoronene.     

Imidazolium-functionalized bipyridine derivatives: a promising family of ligands for catalytical Rh(0) colloids

A new imidazolium-monofunctionalized bipyridine ligand has been synthesized and efficiently used as a protective agent for Rh(0) nanoparticles. Preliminary results in arene hydrogenation have been obtained.