多取代芳香族化合物的合成 5.卤素-苯硒基取代的丁二烯和丁炔二酸二甲酯的环加成-芳构化串连反应

本文报道用环加成－芳构化串连反应制备多取代芳香族化合物的方法。将１－氯－２－卤－３－苯硒基－１，３－丁二烯（５）与丁炔二酸二甲酯进行Ｄｉｅｌｓ－Ａｌｄｅｒ反应时，能直接生成多取代的芳香族化合物４－苯硒基－５－卤代邻苯二甲酸二甲酯（４）。若用２－卤素－３－苯硒基－１，３－丁二烯（１）与丁炔二酸二甲酯进行Ｄｉｅｌｓ－Ａｌｄｅｒ反应，只得到正常的加成产物４－苯硒基－５－卤素－１，４－环己二烯－１，２－二甲酸二甲酯（３），需再用ＤＤＱ处理，才得到多取代芳香族化合物（４）。     

Highly efficient, one-step macrocyclizations assisted by the folding and preorganization of precursor oligomers

Highly efficient, one-step macrocyclizations leading to the formation of macrocyclic hexa(aramides) in high yields (69-82%) are described. The one-step macrocyclizations were facilitated by the preorganization or folding of the backbones of uncyclized precursors in the course of macrocyclization. The preorganization of backbones was achieved by the presence of localized three-centered hydrogen bonds that were adopted in the design of a class of closely related, backbone-rigidified foldamers. The macrocyclization involved reactions between diacid chloride 1 and diamine 2. The crude reaction mixtures and products were conveniently examined by mass spectrometric method (MALDI-TOF). Compared to most traditional one-step macrocyclizations that usually require high dilution conditions and often lead to very low overall yields of the desired products, cyclic hexamers 3 were obtained as the overwhelmingly major product under a variety of reaction conditions, suggesting the generality of this approach.     

Synthesis and electrochemical properties of Zn3V3O8 as novel anode material

Zn₃V₃O₈ two-dimensional micro sheets are successfully synthesized by combination of solvothermal method and heat treatment. The Zn₃V₃O₈ has better electrochemical performances after calcinations.     

5-[(p-Methyl-phenyl)azo]-8-aminoquinoline as a new reagent for trace determination of nickel by adsorptive cathodic stripping voltammetry

The synthesis of p-MPAQ and the electroanalytical chemical properties of the nickel(II)-p-MPAQ complex are reported in this paper. A sensitive adsorptive cathodic stripping procedure for trace nickel determination was developed. For a 3-min preconcentration time the detection limit is 3.0 × 10⁻¹¹M.     

DRY METHOD SYNTHESIS OF PURE SILICEOUS FORM OF ZEOLITE ZSM-35

IntroductionZeoliteZSM-35isclassifiedasfcrricritc(FER)t\pc.x'hicllalsoincludesZSM-ZI.ZSM-38andFER.Zeolitesofthist}'pcha\lcrclatit'CI}UlldiscrinlinablcXRDpattcnlswhichindicatetheirsinlilarit\'illst,u.tu,.,I11.Thehighsiliceousfonllsofthesezeolitesarcgcllcra…     

A fluorescent chemical sensor for Fe based on blocking of intramolecular proton transfer of a quinazolinone derivative

In this paper, 2-(2′-hydroxy-phenyl)-4(3H)-quinazolinone (HPQ), a typical compound that exhibits excited state intramolecular proton transfer (ESIPT) reaction and possesses good photophysical properties, is synthesized and used as fluoroionophore for Fe³⁺ sensitive optochemical sensor. The decrease of fluorescence intensity of HPQ membrane upon the addition of Fe³⁺ was attributed to the blocking of ESIPT reactions of HPQ and quenching its fluorescence. The effect of the composition of the sensing membrane was studied, and experimental conditions were optimized. The sensor shows a linear response toward Fe³⁺ in the concentration range of 7.1 × 10⁻⁷ M to 1.4 × 10⁻⁴ M with a limit of detection of 8.0 × 10⁻⁸ M, and a working pH range from 2.5 to 4.5. It shows excellent selectivity for Fe³⁺ over a large number of cations such as alkali, alkaline earth and transitional metal ions. The proposed sensor is applied to the determination of the content of iron ions in pharmaceutical preparations samples with satisfactory results.     

Surprising selectivity in the transformation of dimethoxy azaindoles

Transformation of 4,7-dimethoxy-6-azaindole into 4-hydroxy-7-methoxy-6-azaindole or 7-hydroxy-4-methoxy-6-azaindole can be readily controlled by careful selection of a reagent. Treatment with concentrated HCl results in hydrolysis at the 4-position exclusively, while TMS-I provides demethylation at the 7-position only. Products were unambiguously identified by single crystal X-ray crystallography.     

Black fungus derived aerogel with double faced properties

Black fungus aerogel (BFA) exhibited interesting double-faced properties. Weexplored the diverse properties of each side of the black fungus in three aspects:water contact angle measurements, liquid selective absorption capacity and air pollutant adsorption abilities.     

Template-synthesized LiCoO2, LiMn2O4, and LiNi0.8 Co0.2 O2 nanotubes as the cathode materials of lithium ion batteries

The first point of this work is to synthesize LiCoO2, LiNi0.8 Co0.2 O2, and LiMn2O4 nanotubes with the template of porous anodic aluminum oxide by thermal decomposition of sol-gel precursors. The as-synthesized materials were open-ended nanotubes with uniform shape and size based on the analysis of scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. An "in situ reaction from nanoparticle to nanotube" mechanism was discussed for the formation process of the nanotubes. The second point of this paper is to investigate the electrochemical properties of the as-synthesized nanotubes for the cathode materials of lithium ion batteries. It was found that the nanotube electrodes exhibited better reversibility and higher discharge capacities than that of their nanocrystalline counterparts. The reason for the improved electrochemical performance of the nanotube electrodes was also interpreted.     

Asymmetric Synthesis of α-Substituted-γ-butyrolactone Empolying Prolinol Type of Auxiliaries

Eleven (S)-(-)-bishydrocarbyl-(l-alkanoylpyrrolidin-2_yl)_methanol derivatives of three types were synthesized from L-proline.asymmtncally selective alkylation products were obtained oy LDA treatment and alkylation using methyl 2-bromoethyl ether, and three types of chiral α-Substituted-γ-butyrolactones were obtained by hydrolyzing the alkylation products, with %e.e. beijing up to 89 percent.