New selective O-debenzylation of phenol with Mg/MeOH

Carboxylate-benzyl and nitro-benzyl groups used in phenols protection were selectively debenzylated with 3-25 equiv of Mg in methanol at room temperature. Good yields of the desired phenols were obtained within 3-10 h from a wide variety of O-(carboxylate-benzyl)- or O-(nitro-benzyl)-phenols. Selective O-debenzylation was possible in the presence of O-(carboxylate-benzyl)- or O-(nitro-benzyl)-phenols with Mg/MeOH.     

Extraction and characterization of adenovirus

A new methodology for the extraction and characterization of proteins from Coomassie-stained sodium dodecylsulfate polyacrylamide gel electrophoresis using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has been described. The utility of this methodology was demonstrated in the characterization of adenovirus proteins. The key steps in the extraction and destaining process involve washing the excised band with a combination of solvents that include 10% acetic acid, acetonitrile, methanol, and formic acid:water:isopropanol mixture. By using this procedure, we determined adenovirus proteins with molecular weights ranging from 10,000 to 110,000 Da by MALDI-MS, obtaining a detection limit of approximately 6 pmol. Parallel experiments were successfully carried out to analyze adenovirus proteins from Cu-stained gels. It was observed that increase in laser intensity resulted in significant improvements in the quality of MALDI mass spectra for the analysis of inefficiently destained proteins from Cu-stained gels.     

Graft copolymerization of methyl acrylate onto potato starch initiated by ceric ammonium nitrate

A study was made of the ceric ammonium nitrate (CAN) initiated graft copolymerization of methyl acrylate (MA) onto potato starch. The variables affecting the graft were investigated. The optimums have been obtained; they are the concentrations of MA, CAN, and nitric acid (HNO₃) (1.08, 5.0 × 10^?3, and 0.081 mol/L, respectively). The reaction temperature is ca. 50°C and the reaction time is 2 h. The molecular weight of grafted poly(methylacrylate) has been determined. On the basis of experimental results, the mechanism of grafting has been explored, a new kinetic equation of the graft copolymerization is established: R_p = Kk_d [STOH] [Ce⁴⁺] + Kk_pk_d/k_t[STOH][M], where K, k_d, k_p, and k_t are constants. The equation fits the results of experiments. © 1993 John Wiley & Sons, Inc.     

碳酸氢铵制纯碱的研究

本文对“中间盐”复分解制碱法进行了研究。“中间盐”的加入不能使两个三盐共饱和点在干盐图上发生明显的移动,但能使三盐介稳平衡点的介稳期延长,从而使得用碳酸氢铵和食盐通过复分解制碱成为可能。     

以乙基紫为活性物质的聚氯乙烯膜氰化亚金电极的研制和应用

以碱性染料为活性物质制备２０余种不同组分ＰＶＣ膜Ａｕ（ＣＮ）２＾－电极，确定较佳膜组成为乙基紫０．９９％，邻苯二甲酸二丁酯６９．２％，ＰＶＣ粉２９．８％。该电极对Ａｕ（ＣＮ）２＾－浓度在５．０×１０＾－７￣１．０×１０＾－２ｍｏｌ／Ｌ范围内接近能斯特响应；斜率为５５．７ｍＶ（３０℃）。稳定性与选择性较好。该电极制备简单，使用方便，已成功用于氰化镀金液中金的测定。     

新型糠醛加氢制糠醇催化剂研究

新型糠醛加氢制糠醇催化剂研究林培滋，黄世煜，周焕文，赵彤彤，刘崇早，罗洪原，梁东白（中国科学院大连化学物理研究所，大连１１６０２３）关键词铜催化剂，糠醛，加氢，糠醇糠醇是重要的化工原料，糖醇树脂是耐酸、碱腐蚀的材料，在工业发达的国家中，铸造工业广泛采...     

A new two‐dimensional CdII coordination polymer constructed by pyrazine‐2,3‐dicarboxyl­ate

In the title compound, poly[μ₅‐pyrazine‐2,3‐dicarboxyl­ato‐cadmium(II)], [Cd(C₆H₂N₂O₄)]_n or [Cd(pdc)]_n, where pdc is the pyrazine‐2,3‐dicarboxyl­ate anion, the Cd^II atom is six‐coordinated by five carboxyl­ate O atoms and one N atom from five different pdc ligands in a distorted octa­hedral CdO₅N coordination geometry. Two Cd^II atoms are bridged by carboxyl­ate groups of the pdc ligands to create a dimeric unit. The dimeric units are further connected by the pdc ligands to generate an inter­esting two‐dimensional structure.     

Free-electron attachment to coronene and corannulene in the gas phase

Electron attachment to the polyaromatic hydrocarbons coronene and corannulene is studied in the electron energy range of about 0-14 eV using a high-resolution crossed electron-neutral beam setup. The major anions observed are the parent anions peaking at about 0 eV with cross sections of 3.8 x 10(-20) and 1 x 10(-19) m(2), respectively. The only fragment anions formed in coronene and corannulene are the dehydrogenated coronene and corannulene anions. Other anions observed in the negative mass spectra at about 0 eV can be ascribed to impurities of the sample. High-level quantum-mechanical studies are carried out for the determination of electron affinities, hydrogen binding energies, and structures of both molecules. The behavior of coronene and corannulene upon electron attachment is compared with that of other polyaromatic hydrocarbons studied previously.     

Xyloketal G,a Novel Metabolite from the Mangrove Fungus <Emphasis Type="Italic">Xylaria sp.</Emphasis> 2508

A novel metabolite 1, named xyloketal G, was isolated from cultures of marine derived mangrove fungus Xylaria sp. 2508. Its structure was elucidated by analysis of spectroscopic data.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 22–23, January–February, 2005.     

Palladium-catalyzed arylation of N,N-dialkylhydrazines and the subsequent conversion to anilines

Palladium-catalyzed aminations of different ArBr with N,N-dialkylhydrazines are described. The reaction proceeded in moderate to excellent yield (up to 90%) with good functional groups compatibilities as cyano, ester, ketone and Boc-amine groups are all well tolerated. Several hydrazines were proved to be good coupling partners and this process provided a general method for the isosteric replacement of benzyl amines with arylhydrazines. Moreover, a method for the N-N bond cleavage of arylhydrazines was discovered, and this two-step sequence could be employed as an alternative synthesis of aniline derivatives.