Coupling needle‐trap devices with comprehensive two‐dimensional gas chromatography with high‐resolution time‐of‐flight mass spectrometry to rapidly reveal the chemical transformation of volatile components from sulfur‐fumigated ginseng

Sulfur‐fumigation could alter the quality of white ginseng by damaging the bioactive compounds and generating sulfur‐containing materials. In the present study, coupling needle‐trap devices with comprehensive two‐dimensional gas chromatography and high‐resolution time‐of‐flight mass spectrometry was applied to rapidly reveal chemical transformation of volatile components from sulfur‐fumigated ginseng. Thirty‐two volatile compounds were not in white ginseng samples after sulfur‐fumigation. Furthermore, 20 sulfur‐containing compounds were identified for the first time in volatile oil of sulfur‐fumigated white ginseng. The established approach could be applied to discriminate sulfur‐fumigated white ginseng among commercial samples and to control the quality of white ginseng.     

糖自氧化及抗氧化剂对其抑制作用的研究进展

近年来随着自由基医学和自由基生物学的发展,大量研究表明,慢性疾病导致的并发症与自由基损伤有着密切的关系。糖尿病作为典型的慢性疾病之一,主要是由于体内血糖浓度过高,糖自氧化产生的自由基增多和蛋白质的非酶修饰,即非酶糖基化加剧,引起的。本文对近年来人体内的还原性单糖的自氧化研究做一总结,以期对开发和筛选针对因糖自氧化或糖基化引起的自由基损伤而导致的疾病的药物有促进作用。文中主要包括:糖的一些基本生物化学信息,糖自氧化现象在疾病尤其是慢性疾病并发症中的作用及其致病原因,过渡金属对糖自氧化的催化作用,抗氧化剂对体内糖自氧化和糖基化现象的影响等内容。     

Synthesis of five- and six-membered lactams via solvent-free microwave Ugi reaction

Five- and six-membered lactams were synthesized via a 4-center 3-component Ugi reaction by combining amines, isocyanides, and ketoacids under solvent-free microwave conditions. The reaction was carried out in much shorter times and the yields were improved in comparison to classical conditions.     

Binucleating behaviour of a proximally-diphosphinated calix[4]arene

The long diphosphine 5,11-diphenylphosphanyl-25,26-dipropyloxy-27,28-bis(2-propenyloxy) calix[4]arene (cone) (5), in which the two phosphorus atoms are separated by a semi-rigid linking unit, was prepared in four steps starting from calix[4]arene. Reaction of 5 with AuCl(SEt(2)) or [RuCl(2)(p-cymene)](2) led to calixarenes bearing two metallated pendant arms, [5·(AuCl)(2)] and [5·{RuCl(2)(p-cymene)}(2)], respectively. In the presence of AgBF(4) or [Ni(C(5)H(5))(1,5-cyclooctadiene)]BF(4), diphosphine 5 displayed a marked tendency to form oligomeric material, but under high dilution conditions dimeric species were obtained selectively. The inability of 5 to form chelate complexes was further illustrated by its reaction with [PdCl(2)(1,5-cyclooctadiene)(2)], which led quantitatively to a rare complex in which a diphosphine spans across the dinuclear [PdCl(μ-Cl)(2)PdCl] unit.