Rearrangements of the carbanions derived from allyl benzyl thioether

The metalation of allyl benzyl thioether involves the benzylic or the allylic hydrogens. The benzylic carbanion undergoes a rapid[2,3] sigmatropic shift whereas the allylic carbanion gives rise to various rearrangements, among them migration of the allylic unit to the para position with allylic inversion. The temperature dependence of the ratio of products arising from the benzylic carbanion vs those from the allylic carbanion shows that the allylic-to-benzylic carbanion transformation occurs only under special conditions: (a) with slow addition of the base; (b) with thioether in excess relative to the base, and (c) on raising the temperature of the reaction medium from ?78° to ?15°. In the last instance, the proton transfer is intramolecular as shown with labeled thioethers. The extent of the different rearrangements depends on the temperature and solvent. A choice of mechanism cannot be made at this time for the para migration 5→9a. A leaving group effect on the reaction regioselectivity of the carbanion from allyl methyl thioether with benzyl halides has been noticed. The presence of dibenzyl indicates that, in addition to S_N2 reactions, some electron transfer process is occurring.     

Bibliometric Analysis of the <Emphasis Type="Italic">Journal of Structural Chemistry</Emphasis>

Bibliometric analysis has been carried out for the Journal of Structural Chemistry (JSC) published since 1960 by the Siberian Branch of the Russian Academy of Sciences. All JSC publications which appeared between 1960 and 2002 have been chosen online from the Chemical Abstracts and Science Citation Index databases of the STN International net and analyzed according to topics, authors, affiliations, and other criteria. JSC authors and publications with the largest numbers of citations have been identified. The impact factor has been determined for JSC 2002.Original Russian Text Copyright © 2004 by V. M. Buznik, I. V. Zibareva, V. N. Piottukh-Peletskii, and N. I. Sorokin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1142–1153, November–December, 2004.     

Implementation of traceability – needs and perspective of the in-vitro-diagnosticum industry

Manufacturers support the concept of traceability. However, only a small number of the medically relevant measurands can be traced to the highest metrological order. In many cases, the measured substances are heterogeneous mixtures where traceability can be established only to either an international conventional reference measurement procedure or to a manufacturers own in-house reference system. The traceability concept needs to be seen in the context that the results of medical laboratories are not an aim per se, but are meant to provide useful medical information to clinicians, and that pre- and post-analytical steps may also contribute significantly to errors. There is a need for the further development of suitable reference measurement systems, but in view of the multitude of tasks and limited resources, priorities need to be set.Presented at BERM-9 – 9^th International Symposium on Biological and Environmental Reference Materials, 15–19 June 2003, Berlin, Germany     

材料表征方法理论与实践课程的改革与建设*

通过与超星专业慕课制作团队合作搭建网络教学平台,将线上慕课教学与线下实验教学相结合,对材料表征方法理论与实践课程进行了全方位的改革。与传统实验教学相比,改革后的课程不仅能够激发学生的学习兴趣,实现时间空间的相对自由,还可以完善考核机制,提升教学质量,从而为高校化学研究生实验课程的改革提供一定的借鉴意义。     

有机化学课程思政教学实践*

结合课程思政教学情况的现状,梳理了有机化学课程思政开展的过程实践,解释了有机化学课程思政教学目标的创设思路,列举了有机化学课程思政元素案例,阐述了有机化学课程思政教学的4个措施,并进行了有机化学课程思政教学效果的初步评价。     

德国有机化学实验项目式教学实践与启示*——以康斯坦茨大学为例

对德国康斯坦茨大学的本科有机化学实验初级阶段和高级阶段的教学方式,从实验前准备、实验内容、实验教学模式、实验考核方式、实验室安全管理等方面进行了综合阐述,可为我国高校相关专业有机化学实验教学与改革提供参考,提高教学质量。     

落实中职课程标准 培养化学核心素养*——中职文化基础课化学教材(高教版)的编写原则及特色

标准建设是以类型教育为特征,新一轮职业教育改革的基础性工作。以《中等职业学校化学课程标准》为依据,由高等教育出版社组织编写出版的化学教材,落实立德树人根本任务,注重学生化学核心素养的培养。全面介绍了教材的编写背景、编写原则、教材结构、教材特色,旨在指导中等职业学校教师落实化学课程标准,以现代职业教育理念实施化学课程改革,提高化学课程教学质量和效果。     

The enormity of the zinc deficiency problem and available solutions; an overview

The societal cost of micronutrient deficiency (MND) or the “hidden hunger” is in millions of dollars/year, reducing the GDP of some countries by as much as 11%. Zn is an important micronutrient for both plants and animals. An estimated 17% of the world population, or around 1.1 billion people, are at the risk of zinc (Zn) deficiency. The deficiency has been related to adverse pregnancy outcomes, stunted growth, premature deaths, immune system dysfunctions, neuro-behavioral disorders, and recently with the failure to recover from COVID-19. These health risks associated with Zn deficiency have compelled FAO and WHO to recommend Zn fortification of diet. Correcting Zn deficiency is a challenge due to several reasons. Close to half of the agricultural soils are Zn deficient, and chemical Zn fertilizers are costly and ineffective. Developing Zn-rich crops through plant breeding and genetic engineering is challenging. Zn-dense diet is costly and cannot be implemented in the low-income region most affected by Zn deficiency. Lack of consensus among regulatory bodies on defining and diagnosing Zn deficiency in plants and Humans. Awareness and other sociocultural issues. Among the most important available solutions are zinc biofortification of the cereal crops, use of zinc biofertilizers, development of Zn-efficient crops with reduced phytate content. The use of Zn supplements, dietary modification, and diversification, especially with fish, are proposed as the most accessible and affordable solutions. Awareness programs in areas suffering the most from Zn deficiency are required. Despite the suggestions from FAO and WHO, global efforts to combat Zn deficiency matching those for combating diseases like HIV are not in place. Coordinated efforts of the international community, especially policy-makers, agricultural scientists, dieticians, physicians, and others, are required to address the issue of hidden hunger.