将生物信息学与有机化学结合初探酶促反应原理与实践——介绍一个国外本科生实验并讨论其相关问题

21世纪是生命科学与信息科学高速发展的时代,化学作为理科的中心学科与此二者均有紧密的联系。伴随着各种交叉学科的诞生与发展,将信息科学技术整合有机化学方法并用于认知生物大分子进而解决生命科学问题也是大势所趋,而在生物化学与化学生物学基础教学中引入相关内容也具有前瞻性与必要性。国外化学本科的基础教育也切合时宜地以一个生物信息学的最常用软件PyMOL为例设计相关实验,让学生在了解反应中的有机化学机理的基础上,学习酶的三维结构,并探究酶催化该反应的原因。此设计结合了有机化学、生物化学、生物信息学、蛋白质结构生物学等多学科,可以加深学生对多肽与蛋白质的高级结构的认识,并为今后的生物化学学习与研究打下基础,同时有利于培养学生对于化学的兴趣,可谓一举多得。这对于培养交叉学科人才,做出开创性研究极为重要。对国内生物有机化学实验的设计有借鉴作用。     

介绍一个针对非化学专业的化学科普实验——头发中微量元素的测定

结合中国科学技术大学的学期改制,在夏季学期面向全校非化学专业的低年级本科生开设了“生活中的化学科普实验”公选课程,课程内容多为与生活密切相关的热点问题。“头发中微量元素的测定”是其实验项目之一。该实验将学生自己的头发作为分析对象,合理地设计教学内容和实验步骤,以期激发学生对化学实验的兴趣,提高学生对化学学科的认识。     

饮用水实验——推荐一个针对非化学专业的生活化学实验

在非化学专业本科生生活化学实验课程中尝试开设饮用水实验,针对非化学专业学生的特点,重新设计实验的教学内容,通过贴近生活的实验内容,普及饮用水常识,培养学生的化学科学素养。     

夏季学期化学科普类实验课程的建设与探索

结合中国科学技术大学的三学期改制,在夏季学期面向全校非化学专业的低年级本科生开设生活中的化学科普实验公选课程。本文将从课程目标、课程内容、课程特色三方面进行介绍。该课程的开设为非化学专业学生提供了一个通过化学实验学习化学的机会,有利于开拓学生知识面,实现学科交融、文理渗透。     

茚-1,3-二酮制备与表征综合实验设计与教学实践

为将混合酯的缩合反应引入本科化学实验教学中，设计了综合化学实验——茚-1,3-二酮的制备实验。该实验以邻苯二甲酸二乙酯和乙酸乙酯为原料，乙醇钠为催化剂，经Claisen酯缩合反应、酸性条件下酯水解反应、热脱羧反应制备了茚-1,3-二酮。实验涉及回流、蒸馏、重结晶、减压过滤、恒温控制和恒压滴液等基本操作，并利用熔点测定、红外光谱及核磁共振氢谱、碳谱等对产品结构进行了表征。本实验综合运用了有机合成、产物分离和结构表征等技术手段，对于培养本科生的多步合成能力及波谱解析能力具有很好的教学效果。     

基于手持技术的乙酸乙酯水解实验研究

乙酸乙酯水解实验是中学有机化学中的重要实验,通过酯层减少或酯香味消失的时间来判断水解反应速率,实验效果并不理想。利用手持技术中的电导率传感器研究氢氧化钠溶液温度和浓度对乙酸乙酯水解反应速率的影响,以及不同酸碱性条件下的乙酸乙酯水解反应速率。将电导率传感器与pH传感器联用,同时测定乙酸乙酯水解过程的电导率和pH变化。对通过实验得到的电导率变化曲线和pH变化曲线进行分析,帮助中学教师和学生从定量的角度理解乙酸乙酯水解反应规律和微观实质,并阐释了此研究对中学化学实验及其教学的启示。     

S_N1溶剂解的动力学研究——值得借鉴的国外本科生有机化学实验

动力学研究是物理化学的一个重要研究方向,对于化学反应的动力学及机理研究是对其深入认识的基础。其中涉及的定量研究的思想与方法学不同于一般有机制备化学,在国内的有机化学课程中少有提及。本文介绍了一个国外大学有机化学实验,即最典型的卤代烃S_N1溶剂解的动力学的探究实验。进而对实验中的3方面基本问题进行了分析。该实验的设计与实施值得借鉴,并应用于国内本科生有机化学实验。     

液质联用仪器分析实验的开发和教学实践

把科研成果引入到仪器分析实验教学中,以二硫甲脒盐酸盐的水解反应为例,介绍了液质联用(HPLC-MS)仪器分析实验的开发。将分离与鉴定结合,通过数据分析与理论结合,使学生运用分析化学的手段解决化学中的问题,不仅培养了学生的综合分析实验能力,同时也激发了学生对科学研究的兴趣。     

综合化学实验:变色传感金属有机框架材料的制备

为了有效提升学生在化学实验过程中的学习积极性及效果,特推荐一个综合型化学实验--变色传感金属有机框架材料的制备。该实验设计思路是将前沿科学研究内容与本科生实验教学相结合,使学生在学习本科基础知识的同时又能了解科学研究的前沿领域。该实验涉及了有机物合成、无机领域金属有机框架材料的制备,还包括了红外、热重、X射线粉末衍射、紫外可见等仪器的使用及分析。鉴于本实验内容涵盖面较广,建议作为高年级本科生综合化学实验设置。     

量子化学和统计热力学结合的实验:确定过氧化氢二面角

介绍一个面向高年级本科生的计算化学实验。通过量子化学计算与统计热力学方法相结合,预测了298 K时过氧化氢的二面角,并与实验值进行比较。通过这一应用实例,使学生能够深入理解结构化学和物理化学的相关理论知识,尤其是对统计热力学的本质有一个直观认识,提升学生利用统计热力学处理科学问题的能力。     

An Update and An Offering

Project Kaleidoscope was founded in 1989 as a national alliance whose purpose is to strengthen undergraduate science and mathematics education. Its programs are designed to accomplish this, first, by finding efforts to reform undergraduate science and mathematics programs and second, by bringing those efforts to the attention of the larger education community. Through workshops, Project Kaleidoscope helps team members from institutions interested in attempting changes in their undergraduate curricula to explore ways of adapting successful efforts to their particular local needs. This article describes those workshops and briefly discusses a new Project Kaleidoscope initiative that brings together future science education leaders.     

An efficient and general urazole synthesis

A general two-step scheme for the synthesis of N4 substituted urazoles (i.e., 1,2,4-triazolin-3,5-diones) is described. The first step involves the reaction of a primary amine with 2.5 equiv of phenyl chloroformate to produce diphenyl (N-substituted)imidodicarbonates. The second step involves the reaction of these compounds with hydrazine to produce N4 substituted urazoles. The mild reaction conditions permit synthesis of N4 oxygenated urazoles, not available via existing methodology. Bicyclic urazoles can be prepared through the subsequent reaction of these N4-protected urazoles with 2.5 equiv of NaH in DMF together with either 1,3-dibromopropane or 2-(tert-butyldimethylsilyloxy)-1,3-dibromopropane in the presence of NaI. The resultant bicyclic urazoles are observed to display varying degrees of pyrimidalization at N1 and N2, depending on substituents.     

An Isolable Phosphaethynolatoborane and Its Reactivity

The synthesis and characterization of a stable phosphaethynolatoborane, [B]OCP ( 1 , [B]=N,N′‐bis(2,6‐diisopropylphenyl)‐2,3‐dihydro‐1H‐1,3,2‐diazaboryl), is described. The increased triple bond character of the P?C bond in 1 relative to the free ion (PCO^?) is probed in a series of reactivity studies. Compound 1 readily dimerises in donor solvents to afford a cyclic five‐membered 6π‐aromatic compound, cyclo‐P₂{C[B]}O{CO[B]} ( 2 ), which decarbonylates on UV irradiation. By contrast the nickel‐mediated dimerisation of 1 affords the isomeric diphosphacyclobutene [P(CO[B])]₂. When 1 is reacted with organolithium reagents such as MesLi (Mes=2,4,6‐trimethylphenyl), the boryl moiety shifts and the formation of the lithoxy‐boryl‐phosphaalkene [LiOC[B]P(Mes)]₂ was observed. The reactivity of this species towards electrophiles is also described.     

An acoustic dielectric and mechanical spectrometer

In this report, the dielectric constant of glycerol solutions (0-70% (w/w)) and the mechanical transitions of poly(2-hydroxylethyl methacrylate-co-methacrylic acid) films (600-800 nm, 1.5-10 mol% cross-linker) have been investigated by the magnetic acoustic resonance sensor (MARS), which is an electrode-free acoustic sensor and operates over a continuous frequency spectrum (6-200 MHz). When a glycerol solution was loaded, the response of the MARS decayed exponentially as the operating frequency was increased. The decay rate against frequency as a function of the glycerol concentration reflects the change of the dielectric property of the glycerol solutions. In addition, mechanical relaxation of the poly(2-hydroxylethyl methacrylate-co-methacrylic acid) film has been observed on the MARS and the corresponding viscoelastic transition frequency has been estimated. The viscoelastic transition frequency increased as the polymer was more highly cross-linked. The MARS system behaved as a dielectric and mechanical spectrometer, monitoring the electrical and mechanical properties of viscoelastic materials or on the solid-liquid interfaces simultaneously, which has prospective application in studies of biomaterials, molecular interactions and drug deliveries.     

An inexpensive and robust conductance electrode

A conductance electrode consisting of carbon "pultrusion" rod embedded in PTFE has been shown to have similar characteristics to those of the traditional platinum-on-glass type. The new electrode has the advantages of being both robust and inexpensive and could prove particularly useful in Karl Fischer analyses of biological material where maceration of the sample is required.     

An alpha,alpha'-dioxothione and its

In the reaction of Ninhydrin (1a)/1,2,3-indantrione (1b) with potassium thiotosylate, 1,4-oxathiin 6 is formed in up to 63% yield as the trapping product of the intermediary alpha,alpha'-dioxothione 1c with trans-cyclooctene (3a). Additionally, up to 18% of the available sulfur is transferred to olefin 3a to thiirane 3b through the intermediary oxathiirane.     

An efficient synthesis of pregaliellalactone and desoxygaliellalactone

A short and efficient total synthesis of rac-desoxygaliellalactone and (+)-desoxygaliellalactone, via the biosynthetic intermediate pregaliellalactone, is described. The synthesis was achieved in only three steps, for (+)-desoxygaliellalactone including an enantioselective alkyl propiolate addition to 4-pentenal, a palladium catalysed alkylative lactonisation and an intramolecular Diels–Alder cycloaddition.     

An expeditious and convergent synthesis of ailanthoidol

An expeditious and concise method has been described for the synthesis of ailanthoidol through convergent route starting from vanillin. The protocol involving intramolecular Wittig as a key reaction afforded ailanthoidol in overall high yield.