邻苯二胺与醛反应合成苯并咪唑衍生物的反应机理研究

以4-甲基苯甲醛与邻苯二胺反应合成2-(4-甲基苯基)苯并咪唑的反应为例,以HPLC方法跟踪反应进程,对关键中间体与产物的结构通过1H NMR,FT-IR及LC-MS等手段进行了表征.实验证明了在邻苯二胺和醛物质的量比为1:1时同时生成单席夫碱和双席夫碱中间体的反应机理,并提出了该类反应的影响规律.     

对二甲基氨基苯甲酰胺基硫脲用于苯甲醛的荧光光度法测定

对二甲氨基苯甲酰胺基硫脲(DMABATU)与苯甲醛反应生成发强荧光的席夫碱,该反应用于苯甲醛的定量测定.在pH 5.30 NaAc-HAc缓冲溶液中(含乙腈20%),苯甲醛浓度在1.25×10-7～3.23×10-6 mol/L范围内与荧光强度呈良好的线性关系,方法检出限为3.75×10-8 mol/L,具有相似反应功能团的物质如甲醛、乙醛、丙酮及苯乙酮的存在均不干扰其测定,表现出较好的选择性.该方法应用于废水中苯甲醛的测定,回收率为97.0%～98.5%.     

新型10-取代小檗碱衍生物的合成

2-羟基-3-甲氧基苯甲醛在酸性条件下脱除甲基制得2,3-二羟基苯甲醛（2）;在不同碱作用下,2与卤代烷烃选择性反应生成邻、间烷氧基单取代中间体（3和4）,经二次烷基化反应制得2-甲氧基-3-烷氧基、2-烷氧基-3-丁氧基苯甲醛（5a~5f）; 5a~5f与3,4-亚甲二氧基苯乙胺经脱水缩合生成席夫碱中间体,再依次经硼氢化钠还原生成胺,并与乙二醛水溶液发生双重环合反应,合成了一系列10-位非甲基取代的小檗碱衍生物（9a~9f）,其中5b~5e和9a~9f为新化合物,其结构经¹H NMR、¹³C NMR和HR-MS(ESI)表征。     

5-取代-4-氨基-1,2,4-三唑硫酮席夫碱合成、表征及生物活性

为了筛选出高活性的1,2,4-三唑席夫碱化合物,本文以二氨基硫脲与取代羧酸为原料,回流反应生成中间体5-取代-4-氨基-1,2,4-三唑硫酮,再与2-氯-6-氟苯甲醛在冰乙酸催化下合成了一系列三唑席夫碱类新化合物。目标化合物结构通过IR、元素分析、1H NMR、ESI-MS进行表征。采用室内平皿法初步测定了标题化合物对烟草赤星病、马铃薯干腐病、小麦赤霉病、西瓜枯萎病4种植物病原菌的生物活性,结果表明,合成的部分化合物具有较好的抑菌活性。     

TTA的席夫反应和分子力学、量化计算

报导了噻吩甲酰三氟丙酮(TTA)与4 氨基安替比林(4 ATP)缩合反应生成的两个席夫碱化合物A和C,利用分子力学和分子动力学方法研究了该缩合反应可能生成的三个席夫碱化合物A、B和C的各种构象.从TTA的量化计算结果可以看出缩合反应生成的两个席夫碱化合物A和C是正确的.     

醋酸锰(Ⅲ)催化2-(4-氨基苯基)苯并噻唑衍生物的合成研究

以取代的邻氨基硫酚为原料,三价醋酸锰催化条件下,与(取代)对硝基苯甲醛发生缩合反应,生成硝基苯并噻唑中间体,该合成工艺具有反应条件温和、操作简单等优点。在此基础上,利用钯碳催化还原反应,制备得到2-(4-氨基苯基)苯并噻唑化合物,总收率达到63-79%,利用IR、1HNMR和元素分析对目标化合物结构进行了表征。     

3-取代苯氧甲基-4-氨基-1,2,4-三唑-5-硫酮席夫碱的合成、结构表征和生物活性研究

以醋酸为反应溶剂和催化剂,用自制的4-氨基-4,5-二氢-3-取代苯氧甲基-1,2,4-三唑-5-硫酮与4-氟苯甲醛反应合成了5个4-氨基-4,5-二氢-3-取代苯氧甲基-1,2,4-三唑-5-硫酮席夫碱化合物,通过1HNMR、IR和元素分析对所有化合物进行了结构表征.初步生物活性测试结果表明所有化合物具有优良的杀菌活性,并对席夫碱结构与活性的关系进行了探讨.     

一步法2-氨基-1-苯乙酮盐酸盐、醛和巯基乙酸三组分反应高效合成噻唑烷酮（英文）

采用一步法在二异丙基乙胺存在下由2-氨基-1-苯乙酮盐酸盐、芳香醛和巯基乙酸三组分反应高效合成了噻唑烷酮.该反应显示出很好的化学选择性.首先2-氨基-1-苯乙酮的N原子与芳香醛选择性反应生成席夫碱,然后巯基乙酸的S原子亲核进攻席夫碱的C原子,最后N原子与羧酸基团环加成生成噻唑烷酮.合成的化合物用光谱技术进行了表征.     

N-取代-α-氨基膦酸酯的不对称合成

本文以手性α-异丙基对氯苄胺为手性诱导试剂和取代苯甲醛生成的席夫碱与亚磷酸酯进行不对称加成反应, 生成具有双手性中心的N-取代-α-氨基磷酸酯。化学产率为40~91%, de%可达到72%。并简单讨论了立体效应对光学诱导能力的影响。     

拉帕替尼新中间体的合成

通过使用市售的5-溴糠醛与2-甲磺酰基乙胺进行亲和加成得到席夫碱,该席夫碱通过还原氢化、氨基保护和与硼酸酯反应,得到一种拉帕替尼的新中间体5-((苄基(2-(甲基磺酰基)乙基)氨基)甲基)呋喃-2-基硼酸,四步反应总收率为66.32%。     

Molybdenum tetracarbonyl complexes with linear chain polyether‐containing Schiff base ligands and their reactivity in the polymerization of methyl methacrylate

Mo(CO)₆ was reacted with the Schiff base ligand obtained by condensation reaction of 2‐acetyl‐ or benzoylpyridine with poly(propylene glycol)bis(2‐aminopropyl ether) to obtain polymeric, dinuclear metal tetracarbonyl compounds. The long‐chain Schiff base complexes are highly soluble even in non‐polar solvents such as petroleum ether, diethyl ether and n‐hexane. These complexes, as free‐radical initiators, afforded methyl methacrylate polymerization in chlorinated solvents. Copyright © 2005 John Wiley & Sons, Ltd.     

Kinetic and mechanism of reactions of L-α-Glutamic acid and L-Glutamine with pyridoxal

The kinetics and mechanisms of condensation of pyridoxal with L-α-glutamic acid and L-glutamine were studied by UV spectroscopy and polarimetry. L-α-Glutamic acid reacts with pyridoxal to form a Schiff base whose subsequent hydrolysis gives rise to pyridoxamine and α-ketoglutaric acid. The reaction of Lglutamine with pyridoxal involves the Γ-NH₂ group and affords a Schiff base whose subsequent hydrolysis gives rise to pyridoxamine and L-α-glutamic acid.     

不对称Schiff碱镍(Ⅱ)配合物的合成及其晶体结构

合成了3个具有不对称结构的Schiff碱配体H2Ln(n=1、2、3)。H2L1由乙酰丙酮、乙二胺和水杨醛缩合作用得到,H2L2由乙酰丙酮、(1R,2R)-环己二胺和水杨醛缩合作用得到,H2L3由苯甲酰丙酮、乙二胺和水杨醛缩合作用得到,每个反应中3个反应物的物质的量之比均为1∶1∶1。配体H2Ln分别与Ni(OAc)2.4H2O进行配位反应得到3个单核Ni(Ⅱ)配合物1,2和3。分别采用1H NMR、FTIR和元素分析对化合物进行了表征,并通过X-射线单晶衍射技术测定了3个配合物的晶体结构。     

牛磺酸与噻吩甲醛缩合形成Schiff碱反应机理的研究

用密度泛函理论(B3LYP)在6-31G**基组水平上, 对牛磺酸与噻吩甲醛缩合生成Schiff碱的反应机理进行了模拟计算, 并利用计算结果按过渡状态理论计算出反应的速率常数. 分析了质子传递介质对这类反应的催化作用原理. 研究结果对于伯胺与活性羰基化合物缩合的一类反应机理的深入研究, 以及对于与Schiff碱的生成与分解有关的生化过程的进一步探讨都有一定意义.     

Covalent Schiff base catalysis and turnover by a DNAzyme: a M2+ -independent AP-endonuclease mimic

A DNAzyme, synthetically modified with both primary amines and imidazoles, is found to act as a M2+ -independent AP lyase-endonuclease. In the course of the cleavage reaction, this DNAzyme forms a covalent Schiff base intermediate with an abasic site on a complementary oligodeoxyribonucleotide. This intermediate, which is inferred from NaCNBH3 trapping as well as cyanide inhibition, does not evidently accumulate because the second step, dehydrophosphorylative elimination, is fast compared to Schiff base formation. The 5'-product that remains linked to the catalyst hydrolyzes slowly to regenerate free catalyst. The use of duly modified DNAzymes to perform Schiff base catalysis demonstrates the value of modified nucleotides for enhancing the catalytic repertoire of nucleic acids. This work suggests that DNAzymes will be capable of catalyzing aldol condensation reactions.     

双氮席夫碱配体对甲基三氧化铼催化烯烃环氧化反应的影响

 利用 2-吡啶甲醛、6-甲基-2-吡啶甲醛或 6-异丙基-2-吡啶甲醛与对甲基苯胺缩合制得双氮席夫碱配体, 考察了席夫碱配体以及溶剂和温度对甲基三氧化铼 (MTO) 催化不同结构烯烃环氧化反应的影响. 结果表明, 这些席夫碱配体与 MTO 构成的催化剂体系在甲醇溶剂中的催化性能最好, 双氮配体能显著提高环氧化反应的选择性. 当以甲醇为溶剂, 环己烯为底物, 在 –10 oC 反应 12 h 时, 环己烯转化率和环氧化物选择性均可达 100%. 席夫碱的配位能力越强, 越有利于提高环氧化物选择性, 而其配位能力取决于吡啶环中 6-位取代基的电子和立体结构. 给电子能力较强和空间位阻较小的烷基对应的配体的配位能力较强.     

新型Schiff碱双核配合物的合成及光谱特征

首次报道了新型Schiff碱双核配合物-双[N,N"-亚烃基-2,2'(苯亚甲基)二(3,4-二甲基吡咯-5醛缩亚胺)]合双锰及双铁配合物的合成方法及光谱特征。     

Novel π-Conjugated Poly（Schiff base） Containing Thiazole and Tetrathiatetrahyd ropentalene Moieties

A new kind of π-conjugated heterocyclic poly(Schiff base) was firstly prepared by the condensation reaction between tetrathiatetrahydropentalene-type diketone and bithiazole-diamine in good yields. The polymers were characterized by VPO, FTIR and ^1H NMR spectroscopy. A large bathochromic shift was observed in UV-Vis spectra for these polymers due to the π-π* transition in the conjugated main chain. Brief examination indicated that the nitrogen-and sulfur-containing polymers exhibited an excellent chelating tendency to metal ions and the corresponding polymeric complexes would be expected to have potential in applications.     

Synthesis of Novel Symmetric Porphyrin Schiff Base Dimers by Solid–Liquid Reaction Methodology

A new convenient solid–liquid condensation reaction procedure for the synthesis of novel asymmetric and symmetric meso‐tetraarylporphyrin and metalloporphyrin Schiff bases is reported. The condensation reaction between β‐formyl porphyrin or metalloporphyrins and aromatic amines was carried out at solid–liquid interface by using neutral alumina powder as a solid support for β‐formyl porphyrin or metalloporphyrins and absolute ethanol as the carrier solvent for aromatic amines. Six different asymmetric porphyrin/metalloporphyrin Schiff bases were synthesized via solid–liquid interface reaction methodology. The same solid–liquid synthetic methodology was applied for the synthesis of six novel symmetric Schiff base porphyrin/metalloporphyrin dimers. The comparison of UV–visible spectra of porphyrin Schiff base monomers and dimers revealed that some degree of electronic perturbation has occurred upon dimerization as the Soret bands of the monomers underwent peak broadening along with red shifts. Column chromatography and crystallization were used to purify the compounds. Fourier transform infrared, UV–visible, elemental analysis, ¹H NMR, and mass spectrometry were used to characterize the newly synthesized compounds.     

Synthesis and characterization of new azo containing Schiff base macrocycle

Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition,a one-pot cyclization procedure of four-component without using a template.The condensation reaction of related bis（hydroxybenzaldehyde） with phenylenediamines to prepare a conjugated[2 + 2]Schiff base macrocycle has been investigated and fluorescent[2 + 2]Schiff base macrocycles with N₂O₂ binding pockets has been prepared and characterized by elemental analysis,¹H NMR,IR,fluorescent,UV-visible and MALDI mass spectroscopies.