酰胺缩醛法合成N,N,N＇-三取代甲脒的研究

脒类化合物用作杀螨、杀虫剂,除草剂,消炎剂等[1,2],也是合成氮杂环化合物的中间体[3].有关脒的合成及应用研究的进展,我们已进行了较为详细的评述[4].早期的合成方法有亚酯胺解法,异腈胺解法和三氯氧磷法[5].我们采用DMF二烷基缩醛,在温和的反应条件下,合成出了N,N,N'-三取代甲脒,产率达90%左右,产物分离简便,除去副产物醇后,得到纯度较高的产物.酰胺缩醛具有较高的反应活性,用其可以合成出其它方法无法得到的脒.因此,酰胺缩醛法操作简便,适用范围广泛,是合成N,N,N＇-三取代甲脒较为理想的方法.     

半甲基六元瓜环和七元瓜环与三种新烟碱类农药的主客体相互作用

本研究通过瓜环与化合物包结配合物的形成,建立了一种防止呋虫胺(DIN)、啶虫脒(AMP)和噻虫嗪(TMX)三种新烟碱类农药降解的策略。在中性水条件下,呋虫胺能分别与半甲基六元瓜环和七元瓜环形成计量比1∶1的主客体包结配合物,结合常数的数量级均为10~4。而啶虫脒和噻虫嗪因体积过大而不能被HMeQ[6]的空腔封装,仅与Q[7]形成计量比1∶1的主客体包结配合物。此外,对农药及其包结配合物进行水中释放实验的结果表明,两种瓜环的包合对呋虫胺有一定的缓释效果,而七元瓜环的包合作用对啶虫脒和噻虫嗪在水中的释放没有影响。     

对氨基苯甲脒亚胺基甲酸正己酯盐酸盐的合成

为了降低对氨基苯甲脒亚胺基甲酸正己酯盐酸盐的合成成本,以对硝基苯甲醛为起始原料,与盐酸羟胺在三氯化铁的催化下反应生成对硝基苯腈,收率75%.硝基苯腈与氯化铵发生成脒反应生成对硝基苯甲脒,收率63.6%.它在碱性条件下与氯甲酸正己酯发生酰化反应得到对硝基苯甲脒亚胺基甲酸正己酯,收率96.7%.得到的正己酯经还原反应得到对氨基苯甲脒亚胺基甲酸正己酯,收率85.3%.最后与氯化氢成盐得对氨基苯甲脒盐酸盐,收率高达99.2%.终产物经1 H NMR和ESI-MS进行表征.     

呋喃胺水杨醛Schiff碱铜(Ⅱ)配合物的合成与结构

以4,5-二甲基-3-腈基-2-呋喃胺与水杨醛为原料,合成了4,5-二甲基-3-腈基-2-呋喃胺水杨醛Schiff碱化合物,再与醋酸铜反应得到一种新型的呋喃胺水杨醛Schiff碱铜(Ⅱ)配合物.目标化合物通过IR、UV,元素分析及摩尔电导分析等进行了表征.应用荧光光谱法研究了该配合物与牛血清白蛋白(BSA)之间的相互作用.实验表明,该配合物能强烈猝灭BSA的内源荧光.     

N,N''''-双(3-羧基水杨醛叉缩胺乙基)草酰胺均双核铜(Ⅱ)的密度泛函研究

草酰胺及其衍生物过渡金属原子配合物是近年来在实验和理论上[1～5]研究都十分活跃的领域,其原因是这些配合物具有良好的磁性质,对磁功能分子设计和磁性材料合成有着十分重要的意义.     

手性二氧大环多胺铜离子配合物的电化学研究

含氧大环多胺是一类含有酰胺结构的特殊的大环多胺,兼有寡肽和大环多胺的双重结构特征,是一类性质独特的大环配体.由于其可以根据不同的质子化状态与不同的分子、离子选择性配位,因而受到人们的关注.Kimura等对于非手性的含氧大环多胺金属配合物的电化学性质进行了广泛而深入的研究,但至目前为止,有关手性含氧大环多胺金属配合物电化学行为的研究还鲜有文献报道.本工作利用循环伏安法,在不同pH值条件下对我们新合成的手性二氧大环四胺及其衍生物(图1)铜离子配合物的电化学行为进行了研究,探讨该类化合物在酶的模拟、不对称催化等方面潜在的应用价值.     

Fe(Ⅱ)三脚架多咪唑配合物的合成与性质表征

三脚架结构配体与过渡金属离子形成的配合物具有较高的热力学稳定性、动力学惰性及特殊的配位模式,显示出优良的物理和化学性质,因而在化学、生物和材料等领域具有潜在的应用价值。三脚架有机多胺自1926年F．G．Mann等合成了Ni与三（3-氨基乙基）胺的配合物后,以后有很多类似结构的出现。作为一类重要和常见的螯合剂,它能与许多的金属离子进行螯合,使所得的螯合物具有优良的热力学稳定性。     

一种新型β-二亚胺镍（Ⅱ）配合物的合成及其结构研究

共轭的含氮配体,特别是其过渡金属配合物作为模拟生命体系中的一些现象而被人们广泛研究和重视［１］。我们在用二（三甲基硅基）甲基锂与两摩尔的不含α－Ｈ的腈进行加成反应时,由于三甲基硅基的１,３－迁移反应得到了一类非常有趣的五元共轭二亚胺配合物［２］。在本...     

高氯酸钪、钇与1,8-萘啶氮氧化物固体配合物的合成及性质

芳香胺及其氮氧化物能与许多金属离子形成配合物,某些金属离子与芳香胺及其氮氧化合物的配合物具有荧光^[1],属于芳香胺氮氧化物类的1,8-萘啶氮氧化物与金属离子形成配合物的报道很少.     

固相萃取/液相色谱-串联质谱法测定鱼塘水中双甲脒及其代谢产物

建立了鱼塘水中双甲脒及其代谢产物的液相色谱-串联质谱检测方法。采用固相萃取前处理,考察了不同的固相萃取柱和洗脱溶剂对检测结果的影响,优化了固相萃取条件。结果表明,在优化条件下,4种目标物在20~2 000 ng/L范围内线性关系良好(r为0.997 5~0.999 1),该方法对双甲脒及其代谢产物的检出限为0.4~1.0 ng/L。鱼塘水中双甲脒及其代谢产物的回收率为69.7%~91.3%,方法具有良好的灵敏度、重现性、稳定性和专属性,可满足日常的分析要求。     

CO2 capture capacity of five- and six-membered cyclic amidines bearing silatranyl group under dry conditions

CO₂ capture and release behaviors of three amidines bearing silatranyl group in DMSO solution were evaluated under dry conditions containing a very small amount of water. A six-membered cyclic amidine with silatranyl group captured CO₂ at 25 °C under atmospheric pressure quantitatively, and the trapped CO₂ was released at 60 °C under Ar atmosphere. A five-membered cyclic amidine with silatranyl group also captured CO₂, but less efficiently, under the same conditions as above. In contrast, an acyclic amidine with silatranyl group did not capture CO₂ at all, as expected from the poor CO₂-capturing ability of the acyclic amidine moiety.     

Induced fit conformational changes of a "reversed amidine" heterocycle: optimized interactions in a DNA minor groove complex

To better understand the molecular basis for recognition of the DNA minor groove by heterocyclic cations, a series of "reversed amidine" substituted heterocycles has been prepared. Amidine derivatives for targeting the minor groove have the amidine carbon linked to a central heterocyclic system, whereas in the reverse orientation, an amidine nitrogen provides the link. The reverse system has a larger dihedral angle as well as a modified spatial relationship with the groove relative to amidines. Because of the large dihedral, the reversed amidines should have reduced binding to DNA relative to similar amidines. Such a reduction is observed in footprinting, circular dichroism (CD), biosensor-surface plasmon resonance (SPR), and isothermal titration calorimetric (ITC) experiments with DB613, which has a central phenyl-furan-phenyl heterocyclic system. The reduction is not seen when a pyrrole (DB884) is substituted for the furan. Analysis of a number of derivatives defines the pyrrole and a terminal phenyl substituent on the reversed amidine groups as critical components in the strong binding of DB884. ITC and SPR comparisons showed that the better binding of DB884 was due to a more favorable binding enthalpy and that it had exceptionally slow dissociation from DNA. Crystallographic analysis of DB884 bound to an AATT site shows that the compound was bound in the minor groove in a 1:1 complex as suggested by CD solution studies. Surprisingly, unlike the amidine derivative, the pyrrole -NH of DB884 formed an H-bond with a central T of the AATT site and this accounts for the enthalpy-driven strong binding. The structural results and molecular modeling studies provide an explanation for the differences in binding affinities for related amidine and reversed amidine analogues.     

One-Pot Convenient and High Yielding Synthesis of Dithiocarbamates

Summary. A convenient and high yielding method for the synthesis of diverse dithiocarbamates having various substituents including alkyl, aryl, heteroaryl, and alkylaryl at the thiol chain or at the amine chain or at both thiol and amine chains were developed by the one-pot reaction of mercaptans, amines, and bis(benzotriazolyl)methanethione in presence of amidine base under mild reaction conditions.     

Three component reaction of aryl diazonium salt with sulfonamide & actonitrile to synthesize N-sulfonyl amidine

A new method was developed to prepare N-sulfonyl amidine compounds through three-component reaction of aryl diazonium salts with sulfonamides and acetonitrile, in which, nitrilium ion intermediate, generated from the reaction of aryldiazonium salt with nitrile, was subsequently trapped by sulfonamides. A series of N-sulfonyl amidine derivatives were synthesized by using various types of aryl diazonium salts, sulfonamides and nitriles. In addition, indolyl imine products could also be prepared by using indole as the nucleophile to trap nitrilium ion intermediate.     

Repeated dihydrogen elimination from amidine adducts of group 13 element hydrides: an evaluation of the reaction pathways

Dinuclear eta2,micro2-bonded amidinate complexes to group 13 element hydrides are of potential interest for applications in the field of hydrogen storage. In this work repeated dihydrogen elimination starting with amidine-stabilized boron, aluminum, and gallium hydrides is discussed on the basis of quantum chemical calculations which give useful information about the thermodynamic properties of these reactions and the possible reaction pathways in dependence of the chosen amidine derivative. It will be shown that, in agreement to recent experimental work, the thermodynamic properties are greatly influenced by the nature of the substituents bonded to the amidine. The amidine stabilized hydrides first eliminate dihydrogen in an intramolecular process leading to mononuclear amidinate complexes. These complexes could dimerize, if the amidine carries not too bulky organic groups, to give dinuclear complexes featuring two eta2,micro2-coordinated amidinate ligands. Further dihydrogen elimination leads to the generation of a dinuclear species with two group 13 elements (E) in the formal oxidation state +II and direct E-E bonding. Finally, elimination of another H2 for E = B possibly gives amidinate complexes featuring a double bond between two boron atoms in the formal oxidation state +I.     

Tandem Coupling of Azide with Isonitrile and Boronic Acid: Facile Access to Functionalized Amidines

Amidine is a notable nitrogen‐containing structural motif found in bioactive natural products and pharmaceuticals. Herein, a novel rhodium(I)‐catalyzed tandem reaction of readily accessible azides with isonitriles and boronic acids via a carbodiimide intermediate is achieved. This protocol offers an alternative approach toward N‐sulfonyl‐, N‐acyl‐, and N‐ phosphoryl‐functionalized, as well as general N‐aryl and N‐alkyl amidines with broad substrate scope. In addition, functionalized guanidines can also been synthesized when amines are used instead. The accomplishment of estrone‐derived amidine and glibenclamide bioisosteres further reveals the practical utility of this strategy.     

TiIV-mediated reactions between primary amines and secondary carboxamides: amidine formation versus transamidation

Titanium(IV)-mediated reactions between primary amines and secondary carboxamides exhibit different outcomes, amidine formation versus transamidation, depending on the identity of the TiIV complex used and the reaction conditions employed. The present study probes the origin of this divergent behavior. We find that stoichiometric TiIV, either Cp*TiIV complexes or Ti(NMe2)4, promotes formation of amidine and oxotitanium products. Under catalytic conditions, however, the outcome depends on the identity of the TiIV complex. Competitive amidine formation and transamidation are observed with Cp*TiIV complexes, generally favoring amidine formation. In contrast, the use of catalytic Ti(NMe2)4 (< or =20 mol %) results in highly selective transamidation. The ability of TiIV to avoid irreversible formation of oxotitanium products under the latter conditions has important implications for the use of TiIV in catalytic reactions.     

Salen-complex-mediated formation of cyclic carbonates by cycloaddition of CO2 to epoxides

Metal complexes of salen ligands are an important class of compounds, and they have been widely studied in the past. Among their successful catalytic applications, the synthesis of cyclic carbonates by the coupling reaction of epoxides with CO(2) has received increased attention; this is mostly due to the importance of using a greenhouse gas as a feedstock for the synthesis of useful molecules. Herein the most relevant past and present research surrounding this topic is presented.     

2,3-Dihydro-1H-1,5-benzodiazepines: A conversion of thiolactams to amidines

Summary The synthesis of a new series of diversely N-4 substituted amidines of 2,3-dihydro-1H-1,5-benzodiazepine has been accomplished starting from tetrahydro-1,5-benzodiazepin-2-one derivatives. These compounds were transformed into the desired thiolactams2a–i which reacted in the presence of mercuric chloride with ammonia, as well as primary or secondary amines to give amidines3a–i. Hydrazidines3j–l were prepared by treatment of thiolactams with an excess of hydrazine.

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2,3-Dihydro-1H-1,5-benzodiazepine: Umwandlung von Thiolactamen in Amidine

Zusammenfassung Einige neue N-substituierte Amidine von 2,3-Dihydro-1H-1,5-benzodiazepinen wurden ausgehend von Tetrahydro-1H-1,5-benzodiazepin-2-onen synthetisiert. Letztere wurden in die Thiolactame2a–i umgewandelt und anschließend durch Behandeln mit Ammoniak, primären oder sekundären Aminen in Gegenwart von Quecksilber(II)-chlorid zu den entsprechenden Amidinen3a–i umgesetzt. Die Hydrazinoamidine3j–l wurden aus den Thiolactamen mit Hydrazineüberschuß erhalten.