Non-Aziridination Approaches to 3-Arylaziridine-2-carboxylic Acid Derivatives and 3-Aryl-(aziridin-2-yl)ketones

Highly functionalized aziridines, including compounds with aromatic moieties, are attractive substrates both in synthetic and medical areas of chemistry. There is a broad and interesting set of synthetic methods for reaching these compounds. Aziridination represents the most explored tool, but there are several other more specific, less well-known, but highly promising approaches. Therefore, the current review focuses on recently described or updated ways to obtain 3-arylated aziridines via different non-aziridination-based synthetic methods, reported mainly since 2000. The presented methods belong to two main directions of synthesis, namely, cyclization of open-chain substrates and rearrangement of other heterocycles. Cyclization of open-chain substrates includes the classic Gabriel-Cromwell type cyclization of halogenated substrates with amines, base-promoted cyclization of activated aminoalcohols (or its analogues), and the oxidative cyclization of β-dicarbonyls. Rearrangements of other heterocycles are presented as the Baldwin rearrangement of 4-isoxazolines, the cycloaddition of 1.3-dipoles or dienes to 2H-azirines, and the addition of C- and N-nucleophiles to the double bond of azirines.     

Advances in nitrogen transfer reactions involving aziridines

In recent years, our search for new nitrogen transfer reactions has concentrated on aziridine chemistry. This Account highlights our efforts toward the synthesis and functionalization of aziridines. In the course of our research, we have investigated the electrochemical aziridination of olefins, the acid-catalyzed ring opening of aziridines, and the development of transition metal mediated nitrogen allylation, arylation, and alkenylation of unprotected aziridines. Our studies have also involved the synthesis of aziridine-based enamine intermediates and their stereoselective transformations into heterocyclic compounds.     

氮杂环丙烷与腈的[3+2]环加成反应生成咪唑啉的研究进展

咪唑啉是一种非常重要的药物中间体,其通过氮杂环丙烷与腈的[3+2]环加成反应是非常有效合成方法.综述了这种方法的研究进展,并且进行了评价与展望.     

Reactivity of Donor-Acceptor Cyclopropanes with Saturated and Unsaturated Heterocyclic Compounds

Strain in the ring engenders versatile reactivity that can be utilized for the synthesis of complex molecules by the assimilation of suitable substituents. In this context, vicinal donor-acceptor cyclopropanes (DACs) serve as three-carbon synthetic equivalents in organic synthesis from the last few decades. Owing to their zwitterionic nature, they have been frequently utilized in [3+n]-annulation reactions with different dipolarophiles like aldehydes, imines, oximes, epoxides, aziridines, etc. This review highlights developed synthetic tools for annulation reactions of vicinal donor-acceptor cyclopropanes with saturated and unsaturated heterocyclic compounds.     

3-芳基取代苯并呋喃-2-酮类化合物的合成进展

本主要阐述了目前3-芳基取代苯并呋喃酮类化合物的研究进展及合成路线。总结了用不同的试剂，通过不同的路线合成该类化合物的方法。较全面地给出了已经合成出的一系列该类化合物。     

Visible Light instead of Transition Metal: Electron Donor Acceptor Complex Enabled Cross-Coupling of Aryl Halides with Active Methylene Compounds

An arylation of anions of active methylene compounds with aryl halides provides an access to synthetically versatile α-arylated 1,3-diketones, β-keto esters, β-keto nitriles, β-cyano esters, etc. Previously, these C−C cross-coupling reactions have been accomplished only using transition metal-based catalysts. Herein, we demonstrate that these arylations can be successfully realized under catalyst-free conditions employing the electron donor-acceptor (EDA) complex photoactivation strategy. The protocol was further optimized for a semi-one pot synthesis of indole derivatives via an intramolecular C−C coupling.     

Cis-Configured aziridines are new pseudo-irreversible dual-mode inhibitors of Candida albicans secreted aspartic protease 2

A series of cis-configured epoxides and aziridines containing hydrophobic moieties and amino acid esters were synthesized as new potential inhibitors of the secreted aspartic protease 2 (SAP2) of Candida albicans. Enzyme assays revealed the N-benzyl-3-phenyl-substituted aziridines 11 and 17 as the most potent inhibitors, with second-order inhibition rate constants (k(2)) between 56,000 and 121,000 M(-1) min(-1). The compounds were shown to be pseudo-irreversible dual-mode inhibitors: the intermediate esterified enzyme resulting from nucleophilic ring opening was hydrolyzed and yielded amino alcohols as transition-state-mimetic reversible inhibitors. The results of docking studies with the ring-closed aziridine forms of the inhibitors suggest binding modes mainly dominated by hydrophobic interactions with the S1, S1', S2, and S2' subsites of the protease, and docking studies with the processed amino alcohol forms predict additional hydrogen bonds of the new hydroxy group to the active site Asp residues. C. albicans growth assays showed the compounds to decrease SAP2-dependent growth while not affecting SAP2-independent growth.     

碳亲核试剂与氮杂环丙烷开环反应的研究进展

氮杂环丙烷化合物是有机合成中重要的杂环化合物之一,其开环反应越来越受到有机化学家的关注.本文综述了近年来各类碳亲核试剂与氮杂环丙烷开环反应的研究进展,大多具有反应条件温和、易控制、区域选择性好、收率高等优点.     

Combustion synthesis of compounds in the Y2O3-Al2O3 system

In the Y₂O₃-Al₂O₃ system, compounds Y₃Al₅O₁₂ (yttrium aluminum garnet, YAG), YAlO₃ (yttrium aluminum perovskite, YAP), and Y₄Al₂O₉ (yttrium aluminate monoclinic, YAM) are well known. YAG and YAP are of considerable technological importance. Conventional solid-state reaction techniques require high sintering temperatures (above 1800°C) to prepare phase-pure compounds. Though several soft chemical routes have been explored for synthesis of YAG, YAP and YAM, most of these methods are complex. Moreover, phase-pure materials are not obtained in one step and prolonged annealing at temperatures around 1000°C is necessary. In this paper, one-step combustion synthesis of these compounds is reported using a modified procedure and employing mixed (glycine + urea) fuel. Phosphors based on Ce³⁺ activation were also prepared and exhibited characteristic photoluminescence.     

FeCl3/NaNO2催化氧化酰基肼化合物的研究

酰基肼化合物氧化制备酰基偶氮化合物是仲氰基化合物合成路线中重要一环。传统氧化方法通常使用等量氧化剂,而催化氧化对该反应进行相关研究鲜有文献报道。本文成功将氯化铁/亚硝酸钠催化氧化体系应用于该反应中。以氧气为氧源,该方法可对脂肪族类酰基肼化合物高效氧化为相应酰基偶氮产物。该法也为仲氰基化合物合成路线中氧化步骤提供一种更优的选择。     

Copper-Catalyzed α-Arylation of Sulfoxonium Ylides Using Hypervalent Iodine Compounds

A Cu(I)-catalyzed synthesis of α-arylated sulfoxonium ylides has been achieved from mesitylene-derived diaryliodonium salts and α-carbonyl sulfoxonium ylides. The reaction is believed to proceed via an electrophilic Cu(III)-aryl intermediate that can be trapped upon nucleophilic attack of the sulfoxonium ylide precursor. The reaction was tolerant to both α-keto and α-ester-derived sulfoxonium ylides, to drug-derived ylide motifs and to electronically-diverse arenes, and enabled the direct synthesis of 32 α-aryl-sulfoxonium ylides in 42–85% yield.     

Regioselective ring-opening of aziridines with diselenides and disulfides using the Zn/AlCl3 system

An efficient Zn/AlCl₃-promoted highly regioselective one-pot procedure has been demonstrated for the synthesis of β -amino selenides and sulfides from a variety of diselenides/disulfides and aziridines by reductive cleavage of Se–Se and S–S bonds using the Zn/AlCl₃ system in acetonitrile under very mild conditions.

     

2-Arylamino-thiophen-3-carbonsäurederivate

2-Arylamino-thiophene-3-carboxylic Acid Derivatives The title compounds 3 are synthesized by reaction of 2-amino-thiophene-3-carboxylic acid derivatives 1 with anilines. The nucleophilic 5-position in 3 allowed the synthesis of 5-aryliden-Δ³-thiolen-2-one-imines 5 , 6 and the oxidative coupling to yield the azo compound 7 . 1-Aryl-thieno-[2,3-d]pyrimid-4-ones 9 , the thieno[2,3-b]chinolin-4-one 10 and the 4-chloro thieno[2,3-b]chinolines 10 , 11 can be obtained from 3 .     

金属有机RReO3化合物研究进展

RReO₃是一种过渡金属有机化合物，其中，甲基三氧化铼是最早被发现的一种稳定的RReO₃型化合物，然而由于当时未能得到一种有效的合成路线，所以对甲基三氧化铼的研究没有引起重视。直到1988年德国Herrmann W A等发明了一种简便有效的合成方法，并且发现这类化合物可以高效催化烯烃环氧化反应后，RReO₃型化合物才引起重视。综述了迄今为止报道的含有不同R基团的RReO₃类化合物的合成方法，主要包括锌路线和锡路线两种合成方法，系统阐述了不同类型R基取代基对化合物稳定性的影响，同时总结了不同类型RReO₃型化合物催化性能的研究进展。然而，除甲基三氧化铼外，目前发现的大多数RReO₃型化合物在空气及潮湿环境下稳定性较差，限制了其催化应用。分析了影响催化剂稳定性的因素，并建议通过深入研究分子构效关系，探讨稳定性与催化性能的作用规律，从而指导催化剂的设计与合成，并对未来的发展方向进行展望。     

聚阴离子型正极材料磷酸钛锂的研究进展

随着锂离子电池受到越来越多的人的重视,找到合适的正极材料成为主要问题。聚阴离子型正极材料由于其出色的特性得到人们的注意,LiTi2（PO4）3作为一种新型的聚阴离子型正极材料也引起了人们研究的兴趣,本文综述了聚阴离子型正极材料LiTi2（PO4）3的一些制备方法和改性研究,并提出了今后研究的一些主要问题。     

氮杂环丙烷开环反应的研究进展

介绍了碳、氧、硫、氮及含其他杂原子等亲核试剂对氮杂环的开环反应,阐述了烷基、芳基、烯胺、烯醇、烯烃等负碳离子对氮杂环的开环研究.     

CoCl2-FeCl3-膨胀石墨层间化合物制备

对CoCl2-FeCl3-膨胀石墨层间化合物(EGICs)的制备进行了探讨.结果表明保持其它制备条件不变,仅改变膨胀石墨(EG)与FeCl3的配比即可合成不同阶结构的EGICs;随着n(EG)∶n(FeCl3)增大,EGICs趋向于高阶,在一定配比下可合成纯阶样品;原料配比固定,提高反应体系的Cl2分压有利于制得纯净的EGICs.     

Synthese und Eigenschaften von 2-Methoxycarbonylmethylen- und 2- (Formyl-methoxycarbonylmethylen)-2H-Thiopyran-3-carbonsäureme-thylester

Synthesis and Properties of Methyl-2-methoxycarbonylmethylene- and -2-(formyl- methoxycarbonylmethylene)-2H-thiopyran-3-carboxylates Dimethyl-2-chloro-propene-l,3-dicarboxylate is a easily available reactive C₂-building block for the synthesis of 2H-thiopyran derivatives la — n in good yields via [C₃S + C₂]-cyclisation reactions using β-thioxoaldehydes and their derivatives as C₃S-synthons. The structure of the stable red products with Z-configuration (side chain in position 2 of the ring) is elucidated by means of several analytical and spectroscopic methods including X-ray analysis of compounds 1h and lk . Treating of 1 with Vilsmeier reagent yields title compounds 2 with a remarkable less reactive formyl group at the exo-methylene group. There is obviously a shielding effect of the carboxylate groups.     

Enantioselective Synthesis of a Positive Allosteric Modulator of the Metabotropic Glutamate Receptor 5 (mGluR5) Receptor via Dynamic Kinetic Resolution of α‐Amino Ketones

The concise synthesis of a pharmaceutical candidate is described. The chiral core of the molecule is assembled using an aza‐benzoin condensation and a dynamic kinetic resolution (DKR) as the key reactions. This enables superb control of the regio‐, diastereo‐ and enantioselectivity of the synthesis. Both biocatalysts and transition metal catalysts are remarkably effective in the key asymmetric reduction step. Similar approaches could be considered in the synthesis of other 1,2‐amino alcohols where traditional approaches based on functionalization of alkenes, epoxides or aziridines may suffer from selectivity issues.

     

Organocatalytic and Stereoselective [3 + 2] Cycloadditions of Azomethine Imines with α,β‐Unsaturated Aldehydes

Bipyrazolidin‐3‐one derivatives are biologically significant compounds and their importance has increased in the past decades. In this paper, the first stereoselective [3 + 2] dipolar cycloadditions of azomethine imines with α,β‐unsaturated aldehydes catalyzed by readily available α,α‐diarylprolinol salts are reported, providing a facile route to the synthesis of various chiral bipyrazolidin‐3‐one derivatives under mild conditions. The organocatalyst 1 g with strongly electron‐withdrawing groups exhibited the best stereoselectivity (exo:endo up to 98:2, for exo product up to 97 % ee), in the combination with trifluoroacetic acid.