Ultrasound-assisted multicomponent synthesis of heterocycles in water – A review

Ultrasound-assisted multicomponent reactions in water are great implements for the development of bioactive compounds. The methodologies for the synthesis of different heterocyclic molecules have acquired enormous attention. Many such techniques are energy-intensive and associated with hazardous chemicals, solvents, expensive work-ups. Low yields and multi-step schemes generate huge organic waste. Hence, researchers thus focussed on benign and eco-friendly techniques to assemble heterocyclic analogs and drug molecules. The ultrasound-assisted synthesis of the target organic moieties frequently facilitates higher product yields than other methodologies. This review is focused on ultrasound-aided multicomponent reactions for synthesizing varied nitrogen-, oxygen-, and sulfur-containing heterocyclic compounds using water as the solvent. The advantages and limitations with respect to yields and reaction conditions are discussed. This evaluation covered the literature reports from 2014 to date.     

Synthesis of thiophene/phenylene co‐oligomers. I. Phenyl‐capped oligothiophenes

We report the synthesis of phenyl‐capped oligothiophenes via improved synthetic schemes. These schemes are based on the Grignard coupling reaction and enable us to obtain the target compounds at high yields. The resulting materials have been fully characterized through nmr and ir spectroscopies. The ir analysis is particularly useful in characterizing the materials of higher molecular weight, since those materials are difficult to dissolve in organic solvent. We also show an improvement on preparation of halogenated (oligo)thiophenes that are used as intermediates for synthesizing the target compounds. An alternative synthetic route to the phenyl‐capped oligothiophenes that utilizes the Suzuki coupling reaction is presented as well.     

Relation between molecular structure and spectral characteristics of some chelating mono-azo dyes based on o-hydroxy aryl aldehydes and carboxylic acids

The electronic absorption spectra of some chelating mono-azo compounds have been studied in some organic solvents of varying polarities. The u.v. bands in ethanol and cyclohexane are assigned in the light of electronic transitions. The effect of microscopic and macroscopic solvent polarity parameters are also discussed. The i.r. spectra of the solid compounds as KBr discs as well as the ¹H NMR spectra have also been assigned and discussed in relation to molecular structure. The azo ⇌ hydrazone tautomerism in some of these compounds is assured. The study indicated that the colour of the materials depends on the polarity and the formation of intermolecular H-bonds with the solvent molecules.     

Materials and biological applications of 1,2,3-selenadiazoles: a review

In recent years, chemistry of metal-nitrogen–bonded compounds have attracted tremendous attention mainly because of unusual properties resulting from such a bond involving carbon and other heteroatoms. M?N–bonded compounds, when containing group VI elements, especially selenium, has attracted great attention in materials chemistry. In addition, the increased interest in synthesis of N-containing bioactive compounds with other heteroatoms such as selenium, sulfur, etc is mainly because of their tremendous potential as antioxidants, additives, dyes for polymers, and as insecticides, in solvent extraction, and in nanotechnology. Thus, the synthesis and applications of 1,2,3-selenadiazoles have attracted recent interest of materials scientists, including nanotechnologists, pharmaceutical chemists, and organic chemists. The chemistry of 1,2,3-selenadiazoles is highly rich and has been practiced ever since its first report in 1972. Such N-containing Se-heterocycles form several types of selenadiazoles that are a rich source of selenium for semiconductor nanoparticles of metal selenides. The materials chemistry of such molecules has been documented for over three decades, and their great scope in semiconductors has emerged. This review article is an attempt to bring a variety of materials and biological application of 1,2,3-selenadiazoles for better understanding of the researchers.     

Highly Efficient Enrichment of Volatile Iodine by Charged Porous Aromatic Frameworks with Three Sorption Sites

The targeted synthesis of a series of novel charged porous aromatic frameworks (PAFs) is reported. The compounds PAF‐23, PAF‐24, and PAF‐25 are built up by a tetrahedral building unit, lithium tetrakis(4‐iodophenyl)borate (LTIPB), and different alkyne monomers as linkers by a Sonogashira–Hagihara coupling reaction. They possess excellent adsorption properties to organic molecules owing to their “breathing” dynamic frameworks. As these PAF materials assemble three effective sorption sites, namely the ion bond, phenyl ring, and triple bond together, they exhibit high affinity and capacity for iodine molecules. To the best of our knowledge, these PAF materials give the highest adsorption values among all porous materials (zeolites, metal–organic frameworks, and porous organic frameworks) reported to date.     

Zn[aminoacid]2 hybrid materials applied as heterogeneous catalysts in the synthesis of β-enaminones

Hybrid materials have seized attention from scientific community mainly as heterogenic catalysts in organic reactions on a large scale succeeding in some organic compounds with high yields. One of the most important classes of hybrid materials used for this purpose involves the complexation of Zn and aminoacids. Herein, we introduced Zn[Pro]₂ and Zn[Gly]₂ in the synthesis of several β-enaminones via solvent free protocol and using an ultrasound device.     

Reduction of Aromatic Nitro Compounds under Solvent-free Condition Using Almnina-suppored Hydrazine/Fe2 (NO3)3· 9H2O

The application of microwave techniques for chemical synthesis has attracted considerable interest in recent years because of their enhanced selectivity, reduced reaction time, easier work-up procedure. Aromatic amines are widely used as intermediate for dyes, photographic materials, pharmaceutical and agricultural chemicals and as antioxidants. So, particularly intense interest has been directed toward the synthesis of these compounds. Reduction of aromatic nitro compounds is one of the important routes to prepare them. Generally, the processes have been carried out in solvent. [ 1 ～ 6] The drawback of these methods is long reaction time.     

Solid-phase and microwave-assisted syntheses of 2,5-diketopiperazines: small molecules with great potential

Diketopiperazines (DKPs) are a well-known class of heterocycles that have recently emerged as a promising biologically active scaffold. Solid-phase organic synthesis has become an important tool in the combinatorial exploration of these privileged structures, expediting the synthesis and, therefore, the discovery of active compounds. To date, certain DKPs have shown potent activities against a range of diseases and biological phenomena, including bacterial infections, various cancers, asthma, infertility, premature labor, and HIV. Recent applications of solid-phase DKP synthesis, with a particular focus on cyclative cleavage and microwave-assisted reactions, are highlighted herein.     

酰肼类化合物的羰基化制备及其在智能材料合成中的应用

酰肼类化合物在农药、医药等领域被广泛应用,其合成方法的研究备受关注.卤代物和有机肼(或单酰肼)的羰基化反应是制备酰肼类化合物的重要合成路线之一.在由羰基化反应制备酰肼类化合物的过程中,除以CO气体作为典型、廉价易得的羰基源外,CO2、DMC(碳酸二甲酯)、固体羰基配合物等都可以作为替代CO气体的潜在羰基源.我们着重介绍...     

Efficient Fixation of Carbon Dioxide by Electrolysis Facile Synthesis of Useful Carboxylic Acids

Electrochemical fixation of atmospheric pressure of carbon dioxide to organic compounds is a useful and attractive method for synthesizing of various carboxylic acids. Electrochemical fixation of carbon dioxide, electrochemical carboxylation, organic halides, organic triflates, alkenes, aromatic compounds, and carbonyl compounds can readily occur in the presence of an atmospheric pressure of carbon dioxide to form the corresponding carboxylic acids with high yields, when a sacrificial anode such as magnesium or aluminum is used in the electrolysis. The electrochemical carboxylation of vinyl bromides was successfully applied for the synthesis of the precursor of nonsteroidal anti-inflammatory agents such as ibuprofen and naproxen. On the other hand, supercritical carbon dioxide （scCO2） has significant potential as an environmentally benign solvent in organic synthesis and it could be used both as a solvent and as a reagent in these electrochemical carboxylations by using a small amount of cosolvent.     

含钒无机有机杂化材料的合成、结构与性质

含钒无机有机杂化材料的结构复杂多样,在吸附、氧化还原、电化学、催化、光学、磁学以及多孔、手性材料研究等方面应用前景广阔,引起人们广泛关注。本文综述了含钒无机有机杂化材料研究的最新进展,介绍了合成含钒无机有机杂化材料的主要方法,按照有机组分与无机骨架作用的方式分类总结了含钒无机有机杂化材料的结构,介绍了其在离子交换、电化学、磁学、光学、催化等方面的应用,并展望了该类材料的研究前景和意义。     

Organic chemistry in water

Water has emerged as a versatile solvent for organic chemistry in recent years. Water as a solvent is not only inexpensive and environmentally benign, but also gives completely new reactivity. The types of organic reactions in water are broad including pericyclic reactions, reactions of carbanion equivalent, reactions of carbocation equivalent, reactions of radicals and carbenes, transition-metal catalysis, oxidations-reductions, which we discuss in this tutorial review. Aqueous organic reactions have broad applications such as synthesis of biological compounds from carbohydrates and chemical modification of biomolecules.     

Novel Methods for the Synthesis of Phosphonate Esters on the Solid Surface

Phosphonate esters are versatile intermediate in organic synthesis. These compounds have found a wide range of application in the areas of industrial, agricultural, and medicinal chemistry owing to their physical properties as well as their utility as synthesis intermediates. The synthesis of some phosphonate esters under solvent free condition was described. These methods are easy, rapid, and high-yielding reactions for the synthesis of phosphonate esters.     

Synthesis of thiophene/phenylene co‐oligomers. III . thienyl‐capped oligophenylenes

The author reports the synthesis of thienyl‐capped oligophenylenes via improved synthetic schemes. These schemes are based on either the Grignard or Suzuki coupling reaction and enable the author to obtain the target compounds at appreciably high yields. Regarding several of these compounds, their synthesis and characterization are believed to be reported for the first time. The resulting materials have been fully characterized through the nmr and ir spectroscopy. The ir analysis is particularly useful in characterizing the materials of higher molecular weight, since those materials are difficult to dissolve in organic solvents.     

Silica-based mesoporous organic-inorganic hybrid materials

Mesoporous organic-inorganic hybrid materials, a new class of materials characterized by large specific surface areas and pore sizes between 2 and 15 nm, have been obtained through the coupling of inorganic and organic components by template synthesis. The incorporation of functionalities can be achieved in three ways: by subsequent attachment of organic components onto a pure silica matrix (grafting), by simultaneous reaction of condensable inorganic silica species and silylated organic compounds (co-condensation, one-pot synthesis), and by the use of bissilylated organic precursors that lead to periodic mesoporous organosilicas (PMOs). This Review gives an overview of the preparation, properties, and potential applications of these materials in the areas of catalysis, sorption, chromatography, and the construction of systems for controlled release of active compounds, as well as molecular switches, with the main focus being on PMOs.     

多孔有机骨架材料对顺式二醇化合物富集分离的研究进展

基于在碱性环境下硼酸能与顺式二醇化合物可逆共价结合形成稳定的五元或六元环酯,而在酸性环境下环酯开环释放顺式二醇化合物这一特性,设计合成高效、高选择性、高富集性能的硼亲和材料的研究备受关注。近年来,许多研究工作者合成了各种类型的硼亲和材料,应用于高选择性富集顺式二醇化合物。金属有机骨架(MOFs)和共价有机骨架(COFs)由于具有孔径可调、高孔隙率、高比表面积、骨架结构可调和化学及热稳定性良好等特点,被广泛应用于色谱分离和样品前处理领域。为赋予MOFs和COFs材料对顺式二醇化合物的富集选择性,各种不同结构和不同种类的硼酸修饰的MOFs和COFs被合成出来。该综述主要是对近几年来80余篇源于科学引文索引关于硼酸功能化MOFs和COFs的种类、合成方法及其应用文章的总结,包括“金属配体-片段共组装”“合成后修饰”和“自下而上”的硼酸功能化多孔材料的修饰策略,以及硼酸功能化MOFs和COFs的种类,介绍了其在化学分析和生物分析领域的发展概况和应用前景,客观评价了硼酸功能化MOFs和COFs的区别和优缺点。该文旨在让研究人员能够充分了解近几年硼酸功能化多孔有机骨架材料的研究现状、掌握合成思路和方法,为其应用提供一定的理论指导和技术支撑,为加快硼酸功能化多孔有机骨架材料的商业化脚步贡献绵薄之力。     

The unusual physicochemical properties of azulene and azulene-based compounds

This review shows the unusual physicochemical properties and wide application of azulene and its derivatives. The recent synthesis strategies of kinds of substituted azulene are also listed.     

Combinatorial library of low molecular-weight organo- and hydrogelators based on glycosylated amino acid derivatives by solid-phase synthesis

A combinatorial approach for the synthesis of supramolecular gelators as new organic materials is described herein. In the course of the development of a convenient and flexible solid-phase synthesis of the artificial glycolipids, some of these compounds were accidentally found to act as low molecular-weight gelators toward organic solvents. Using this combinatorial solid-phase synthesis of glycosylated amino acetates, screening and optimization of low molecular-weight organo/hydro-gelators were efficiently carried out. We found that an N-acetyl-galactosamine-appended amino acid ester (GalNAc-aa) efficiently gelates a broad spectrum of organic solvents. More interestingly, some GalNAc-aa derivatives displayed an excellent hydrogelation capability. Transmission electron microscopy, scanning electron microscopy, confocal laser scanning microscopy, and FT-IR were used for characterization of the gel structure. It is indicated that supramolecular fibers supported by strong hydrogen-bonding networks are entangled so that the resulting spaces can immobilize a number of solvent molecules effectively. In addition, the supramolecular hydrogel consisting of GalNAc-suc-glu(O-methyl-cyc-pentyl)(2) is stable even under high salt concentrations probably due to its nonionic character and as a result, a native protein is successfully entrapped in the gel matrix without denaturation.     

Ionic liquids for the convenient synthesis of functional nanoparticles and other inorganic nanostructures

Ionic liquids are a new class of organic solvents with high polarity and a preorganized solvent structure. Very polar reactions can be carried out in these liquid in the absence of or with a controlled amount of water, and crystalline nanoparticles can be synthesized conveniently at ambient temperatures. The pronounced self-organization of the solvent is used in the synthesis of self-assembled, highly organized hybrid nanostructures with unparalleled quality. The extraordinary potential of ionic liquids in materials synthesis is described in this minireview and a physicochemical explanation is given.     

The unusual physicochemical properties of azulene and azulene-based compounds

Azulene, an isomer of naphthalene, has become one of hot chemical structures in the research field of functional materials, due to its anti-Kasha’s rule emissions and unusual physicochemical properties (e.g., photophysical, electrochemical, and photoelectrochemical properties). In the past, the synthesis of azulene-based compounds is relatively inconvenient. Recently, there have been more and more reports about the synthesis strategies of the azulene-based compounds for finely tuning the physicochemical properties. In this article, we introduce several synthetic methods for kinds of azulene-based compounds which has unusual physicochemical properties. With these convenient methods and unique physicochemical properties, azulene-based compounds can be applied into many fields such as specific bioimaging, advanced molecular switches, organic field-effect transistor (OFET), organic light emitting diode (OLED), solar cells, and so forth. And these properties are also summarized here.