Alkali Metal Adducts of Aromatic Nitro Compounds—Reactions and Use in Polymerization of Vinyl Monomers

Abstract

The reaction of alkali metals with nitrobenzene and p-nitro-toluene in THF at various molar ratios was found to lead to the formation of radical ions, dianions, and alkali metal adducts of reduction derivatives of the nitro compounds such as azo- and azoxybenzene. The anionic polymerization of styrene, methyl methacrylate, methacrylonitrile, and acrylo-nitrile by these anions was investigated. All the initiators did not polymerize styrene while the least reactive radical-anion was found to polymerize acrylonitrile completely, methacrylonitrile to a small extent, but not methyl methacrylate.

The order of reactivity of those adducts toward organic halides was similar to that found in polymerization. Metalla-tion of polynitrostyrene by lithium biphenyl solution led only to partial conversion of the nitro groups to radical-anions which were not reactive.     

Synthesis, Mechanism of Formation and Insecticidal Activity of Novel Fluorinated Organophosphorus Compounds

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The Chemistry of Fused Cyclotriazaphosphole – Synthesis,Reactions, Mechanism and Conformation

Abstract

Fused tricyclotriazaphosphole was first synthesized in our laboratory. It is a very interesting series in phosphoorus us heterochemistry.     

Regioselective Synthesis of Polycyclic and Heptagon-embedded Aromatic Compounds through a Versatile π-Extension of Aryl Halides

A versatile π-extension reaction was developed based on the three-component cross-coupling of aryl halides, 2-haloarylcarboxylic acids, and norbornadiene. The transformation is driven by the direction and subsequent decarboxylation of the carboxyl group, while norbornadiene serves as an ortho-C−H activator and ethylene synthon via a retro-Diels–Alder reaction. Comprehensive DFT calculations were performed to account for the catalytic intermediates.     

The Reactions of Sydnone Compounds

The duality in electronic effect of sydnone ring and the effect of delocalization of 4-substitutedgroup to sydnone ring are investigated by the nitration of 3-benzyl-4-phenylsydnone and 4-formyl-3-arylsydnones. Sydnones are typical mesoionic compounds and their chemical, physical and biological properties     

Borosulfates—Synthesis and Structural Chemistry of Silicate Analogue Compounds

Borosulfates are oxoanionic compounds consisting of condensed sulfur- and boron-centered tetrahedra. Hitherto, they were mostly achieved from solvothermal syntheses in SO₃-enriched sulfuric acid, or from reactions with the superacid H[B(HSO₄)₄]. The crystal structures are very similar to those of the corresponding class of silicates and their substitution variants, especially regarding the typical structural motif of corner-sharing tetrahedra. However, the borosulfates are supposed to be even more versatile, because (BO₃) units might also be part of the anionic network. The following article deals with detailed reports on the different synthesis strategies, the crystal chemistry of borosulfates in comparison to silicates, and their hitherto identified properties.     

New Visible-Light-Triggered Photocatalytic Trifluoromethylation Reactions of Carbon–Carbon Multiple Bonds and (Hetero)Aromatic Compounds

Visible-light-photocatalyzed methods employed in synthetic transformations present attractive properties such as environmentally friendly, safety, availability and excellent functional group tolerance. In this regard, research on the visible-light photocatalytic incorporation of the trifluoromethyl CF₃ moiety into organic substrates, in particular, has contributed to a clear evolution of the field of photocatalysis. Although this particular area is constantly evolving and has been reviewed, the last five years have experienced an outburst of seminal and significant photocatalytic trifluoromethylation examples that are leading the way and opening new synthetic avenues. Recent review articles on Ru- and Ir-based photocatalytic trifluoromethylation reactions have borne witness of this evolution. Although this account will show the new Ru- and Ir-based photocatalytic trifluoromethylations, Sections 2 and 3 will also illustrate other photocatalytic systems, such as organic dyes, organic semiconductors and newly-developed all-organic photocatalysts. All the known and reviewed strategies for photocatalytic trifluoromethylation reactions of olefins and (hetero)aromatic compounds will not be discussed but will be summarized in two figures (Figures 4 and 5), and new examples (2015–present) will be presented and discussed.     

Reactions of Aromatic Nitro Compounds: LXXIV. Azo Coupling of Anionic Nitroarene σ-Complexes with Aromatic Diazo Compounds. Effect of Reaction Conditions on the Yield of Nitroazobenzenes

Effect of a number of factors on the yield of nitroazobenzenes in the reaction of 4-nitro- and 4-dimethylaminobenzenediazonium tetrafluoroborates with anionic adducts derived from 1,3-dinitrobenzene was studied. Conditions were found which allow nitroazobenzenes to be prepared in 80-90% yield.     

Synthesis of Tetraarylethene Luminogens by C−H Vinylation of Aromatic Compounds with Triazenes

Tetraarylethenes are obtained by acid-induced coupling of vinyl triazenes with aromatic compounds. This new C−H activation route for the synthesis of aggregation-induced emission luminogens is simple, fast, and versatile. It allows the direct grafting of triarylethenyl groups onto a variety of aromatic compounds, including heterocycles, supramolecular hosts, biologically relevant molecules, and commercial polymers.     

Azoxy Compounds—From Synthesis to Reagents for Azoxy Group Transfer Reactions

The azoxy functional group is an important structural motif and represents the formally oxidized counterpart of the azo group. Azoxy compounds find numerous applications ranging from pharmaceuticals to functional materials, yet their synthesis remains underdeveloped with a main focus on the formation symmetric azoxy compounds. To overcome challenges in the synthesis of such unsymmetric azoxy compounds, we designed a process employing readily accessible nitroso compounds and iminoiodinanes. This method builds on the use of visible light irradiation to generate a triplet nitrene from iminoiodinanes, which is trapped by nitroso arenes to give access to sulfonyl-protected azoxy compounds with a good substrate scope and functional group tolerance. We further describe two applications of these sulfonyl-protected azoxy compounds as radical precursors in synthesis, where the whole azoxy group can be transferred and employed in C(sp³)−H functionalization of ethers or 1,2-difunctionalization of vinyl ethers. All of the reactions occurred at room temperature under visible light irradiation without the addition of any photoredox catalysts and additives. Control experiments, mechanism investigations, and DFT studies well explained the observed reactivity.     

Determination of Aromatic Hydrocarbons,Phenols, and Polycyclic Aromatic Hydrocarbons in Water by Stir bar Sorptive Extraction and Gas Chromatography–Mass Spectrometry

The paper presents procedures for stir bar sorptive extraction for selected priority substances that include polycyclic aromatic hydrocarbons, phenols, and benzene and its aromatic homologs. Three extraction and instrumental analysis procedures were developed for the determination of 16 compounds. The developed solid-phase extraction methods using a movable element had high recoveries above 70%. Extraction methods were optimized by selecting an appropriate time and temperature of the process, the sample pH, and stirring speed. The detection limits for the polycyclic aromatic hydrocarbons ranged from 0.33?µg/dm³ for naphthalene to 2.22?µg/dm³ for phenanthrene. Slightly higher limits of quantification were obtained for phenols: from 9.21?µg/dm³ for phenol to 0.51?µg/dm³ for 2,4,6-trimethylphenol. The highest limit of quantification for the tested compounds was obtained for benzene, with a value of 36.6?µg/dm³, while for toluene and ethylbenzene, the values did not exceed 2.7?µg/dm³.     

Cupric Chloride–Catalyzed Synthesis of Symmetrical Azo Compounds from Primary Aromatic Amines

Symmetrical azo compounds were synthesized from primary aromatic amines using n-BuMgBr as a base, oxygen as an oxidant, and CuCl₂ as a catalyst.     

Synthesis and Antibacterial Activity of New Cephalosporin Compounds

The fourth generation cephalosporin cefepime I exhibited potent antibacterial activity with board antibacterial spectrum1,2.Based on the structure of cefepime,we synthesized its analogs Ia having fluoro atom at the aminothiazolyl oxime moiety at the7-position of the cephem nucleus,and Ib possessing1-(2-fluoroethyl)pyrrolidium methyl group at the3-position.It was reported that cephalosporin derivatives with a quaternary ammonium moiety at the3-position of the cephem nucleus,showed enhanced ant…     

DAR Assisted Layer-by-Layer Assembly of Aromatic Compounds

A facile DAR (diphenylamine-4-diazonium-formaldehyde resin)assisted layer-by-layer (LbL) assembly of uitrathin organic film of aromatic compounds has been investigated. The muitilayer of pyrene or anthracene was fabricated through simple dipping of the glass slide into the mixed solution of DAR with the target compounds. In this method, DAR acted as an assistant compound to help the assembling of the aromatic compounds. Such a convenient deposition method not only reserves the advantages of the traditional LbL technique but also simplifies the technique and extends the effectiveness of LbL technique to small molecules without any charge.     

Synthesis and Acid-Base Properties of α-Aminophosphoryl Compounds

-Aminophosphoryl compounds of the phosphonate, phosphine oxide, and ,-bis(phosphine oxide) series and some of their thiophosphoryl analogs were synthesized. Potentiometric measurements of the pK_a of the conjugate acids revealed an insignificant effect of variation of substituents on the phosphorus, nitrogen, and -carbon atoms on the basicity of the phosphorylated amines. The latter are weak bases. Organophosphorus groups decrease the basicity of the amines by almost 5 pK _a units. The role of the hydrophobic effect and intramolecular H-bonding in the obtained substances was discussed.     

Reactions of β-Pinene with Aromatic Aldehydes

Aromatic aldehydes add to β-pinene under Lewis acid catalyzed Prins reaction conditions and yield the corresponding homoallylic alcohols. The reactions proceed in poor yield when electron donating substituents are present on the aromatic ring.     

Microwave Irradiated Reactions of N-Phenacylpyridinium Chloride with Aromatic Aldehydes and Ketones

Pyridinium cations show a great variety of synthetic applications,due to the aromatic character of the pyridine heterocycle, to its basicity, and the electron-attracting influence of the nitrogen atom1-3. N-phenacylpyridium bromide in the presence of base…     

Design and Synthesis of Glycosylated Aromatic Nitrogen Mustard Derivatives

Antibody-directed enzyme prodrug therapy(ADEPT) is a new strategy for the treatment of cancer that has arisen in recent twenty years, the main merits of which are that it can improve the selectivity of anticancer drugs and reduce the side effects in remote tissue. In the present study, two prodrugs-glycosylated aromatic nitrogen mustard derivatives were synthesized. Glucose and lactose were converted into glycosyl donors-trichloroacetimidate; the obtained glycosyl donors were glycosylated with p-nitrophenol(glycosyl donors) to form β-glucosyl p-nitrobenzene and β-lactosyl p-nitrobenzene that were protected by acetyl in a stereoselective manner; the two products were reduced by zinc dust and then treated with ethylene oxide, afforded two glycosylated nitrogen mustard derivatives that were protected by acetyl; the last step was to deacetylate and then afforded the two target compounds that could be used as prodrugs of ADEPT for further Anti-tumor research.     

Ammonium Sulphate—Magnesium Promoted Selective Reduction of Aromatic Nitro Compounds

Various nitroarenes and 2,1,3-benznooxadiazole-1-oxides were selectively and rapidly reduces to their corresponding amino and diamino compounds respectively in high yields using (NH₄SO₄-Mg/A1/Bi, a new reduction system.     

Synthesis of Related Compounds of Carotenoid

类胡萝卜素是一类奇特的色素，由高等植物和微生物光化学合成，作为防止单线氧通过光敏反应产生危害的必要基团，类胡萝卜素最近受到了关注。类胡萝卜素联于富勒烯上，既可大大增加在可见光区域光诱导电子转移的有效吸收断面，又可抑制富勒烯敏化单线氧的危害能力。合成了类胡萝卜素的相关化合物，报道的某些反应条件先进且简洁。