Synthesis,Electrochemistry, and Hydrolysis of Anthraquinone Derivatives

Anthraquinone (AQ) derivatives, including members of the anthraquinone imide (AQI) family, have been synthesized to afford good candidates for electron-transfer studies in DNA. Electron-withdrawing groups on the AQ ring give a less negative reduction potential, as desired. As expected, the AQI derivatives have less negative reduction potentials than AQ derivatives. The AQI ring system has a half-life for hydrolysis of about 75 min in a 3:7 MeCN and 0.005 M K₂CO₃ in MeOH.     

Furfuroxides of lanthanum,praseodymium, neodymium,and samarium

Ln(R)₃, Ln(R)₂(OPrⁱ), and Ln(R)(OPrⁱ)₂ (where Ln = La, Pr, Nd, and Sm; R = deprotonated furfuryl alcohol, RH) were prepared from lanthanide isopropoxide and furfuryl alcohol in 1:3, 1:2 and 1:1 stoichiometric ratios respectively in anhydrous benzene under reflux. Ln(R)₂-(OPrⁱ) and Ln(R)(OPrⁱ)₂ were also obtained at room temperature. The isopropoxy group(s) of these derivatives were replaced by tertiary butoxy group(s) during the alcohol exchange reactions with tertiary butanol. All these derivatives are soluble in benzene except the tertiary butoxy derivatives which are only sparingly soluble. However, they become insoluble on standing. These furfuroxides did not distil at ～300°C/10² torr but decomposed. Isopropoxy/butoxy furfuroxides were characterized by the elemental analysis and also by estimating the liberated isopropanol. The i.r. spectra of Ln(R)₃ clearly supports the presence of furfuroxide groups in these derivatives.     

Mercury derivatives of polyhedral boranes,carboranes, and metallacarboranes

The review concerns the synthesis, structure, and chemical transformations of mercury derivatives of various polyhedral boron hydrides (carboranes, metallacarboranes, and boranes) and covers a period of time since the pioneering studies of Prof. V. I. Bregadze on chemistry of C- and B-substituted derivatives of icosahedral carboranes C₂B₁₀H₁₂ up to date. The emphasis is placed on recent results obtained in this field, in particular, Hg-promoted substitution in nido-carboranes as well as the synthesis and properties of mercury derivatives of monocarbon carborane anion [CB₁₁H₁₂]^–.

     

Mass spectrometry of the triethylsilyl,tri-n-propylsilyl and tri-n-butylsilyl derivatives of some alcohols,steroids and cannabinoids

The 25 _eV mass spectra of the trialkylsilyl (R = Et, Pr, Bu) derivatives of several alcohols, steroids and cannabinoids are compared with those of the corresponding trimethylsilyl (TMS) derivatives. Abundant ions produced by elimination of one of the alkyl groups characterize most of the spectra. Although the presence of such ions is advantageous in certain cases, such as for single ion monitoring studies, the spectra usually contain fewer ions of diagnostic use than the spectra of corresponding TMS derivatives. Successive elimination of C_nH_2n fragments is also a feature of these spectra.     

Theoretical investigations on structure,density, detonation properties,and sensitivity of the derivatives of PYX

The ? NH₂, ? NO₂, ? N₃, ? NHNO₂, and ? ONO₂ substitution derivatives of PYX (2,6‐bis(picrylamino)‐3,5‐dinitropyridine) were studied at the B3LYP/6‐31G** level of density functional theory. The sublimation enthalpies and heats of formation (HOFs) in gas phase and solid state of these compounds were calculated. The theoretical predicted density (ρ), detonation pressure (P), and detonation velocity (D) showed that these derivatives have better detonation performance than PYX. The effects of substituent groups on HOF, ρ, P, and D were discussed. The order of contribution of various groups to P and D was ? ONO₂ > ? NO₂ > ? NHNO₂ > ? N₃ > ? NH₂. Sensitivity was evaluated using the frontier orbital energies, bond orders, bond dissociation enthalpies (BDEs), and characteristic heights (h₅₀). The trigger bonds in the pyrolysis process for these PYX derivatives may be Ring‐NO₂, NH? NO₂, or O? NO₂ varying with the substituents. The h₅₀ of most compounds are larger than that of CL‐20, and those of ? NH₂, ? NO₂, and most ? ONO₂ derivatives are larger than that of RDX. The BDEs of the trigger bonds of all but the ? ONO₂ derivatives are sufficiently large. Taking both detonation performance and sensitivity into consideration, some derivatives of PYX may be good candidates of explosives. © 2012 Wiley Periodicals, Inc.     

Theoretical studies on heats of formation,detonation properties,and bond dissociation energies of monofurazan derivatives

The heats of formation (HOFs) for a series of monofurazan derivatives were calculated by using density functional theory. It is found that the ? CN or ? N₃ group plays a very important role in increasing the HOF values of the furazan derivatives. The detonation velocities and detonation pressures of the furazan derivatives are evaluated at two different levels. The results show that the ? NF₂ group is very helpful for enhancing the detonation performance for the furazan derivatives, but the case is quite the contrary for the ? CH₃ group. An analysis of the bond dissociation energies and bond orders for the weakest bonds indicate that the substitutions of ? CN group are favorable and enhances the thermal stability of the furazan derivatives, but the ? NO₂ groups produce opposite effects. These results provide basic information for the molecular design of novel high‐energy density materials. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

CoFe2O4@SiO2-PA-CC-guanidine nanoparticles: A novel,efficient, and recyclable catalyst for the synthesis of 3,5-disubstituted-2,6-dicyanoaniline derivatives

A new and efficient procedure for the synthesis of 3,5-disubstituted-2,6-dicyanoaniline derivatives by CoFe₂O₄@SiO₂-PA-CC-guanidine magnetic nanoparticles (MNPs) was reported. 3,5-Disubstituted-2,6-dicyanoaniline derivatives were synthesized from malononitrile, aldehydes, and β-nitrostyrene derivatives in good yields. MNPs used for the synthesis of aniline derivatives were easy to recover and reuse. The CoFe₂O₄@SiO₂-PA-CC-guanidine MNPs were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, and vibration sample magnetometry techniques.     

Reaction, identification, and fluorescence of aminoperfluorophenazines

Perfluorophenazine regiospecifically reacted with monoalkyl-, dialkyl-, and arylamines to afford the corresponding 2-amino-substituted derivatives. 2-(Ethylamino)- and 2-(diethylamino)perfluorophenazine reacted with another molar amount of ethylamine and diethylamine to preferentially provide the 2,7-disubstituted derivatives, respectively. Perfluoro(2,7-dimethylphenazine) was allowed to react with ethylamine to give the 1-ethylamino derivative. These regiospecific reactions were explained by the density functional theory (DFT) calculations. Perfluorophenazine reacted with ethylenediamine to afford the 2,3-cyclized and N,N′-bis(2-perfluorophenazinyl) derivatives. These amino-substituted products showed UV-vis absorption (λ_max) and fluorescence maxima (F_max) in the range of 439-536 and 524-613 nm in hexane, respectively. Some of them exhibit intense fluorescence.     

Anodic benzylic fluorination of toluene,ethylbenzene, and cumene derivatives

Anodic fluorination of toluene, ethylbenzene, and cumene derivatives was comparatively studied using Et₄NF-4HF as a supporting electrolyte and a fluorine source. Anodic benzylic fluorination occurred except for some cumene derivatives and the yields of the fluorinated products greatly depended on the stability of benzylic cations.     

Regioselective electrophilic trifluoromethylation of indolines, oxindoles and indoles in superacid

Treatment of indolines and N-acylindoles with HF/SbF₅/CCl₄ yields 6-trifluoro derivatives (indole numbering) whereas indoles and oxindoles give the 5-trifluoro derivatives in good yield.     

Synthesis of Difluoroglycine Derivatives from Amines,Difluorocarbene, and CO2: Computational Design,Scope, and Applications

A three-component reaction (3CR) for the synthesis of difluoroglycine derivatives has been achieved by using amines, difluorocarbene (generated in situ), and the abundant, inexpensive, and nontoxic C₁ source CO₂. Various tert-amines and pyridine, (iso)quinoline, imidazole, thiazole, and pyrazole derivatives were incorporated, and the corresponding products were isolated in solid form without purification by column chromatography on silica gel. Detailed reaction profiles of the 3CR were obtained from computational analysis using DFT calculations, and the results critically suggest that simple ammonia is not applicable to this reaction. In addition, as strongly supported by computational predictions, a new reagent that can generate difluorocarbene at 0 °C without any additives was discovered. Finally, radical substitution reactions of the obtained difluoroglycine derivatives under photoredox conditions, as well as a synthetic application as an N-heterocyclic carbene ligand are shown.     

Synthesis,Photophysical and Electronic Properties of Mono-, Di-, and Tri-Amino-Substituted Ortho-Perylenes,and Comparison to the Tetra-Substituted Derivative

We synthesized a series of new mono-, di-, tri- and tetra-substituted perylene derivatives with strong bis(para-methoxyphenyl)amine (DPA) donors at the uncommon 2,5,8,11-positions. The properties of our new donor-substituted perylenes were studied in detail to establish a structure-property relationship. Interesting trends and unusual properties are observed for this series of new perylene derivatives, such as a decreasing charge transfer (CT) character with increasing number of DPA moieties and individual reversible oxidations for each DPA moiety. Thus, (DPA)-Per possesses one reversible oxidation while (DPA)₄-Per has four. The mono- and di-substituted derivatives display unusually large Stokes shifts not previously reported for perylenes. Furthermore, transient absorption measurements of the new derivatives reveal an excited state with lifetimes of several hundred microseconds, which sensitizes singlet oxygen with quantum yields of up to 0.83.     

Syntheses,silylation, characterization,and antimicrobial and antifertility activities of organoboron derivatives of some bioactive monofunctional bidentate semicarbazones

Some new mononuclear organoboron derivatives of the type PhBL^1–5(OH) ( 1a – 1e ) were synthesized by the reaction of PhB(OH)₂ and LH (LH = OC(NH₂)NH:NC(CH₃)₄C₆H₄R, where R = H (L¹H); CH₃(L²H); OCH₃(L³H); Cl (L⁴H); Br (L⁵H)) in 1:1 molar ratio in refluxing tetrahydrofuran (THF). This was followed by the reactions of PhBL^1–5(OH) with NH(SiMe₃)₂ in 2:1 molar ratio in THF to yield new heterodinuclear derivatives of the type PhBL^1–5(OSiMe₃) ( 2a – 2e ). All these newly synthesized complexes were characterized using elemental analyses and their probable structure was proposed on the basis of infrared, ¹H NMR, ¹³C NMR, ¹¹B NMR and ²⁹Si NMR spectral data and mass spectrometry. Semicarbazone ligands and their corresponding mono‐ and heterodinuclear boron derivatives were screened against pathogenic bacteria (E. coli and P. aeruginosa) and fungi (A. niger and P. peniculosum) to examine their antimicrobial activities. Representative compounds of each series of mono‐ and heterodinuclear boron derivatives and a ligand were screened for their antifertility activity on male adult Wistar rats.     

Dynamic polarizabilities and raman intensities of CO,N2, HCl and Cl2

We have performed first-order (identical to coupled Hartree-Fock) and second-order polarization propagator calculations of the dynamic dipole polarizability tensor for the CO, N₂, HCl and Cl₂ molecules. The derivatives of the polarizability tensor with respect to the internuclear distance at the equilibrium internuclear separation are compared with related data obtained from non-resonance Raman spectra. In most cases the correlation contributions beyond the coupled Hartree-Fock approximation have a more pronounced effect on the derivatives of the polarizability tensor than on the polarizability tensor itself. At both levels of approximation we found that derivatives of the dynamic polarizability tensor with respect to the internuclear separation increase with 10–15% for variation of the frequency from 0 (static polarizability) to about 28500 cm^?1. The depolarization ratio calculated from the polarizability derivatives shows no variation with frequency in the same frequency range.     

Halogen derivatives of triphenylphosphine,triphenylarsine and triphenylstibine substituted molybdenum carbonyls

Summary Halogen oxidation of several LMo(CO)s andcis-L₂Mo(CO)₄ (L = Ph₃P₁Ph₃As and Ph₃Sb) derivatives has been studied. The LMo(CO)₅ complexes react with halogens to give hexacoordinate LMo(CO)₃ X₂ (X = Cl, Br or I) derivatives which are of very rare occurrence. Similar reactions withcis-L₂Mo(CO)₄ give heptacoordinate L₂Mo(CO)₃X₂ derivatives. The complexes have been characterised by elemental analysis, i.r. and conductivity measurements.     

Syntheses,characterization, antibacterial activity and molecular modelling of phenylantimony(III) heteroleptic derivatives containing substituted oximes and piperidine dithiocarbamate

Six new heteroleptic phenylantimony(III) derivatives containing substituted oximes and dithiocarbamate moieties of the type (where R = ─C₆H₅, X = ─CH₃ ( 2a ); R = ─C₆H₄CH₃, X = ─CH₃ ( 2b ); R = ─C₆H₄Cl, X = ─CH₃ ( 2c ); R = ─C₆H₄Br, X = ─CH₃ ( 2d ); R = ─C₆H₄OH, X = ─H ( 2e ); R(X)C = ( 2f )) have been synthesized by the reactions of phenylantimony(III) dichloride with the sodium salt of substituted oximes and dithiocarbamate moiety in unimolar ratio with stirring in dichloromethane. All these newly synthesized derivatives have been characterized using physicochemical and elemental analyses. Structures have been proposed on the basis of infrared, ¹H NMR, ¹³C NMR and LC–MS spectral studies and molecular modelling. In these derivatives the oxime behaves in an unidentate manner whereas dithiocarbamate behaves in a monofunctional anisobidentate manner. Pseudo‐trigonal bipyramidal (ψ‐TBP) geometry around the antimony metal centre is proposed for these phenylantimony(III) heteroleptic derivatives. The geometry of a representative complex has been optimized through molecular modelling. These newly synthesized derivatives were screened against Bacillus subtilis (Gram‐positive) and Escherichia coli (Gram‐negative) bacteria to evaluate their antibacterial potential. The structure–activity relationship for antibacterial activity among the four derivatives 2a , 2c , 2e and 2f is discussed.     

Synthesis,cytotoxic assessment,and molecular docking studies of 2,6-diaryl-substituted pyridine and 3,4- dihydropyrimidine-2(1H)-one scaffolds

Cancer is one of the main global health problems. In order to develop novel antitumor agents, we synthesized 3,4-dihydropyrimidine-2(1H)-one (DHPM) and 2,6-diaryl-substituted pyridine derivatives as potential antitumor structures and evaluated their cytotoxic effects against several cancer cell lines. An easy and convenient method is reported for the synthesis of these derivatives, employing cobalt ferrite (CoFe ₂ O ₄ @SiO ₂ -SO ₃ H) magnetic nanoparticles under microwave irradiation and solvent-free conditions. The structural characteristics of the prepared nanocatalyst were investigated by FTIR, XRD, SEM, and TGA techniques. In vitro cytotoxic effects of the synthesized products were assessed against the human breast adenocarcinoma cell line (MCF-7), gastric adenocarcinoma (AGS), and human embryonic kidney (HEK293) cells via MTT assay. The results indicated that compound 4r (DHPM derivative) was the most toxic molecule against the MCF-7 cell line (IC ₅₀ of 0.17 μg/mL). Moreover, compounds 4j and 4r (DHPM derivatives) showed excellent cytotoxic activities against the AGS cell line, with an IC ₅₀ of 4.90 and 4.97 μg/mL, respectively. Although they are pyridine derivatives, compounds 5g and 5m were more active against the MCF-7 cell line. Results showed that the candidate compounds exhibited low cytotoxicity against HEK293 cells. The kinesin Eg5 inhibitory potential of the candidate compounds was evaluated by molecular docking. The docking results showed that, among the pyridine derivatives, compound 5m had the most free energy of binding (–9.52 kcal/mol) and lowest Ki (0.105 μM), and among the pyrimidine derivatives, compound 4r had the most free energy of binding (–7.67 kcal/mol) and lowest Ki (2.39 μM). Ligand-enzyme affinity maps showed that compounds 4r and 5m had the potential to interact with the Eg5 binding site via H-bond interactions to GLU116 and GLY117 residues. The results of our study strongly suggest that DHPM and pyridine derivatives inhibit important tumorigenic features of breast and gastric cancer cells. Our results may be helpful in the further design of DHPMs and pyridine derivatives as potential anticancer agents.     

Approaches to the Synthesis of Perfluoroalkyl-Modified Carbohydrates and Derivatives: Thiosugars,Iminosugars, and Tetrahydro(thio)pyrans

Fluoroalkyl-substituted carbohydrates play relevant roles in diverse areas such as supramolecular chemistry, glycoconjugation, liquid crystals, and surfactants, with direct applications as wetting, antifreeze, and coating agents. In light of these promising applications, new methodologies for the late-stage incorporation of fluoroalkyl R_F groups into carbohydrates and derivatives are herein presented as they are relevant to the synthetic carbohydrate community. Previously reviewed protocols for the installation of R_F groups onto carbohydrates and derivatives will be succinctly summarized in the light of the new achievements. Fluoroalkyl-substituted iminosugars, on the other hand, are also interesting glycomimetic derivatives with prominent roles as glycosidases and glycosyltransferases inhibitors, as has recently been demonstrated. Also, they positively contribute to the study of sugar–protein interactions and enzyme mechanisms. New advances in the syntheses of fluoroalkyl-substituted iminosugars will also be presented here.     

Synthesis, luminescence properties, and theoretical insights of N-alkyl- or N,N-dialkyl-pyrene-1-carboxamide

We report the synthesis and photophysical properties of N-alkyl- or N,N-dialkyl-pyrene-1-carboxamide. These derivatives, as well as pyrene, exhibited blue emission. N-Alkyl-type derivatives exhibited strong fluorescence emission (Φ_fl = 0.61 in EtOH) in both nonpolar and polar solvents. On the other hand, N,N-dialkyl-type derivatives showed weak fluorescence emission (Φ_fl <0.01) due to vibrational deactivation. However, in highly viscous solvents such as glycerin, the quantum efficiencies of N-alkyl-type (Φ_fl = 0.91) and N,N-dialkyl-type (Φ_fl = 0.082) derivatives were increased. We also investigated the fluorescence mechanism of these compounds using time-dependent density-functional theory (TD-DFT). From these results, we find that highly fluorescent pyrene-1-carboxamide derivatives can be designed by introducing an appropriate functional group at the nitrogen atom of the amide. Thus, N,N-dialkyl-type pyrene-1-carboxamide has considerable potential for use in applications such as environmental response sensors and probes.     

Thermal,IR, cation exchange and adsorption studies of new synthetic zeolite (Deolite)

Cadmium(II) and Pb(II) ions replace the sodium(I) ion in commercial molecular sieve deolite. These exchanged derivatives have been interacted with adsorbates like CO₂ and NH₃ and the new exchanged and adsorbed derivatives characterized by their TG and IR spectral data. It is concluded that deolite can be effectively employed for removal of hazardous Cd(II) and Pb(II) ions as well as the gaseous adsorbates.