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One or more nitrogen‐containing molecules constitute an important class of heterocyclic compounds in organic synthesis, due to their reactivity and their presence in many molecules of natural, human or plant origin. These nitrogenous heterocycles play an essential role in various scientific domains, whether they are chemical, biological or pharmacological. N‐heterocycles are the privileged source of many research topics developed by several groups of researchers. Thus, different methods have been developed to access these heterocyclic compounds with nitrogenous rings, such as triazolopyrimidines. In this review, a bibliographic study summarizing the pharmacological importance of the triazolo[1,5‐a]pyrimidine ring, the different synthesis routes of these derivatives as well as their reactivity was reported. [ABSTRACT FROM AUTHOR]

Surface analysis was used to study the dynamics of the martensitic transformation on macro- and mesoscopic scales. The chemical state, morphology, and magnetic and surface structure were monitored at particular stages of the phase transition. At room temperature, the martensitic phase of the Ni49.7Mn29.1Ga21.2 (100) single crystal exhibited macroscopic a/c twinning and a corresponding magnetic domain structure characterized by magnetization vector in and out of the surface plane. Induced by radiation heating, the transformation from martensite to austenite takes place separately at the surface and in the bulk. Its dynamics depend on the history of the sample treatment which affects the crystallographic orientation of twins and minor changes of the surface stoichiometry. The interfaces (twin planes) between twin variants in the martensitic phase were noticeable also in the austenitic phase, thanks to the shape memory effect of this material. [ABSTRACT FROM AUTHOR]

Molecular beam epitaxy growth and basic physical properties of quaternary AlInGaN layers, sufficiently thick for construction of electron blocking layers (EBL), embedded in ternary InGaN layers are presented. Transmission electron microscopy (TEM) measurement revealed good crystallographic structure and compositional uniformity of the quaternary layers contained in other nitride layers, which are typical for construction of nitride based devices. The AlInGaN layer was epitaxially compatible to InGaN matrix, strained, and no strain related dislocation creation was observed. The strain penetrated for limited depth, below 3 nm, even for relatively high content of indium (7%). For lower indium content (0.6%), the strain was below the detection limit by TEM strain analysis. The structures containing quaternary AlInGaN layers were studied by time dependent photoluminescence (PL) at different temperatures and excitation powers. It was shown that PL spectra contain three peaks: high energy donor bound exciton peak from the bulk GaN (DX GaN) and the two peaks (A and B) from InGaN layers. No emission from quaternary AlInGaN layers was observed. An accumulation of electrons on the EBL interface in high-In sample and formation of 2D electron gas (2DEG) was detected. The dynamics of 2DEG was studied by time resolved luminescence revealing strong dependence of emission energy on the 2DEG concentration. Theoretical calculations as well as power-dependence and temperature-dependence analysis showed the importance of electric field inside the structure. At the interface, the field was screened by carriers and could be changed by illumination. From these measurements, the dynamics of electric field was described as the discharge of carriers accumulated on the EBL. [ABSTRACT FROM AUTHOR]

Undoped and N-doped ZnO nanocomposites are produced by a simple and low-cost mechanochemical method. The characterizations of all nanocomposites are examined by X-ray diffraction (XRD), Fourier transform-infrared (FT-IR), scanning electron microscopy (SEM) and UV-Vis-NIR spectroscopy. The XRD measurements show that the crystal sizes of undoped and N-doped ZnO nanocomposites are ~29 and ~28 nm, respectively. The UV-Vis-NIR spectroscopy results illustrate that the transmittance of the 7 wt% N/ZnO in the visible and infrared region is a bit higher than the undoped ZnO. The photocatalytic activity of undoped and N-doped ZnO nanocomposites is investigated for the degradation of Methylene Blue (MB) and Rhodamine B (RhB) aqueous solution with direct sunlight irradiation. The photocatalytic degradation percentages with 7 wt% N/ZnO for 5 and 10 mg/L MB dye solution are found to be 93.70% and 98.11%, respectively, whereas 78.40% and 89.15% degradation percentages are found with undoped ZnO, after 3 h sunlight irradiation. Under the same conditions, the photocatalytic degradation value of RhB dye (10 mg/L) solution is measured to be 86.21% for 7 wt% N/ZnO and 64.75% for undoped ZnO. The N-doped ZnO nanocomposites are found to exhibit enhanced photocatalytic performance for both dyes’ degradation under sunlight irradiation in comparison with the undoped ZnO. Therefore, the photocatalytic degradation treatment of wastewater including dye pollutants with sunlight is an easy and simple technique, and cost-effective. [ABSTRACT FROM AUTHOR]

In order to screen the candidate genes of Fenneropenaeus chinensis related to low-temperature tolerance, this research takes juvenile prawns of F. chinensis (P40) in low temperature stress group (4°C) and normal temperature group (18°C) as experimental materials. The results showed that a total of 127,939 Unigenes with average length of 1,190 bp were obtained by assembly, of which 46% were annotated in the Nr database. A total of 1,698 differentially expressed genes were screened by differential gene expression analysis, of which 920 genes showed up-regulated expression and 778 genes showed down-regulated expression. Both GO and KEGG enrichment analysis revealed that differentially expressed genes were enriched in spliceosomes, ribosomes, bile secretion, ABC transport pathways, and cellular nitrogen compound synthesis. A further in-depth analysis obtained 8 genes that may be associated with low-temperature traits of F. chinensis. Five of them displayed up-regulated expression, including ATP-binding cassette protein C, acid ceramidase, glutathione transferase, C-type lectin and heat shock protein HSP70. The remaining three genes, γ-butyl betaine hydroxylase, β-hexosaminidase A and long chain fatty acid-CoA ligase displayed down-regulated expression. Eight differentially expressed genes were randomly selected and the real time RT-PCR verification showed that their expression levels were consistent with the sequencing results, demonstrating the accuracy of the sequencing results. The results of this study provide basic data for revealing the molecular mechanisms of F. chinensis in response to low temperature stress and the molecular assisted breeding of F. chinensis in low temperature. [ABSTRACT FROM AUTHOR]

Double Mannich bases obtained from α-indanone and α-tetralone contain a bis-β-amino ketone fragment and are promising intermediate compounds for the synthesis of nitrogen heterocycles via reactions with dimethyl acetylenedicarboxylate and methyl propiolate. The products of these reactions are determined by the activated acetylene structure. The reaction begins with attack of the activated acetylenic compound on the tertiary nitrogen atom of the Mannich base to give 1,3-zwitterionic intermediate. The subsequent domino reaction is driven by neutralization of the charge on the nitrogen atom through formation and/or rupture of several C–C bonds. Intramolecular attack of the negatively charged center of the 1,3-zwitterion derived from the indanone base and dimethyl acetylenedicarboxylate on the carbonyl carbon atom of the indanone fragment is followed by domino process, leading to the formation of dimethyl 2-methyl-1,2-dihydro-9H-indeno[2,1-c]-pyridine-3,4-dicarboxylate. The reaction of the same Mannich base with methyl propiolate involves 1,3-sigma-tropic rearrangement with neutralization of the positive charge on the nitrogen atom in the intermediate structure and negative charge transfer to the carbonyl oxygen atom. Next follows aldolization/crotonization with the second β-amino carbonyl fragment to produce methyl 2′-methyl-1-oxo-1,1′,2′,3,5′,11′-hexahydrospiro-[indene-2,6′-indeno[2,1-c]azocine]-4′-carboxylate. One more reaction direction leading to the formation of linear enamines via intramolecular proton migration from the indan fragment to the C-anionic center in the 1,3-zwitterion with simultaneous elimination of 2-methylideneindan-1-one has been revealed by HPLC/MS analysis of both reaction mixtures. Such enamines, methyl 3-{methyl[(1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)methyl]amino}prop-2-enoate and dimethyl (2Z)-2-{methyl[(1-oxo-1,2,3,4-tetrahydronaphthalen-2-yl)-methyl]amino}but-2-enedioate, were isolated in the reactions of activated acetylenic compounds with the Mannich base derived from tetralone. Previously described synthesis of 1-azabicyclo[3.3.1]nonanes from Mannich bases has been reproduced, and detailed analysis of the reaction mixtures has revealed products resulting from elimination of one alkylaryl group from the zwitterionic intermediate. The formation of linear enamines, dimethyl (2Z)-2-[methyl(3-oxo-3-phenylpropyl)amino]but-2-enedioate and dimethyl (2Z)-2-{methyl-[3-oxo-3-(thiophen-2-yl)propyl]amino}but-2-enediate, suggests facile retro-aldol reaction of 3-aroyl-4-aryl-1-methylpiperidin-4-ols as the necessary step. PASS online predicted diverse biological activities of all newly synthesized compounds with a probability of 65–80%. [ABSTRACT FROM AUTHOR]

Abstract In-situ synthesis of C 3 N 4 on the carbon fiber surface was reported for enhancing interfacial properties of carbon fiber reinforced epoxy resin composite. The formed C 3 N 4 on the carbon fiber surface can greatly increase the roughness, polar functional groups and wettability of carbon fiber surface, thereby leading to significant enhancement of interfacial properties of composites. After modification, interlaminar shear strength (ILSS) and interfacial shear strength (IFSS) of carbon fibers composites are increased from 44.3 to 60.7 MPa and from 43.1 to 75.9 MPa, respectively. Moreover, the surface free energy of carbon fibers is increased by 65.6%. The improved interfacial properties endow carbon fiber composites with better mechanical properties, leading to an increased tensile strength of composites from 1063 to 1279 MPa and total absorbed energy of impact experiment from 1.22 to 1.75 J. Meanwhile, the dynamic mechanical properties and hydrothermal aging resistance are also enhanced significantly. The storage modulus increases from 64.3 to 74.1 GPa. The markedly enhancement of interfacial mechanical properties and mechanical properties could be attributed to the improved resin wettability, enhanced mechanical interlocking and increased chemical bonding induced by the existence of C 3 N 4 on the carbon fiber surface. [ABSTRACT FROM AUTHOR]

In this study, we focus on the preparation of a nanocarbon and ZnO based hybrid with the incorporation of nitrogen to form diamond nanowires (N-DNW) and ZnO nanotubes (ZNTs) using simple routes. The potential of the carbon enriched hybrid material for application as UV photodetectors (PDs) or electron field emitters (EFE) is evaluated. Firstly, the ZNT/N-DNW based UV PDs with their multifinger anode cathode configuration offer a high photoresponse ratio of 1930, which is superior to that of bare ZnO PDs (12.6). The obtained photoresponse values also have greatly enhanced stability and photoresponsivity of 49.2 AW −1 compared with the ZNRs (0.4 AW −1 ). In addition, EFE study of the ZNT/N-DNW hybrid device reveals an electron emission at voltage as low as 2.59 V/μm with a high current density of 5.2 mA/cm 2 . This striking improvement in the multifunctional measurements of the annealed ZNT/N-DNW - based device can be attributed to its fast adsorptivity and oxygen vacancies. Moreover, the respective band model of this hybrid structure was also proposed to demonstrate its heterostructure. Furthermore, the outstanding feature of this combination are its cost-effective synthesis routes, reliability, and long-term stability, which makes it a potential applicant for multifunctional opto-electronic devices. [ABSTRACT FROM AUTHOR]

Nitrogen-doped three-dimensional porous graphene frameworks (NGAs) are fabricated through a unique strategy of adopting the supramolecular assembly-assisted method with GO as building block, and supramolecular aggregate of self-assembled melamine and cyanuric acid as not only a “spacer” to suppress the re-stacking of graphene nanosheets but a self-sacrificial pore-forming agent as well as a nitrogen source leading to simultaneous N-doping. Supramolecular aggregates function as the structure-directing agent playing a vital role in generating the loose porous and free-stacking structure and guiding the formation of unique 3D architecture. The resulting metal-free NGA products possess high specific surface area, porous structure and free-stacking properties, and exhibit enhanced ORR performance in terms of positive half-wave potential which is only ∼43 mV lower than that of a commercial Pt/C, four-electron-transfer process, good durability and outstanding methanol poisoning tolerance. Besides, it also performs as a good support for Pt particles. Consequently, Pt/NGA catalyst displays impressive catalytic activity and stability towards efficient methanol electrooxidation reaction. This simple and robust synthetic strategy of 3D N-doped graphene has put forward a new prospect for rational synthesis of heteroatoms doped carbon materials for sustainable energy conversion applications. [ABSTRACT FROM AUTHOR]

Specific features of the synthesis of polycyclic crown ethers dibenzo-18-crown-6 and dibenzo-24-crown-8 and their dinitro and diamino derivatives have been studied. A mixture of isomers of dibenzocrown ether derivatives was obtained and separated. The spectral and thermal characteristics of the synthesized compounds and the kinetics of synthesis of dibenzo-24-crown-8 by the two-component condensation of pyrocatechol with 1-chloro-2-[2-(2-chloroethoxy)ethoxy]ethane in an alcoholic medium in the presence of a KOH template agent were studied. [ABSTRACT FROM AUTHOR]

Abstract: A nitrogen‐rich compound, ReN8⋅x N2, was synthesized by a direct reaction between rhenium and nitrogen at high pressure and high temperature in a laser‐heated diamond anvil cell. Single‐crystal X‐ray diffraction revealed that the crystal structure, which is based on the ReN8 framework, has rectangular‐shaped channels that accommodate nitrogen molecules. Thus, despite a very high synthesis pressure, exceeding 100 GPa, ReN8⋅x N2 is an inclusion compound. The amount of trapped nitrogen (x) depends on the synthesis conditions. The polydiazenediyl chains [−N=N−]∞ that constitute the framework have not been previously observed in any compound. Ab initio calculations on ReN8⋅x N2 provide strong support for the experimental results and conclusions. [ABSTRACT FROM AUTHOR]

Rational synthesis and development of earth-abundant materials with efficient electrocatalytic activity and stability for water splitting is a critical but challenging step for sustainable energy application. Herein, a family of bimetal (CoFe, CoCu, CoNi) embedded nitrogen-doped carbon frameworks is developed through a facile and simple thermal conversion strategy of metal-doped zeolitic imidazolate frameworks. Thanks to collaborative superiorities of abundant M-N-C species, modulation action of secondary metal, cobalt-based electroactive phases, template effect of MOFs and unique porous structure, bimetal embedded nitrogen-doped carbon frameworks materials manifest good oxygen and hydrogen evolution catalytic activity. Especially, after modulating the species and molar ratio of metal sources, optimal Co 0.75 Fe 0.25 nitrogen-doped carbon framework catalyst just requires a low overpotential of 303 mV to achieve 10 mA cm −2 with a low Tafel slope (39.49 mV dec −1 ) for oxygen evolution reaction, which even surpasses that of commercial RuO 2 . In addition, the optimal catalyst can function as an efficient bifunctional electrocatalyst for overall water splitting with satisfying activity and stability. This development offers an attractive direction for the rational design and fabrication of porous carbon materials for electrochemical energy applications. [ABSTRACT FROM AUTHOR]

A Cu(ii) coordination polymer, [Cu(tza)2]n (Htza, tetrazole-1-acetic acid), was investigated as an efficient water oxidation catalyst in the well-established Ru(bpy)32+/S2O82− (bpy = 2,2′-bipyridine) photocatalytic system. The turnover frequency (TOF) was measured to be 1.68 s−1, which is the highest among all reported copper-based photocatalytic water oxidation systems. [ABSTRACT FROM AUTHOR]

Nitrogen-doped hollow carbon spheres with a well-defined shape, uniform diameter, and high doping concentration (11 at%) are synthesized via space-confined thermal decomposition of a single source precursor zinc carbodiimide, which can serve as both carbon and nitrogen sources and also a self-template. [ABSTRACT FROM AUTHOR]

Nitrogen doped hollow carbon spheres (NHCSs) with tunable surface morphology have been prepared through one-pot carbonization method by using melamine-formaldehyde spheres as template and resorcinol-based resin as carbon precursor in ethanol-water solution. Well-dispersed NHCSs with particle size of 800 nm were obtained and the surface of NHCSs turn from smooth to tough, wrinkled, and finally concave by increasing the ethanol concentration. The fabricated NHCSs possessed high nitrogen content (3.99–4.83%) and hierarchical micro-dual mesoporous structure with surface area range of 265–405 m 2  g −1 and total pore volume of 0.18–0.29 cm 3  g −1 , which contributed to high specific capacitance, excellent rate capability and long cycle life. [ABSTRACT FROM AUTHOR]

The Cl substitution reactions of the N/N (1‐3) and N/O (4 and 5) spirocyclic monoferrocenylphosphazenes with 1,4‐dioxa‐8‐azaspiro[4,5]decane (DASD) produce the mono‐ (1a‐5a), geminal‐ (1b‐5b) and tetrakis‐DASD‐substituted ferrocenylspirocyclotriphosphazenes (1c‐5c). The mono‐ and geminal‐DASD‐substituted phosphazenes have two and one stereogenic P‐centers, respectively. The structures of the compounds were established by spectroscopic techniques. The molecular structures of 3a and 2b were evaluated using X‐ray crystallography. Additionally, the ultrathin and highly ordered Langmuir‐Blodgett (LB) films of 3a and 2b were also prepared. The characterizations of the LB films were done using p‐polarized grazing angle (GAIR) and horizontal attenuated total reflectance (HATR) techniques. On the other hand, the antimicrobial activities of the eight phosphazene derivatives against G(+) and G(‐) bacteria and fungi were investigated. Furthermore, the interactions between the compounds and plasmid DNA were studied by agarose gel electrophoresis. [ABSTRACT FROM AUTHOR]

In this work, nearly single phase SrTaO 2 N powder was directly prepared from strontium carbonate (SrCO 3 ) and tantalum mononitride (TaN), instead of the nitridation of the oxide precursors using NH 3 . The phase evolution and reaction mechanism together with the chemical composition, crystal structure and particle size of SrTaO 2 N product were investigated. Similar to the reactions between SrCO 3 and Ta 3 N 5 , the evolution of CO 2 , CO and N 2 was detected during the reactions. The results revealed that this novel reaction was able to successfully synthesize orange-coloured SrTaO 2 N powder with nearly pure phase at 1200 °C and the powder possessed the uniform size distribution with the mean diameter of 6.63 µm. [ABSTRACT FROM AUTHOR]

The fluorinated piperidine iminosugars 2a-4a and their N -octyl and N -decyl derivatives 2b,c-4b,c were synthesized from d -mannose/ d -xylose using nucleophilic fluorination as the key step. The conformation of iminosugars 2 / 3 , either 2 C 5 or 5 C 2 , was assigned based on the 1 H NMR studies at different pH. Immunomodulatory activity of 2a,c-4a,c was examined using Mixed Lymphocyte Reaction (MLR) and B-cell assay. The N -alkylated fluorinated d - manno -iminosugars 3b/4b were found to be better immunosuppressive agents (IC 50  = 5–6  μ M) on T-cells. The fluorinated iminosugar 3a/4a act as potent and selective inhibitors of β -glucosidase (IC 50  = 4–8  μ M). The N -alkyl-iminosugars 4b-c were found to be moderate inhibitors of α -glucosidase (yeast) and α -galactosidase (coffee beans), respectively. [ABSTRACT FROM AUTHOR]

In this work, a nitrogen-containing bidentate ligand named 5,50-(9-octyl-9H-carbazole- 2,7-diyl)bis(1,10-phenanthroline) (OCBP) was synthesized as a nitrogen precursor for making an oxygen reduction catalyst. The 1,10-phenanthroline unit provides a coordination site for copper ions, and the resulting Cu-Nx unit may be responsible for the catalytic activities of the catalyst. Carbon black was selected as a support to improve the electroconductibility of the resulting catalyst. The metallo-supramolecule (Cu-SOCBP) was dispersed on the surface of Vulcan XC-72 carbon and was used as a catalyst (designated as Cu-SOCBP/C) for the oxygen reduction reaction (ORR). The microscope structure and surface components of the catalyst were acquired via scanning electron microscopy and X-ray photoelectron spectroscopy, as well as X-ray powder diffraction. The electrochemical property and ORR mechanism of Cu-SOCBP/C were analyzed using a variety of electroanalytical methods including cyclic voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry. These results show that Cu-SOCBP/C was successfully synthesized and that ORR was achieved mainly via a four-electron transfer process to water. Thus, Cu-SOCBP/C was an effective catalyst and might have potential application as a cathodic catalyst in microbial fuel cells, which operate in an aqueous medium. [ABSTRACT FROM AUTHOR]

Abstract: Graphitic carbon nitride (g‐CN) has emerged as a promising material for energy‐related applications. However, exploitation of g‐CN in practical devices is still limited owing to difficulties in fabricating g‐CN films with adjustable properties and high surface area. A general and simple pathway is reported to grow highly porous and large‐scale g‐CN films with controllable chemical and photophysical properties on various substrates using the doctor blade technique. The growth of g‐CN films, ascribed to the formation of a supramolecular paste, comprises g‐CN monomers in ethylene glycol, which can be cast on different substrates. The g‐CN composition, porosity, and optical properties can be tuned by the design of the supramolecular paste, which upon calcination results in a continuous porous g‐CN network. The strength of the porous structure is demonstrated by high electrochemically active surface area, excellent dye adsorption and photoelectrochemical and photodegradation properties. [ABSTRACT FROM AUTHOR]

Porous carbon materials with hierarchical structures attract intense interest for the development of high-performance supercapacitors. Herein, we demonstrate a facile and efficient strategy to synthesize nitrogen-doped hierarchically porous carbons with tailored porous structure combined with high specific surface area (SSA), which involves a pre-carbonization and a subsequent carbonization combined with KOH activation of silkworm cocoon precursors. Through adjusting the mass ratio of the activator (KOH) to pre-carbonized precursor in the activation process, the hierarchically porous carbon prepared at the mass ratio of 2 (referred to as NHPC-2) possesses a high defect density and a high SSA of 3386 m 2 g −1 as well as the relatively high volumetric proportion of mesopores and macropores (45.5%). As a result, the energy density and power density of the symmetric supercapacitor based on NHPC-2 electrode are as high as 34.41 Wh kg −1 and 31.25 kW kg −1 in organic-solvent electrolyte, and are further improved to 112.1 Wh kg −1 and 23.91 kW kg −1 in ionic-liquid electrolyte. [ABSTRACT FROM AUTHOR]

Inspire by the vision of finding a simple and green method for simultaneous reduction and nitrogen (N)-functionalization of graphene oxide (GO), a N-rich reduced graphene oxide (rGO) has been synthesized through a facile and ecofriendly hydrothermal strategy while most of the existing methods are involving with multiple steps and highly toxic reducing agents that are harmful to human health and environment. In this paper, the simultaneous reduction and N-functionalization of GO using as available lemon juice (denoted as Lem-rGO) for metal-free electrocatalysis towards oxygen reduction reaction (ORR) is described. The proposed method is based on the reduction of GO using of the reducing and the N-precursor capability of ascorbic acid and citric acid as well as the nitrogenous compounds, respectively, that containing in lemon juice. The resultant Lem-rGO has higher reduction degree, higher specific surface area and better crystalline nature with N-incorporation than that of well investigated ascorbic acid and citric acid treated rGO. As a result, it shows better ORR electrocatalytic activity in respect to the improved onset potential, electron transfer rate and kinetics than those typical rGO catalysts. Moreover, it shows a significant tolerance to the anodic fuels and durability than the Pt/C during ORR. [ABSTRACT FROM AUTHOR]

A series of Co/CeO 2 catalysts with different morphology of CeO 2 support were prepared. It was shown that part of Co species could be introduced into the CeO 2 lattice and thus a new Co O bonding would be created for the ceria-supported Co catalysts. The morphology of CeO 2 was found to affect the reduction of both the cobalt oxides and CeO 2 . A larger amount of CeO 2 was reduced in the case of Co supported on polyhedral CeO 2 . Catalytic tests showed that the higher concentration of Ce 3 + and the lower binding energy of Co species present in the catalyst are key factors that led to higher ammonia synthesis rates for the Co/CeO 2 catalysts. [ABSTRACT FROM AUTHOR]

Unprotected tertiary sulfonimidamides have been prepared in good to excellent yields in a one-pot transformation from tertiary sulfinamides through NH transfer. The reaction is mediated by commercially available (diacetoxyiodo)benzene and ammonium carbamate in methanol under convenient conditions. A wide range of functional groups are tolerated and initial results indicate that the NH transfer is stereospecific. A small molecule X-ray analysis of NH sulfonimidamide 2 a and its behavior in selected in vitro assays in comparison to the matched sulfonamide are also reported. This new reaction provides a safe, short and efficient approach to sulfonimidamides, which have been the subject of recent, growing interest in the life sciences. [ABSTRACT FROM AUTHOR]

The stereoselective synthesis of two broussonetine analogues 14 · HCl and ent - 14 · HCl with differing stereochemistry of the polyhydroxylated pyrrolidine core and a simple C 13 alkyl fragment has been achieved. For their construction, the known oxazolidinones 15 and 16 were chosen as appropriate advanced scaffolds. The common hydrophobic side chain was incorporated at an early stage of the synthesis through Grubbs’ cross metathesis chemistry. The required pyrrolidine skeleton was then formed by the cyclization of open chain intermediates 17 and 18 . Four synthesized compounds were screened in vitro for antiproliferative/cytotoxic activity against six cancer cell lines by MTT assay. Compounds 14 · HCl (HeLa and A-549) and ent - 14 · HCl (Caco-2 and Jurkat) showed comparable or higher potency than conventional anticancer agent cisplatin on at least two evaluated cancer cells, respectively. [ABSTRACT FROM AUTHOR]

Nitrogenous bicycles are an apparently endless field of organic and biological research. In this study, we disclose an efficient pathway to the synthesis of the pyrazolo[3,4- d ]pyrimidine scaffold in three steps from allopurinol. This key intermediate was engaged in the first example of regioselective C H arylation catalyzed by palladium to access a library of 3-substituted-1-methyl-4-phenyl-1 H -pyrazolo[3,4- d ]pyrimidines. [ABSTRACT FROM AUTHOR]

Nitrogen-sulfur-doped carbon spheres (NS-CSs) were prepared from sucrose and thiourea through a simple hydrothermal process. NS-CSs were characterized by TEM, FTIR, TGA, XRD, Raman spectroscopy and elemental analyses. The results revealed that the synthesized carbon spheres have an amorphous structure with diameters of 300-500 nm. The microspherical carbon catalyst that is recyclable has been used in the synthesis of α-aminophosphonates derived from 2-aminobenzothiazoles. Three-component reaction was performed between 2-aminobenzothiazoles, aromatic aldehydes and trimethyl phosphite in the presence of NS-CSs as microorganocatalyst at 50 °C under solvent-free conditions in high yield. Graphical Abstract: [ABSTRACT FROM AUTHOR]

The Cl substitution reactions of octachlorocyclotetraphosphazene, N4P4Cl8, with one equimolar amount of (4-fluorobenzyl)diamines (1–3) affords mono(4-fluorobenzyl)spirocyclotetraphosphazenes (4–6) as minor products. However, the reactions of N4P4Cl8 with two equimolar amounts of (4-fluorobenzyl)diamines (1–3) leads to the formation of mono (4–6), 2-trans-6-bis (7–9, as major products) and 2-cis-6-bis (4-fluorobenzyl)spirocyclotetraphosphazenes (10–12). The 2-cis-6-bis compounds (10 and 12) were separated and purified using column chromatography as minor products, whereas compound 11 could not be isolated. The mono-spiro (4–6) and 2-trans-6-bis-spiro (7–9) cyclotetraphosphazenes were reacted with excess pyrrolidine in THF to afford the fully substituted hexapyrrolidino (4a-6a) and tetrapyrrolidino (7a-9a) products in high yield. Compound 9 was also reacted with piperidine, morpholine and 1,4-dioxa-8-azaspiro[4,5]decane (DASD) to obtain the tetraamino products (9b, 9c and 9d), respectively, due to its very high yield. The elemental analyses, mass spectra (ESI-MS), Fourier transform infrared (FTIR) spectra, and 1H, 13C{1H}, and 31P{1H} NMR data of the cyclotetraphosphazenes were in agreement with the suggested structures. The molecular structures of 7, 9 and 12 were established by X-ray crystallography. The antibacterial activities of the compounds against G(+) and G(−) bacteria and their antifungal activities against yeast strains were scrutinized. The results indicated that 4a and 5a were the most active compounds, especially to yeast strains. In addition, it was found that the most active compound toward DNA was 8. The cytotoxic activities of the cyclotetraphosphazenes against L929 fibroblast and MCF-7 breast cancer cell lines were elucidated. Compound 8a exhibited the most toxic effects against both types of cells. [ABSTRACT FROM AUTHOR]

Three-dimensional porous nitrogen-doped graphene aerogels ( NGAs) were synthesized by using graphene oxide ( GO) and chitosan ( CS) via a self-assembly process by one-pot hydrothermal method. The morphology and structure of the as-prepared materials were characterized by means of scanning electron microscopy, transmission electron microscopy, X-ray diffraction, XPS spectroscopy, Raman spectroscopy, nitrogen adsorption/desorption measurement and Fourier transform infrared spectroscopy. The electrochemical performance of NGAs was studied by cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy measurements. The microstructure, surface area and capacitance of NGAs could be facilely controlled by adding different amounts of chitosan. The prepared NGA-4 showed a specific capacitance of 148.0 F/g at the discharge current density of 0.5 A/g and also retained 95.3% of the initial capacitance after 5000 cycles at the scan rate of 10 mV/s. It provided a possible way to obtain graphene based materials with high surface area and capacitance. [ABSTRACT FROM AUTHOR]

Acetylcholinesterase has important role in synaptic cleft. It breaks down the acetylcholineat cholinergic synapsesand terminates the cholinergic effects. Some chemical agents like organophosphorus compounds (OPCs) including nerve agents and pesticides react with acetylcholinesteraseirreversibly. They inhibit normal biological enzyme action and result in accumulation of acetylcholineand show toxic effects andcholinergic symptoms. The process of Acetylcholinesterase (AChE) inhibition can be reversed by a nucleophilic agent to dephosphorylate and reactivate the enzyme. In this study, design and docking studies of 15 novel nitrone based onoximes as reactivators were performed by using AutoDock program. Then, more effective reactivatorsoximes in terms of binding energy and orientation within the active site were synthesized and evaluated in-vitro on human AChE (hAChE) inhibited by paraoxon and compared to standard hAChE reactivators (2-PAM and obidoxime). Our results used to design new derivatives of Oxim with better efficacy than 2-PAM and obidoxime. Syntheses of some selected bis-pyridiniumoximes based on the nitrones are underway. [ABSTRACT FROM AUTHOR]

The development of green, sustainable and simple synthetic pathways for the design of polymer and carbonaceous materials with well controlled features is of great importance in various fields of applications. Herein, we report a green synthetic method for polymer and carbon particles with well-defined shapes and sizes. This approach involves the use of green precursors, water as the solvent, and no templates under ambient temperature and pressure conditions, simultaneously. Green polymer resins (phloroglucinol-glyoxylic acid) and a catalyst/nitrogen source (triethylenediamine) are dissolved in water at room temperature resulting in polymer particles, which by subsequent thermal treatment transform into carbon particles. Mainly spherical carbon particles with controlled sizes from 500 nm to 10 μm are obtained by simply adjusting the experimental conditions, i.e., the synthesis time and molar ratio between the precursors or solvent. In some conditions, a flower-like morphology is obtained as well. The synthetic mechanism for the formation of the polymer resin spheres up to their conversion into carbon spheres is proposed based on several techniques, i.e., 13C NMR spectroscopy, SEM, XPS and TPD-MS (temperature programmed desorption coupled with mass spectrometry). [ABSTRACT FROM AUTHOR]

A novel N5-linear energetic moiety of pentazadiene has been constructed for the first time from a triazene precursor. Thus, a series of 1,3,5-tri(tetrazol-5-yl)pentaza-1,4-dienes have been synthesized in moderate to high yields by treatment of 1,3-bis(tetr-azol-5-yl)triazenes with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) under mild conditions. All compounds were fully characterized using IR spectroscopy, 1H and 13C NMR spectroscopy, HRMS, and differential scanning calorimetry (DSC), and, in the case of 1,3,5-tri(2-methyltetrazol-5-yl)pentaza-1,4-diene (2a) together with single crystal X-ray structuring and 15N NMR spectroscopy. Calculations predict that 2a has a heat of formation of 1699.2 kJ mol−1. [ABSTRACT FROM AUTHOR]

Compounds containing oxygen, nitrogen, or sulfur atoms inside the rings are attracting much attention and interest due to their biological importance. In recent years, several methods for the synthesis of such molecules have been reported by using aldo-X bifunctional building blocks (AXB3 s) as substrates; these are a wide class of organic molecules that contain at least two reactive sites, among them, one aldehyde, acetal, or semiacetal group was involved. Because of the multiple reactivities, AXB3 s are widely used in the one-pot synthesis of biologically important heterocycles. This review summarizes the synthesis of important heterocycles by using AXB3 s as pivotal components in establishing multicomponent reactions, tandem reactions, and so forth. In many cases, the established reaction systems with AXB3 s were characterized by some green properties, such as easy access to the substrate, mild and environmentally benign conditions, and wide scope of the substrate. [ABSTRACT FROM AUTHOR]

The mechanism of the copper-catalyzed arylation of nitrogen heterocycles using anilines via diazonium salts has been studied by combining DFT and experimental data. A CuI/CuIII redox mechanism is proposed. Our study has revealed the multiple roles of the acid/base couple AcOH/AcO-. An in situ formed triazene species maintains a low concentration of diazonium salts in the reaction medium, which ensures limited formation of decomposition products. The results of DFT calculations have explained the lower reactivity of imidazole nucleophiles as compared with pyrazole in the arylation reaction. [ABSTRACT FROM AUTHOR]

The condensation reactions of hexachlorocyclotriphosphazene (N3P3Cl6, trimer) with the symmetric N2N2 or N2O2 donor type tetradentate bulky ligands (1–4) gave partly substituted spiro-bino-spiro (sbs) (5–8) trimeric phosphazenes. Compounds 5–8 reacted with pyrrolidine, morpholine and 1,4-dioxa-8-azaspiro[4,5]decane (DASD) to give octapyrrolidino- (9–12), morpholino- (13–16) and DASD-substituted cyclotriphosphazenes (17–20). The structures of the phosphazenes have been elucidated using FTIR, MS, 1H, 13C{1H} and 31P{1H} NMR, and HSQC spectral data. The molecular and solid-state structures of 5, 6 and 12 were verified by single crystal X-ray diffraction techniques. On the other hand, the ultrathin and highly ordered Langmuir–Blodgett (LB) films of compounds 6, 7, 9 and 12 were also fabricated. The structural characterization of the LB films was made using p-polarized grazing angle (GAIR) and horizontal attenuated total reflectance (HATR) techniques. All the novel phosphazene derivatives were evaluated for antibacterial activities against Gram-positive (G+) and Gram-negative (G−) bacteria and for antifungal activities against yeast strains. In addition, the cytotoxic effects of compounds 9, 13, 15, 16, 19 and 20 were investigated against L929 fibroblast and MDA-MB-231 breast cancer cells. The most active one among these compounds was compound 9 at 6.25 μg mL−1 concentration. The interactions between compounds 5–20 and pBR322 plasmid DNA were determined by agarose gel electrophoresis. [ABSTRACT FROM AUTHOR]

Deoxygenation of 2-nitrodiarylamines by triphenylphosphine is presented as an efficient method for synthesis of 2-(arylamino)aryliminophosphoranes, useful as starting materials in the synthesis of benzannulated nitrogen heterocycles. The reaction is complementary for the known synthesis of aryliminophosphoranes from 2-nitrosodiarylamines giving rise to obtain the title products in the broader scope. The presented protocol is simple and efficient although limited to secondary 2-nitrodiarylamines. [ABSTRACT FROM AUTHOR]

In pursuit of new lithium-rich phases and potential electrides within the Li–N phase diagram, we explore theoretically the ground-state structures and electronic properties of Li4N at P = 1 atm. Crystal structure exploration methods based on particle swarm optimization and evolutionary algorithms led to 25 distinct structures, including 23 dynamically stable structures, all quite close to each other in energy, but not in detailed structure. Several additional phases were obtained by following the imaginary phonon modes found in low-energy structures, as well as structures constructed to simulate segregation into Li and Li3N. The candidate Li4N structures all contain NLin polyhedra, with n = 6–9. They may be classified into three types, depending on their structural dimensionality: NLin extended polyhedral slabs joined by an elemental Li layer (type a), similar structures, but without the Li layer (type b), and three-dimensionally interconnected NLin polyhedra without any layering (type c). We investigate the electride nature of these structures using the electron localization function and partial charge density around the Fermi level. All of the structures can be characterized as electrides, but they differ in electronic dimensionality. Type-a and type-b structures may be classified as two-dimensional (2-D) electrides, while type-c structures emerge quite varied, as 0-D, 2-D, or 3-D. The calculated structural variety (as well as detailed models for amorphous and liquid Li4N) points to potential amorphous character and likely ionic conductivity in the material. [ABSTRACT FROM AUTHOR]

We reveal here the first hydrogenation of nitrogen heterocycles catalyzed by carbon-metal covalent bonds-stabilized palladium nanoparticles in water under mild conditions. Using a one-phase reduction method, smaller metal-carbon covalent bond-stabilized Pd nanoparticles were prepared with a size distribution of 2.5±0.5 nm, which showed extraordinary synergistic effects with water in the catalytic hydrogenation of nitrogen heterocycles. Water was supposed to accelerate substrate absorption and synergistic activation of molecular hydrogen on the Pd nanoparticles surface. The nanosized Pd catalyst could be easily recovered and reused for 5 runs. [ABSTRACT FROM AUTHOR]

All reported attempts to synthesize the tert-butyl-substituted adamantoid phosph(III)azane P4(N tBu)6 have failed, leading to the classification of this molecule as inaccessible and a literature example of steric control in chemistry of phosphorus-nitrogen compounds. We now demonstrate that this structure is readily accessible by a solvent-free mechanochemical milling approach, highlighting the importance of mechanochemical reaction environments in evaluating chemical reactivity. [ABSTRACT FROM AUTHOR]

A method for synthesis of 2-(2,2,2-trinitroethylamino)-4,6-diazido-1,3,5-triazine from 2-amino-4,6-diazido-1,3,5-triazine was elaborated. The molecular and crystal structures of this compound were studied using X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Simple benzo-fused nitrogen heterocycles (indolines, tetrahydroquinolines, and their homologues) undergo migratory ring expansion through deprotonation of their benzylic urea derivatives with lithium diisopropylamide (LDA) in the presence of N,N′-dimethylpropylideneurea (DMPU). The products of the reactions are benzodiazepines, benzodiazocines, and their homologues, with ring sizes of 8-12. The reactions tolerate a range of substituent patterns and types, and may exhibit enantiospecificity or diastereoselectivity. Considerable complexity is rapidly generated in an efficient synthesis of these otherwise difficult-to-obtain medium-ring nitrogen heterocycles. [ABSTRACT FROM AUTHOR]

Diverse nitrogen-containing heterocyclic compounds can be synthesised by the N-acylation of imines using functionalised carboxylic acids (Direct Imine Acylation, DIA). The carboxylic acids are activated in situ using the coupling agent propylphosphonic acid anhydride (T3P), before reacting with the imine coupling partner to generate N-acyliminium ions in situ, that can then be trapped by oxygen-, nitrogen-, sulfur- or carbon-based nucleophiles built into the carboxylic acid. This versatile, convergent method has been used to generate a wide range of products, including aromatic and aliphatic heterocycles, β-lactams, azaspirocycles and natural products. [ABSTRACT FROM AUTHOR]

We report about the preparation of novel protected N(ω-drug) amino acid building units and their straightforward incorporation in solid phase synthesis for the preparation of peptide-drug conjugates. These building units were synthesized applying various coupling methods between anticancer drugs and the side chains of different N protected amino acids. Subsequent incorporation of these amino acid-drug motifs into linear and cyclic integrin RGD and NGR containing ligands enabled a non-linear/divergent synthetic pathway of medicinally potential peptide-drug conjugates. The synthetic routes reported in this work are both general and applicable, and significantly expand the scope of the conjugation capabilities for peptide drug conjugates. For the preliminary in vitro evaluation of the novel peptide-drug conjugates reported herein, selective cytotoxicity of two representatives-one linear and one cyclic RGD-camptothecin conjugates were evaluated on αβ integrin overexpressed cancer cell lines. Graphical Abstract: [ABSTRACT FROM AUTHOR]

A metal-free, thermal, intramolecular Diels-Alder (IMDA) reaction of furan in aqueous media without the use of microwave irradiation was investigated. Protection of the amine functionality and the cycloaddition reaction were performed as a one-pot, two-component process. Various nitrogen-protecting groups and their electronic and steric effects on the cycloaddition reaction were studied. The protection- intramolecular Diels-Alder reaction sequence proceeds under environmentally benign aqueous conditions, which are tolerated by substrates with a broad range of nitrogen-protecting groups such as benzyloxycarbonyl (Cbz), trityl, tert-butoxycarbonyl (Boc), trifluoroacetyl, tosyl, mesyl, and p-nosyl [(4-nitrophenyl)sulfonyl]. This study allowed the development of a stereoselective, tandem allylamine isomerization- Diels-Alder cycloaddition sequence leading to the rapid assembly of complex nitrogen-containing heterocycles in a simple onepot process. [ABSTRACT FROM AUTHOR]

Cyclodiphosphazanes, also known as diazadiphosphetidines, are saturated inorganic ring systems containing alternating trivalent phosphorus and nitrogen atoms. With a rigid planar structure and moderately stable P–N bonds, cyclodiphosphazanes have shown versatility not only in coordination chemistry as both neutral and anionic ligands but also as useful scaffolds in supramolecular chemistry, resulting in a plethora of molecules with interesting structural features. Recent reports on their utility in generating several 3D-coordination polymers including those with sodalite structures, cyclodiphosphazane based N-heterocyclic carbenes and stable biradicaloids highlight the versatility of these novel phosphorus–nitrogen cyclic compounds. This review describes mainly the coordination chemistry of cyclodiphosphazanes as neutral ligands and their applications besides recent advances in cyclodiphosph(iii)azane chemistry. The key points on the empirical model proposed to highlight the coordinating ability of cyclodiphosphazanes to build soft–soft MOFs and an analysis of pertinent structural features are also presented. [ABSTRACT FROM AUTHOR]

LiSiN crystals are synthesized by direct reaction between LiN and SiN with the molar ratio LiN/SiN of 10:1. Reaction is performed at 1073 K for 1 h under a nitrogen atmosphere of 700 Torr. The lattice constant determined by the X-ray powder diffraction method is 4.718 Å. Four broad Raman peaks are observed at 196, 286, 580, and 750 cm. By analogy with LiMgN, the broad peak at 580 cm with a half width of 140 cm is attributed to homogenously random distribution of Li and Si atoms. The band gap of LiSiN is found to be a direct gap of about 2.5 eV by optical absorption and photoacoustic spectroscopy methods. Comparison with the conventional cathode materials for lithium ion batteries, this gap value is close to d-d transition energy of Mn in LiMnO (1.63 eV or 2.00 eV) and that of Co in LiCoO (2.1 eV), suggesting that LiSiN is a possible cathode material. The 5 × 5 mm-sized lithium secondary battery of LiSiN cathode/propylene carbonate + LiClO electrolyte/Li anode structure shows a discharge capacity of 2.4 μAh cm for a discharge current of 1.0 μA. [ABSTRACT FROM AUTHOR]

The cyclo-condensation of 1R,2R-diaminocyclohexane with 2,2′-(ethane-1,2-diyldisulfanediyl)dibenzaldehyde gave the 1 : 1 addition compound chxn-imN2S2 in high yield. When the same condensation reaction was performed with 1R,3S-diamino-1,7,7-trimethylcyclopentane as the diamine, the 2 : 2 addition compound tmcp-imN4S4 was obtained selectively. Reduction of the diimines gave the saturated analogues chxn-N2S2 (1) and tmcp-N4S4 (3) the former of which could be phosphorylated with PhP(NMe2)2 to give the novel 13-membered macrocycle chxn-PS2, 2. Introduction of the phenylphosphine function proved stereoselective with a preference for the N(R)/N(S) configuration at the nitrogen atoms. The coordination chemistry of the novel phosphine has been explored with Cu(i) and Mo(0) through formation of the complexes Cu(2)I, 4, and Mo(CO)3(2), 5. Extension of the phosphorylation chemistry to tmcp-N4S4 (3) proved unsuccessful but ring closure reactions of both 1 and 3 with triethylorthoformate gave cyclic amidinium salts which are potential precursors to macrocyclic N-heterocyclic carbenes. [ABSTRACT FROM AUTHOR]

This work presents a novel approach for the treatment of nitrogen contaminated natural gas streams. Literature states that for small and medium scale production wells (<400 MNm 3 /day), such stream can be treated by PSA. For larger scale natural gas production, the only mature option available is cryogenic distillation. Computer simulations were performed to evaluate the usage of silicalite in a PSA process for the separation of a nitrogen rich N 2 /CH 4 mixture. This unit is designed for coupling to a cryogenic distillation process. The differential algebraic equations system, composed of mass and energy balances as well as other constitutive equations, was solved in the spatial dimension using the finite volumes method. Numerical methods employed were analyzed for numerical dispersion and oscillation. In order to test the numerical approach, parameters and model, data from the literature was correlated. A Rotated Central Composite Design (RCCD) was performed in order to determine optimum operational pressures. In the chosen set of operational values, the process presented nitrogen purity greater than 96% and a recovery beyond 50%. The nitrogen rich outlet stream purity is specified for venting, while the methane rich stream is proper for recycling to the cryogenic process. [ABSTRACT FROM AUTHOR]

Graphene-Bi2WO6 composite photocatalyst with excellent photocatalytic properties were synthetized by ultrasonic-microwave synergistic method. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier infrared (FT-IR) spectrum, specific surface area analyzer (BET) and UV-Vis diffuse reflectance spectra. The photocatalytic activities of as-prepared samples were evaluated by degradation of pyridine in light oil under visible light irradiation. The results show that graphene changed appearance structure of Bi2WO6, which prevented the Bi2WO6 nanosheets reunion arrangement, and increased specific surface area of the catalyst. It can also reduce the recombination probability of photogenerated carrier, so as to improve the photocatalytic activity of the composite catalyst. The optimal amount of graphene is 2%, with the denitrification rate as high as 89.28%, much higher than that of pure Bi2WO6. Bi2WO6 is incorporated onto graphene sheets using an ultrasonic-microwave synergistic method to shorten the time of preparation of catalyst and graphene oxide which could be efficiently reduced under the microwave reaction. The graphene sheets not only function as a good substrate and stabilizer of Bi2WO6 but they could also efficiently improve the electron transport and reduce the charge recombination. [ABSTRACT FROM AUTHOR]

Heteroatom-doped carbon materials are currently drawing increasing interest because they show remarkable performance when applied in lithium-ion batteries, supercapacitors, and fuel cells. In this work, a facile method was developed to synthesize N and S co-doped graphene-like carbon materials using montmorillonite (Mt) after the adsorption of methyl blue (MB). The MB–Mt composites were pyrolyzed in a N 2 atmosphere to carbonize the adsorbed MB within the interspace of Mt. The resulting pyrolyzed carbon/Mt composite showed a basal spacing value of approximately 0.44 nm, close to the thickness of a single graphene sheet, suggesting the formation of graphene-like carbon materials within the interspace of Mt. Then, the carbon/Mt composite was demineralized by acid washing to liberate the carbon materials. Transmission electron microscopy and atomic force microscopy results directly showed the morphology of the resulting carbon material, i.e., the stacking of thin carbon sheets. Raman spectra showed the simultaneous presence of both a D-band and G-band for the obtained carbon materials, and their intensity ratio decreased with increasing pyrolysis temperature. X-ray photoelectron spectroscopy results indicated the presence of C, S, and N atoms in the carbon materials, and the doping sites of the S and N atoms were proposed. Finally, the obtained carbon materials showed interesting electrocatalytic activity for the oxygen reduction reaction, suggesting their potential application as efficient metal-free electrocatalysts in fuel cells. Our work synthesized N and S co-doped graphene-like materials with interesting electrocatalytic activity, which proved that the templated synthesis method could be a facile approach to synthesize various heteroatom-doped graphene-like carbon materials. [ABSTRACT FROM AUTHOR]