1-Fluoro-2,5-dimethoxy-4-nitrobenzene

1-Fluoro-2,5-dimethoxy-4-nitrobenzene was synthesized in 90% yield by the reaction of commercial 2-fluoro-1,4-dimethoxybenzene with nitric acid. The structure was confirmed by X-ray crystallography. The new title compound was characterized by 1H and 13C-NMR, elemental analysis, EI-MS and FT-IR

A Survey of Artificial Intelligence Techniques Employed for Adaptive Educational Systems within E-Learning Platforms

Abstract The adaptive educational systems within e-learning platforms are built in response to the fact that the learning process is different for each and every learner. In order to provide adaptive e-learning services and study materials that are tailor-made for adaptive learning, this type of educational approach seeks to combine the ability to comprehend and detect a person’s specific needs in the context of learning with the expertise required to use appropriate learning pedagogy and enhance the learning process. Thus, it is critical to create accurate student profiles and models based upon analysis of their affective states, knowledge level, and their individual personality traits and skills. The acquired data can then be efficiently used and exploited to develop an adaptive learning environment. Once acquired, these learner models can be used in two ways. The first is to inform the pedagogy proposed by the experts and designers of the adaptive educational system. The second is to give the system dynamic self-learning capabilities from the behaviors exhibited by the teachers and students to create the appropriate pedagogy and automatically adjust the e-learning environments to suit the pedagogies. In this respect, artificial intelligence techniques may be useful for several reasons, including their ability to develop and imitate human reasoning and decision-making processes (learning-teaching model) and minimize the sources of uncertainty to achieve an effective learning-teaching context. These learning capabilities ensure both learner and system improvement over the lifelong learning mechanism. In this paper, we present a survey of raised and related topics to the field of artificial intelligence techniques employed for adaptive educational systems within e-learning, their advantages and disadvantages, and a discussion of the importance of using those techniques to achieve more intelligent and adaptive e-learning environments.</jats:p

Synthesis of N-[(dialkylamino)methyl)]acrylamides and N-[(dialkylamino)methyl]methacrylamides from Schiff base salts : useful building blocks for smart polymers

The traditional thermal Mannich reaction is unsuitable for preparing polymerizable N-methylene amino substituted acrylamides and methacrylamides. Herein we provide a facile multi-gram high yield synthesis of these monomeric precursors to stimuli-responsive polymers by addition of acrylamide and methacrylamide onto in situ generated or freshly isolated methylene Schiff base (iminium) salts. X-ray crystal structure of the hydrated iminium salt, 1-(hydroxymethyl)azocan-1-ium chloride and monomer.HCl salt, (N-[(azocan-1-yl)methyl]prop-2-enamide hydrochloride) is described

Radical polymerization of alkyl 2-cyanoacrylates

Cyanoacrylates (CAs) are well-known fast-setting adhesives, which are sold as liquids in the presence of stabilizers. Rapid anionic polymerization on exposure to surface moisture is responsible for instant adhesion. The more difficult, but synthetically more useful radical polymerization is only possible under acidic conditions. Recommendations on the handling of CAs and the resulting polymers are provided herein. In this review article, after a general description of monomer and polymer properties, radical homo- and copolymerization studies are described, along with an overview of nanoparticle preparations. A summary of our recently reported radical polymerization of CAs, using reversible addition-fragmentation chain transfer (RAFT) polymerization, is provided

Photochemical aryl radical cyclizations to give (E)-3-Ylideneoxindoles

(E)-3-Ylideneoxindoles are prepared in methanol in reasonable to good yields, as adducts of photochemical 5-exo-trig of aryl radicals, in contrast to previously reported analogous radical cyclizations initiated by tris(trimethylsilyl)silane and azo-initiators that gave reduced oxindole adduct

Synthesis of fluorinated alkoxyamines and alkoxyamine-initiated nitroxide-mediated precipitation polymerizations of styrene in supercritical carbon dioxide

TIPNO (2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide)-alkoxyamine was found to give reasonably controlled/living nitroxide-mediated (NMP) precipitation polymerizations of styrene in supercritical carbon dioxide (scCO(2)). In contrast under the same conditions, the analogous SG1 (N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl)nitroxide)-alkoxyamine gave higher rates of polymerization and inferior controlled/living character. The circumvention of the requirement for excess free (nitroxide](0) allowed the study of nitroxide partitioning effects in scCO(2) for three newly synthesized fluorinated alkoxyamines. Two alkoxyamines dissociated into scCO(2)-philic fluorinated TIPNO-nitroxide derivatives, while another contains a similar sized fluorinated "foot". Despite the increased steric bulk about the N-O bond for the novel fluorinated alkoxyamines, all polymerizations proceeded at a similar rate and level of control to the TIPNO system in solution (toluene). PREDICI simulations for the styrene/TIPNO system are used to support extensive partitioning effects observed in scCO(2) for the fluorinated alkoxyamines.Irish Research Council (formerly IRCSET) IUPAC Transnational Call in Polymer Chemistry to F.Aldabbagh. National Science Foundation (NSF CHE-1057927, USA) to R. Braslau.peer-reviewe

Syntheses and structural characterisations of amidinates, diaminates and phenolates antimony (I and III) and aluminium (III) complexes

This thesis focuses on the synthesis and characterisation of antimony(III) and aluminium(III) amidates with an emphasis on structural characterisation, presenting the isolation of 22 new complexes. In addition, some chemistry of (2,6-di–tert-butyl-4-methyl) antimony and aluminium (III) complexes is added in the appendix of this thesis. Below is a general outline for each chapter of original research (2-4), showing the diverse range of compounds obtained from the following formamidinate and polyfluorophenylamidate ligands. Chapter 1 gives an overall introduction to antimony and aluminium (III) chemistry. This chapter describes the general aspects and overview of the relevant literature highlighting the most common synthetic methods used to synthesis antimony and aluminium compounds, particularly formamidinates, amidates, phenolates and their applications. Chapter 2 describes the metathesis reactions employed for the preparation of a range of mono- and bis-substituted formamidinato antimony (III) complexes. The bissubstituted complexes include [Sb(DippForm)₂Cl] (2.2), [Sb(DippForm)₂Br] (2.3) and [Sb(DippForm)₂I] (2.4) and mono-substituted products include [Sb(DippForm)Br₂] (2.5) and [Sb(DippForm)I₂] (2.6). Other complexes have been prepared as dimers [Sb(DippForm)(NSiMe₃)]₂ (2.8) and [Sb(DippForm)Cl(C₆F₅)]₂.(THF)₂ (2.12), also the formamidinato-bridged distibane [Sb₂{μ-(DippForm}₂].(THF)₈ (2.1) that represents an example of monovalent antimony. Fundamentally, the synthesis of antimony (I) and (III) formamidinate complexes was accomplished through deprotonation of N,N'-2,6-diisopropylphenylformamidine (DippFormH) by a metal alkyl/amide reagent (n-BuLi, LiN(SiMe₃)₂, NaN(SiMe₃)₂) in a donor solvent THF or in PhMe and then combined with SbX₃ in THF and/or PhMe. The unexpected [(DippForm)ClSb(μ-O)SbCl₂(Me₂NC₂H₄NMe₂)]₂.(C₆D₆) (2.11) was the only type of halogenated hetero dinuclear complex isolated in this study. Chapter 3 details the synthesis and characterisation of a series of heteroleptic and homoleptic N,N-dimethyl-N'-2,3,5,6-tetrafluorophenylethane-1,2-diaminate antimony (III) complexes. [Sb(p-HC₆F₄NC₂H₄NMe₂)₂Cl] (3.2) and [Sb(p-HC₆F₄NC₂H₄NMe₂)3] (3.3) complexes were isolated by metathesis reactions between SbCl3 and Li(p-HC₆F₄N(CH₂)₂NMe₂), a common synthetic route to antimony complexes; while the direct reaction between SbCl3 and p-HC₆F₄NH(CH₂)₂NMe₂ was used to synthesise [Sb(p-HC₆F₄NC₂H₄NMe₂)Cl₂] (3.1). Halo- and nonhalo-polyfluorophenylamido antimony (III) complexes were gained as monomers in the solid state. Chapter 4 Extending this chemistry to formamidinate aluminium resulted in the isolation of a group of new and interesting formamidinato aluminium (III) complexes ranging from mono- to bis-substituted, involving different bonding modes. Metathesis reactions between AlX₃ (X = Cl, Br, I) and two different deprotonated N,N'-chelating ligands (XylForm) and (DippForm) of varying steric bulk and functionality were used to increase the range of the haloorgano(formamidinato) aluminium (III) system. These complexes are [Al(XylForm)₂Cl] (4.1), [Al(XylForm)₂I].PhMe (4.2), [Al(XylFormH)Br₃] (4.3), [Al(DippFormH)Br₃] (4.5) and [Al(DippForm)₂Cl] (4.8). Using the bulkier formamidinate ligand (DippForm) allowed the isolation of [Al(DippForm)Cl₂(thf)] (4.6) and [Al(DippForm)ClBr(thf)] (4.7). The heteroleptic [Al₃(XylForm)₂(μ₃-O)(OH)Cl₄]₂.PhMe (4.4) was isolated as a monomer and represents a compound contained three aluminium atoms bridged by an oxygen atom. In a different approach, a chlorine/methyl exchange reaction was used for forming bimetallic Al/Sb (III) ionic complexes [Me₃Sb-SbMe₂][AlCl₄] (4.9) and [Br₃Sb-μBr-SbBr₃][AlCl₂(thf)₄] (4.10), showing relatively rare coordination modes. Overall, the knowledge regarding amidato antimony and aluminium (III) complexes has been enhanced and more information has been obtained regarding their structural motifs and bonding modes. The N,N'-bis(aryl)formamidinate ligands can form stable and structurally interesting mono/trivalent antimony and trivalent aluminium species using metathesis route, due to their ease of steric variability. In addition, this thesis demonstrates the ability of N,N-dimethyl-N'-2,3,5,6-tetrafluorophenylethane-1,2-diaminate ligand to stabilise antimony in its most common and stable oxidation state (III). Many of these compounds, particularly the compounds with M-X bonds, are now well set for potential reduction to low valent species. Reaction with KC₈ should form isolable low valent Sb or Al complexes and this work could be performed in future work. There are also many other formamidinate, guanidinate and amidinate ligands that could be used to extend this work

Radical cyclisations onto imidazoles

This thesis describes the development of new pathways towards the synthesis of novel antimicrobial (and anticancer) agents. Two synthetic protocols based on free radical chemistry are studied, which are used to access polycyclic heterocyclic compounds of potential biological importance. Both these procedures involve the generation of radicals using Bu3SnH and AIBN initiators, and the subsequent intramolecular radical cyclisation onto the imidazole ring. Radical cyclisations onto benzimidazoles and pyrroles are also described. [Continues.

6-Imino-1,2,3,4,8,9,10,11-octahydropyrido[1,2- a ]pyrido[1′,2′:1,2]imidazo[4,5- f ]benzimidazole-13-one : synthesis and cytotoxicity evaluation

The first report of an iminoquinone of imidazo[4,5-f]benzimidazole is described. The 2D-NOESY spectrum of 1,2,3,4,8,9,10,11-octahydropyrido[1,2-a]pyrido[1&rsquo;,2&rsquo;:1,2]imidazo[4,5-f]benzimidazol-6-amine was used to confirm the location of the imine moiety at the C-6 position of the title compound. Cytotoxicity data from the National Cancer Institute are included