Tesi: "Heterocyclic compounds"

1

Locke, Julie Myree, University of Western Sydney, College of Health and Science e School of Biomedical and Health Sciences. "Synthetic and conformational studies of hexahydropyrimidines and related heterocycles". THESIS_CHS_BHS_Locke_J.xml, 2003. http://handle.uws.edu.au:8081/1959.7/638.

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Abstract (sommario):

This thesis explores the synthesis and conformational behaviour of hexahydropyrimidines and related heterocycles, with particular emphasis on 5- hyrdohexahydropyrimidines. The conformational behaviour of these compounds was investigated using dynamic NMR spectroscopy, molecular modelling techniques and X-ray crystal structure analysis. The conformational behaviour of 5- hyrdohexahydropyrimidine, hexahydropyrimidine and their analogous oxygen compounds as well as a series of hexahydropyrimidines with various exocyclic substituents, were examined. The preferred conformations of all these compounds are attenuated by a combination of steric and electronic influences. These influences include intramolecular hydrogen bonding as well as anomeric and gauche interactions. The conformational behaviour of the selected seven membered benzodiazepine rings, which share structural characteristics with the six-membered 5- hyrdohexahydropyrimidines was also explored. The increased flexibility of the seven membered rings facilitates intramolecular hydrogen bonding, which in turn retards ring inversion in these systems
Doctor of Philosophy (PhD)

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2

Hu, Gang. "Conducting polymers from heterocyclic compounds". Thesis, Open University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240331.

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3

Armugam, S. "Studies on N-Heterocyclic Compounds". Thesis, Indian Institute of Science, 1994. https://etd.iisc.ac.in/handle/2005/108.

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The thesis entitled "Studies on N-Hetero cyclic Compounds: (a) Reaction of 5,6,7,8-Tetrahydroisoquinolines with Vilsmeier Reagent and (b) Amide Induced in situ Alkylation of 5,6-Dihydroisoquinolines" is presented in two parts. Part I involves a study of the Vilsmeier reaction of 4-cyano-1,3-dihydroxy-5,6,7,8 tetrahydroisoquinoline derivatives, while Part II concerns the in situ alkylation of l-alkyl-4-cyano-3-methoxy-5,6- dihydroisoquinolines in presence of KNH2/liq.NH3.

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4

Armugam, S. "Studies on N-Heterocyclic Compounds". Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/108.

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The thesis entitled "Studies on N-Hetero cyclic Compounds: (a) Reaction of 5,6,7,8-Tetrahydroisoquinolines with Vilsmeier Reagent and (b) Amide Induced in situ Alkylation of 5,6-Dihydroisoquinolines" is presented in two parts. Part I involves a study of the Vilsmeier reaction of 4-cyano-1,3-dihydroxy-5,6,7,8 tetrahydroisoquinoline derivatives, while Part II concerns the in situ alkylation of l-alkyl-4-cyano-3-methoxy-5,6- dihydroisoquinolines in presence of KNH2/liq.NH3.

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5

Nyoni, Dubekile. "Application of the Baylis-Hillman methodology in the construction of novel heterocyclic derivatives". Thesis, Rhodes University, 2008. http://eprints.ru.ac.za/1134/.

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6

Miah, Soyfur. "The metallocarbene route to heterocyclic compounds". Thesis, Loughborough University, 1997. https://dspace.lboro.ac.uk/2134/26972.

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7

Wilson, Jennifer M. "Synthesis of biologically active heterocyclic compounds". Thesis, University of Glasgow, 2007. http://theses.gla.ac.uk/45/.

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Abstract (sommario):

More than 11 million people worldwide are diagnosed with cancer every year. New cancer drugs are required that are more effective and selective. Nitrogen mustard alkylating agents crosslink DNA inhibiting transcription and replication. Use of the mustard pharmacophore as part of a macrocycle allows metal complexation and produces a prodrug. Hypoxic tumour cells have increased concentrations of reductase enzymes which could lead to reduction of the complex in situ and release of a cytotoxic drug. Human African Trypanosomiasis is commonly known as Sleeping Sickness and affects over 36 countries of sub-Saharan Africa. It is transmitted to humans by the tsetse fly which carries the parasitic subspecies Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense. Any compounds synthesised would also be tested to assess their potential as anti-parasitic agents. Parker synthesised a range of polyazamacrocycles. Testing of compound A in vitro gave highly efficient DNA crosslinking activity. Copper complexes were formed of the macrocycles and B was found to be 24 times more toxic against hypoxic cells than oxic cells thus exploiting tumour hypoxia and creating a selective drug. Jones synthesised a range of oxaazamacrocycles such as C which when tested in vitro exhibited comparable cross-linking activity to the azamacrocycles although it proved impossible to synthesise the corresponding copper complexes. It was decided to vary the leaving group on the alkylating arms to see if the DNA crosslinking results could be improved. Eight carbamates and the corresponding copper complexes were synthesised. The R-groups were alkyl and aromatic. Anti-cancer DNA crosslinking and hypoxia selectivity results were disappointing however, a number of compounds displayed significant activity when tested against T. brucei. A range of thiaazamacrocycles would complete the set of heteroatom-containing macrocycles (N, O, S) and might produce good DNA crosslinking results. It might also be possible to synthesise the corresponding copper complexes producing prodrugs. Six thiaazamacrocycles were synthesised and 2-hydroxyethyl arms were attached. However it proved impossible to isolate the desired alkylating agents with the 2-chloroethyl arms. In the body, the p53 protein activates the transcription of specific genes. In healthy cells, the levels of p53 have to be kept to a minimum to allow the normal running of the cell, e.g. growth and replication. This function is carried out by the HDM2 protein, which forms an auto-regulatory feedback loop with p53. In some tumours, the p53 function is disrupted due to genetic mutations of p53. However other tumours possess ‘wild type’ p53 – this type of p53 has lost the ability to respond to oncogenic stress due to over-expression of HDM2. Drugs that inhibit HDM2 should cause stabilisation of p53 and induce apoptosis in cancer cells. A small library of 5-deazaflavins were synthesised and biologically tested producing some interesting biological results.

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8

MacDonald, Ranald John. "Novel routes to heterocyclic Azo compounds". Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5787.

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The potential use of electron-deficient heterocyclic azo compounds as inkjet dyes was explored. 2-Nitrosopyridine could be used to form a series of azo compounds via the Mills’ reaction with electron-rich aromatic amines. Conditions for this process were optimised by varying solvent and pH. In the presence of ethers, 2-nitrosopyridine is quickly reduced to azoxypyridine. This reaction follows first order kinetics; diethyl and diisopropyl ether react at similar rates, whereas cyclic ethers such as THF are far slower. Organic bases such as Hunigs base were also found to promote formation of azoxypyridine. The mechanism of this reduction was studied. The electrochemistry of 2-nitrosopyridine and azoxypyridine was also explored. Using the optimised conditions for the Mills’ reaction, 2-nitrosopyridine not only reacts with electron-rich amines but also electron-deficient examples. The series was also expanded to include other heterocycles as well as pyridine via the corresponding heterocyclic nitroso compound. Other nitroso compounds prepared were 1- nitrosoisoquinoline, 2-nitrosopyrazine, 4-nitrosopyrimidine and 2-nitrosopyrimidine. The absorption maxima of azo compounds prepared from these precursors were found to correlate with the values for the corresponding azobenzenes. 2-Nitrosopyridine and 2-nitrosopyrimidine react with diamines to give monoazo products. These in turn could be diazotised and coupled with various components to give either bisazo or trisazo compounds. These dyes were tested for their ozone and light fastness properties. The bisazo examples were found to have good ozone fastness but poor light fastness. The pyrimidine examples only showed a slight improvement in ozone and light fastness compared to their pyridine analogue. 2,3-Phthalocyanines are important components in cyan dyes. New routes to precursors of these compounds were explored using flash vacuum pyrolysis (FVP).

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9

Jamalis, Joazaizulfazli. "Synthesis of heterocyclic containing oxygen compounds". Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.529847.

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10

Lee, On-yi. "Synthesis of heterocycles via phenylseleno group transfer radical cyclization and chemoselective reductive amination promoted by InCl3". Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B3955756X.

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11

Duan, Gongping. "Design, synthesis, and photophysics and photochromic study of dithienylethene-containing heterocyclic derivatives and N-heterocyclic carbene-ruthenium (II) complexes". Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B44248246.

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12

Williams, Christopher Ian. "A computational study of nitrogen heterocyclic compounds". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq30417.pdf.

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13

Harper, Mark F. "Studies on heterocyclic compounds related to anthracyclines". Thesis, Heriot-Watt University, 1985. http://hdl.handle.net/10399/1613.

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14

Crockett, Rowena. "Generation of free radicals from heterocyclic compounds". Thesis, University of Aberdeen, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290239.

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Abstract (sommario):

Tetrazolinones, thiatriazole 1-oxides and meso-ionic oxatriazoles were investigated as sources of free radicals. Mono-substituted tetrazolinones decomposed at their melting points. Nitrosation and nitration of the tetrazolinone ring was unsuccessful, although alkoxyalkylation of the ring took place in ether in the presence of nitrosomium and nitronium tetrafluoroborate. The tetrazolinone ring was photolytically unstable, and both eliminated nitrogen and cycloreverted. γ-irradiation of the naphthyl deivative caused cleavage of the nitrogen-hydrogen bond to give a radical which was identified by spin trapping and esr spectroscopy. Thiatriazolyl radicals were generated from thiatriazol-1-ium salts by reduction over sodium metal. Deuterium and nitrogen-15 labelled diphenylthiatriazolium salts were prepared in the reaction between thiatriazole 1-oxides and phosphorus pentachloride or pentabromide. This allowed an unambiguous assignment of the nitrogen and hydrogen hyperfine coupling constants in the esr spectrum of the unlabelled thiatriazolyl radical. X-ray crystallographic analysis was carried out on single crystals of 2,4-diphenyl-2,5-dihydro-1,2,3,5-thiatriazol 1-oxide and 2,4-diphenyl-2H-1,2,3,5-thiatriazol-1-ium bromide. Meso-ionic oxatriazolones were relatively stable to thermolysis, whereas oxatriazolimines decomposed at their melting points. The oxatriazolones decomposed on photolysis via two mechanistic pathways, while the oxatriazol-imines were resistant to photolysis. Radicals were generated by γ-irradiation and oxidation via decomposition of the heterocyclic ring. Electrochemical reduction of nitrophenyl derivatives allowed an investigation of radicals in which the heterocyclic ring was remote from the radical centre. Photochemical reaction between the nitrophenyl derivatives of the oxatriazole and tetrahydrofuran produced oxy-nitroxide radicals which were realatively long-lived and in which the heterocyclic ring was intact. The rates of hydrolysis and crystal structures of three diacetylazolinones, including diacetyltetrazolinone were investigated with the aim of determining whether a correlation existed between bond lengths and reactivity. The relative rates of hydrolysis were found to be independent of the bond lengths. However a correlation was found between the rates of hydrolysis and the acidity of the unsubstituted azolinones.

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15

Brookman, Charles Alexander. "The molecular structures of some heterocyclic compounds". Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/12791.

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Abstract (sommario):

The gas-phase molecular structures of 2-chloropyridine, 3-chloropyridine, 4-chloropyridine, chloropyrazine, 1,2,3-triazine, 1,3,5-triazine and 1,2,4,5-tetrazine have been determined by electron differaction, and, in the case of the first two and the fourth, by combining them with microwave spectoscopy data. Of particular interest was the combination of ring distortion effects arising from both the chlorine substituent and the nitrogen heteratom. The results tend to indicate a more complicated system than that of purely substituent effects, an area already well documented. One of the interesting facts to emerge from this study is the possible breakdown of this superposition method of predicting distortions when the ring geometry is highly distorted from the hexagonal . When several heteroatoms are present in the ring, especially if they distort in a mutually constructive manner, such high distortions may result. Predictions are then unreliable for determining the extent to which each ring angle is affected. It was also found that the presence of the nitrogen enhances the power of the chlorine to distort the ring, adding further to the evidence that the distortions might not be merely additive.

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16

Ohshiro, Takashi. "MICROBIAL SULFUR METABOLISM OF HETEROCYCLIC SULFUR COMPOUNDS". Kyoto University, 1996. http://hdl.handle.net/2433/78073.

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17

Taylor, Lynne M. "Interactions of platinum compounds with heterocyclic bases". Thesis, Robert Gordon University, 1990. http://hdl.handle.net/10059/2356.

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Abstract (sommario):

It is generally accepted that platinum antitumour drugs bind, preferentially, to Guanine N7 in DNA. Thus the kinetics of formation and the energetics of dissociation of platinum-nitrogen bonding have been investigated, using simple model bases, namely pyridine. pyrimidine. purine and some derivatives. Six complexes of the type cis-PtCl2L2, where L is a N-heterocycle, have been successfully prepared and characterized. The kinetics of the reaction between K2PtCl4 and the N-heterocyclic bases in aqueous solution have beeD studied. This was best achieved by pre-aquating the PtCl4(2-) and measuring the decrease in concentration of platinum or ligand by AA or UV spectroscopy respectively. It was found that the rate of reaction is second order, the rate being dependent on the concentration of both platinum complex and the ligand. The substitution of ligand takes place by direct replacement, involving an associative S.2 mechanism. It was found that the activation entropy and the activation energy for the reactions of platinum complexes in solution are strongly correlated. The energetics of platinum-nitrogen bond dissociation were followed using thermogravimetric analysis. Quantitative data, which enabled calculation of the activation energy for the decomposition process involving the loss of one molecule of ligand was obtained from isothermal studies. No correlation was found between the solid state studies, involving bond breaking, and the syntheses of the complexes, probably because in solution the reaction is complicated by solvent effects. Theoretical studies, which involved Molecular Orbital calculations on the N-heterocyclic bases themselves, were also carried out in an attempt to correlate the kinetic and energetic parameters with the electronic structure of the ligand. Several correlations were attempted but only one was found. This was the relationship between the solid state decomposition energy and the LUMO energy of the quarternized base.

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18

Lewis, William. "Chiral Heterocyclic Ligands". Thesis, University of Canterbury. Chemistry, 2007. http://hdl.handle.net/10092/1383.

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Abstract (sommario):

This thesis describes the preparation and characterisation of a number of homochiral coordination and metallosupramolecular assemblies. These species were formed from the reaction of chiral pyridine and quinoline containing ligands and metal ions. The combination of traditional coordination chemistry and supramolecular interactions led to a range of polymeric and network structures being formed. The ligands used in this thesis can be divided into two broad categories: alkaloids and ligands derived from them, and amino acid-based ligands. In the first category three new ligands were synthesized, and a variety of routes towards alkaloid-based homochiral ligands were investigated. The second category focused on three ligand motifs, and resulted in the preparation of 16 ligands. These two categories of ligands were reacted with a range of metal salts to investigate their coordination and supramolecular chemistry. The structure of twenty complexes was determined by single crystal X-ray crystallography. The complexes had a range of structures, with discrete and polymeric species being formed. Hydrogen bonding was an important feature in the supramolecular chemistry of the complexes, playing a different role in different series of complexes. Two chiral coordination polymers and one chiral coordination network were synthesized. All three of these structures possessed directionality to some degree: in the coordination network and one of the polymers the directionality is counterbalanced by the opposite directionality being present in the crystal, while the second coordination polymer is generated by the screw axis present and has a high degree of overall directionality.

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19

Layman, William Joseph. "The SRN1 reactivity of halobenzenesulfonamides and related compounds". Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-08252008-162626/.

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20

Emans, John. "Synthesis of novel heterocyclic polymers". Thesis, University of St Andrews, 1987. http://hdl.handle.net/10023/15299.

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Abstract (sommario):

This work details the synthesis, characterisation and fabrication of a range of copolyesters, containing various angular disrupters, especially disubstituted 2,5-diphenyl- -1,3,4-oxadiazoles. These disrupters were incorporated into the polymers, to reduce the temperature at which the polymers may be processed, to enable their fabrication into fibres. The majority of the polymers prepared were found to be liquid crystalline. However, if the angular disrupter content of the polymer was high, it was found that the resultant polymers were non-liquid crystalline. The polymers were prepared by a melt acidolysis process carried out under a nitrogen flow and subsequently under vacuum, as described in Chapter 3. Eighteen of the polymers were characterised in some detail, though a measure of the relative molecular weights was thought to be of little importance in this work, since all polymers were of a different composition. Differential scanning calorimetry and hot-stage microscopy revealed that several of the polymers had rather unusual melting behaviour. The eighteen polymers that were closely characterised were spun into fibres, using a small melt-spinning apparatus that was designed and produced by Bradford University Research Ltd, The resultant fibres were characterised by differential scanning calorimetry, X-ray diffraction end tensile testing. The general conclusion of the work is that although a reduction in the processing temperature of the polymer is achieved by the incorporation of angular disruptors, which is advantageous, the tensile strength and thermal stability of the fibres produced from such polymers are reduced.

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21

Khan, Musharraf Naveed. "Synthesis of different heterocyclic compounds of pharmaceutical relevance". Thesis, University of Huddersfield, 2013. http://eprints.hud.ac.uk/id/eprint/19503/.

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This thesis describes the synthesis of different cyclic imines and the exploration of their reactivity with cyclopropenones and 1,3-dipoles,as well as an investigation of the chemistry of the products. The synthesis of biologically and pharmaceutically important heterocyclic natural product analogues, such as the pyrroloazepines, indolizidines and pyrrolizidines has been achieved using a cycloaddition reaction between cyclic imidates and cyclopropenones. A new route to pyridines has been developed using the generation of a proposed 3-azacyclopentadienone as the key step. The 3-azacyclopentadienones are generated by using boiling toluene to induce a [2+2]-cycloreversion in a series of azabicyclo[3.2.0]hept-2-en-4- ones. Regiospecific Diels-Alder reaction of the intermediate 3-azacyclopentadienone with a styrene is followed by chelotropic extrusion of carbon monoxide and loss of hydrogen to give the pyridine. The process is similar to the well-known process by which benzenes are accessed from cyclopentadienones. The azabicyclo[3.2.0]hept-2 en-4-ones were available from the reaction of cyclopropenones with 1-azetines, where cyclopropenones behave as an all carbon 1,3- dipole equivalents. Using the same methodology 1,3-dipolar cycloaddition of nitrile oxides to 4-aryl-2-alkylthio-1-azetines afforded a series of oxadiazabicyclo[3.2.0]heptenes as single diastereoisomers. Heating these cycloadducts in toluene resulted in an overall [2+2]- cycloreversion to give 5-alkylthio-3-aryl-1,2,4 oxadiazoles. Cycloaddition reactions of a series of benzodiazepines were also studied. The benzodiazepines were formed using literature methods and converted to cyclic imines with the help of Meerwein’s reagent. Reactions between such cyclic imines and cyclopropenones and 1,3 dipoles were attempted to produce tricyclic and tetracyclic benzodiazepine analogues. Finally, some multicomponent reactions of aryl aldehydes with cyanides and 1,3-dicarbonyl compounds were investigated to produce fully substituted heterocyclic compounds like dihydropyridines and pyrans with substituents suitable for intramolecular cyclization and imine formation. The main substituent of interest was the azide group as this had been used in section 2.3.3.1.2 & 2.3.3.1.3 in this thesis.

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22

Stewart, Lesley Ann. "Synthesis of heterocyclic compounds as potential anticancer agents". Thesis, University of Glasgow, 1996. http://theses.gla.ac.uk/4936/.

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23

Philbin, Simon Patrick. "Studies of novel nitro-substituted nitrogen heterocyclic compounds". Thesis, Brunel University, 2001. http://bura.brunel.ac.uk/handle/2438/2165.

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Abstract (sommario):

The novel candidate high energy insensitive explosive; 2,5-diamino-3,6-dinitropyrazine (ANPZ-i) has been prepared in acceptable overall yield. ANPZ-i was synthesised by the nitration of 2,5-diethoxypyrazine using nitronium tetrafluoroborate (NO2+BF4-) in sulfolane and the subsequent amination of 2,5-diethoxy-3,6-dinitropyrazine, under autoclave conditions. Oxidation studies towards the dioxide derivative of ANPZ-i, 2,5-diamino-3,6-dinitropyrazine-1,4-dioxide (PZDO), were unsuccessful. The synthesis of existing high explosives; 2,6-diamino-3,5-dintropyrazine (ANPZ) and 2,6-diamino-3,5-dinitropyrazine-1-oxide (PZO) has been scaled up to produce approximately 25 g batches of material. A number of novel nitrations using NO2+BF4- have been carried out on a range of chloro-, methyl- and hydroxy-functionalised quinoxalines and quinazolines. A range of novel functionalisations have also been carried out on the platform molecule; 2,4-diamino-6,8-dinitroquinazoline giving rise to 2,4-diamino-6,8-dinitroquinazoline-1,3-dioxide (di-N-oxidation product), 2,4,7-triamino-6,8-dinitroquinazoline (monoamination product) and 2,4,6,8-tetra-aminoquinazoline (dihydrogenation product). Detonics molecular modelling was carried out on the following target molecules: 2,5-diamino-3,6-dinitropyrazine-1,4-dioxide (PZDO), 2,5,8-triamino-3,6,7-trinitroquinoxaline-1-oxide and 2,5,7-triamino-4,6,8-trinitroquinazoline-1-oxide. The detonation velocity of the new explosive molecule; 2,5-diamino-3,6-dinitropyrazine (ANPZ-i) was calculated and it was found to be a similar value to that obtained experimentally for the existing high explosive RDX. Calculation by molecular modelling of the steric energies of ANPZ, PZO, ANPZ-i and PZDO gave a quantitative assessment of the difficulty in oxidising ANPZ-i to give PZDO. Extensive analysis of carbon-13 NMR spectroscopy shift values was carried out for approximately twenty nitrogen heterocyclic compounds. Comparison of shift values indicated consistency in the interpretations. On-line literature searches have shown that the following compounds prepared in this project are new: 2,3,6-trichloro-5-nitroquinoxaline, 2,3-dimethoxy-6,7-dinitroquinoxaline, 2,3,6-trichloroquinoxaline-1-oxide, 2,4-diamino-6,8-dinitroquinazoline-1,3-dioxide, 2,4,7-triamino-6,8-dinitroquinazoline and 2,5-diamino-3,6-dinitropyrazine (ANPZ-i). Furthermore, new synthetic routes have been used in the preparation of the following compounds: 2,3-dichloro-5-nitroquinoxaline, 2,3,6,7-tetrachloro-5-nitroquinoxaline, 2-hydroxy-6-nitroquinoxaline, 2-hydroxy-3-methyl-6-nitroquinoxaline and 2,5-diethoxy-3,6-dinitropyrazine.

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24

Al-Suwaidan, I. A. "Heterocyclic compounds as novel substrates for glutathione transferase". Thesis, University of Bradford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378114.

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25

Black, Helen Dinah. "Kinetics of hydroxyl radical reactions with heterocyclic compounds". Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305373.

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26

Fallah, Asadollah. "Stereochemistry and reactivity of some 1,3-heterocyclic compounds". Thesis, University of Portsmouth, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328185.

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27

Mojally, Mariam. "DNA binding studies of fluorinated bioactive heterocyclic compounds". Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/16732.

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Abstract (sommario):

Fluorinated heterocyclic compounds have drug like properties and possess a valuable biological activity due to their rigid chemical structures and the high solubility profile. Novel fluorinated heteroarenes have been synthesised by SNAr reaction of a range of fluorinated arenes including pentafluoropyridine, hexafluorobenzene and pentafluorotoluene to introduce a range of groups specially nitriles, benzimidazole, carbazole and benzimidazole. A number of cyclization reactions have been investigated with the aim of forming polycyclic structures that could act as DNA intercalators. The synthesised compounds have been characterized by elemental analysis, IR, 1H and 19F NMR spectroscopy and single crystal analysis. These compounds have been screened for their biological activities including DNA thermal denaturation assay, UV-Visible spectroscopy, fluorescence spectroscopy, X-ray co-crystallization and antimicrobial activity study. Some of the compounds showed potential DNA bonding activity in particular the carbazole derivatives.

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28

Gavryliuk, O. I. "Heterocyclic compounds as the basis of medical drugs". Thesis, БДМУ, 2022. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/19711.

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29

Robinson, William J. III. "Development of Tetrathiafulvalene Fused N-Heterocyclic Carbene Compounds". Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610382201476554.

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30

Taher, Abutariq. "Novel cyclisations of nitro-compounds for heterocyclic synthesis". Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/34705.

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Abstract (sommario):

The research described in this thesis is aimed at developing novel methods of synthesis for heterocyclic compounds, in particular cyclisation reactions involving the nitro functional group. The first chapter describes investigations into the Wallach imidazole synthesis. A number of chloroimidazoles were prepared, but the possible extension to highly functionalised imidazoles proved elusive. The second chapter describes studies on the successful conversion of nitroimidazolyl malonates 1 into imidazo[4,5-c]isoxazoles 2, Scheme 1. Related cyclisations are described in chapter three and the thiophene fused isoxazole 3 was successfully prepared. Chapter four investigates the reactivity of the strained imidazo[4,5-c]isoxazole heterocycles. Ring opening of the isoxazole occurred on reaction with phosphines to give iminophosphorane derivatives. Reactions with electron deficient acetylenes led to pyrrolyl imidazoles 4, and a novel [1,4]diazepino[2,3-c]isoxazole 5, Scheme 1, but no reaction was observed with alkenes. [Illustration omitted.] Chapter five entails synthesis of a series of 5-aryl-2H,1H-imidazo[4,5-d][1,2,3]triazole derivatives 7. Triethyl N-1-ethyl-2-methyl-4-nitro-1H-imidazol-5-yl phosphoramidate compound 6 was treated with a range of aryl isocyanates which gave imidazo[4,5-c]triazoles 7 in moderate to good yields. A mechanism involving carbodiimide formation was postulated and was supported using infra-red spectroscopy, Scheme 2. Chapter six reports a new synthesis of 5-aryl-2H indazole derivatives 9 by base catalysed reaction of 2-nitrobenzyl triphenylphosphonium bromide salts 8 with a range of aryl isocyanates. A mechanism of this reaction was proposed and investigated by infra-red spectroscopy, Scheme 3.

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31

Venkatraman, M. S. "Synthetic studies towards camptothecin and other heterocyclic compounds". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 1997. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/3278.

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32

Leu, Chao-Wei Chemistry Faculty of Science UNSW. "Synthesis of heterocyclic analogues of phytoestrogens". Publisher:University of New South Wales. Chemistry, 2008. http://handle.unsw.edu.au/1959.4/40824.

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The pyrrolo[3,2,1-ij]quinolin-6-one ring system was synthesised from 3-aryl-4,6-dimethoxyindoles and 2,3-disubstituted-4,6-dimethoxyindoles. The reaction of 4,6-dimethoxyindoles under Friedel-Crafts or Vilsmeier-Haack acylation gave the 2- and 7-indolyldeoxybenzoins in good yield. Cyclisation of 7-indolyldeoxybenzoins with N,N-dimethylformamide dimethyl acetal as a one carbon reagent gave the pyrroloquinolin-6-ones in high yield. Reduction of pyrroloquinolin-6-ones with hydrogen gas and 10% palladium on carbon or lithium aluminium hydride yielded the dihydropyrroloquinolin-6-ones. Demethylation of pyrroloquinolin-6-ones with 48% hydrobromic acid in glacial acetic acid gave a mixture of the monohydroxy and dihydroxy analogues in high yield. The synthesis of quinolin-4-ones using the Conrad-Limpach method was attempted using three different cyclisation conditions such as Dowtherm A, polyphosphoric acid and a mixture of diphenyl ether and methanesulfonic acid. Quinolin-2-ones such as 4-methyl-3-aryl-, 3,4-diaryl- and 3-aryl-4-benzyl-5,7-dimethoxyquinolin-2-ones could be synthesised from either the N-phenylacetylaniline or the N-trifluoroacetyl aniline strategy. Attempted reduction of the quinolin-2-ones with standard metal hydride reagents was unsuccessful. However reduction was achieved via the conversion of quinolin-2-one to the corresponding 2-chloroquinoline followed by reaction of the chloroquinoline with zinc powder and glacial acetic acid to produce a novel, highly substituted quinoline system. Demethylation was successfully carried out with 48% hydrobromic acid in glacial acetic acid to give the trihydroxyquinolin-2-one in high yield. The reactions of 4-substituted-5,7-dimethoxyquinolin-2-ones and the corresponding 2-chloroquinolines as potential organic intermediates were explored. Facile formylation of both quinolin-2-ones and 2-chloroquinolines was observed under Vilsmeier-Haack conditions while acetylation was successful under Friedel-Crafts conditions using antimony (V) pentachloride as the Lewis acid. Further reaction of 8-formyl-quinolin-2-one with 1,2-diaminobenzene in N,N-dimethylformamide led to the formation of a new 8-(benzimidazolyl)-quinolin-2-one ring system. The quinolin-2-ones exhibited selective electrophilic substitution at the C8 position for a range of reactions. However, an unexpected nitration occurred at the C3 position for the 4-methoxy and 4-phenyl-5,7-dimethoxyquinolin-2-ones with good yields. A series of novel 4,6-hydroxylindoles was successfully synthesised from the corresponding methoxy analogues in high yield using anhydrous aluminium chloride. When 3-(4-bromophenyl)-4,6-dimethoxyindole was reacted with 48% hydrobromic acid in glacial acetic acid a 2,2?-indolylindoline dimer was formed. The 5,7-dihydroxyquinolin-2-ones were similarly synthesised in high yield using anhydrous aluminium chloride in chlorobenzene.

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33

Orton, Edward. "Synthesis and chemistry of 4,5-dimethylene-1,3-dioxolan-2-one and related compounds /". Thesis, Connect to this title online; UW restricted, 1985. http://hdl.handle.net/1773/8620.

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34

Nchinda, Aloysius Tchangwe. "Chemical studies of selected chromone derivatives". Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1007442.

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This investigation has been geared towards several aspects of chromone chemistry. Selected 2-(N,N-dimethylarnino)chromones have been synthesized via 2-hydroxyacetophenone boron difluoride complex intermediates, and potentiometric analysis of these compounds in ethanolwater has been used to determine the influence of substituents on their basicity. The pKa values have been found to lie within a narrow range (1.92 - 2.52), and the observed substituent effects have been rationalized with the aid of semi-empirical and ab initio molecular orbital calculations. An efficient route has been developed for the synthesis of the naturally-occurring chromone, "granulosin" [7,8-(methylenedioxy)-2-propylchromone], and several C-2 side chain analogues in good yields, by condensing 2'-hydroxy-3',4'-(methylenedioxy)acetophenone with a range of ethyl carboxylate esters. These compounds show significant cytotoxic activity against the brine shrimp, Artemia salina, and two of them, the 2-ethyl and 2-benzyl derivatives also show 100% activity as pesticides on Beet army worms (BAW). Another naturally-occurring chromone derivative, 5-hydroxy-2-isopropyl-7-methoxychromone, and four C-2 side chain analogues have been prepared in moderate yields. These compounds also show significant cytotoxic activity against the brine shrimp, Artemia salina, and it is apparent that the presence of the hydroxyl group at C-5 is critical for such activity. The electronimpact mass spectra of both series of chromone derivatives have been investigated, permitting the elucidation of characteristic fragmentation patterns. In work directed towards the synthesis of potential HIV -1 protease inhibitors, five novel chromone-containing analogues of the clinically useful drug, ritonavir, have been synthesized. The design strategy has involved the coupling of substituted chromone-2- carboxylic acids with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing chromone termini. An interactive docking procedure has been used to explore the docking of ritonavir and the novel chromone-containing analogues into ' the active site of the enzyme, and has indicated the capacity of the ritonavir analogues to form hydrogen-bonds with the HJV-l enzyme receptor. Various substituted cbromone-3-carbaldehydes, which have been synthesized from the corresponding o-hyclroxyacetophenones using Vilsmeier-Haack methodology, have been examined as substrates for Morita-Baylis-Hillman reactions, using 3-hyclroxyquinuclidine as the catalyst and arcylonitrile and methyl acrylate as the activated alkenes. Optimization of the reaction conditions has permitted efficient conversion of the cbromone-3-carbaldehydes to the Morita-Baylis-Hillman products and, in some cases, dimeric products, within 24 h. Heating of the Morita-Baylis-Hillman products, arising from reactions with methyl acrylate, at 80 ºC for 3 h in the presence of DABCO as catalyst, has been shown to effect transformation to the corresponding dimers in good yield.

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35

Rogers, James William. "1-benzotriazolyl-2-propynones as novel 1,3-biselectrophiles, benzotriazole-assisted thioacylation and synthesis of energetic materials". [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013389.

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36

Cai, Chunming. "Microwave mediated synthesis of nitrogen- and/or oxygen-containing compounds". [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0013762.

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37

Brown, Eric Carroll. "Computational studies on the effects of heteroatom substitution in delocalized pi systems /". Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/8558.

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38

Ganto, Mlungiseleli MacDonald. "Application of Baylis-Hillman methodology in the construction of complex heterocyclic targets". Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1006703.

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Abstract (sommario):

Baylis-Hillman reactions using various aromatic aldehydes, activated alkenes and catalysts have been used to: - access an extensive range of poly-heterocyclic products;explore chemoselectivity; and optimise reaction efficiency. Chromone-3-carbaldehydes and chromone-2-carbaldehydes, prepared via Vielsmeier-Haack and Kostanecki-Robinson methodology, respectively, have been used as Baylis-Hillman substrates with four different catalysts, viz., 1,4-diazabicyclo[2.2.2]octane (DABCO), 3-hydroxyquinuclidine (3-HQ), imidazole and N’,N’,N’,N’- tetramethylpropanediamine (TMPDA), and with methyl vinyl ketone (MVK), methyl acrylate, cyclic enones (2-cyclohexen-1-one, 2-cyclopenten-1-one and chromones) as activated alkenes. Reactions of the chromone- -carbaldehydes with MVK afforded dimeric Baylis-Hillman adducts when catalyzed by DABCO but when the same reactions were repeated using 3-HQ as catalyst, the dimeric products were accompanied by tricyclic Baylis-Hillman adducts. Use of excess MVK, however, led to mixtures of the normal Baylis-Hillman adducts and the tricyclic adducts – interestingly, with the apparent absence of the dimeric products. While reactions of chromone-3-carbaldehydes with methyl acrylate afforded the normal Baylis-Hillman adducts, the chromone-2- carbaldehydes produced, instead, rearrangement products, consistent with an earlier, single observation. Reactions of 2-nitrobenzaldehydes with cyclic enones using imidazole as catalyst afforded the normal Baylis-Hillman adducts, reductive cyclisation of the 2-cyclohexen-1- one and 2-cyclopenten-1-one adducts, using acetic acid and iron powder, afforded the corresponding quinoline erivatives. Treatment of cyclic enones with pyridine-2-carbaldehydes and quinoline-2-carbaldehydes using TMPDA as catalyst generally gave the expected Baylis-Hillman adducts. However, indolizine derivatives were isolated directly from Baylis-Hillman reactions involving pyridine-2-carbaldehydes and 2-cyclohexen-1-one. The remaining Baylis-Hillman adducts were cyclized to the corresponding indolizines by treatment with acetic anhydride both under reflux and under microwave-assisted conditions, the latter approach providing remarkably rapid and efficient access to the polycyclic products. Computer modelling studies have been conducted on selected polycyclic products at the Molecular Mechanics (MM), Quantum Mechanical (QM) and Density Functional (DFT) levels. The theoretical results have been used to calculate UV, IR and NMR absorption data, which have been compared, in turn, with the experimental spectroscopic data. Use has also been made of the estreNova NMR prediction programme and, generally, good agreement has been observed between the predicted and experimental spectroscopic data.

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39

Nocanda, Xolani Wittleton. "Applications of Baylis-Idllman methodology in the synthesis of chromene derivatives". Thesis, Rhodes University, 2001. http://hdl.handle.net/10962/d1018257.

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Abstract (sommario):

The reaction of salicylaldehyde with various activated alkenes, viz., methyl vinyl ketone, ethyl vinyl ketone, phenyl vinyl sulfone, phenyl vinylsulfonate, acrolein and acrylonitrile, under Baylis-Hillman conditions, has been found to proceed with the chemoselective formation of chromene derivatives. The reaction conditions have been optimised and chromene derivatives have been obtained in isolated yields up to 87 %. The generality of the reaction, using 1,4-diazabicyclo[2.2.2]octane (DABCO), as the catalyst, and a heterogeneous (chloroform-water) solvent system, has been established using a range of salicylaldehyde derivatives,. including 2-hydroxynaphthaldehyde. The formation of chromene derivatives, under these conditions, has been assumed to proceed via an initial, Baylis-Hillman reaction, followed by cyclisation involving intramolecular conjugate addition, and subsequent dehydration. Evidence supporting this sequence has been obtained from the isolation ofBaylis-Hillman products from reactions involving the use of tertbutylclimethylsilyl-protected salicylaldehyde, 4-hydroxybenzaldehyde and tert-butyl acrylate as substrates. The potential of the ''Baylis-Hillman zwitterion" to participate as a donor species in Michael-type addition reactions has been explored and a series of climeric products has been isolated. The Baylis-Hillman methodology has also been successfully extended to the synthesis of sulfurcontaining heterocyclic systems, and a range of 3-substituted thiochromenes has been obtained in moderate yields, using 2,2'-dithiobenzaldehyde and various activated alkenes in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as catalyst. The electron-impact mass spectra of selected chromene and thiocbromene derivatives have been investigated permitting comparison of the fragmentation of the oxygen- and sulfur-containing analogues. In a study directed at the synthesis of potential HIV -1 protease inhibitors, chromene- and thiocbromene-containing analogues of the clinically useful drug, ritonavir, have been prepared. Thiochromene and chromene derivatives were converted to the corresponding 3 -carboxylic acids and coupled with a specially prepared, hydroxyethylene dipeptide isostere to afford ritonavir analogues containing cbromene and thiochromene termini in ca. 60% yield.

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40

Cow, Christopher N. "Orchestration of reactions on glycoluril templates /". *McMaster only, 1997.

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41

李安怡 e On-yi Lee. "Synthesis of heterocycles via phenylseleno group transfer radical cyclization and chemoselective reductive amination promoted by InCl3". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B3955756X.

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42

Zinser, Caroline Magdalene. "Palladium and gold N-heterocyclic carbene complexes : synthesis and catalytic applications". Thesis, University of St Andrews, 2019. http://hdl.handle.net/10023/17066.

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43

Johansson, Maria. "Influence of lipids and pro- and antioxidants on the yield of carcinogenic heterocyclic amines in cooked foods and model systems". Lund, Sweden : Dept. of Applied Nutrition and Food Chemistry, Lund Institute of Technology, Lund University, 1995. http://catalog.hathitrust.org/api/volumes/oclc/38206526.html.

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44

Dupuy, Stéphanie. "N-heterocyclic carbene gold hydroxide complexes as bond activation reagents". Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6613.

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Abstract (sommario):

Although known since the 1930s, organogold chemistry has been dormant until recently, primarily due to preconceptions about the inertness of gold in transformations. However, this last decade has witnessed the emergence of a Golden Age with the development of a wealth of reports on gold in a plethora of reactions. In recent years, the drive for more atom- and step-economical and environmentally friendly reactions has become a field of intense research. In our on-going research on well-defined transition metal complexes bearing NHC ligands, our group recently discovered a new gold(I) hydroxide complex [Au(OH)(IPr)] (1a) that can be easily synthesised from the chloride precursor [AuCl(IPr)] (1b). A preliminary survey of the reactivity of this gold synthon has demonstrated interesting reactivity that holds great potential in bond activation reactions and the development of useful synthetic methods. Simplistically, this gold hydroxide complex can be seen as a strong Brønsted base. This thesis is dedicated to an in-depth examination of the reactivity of this complex in base-free bond activation reactions. Two themes predominate in the following chapters: the first part demonstrates the activity of gold(I) hydroxide as a bond activation agent to readily and efficiently access organogold complexes while the second part studies the reactivity of this compound in decarboxylation processes with carboxylic acids. Chapter 2 and 3 were dedicated to the development of new synthetic routes to access organogold complexes via base-free transmetalation reactions with organoborons and silanes using 1a. The combination of experimental and computational studies allowed identification and isolation of key intermediates in these reactions. Chapter 4 can be seen as a transition between the development of novel methodologies to synthesise aryl and heteroarylgold complexes and the first steps of gold hydroxide 1a as mediator in decarboxylation reaction. As a result, a novel mode of reactivity for gold was discovered and the synthetic route developed constitutes one of the greenest procedures to prepare organogold complexes with the generation of water and CO₂ as only side products. Chapter 5 and 6 venture further into the exploration of 1a in decarboxylation reactions and detail the development of a catalytic process for the protodecarboxylation reaction and subsequent mechanistic investigations of this reaction through stoichiometric experiments and kinetic and computational studies.

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45

區逸貫 e Yat-kun Au. "Chemical reactivities of triosmium carbonyl clusters with nitrogen heterocycles and organomercurials". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31234604.

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46

Au, Yat-kun. "Chemical reactivities of triosmium carbonyl clusters with nitrogen heterocycles and organomercurials /". Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B17490340.

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47

Fletcher, Kristin A. "Mobile Order Theory as Applied to Polycyclic Aromatic Heterocycles". Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc278994/.

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Abstract (sommario):

Experimental mole fraction solubilities of benzil, thianthrene, trans-stilbene, thioxanthen-9-one, diphenyl sulfone and dibenzothiophene sulfone are determined in pure noncomplexing and complexing solvents. Predicted solubility values are calculated for benzil, thianthrene, trans-stilbene and thioxanthen-9-one using expressions derived from Mobile Order theory. Large deviations between experimental and predicted solubilities in alcohol solvents exist, therefore optimized solute - solvent association constants are determined. Previously measured thianthrene solubilities in five binary alkane + cyclohexane solvent mixtures are compared with values predicted from Mobile Order theory using the measured solubility in each of the pure solvents as input parameters. The experimental mole fraction solubility of benzil in eight binary alcohol + 1-octanol solvent mixtures are also measured and compared with predicted values.

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48

Burnett, Duane Arthur. "Synthesis of nitrogen containing heterocycles /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487264603219377.

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49

Laserna, Ayora Victor. "Small Molecule Activation for the Formation of Heterocyclic Compounds". Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/457704.

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La tesi se centra en l'activitat dels aminotrifenolatos d'alumini en l'activació de epòxids i la seva posterior acoblament a altres molècules en la formació de diferents heterocicles. El catalitzador és un àcid de Lewis que en interaccionar amb el epòxid augmenta la electrofilia d'aquest, afavorint processos d'obertura de cicle i acoblament a heterocumulenos com el CO2 o el SO2. Hem aconseguit descriure metodologies per a la síntesi de oxazolidinones, carbamats, sulfits cíclics o carbonats cíclics. Molts d'aquests processos ja havien estat descrits amb anterioritat per epòxids terminals, per això nosaltres ens hem centrat en epòxids cíclics la reactivitat és menor ia més els seus productes són més interessants en ser més similars a productes naturals. Estudiant els diferents mecanismes relacionats amb aquestes reaccions i variant les condicions i components dels nostres sistemes catalítics hem aconseguit que totes les nostres síntesi siguin estereoselectives i en algun cas fins i tot estereodivergente.
La tesis se centra en la actividad de los aminotrifenolatos de aluminio en la activación de epoxidos y su posterior acoplamiento a otras moleculas en la formación de distintos heterociclos. El catalizador es un acido de Lewis que al interaccionar con el epóxido aumenta la electrofilia de este, favoreciendo procesos de apertura de ciclo y acoplamiento a heterocumulenos como el CO2 o el SO2. Hemos conseguido describir metodologías para la sintesis de oxazolidinonas, carbamatos, sulfitos cíclicos o carbonatos cíclicos. Muchos de estos procesos ya habían sido descritos con anterioridad para epóxidos terminales, por ello nosotros nos hemos centrado en epóxidos cíclicos cuya reactividad es menor y además sus productos son más interesantes al ser mas similares a productos naturales. Estudiando los distintos mecanismos relacionados con estas reacciones y variando las condiciones y componentes de nuestros sistemas catalíticos hemos conseguido que todas nuestras síntesis sean estereoselectivas y en algún caso incluso estereodivergente.
This thesis focuses on the activity of aluminium aminotriphenolates in the activation of epoxides and their couplings to other molecules in the formation of a series of heterocycles. The catalyst is a Lewis Acid which interacts with the epoxide enhancing its electrophilicity, favoring ring opening processes and couplings to heterocumulenes such as CO2 or SO2. We describe methodologies for the synthesis of oxazolidinones, carbamates, cyclic sulfites or cyclic carbonates. Many of these processes had already been described for other catalyst systems, but we have focused on the less reactive cyclic epoxides, whose products are more interesting as they have similarities to many natural products. Studying the different reaction mechanisms related to these reactions and changing the components and conditions of our catalytic system we have achieved complete stereoselectivity in our reactions and even in some cases stereodivergence.

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50

Berlin, Stefan. "Construction of Five-Membered Heterocyclic Compounds via Radical Cyclization". Doctoral thesis, Uppsala University, Department of Chemistry, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3429.

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Abstract (sommario):

This thesis describes how radical cyclization chemistry can be applied for the construction of heterocyclic compounds.

In the first part, a series of electron deficient α-phenylselenenylalkenes were prepared via a PhSeCl-addition/HCl-elimination sequence. Allyl- and propargylamines readily underwent conjugate addition to these species to produce pyrrolidines or dihydropyrrol derivatives, after triethylborane initiated reductive radical cyclization in the presence of tris(trimethylsilyl)silane.

The second part describes a convergent synthesis of the pineal hormone melatonin. The indole nucleus is secured via a tris(trimethylsilyl)silane mediated 5-exo radical cyclization. The protocol provides convenient and simple access to compounds useful for studies of biological activity and structure activity relationships.

The third part describes construction of substituted tetrahydrofuran-3-ones and pyrrolidin-3-ones. Regioselective ring-opening of epoxides or aziridines with benzeneselenolate/tellurolate, followed by Michael addition to electron deficient alkynes afforded the corresponding O/N-vinylated compounds. The tetrahydrofuran-3-ones and pyrrolidin-3-ones were secured via radical carbonylation/reductive cyclization using pressurized carbon monoxide (80 atm).

The fourth part is concerned with the effect of an N-protecting group on the cyclization of 2-substituted-3-aza-5-hexenyl radicals. Relative energies for reactants and transition states were determined using density functional calculations. Reactant and transition state conformers leading to cis-product were lower in energy than those leading to trans-product. The results can be explained by the unfavorable 1,2-strain present in chair-equatorial and boat-equatorial conformers.

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Tesi sul tema "Heterocyclic compounds"

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