Six bis(silyl)acetylenes with the following varied silicon substituents were prepared: I (Me, Me); II (H, H); III (Cl, H); IV (Cl, Cl); V (OMe, H); VI (OMe, OMe). While I and II may be prepared by the reaction of dilithio- or bis(bromomagnesium)-acetylide with appropriate chlorosilane, similar reactions designed to give III - VI give oligomers, YMe_2Si(C≡C-SiMe_2)_nY, VII, Y = Cl, OMe, as the major products indicating that the acetylenic functionality on silicon activates the chlorosilane toward nucleophilic substitution. Compounds III and IV were prepared by free radical chlorination of II. Methanolysis of III and IV gave quantitative yields of V and VI, respectively. In the presence of mineral acid, VI readily cyclized to give high yields of the cyclic siloxane octamethyl-4,9-dioxa-3,5,8,10-tetrasila-cyclodeca-1,6-diyne, VIII, and the analogous triyne, IX. It was determined that V and VI could be prepared directly from II in high yield by methanolysis with palladium catalyst. Vaska's complex also accomplished the conversion. I attempted to prepare bis(ethoxydimethylsilyl)acetylene by using of Wilkinson 's catalyst for hydrosilylation with acetaldehyde. The principal product of this reaction was 1-(dimethylsilyl)-3,5,5-trimethyl-4-oxa-3-silacyclopent-1-ene, XI.

As part of a continuing study of the synthesis and chemistry of new, substituted pentacyclo(5.4.0.0²，⁶.0³，¹º.0⁵，⁹)undecanes, the following compounds have been synthesized: 1: X=O, Y=SiMe_3; 2: X=CH_2, Y=SiMe_3; 3: X=O, Y=Cl; 6: X=OAc, Y=H; 8: X=OC(O)Ph, Y=H; 9: X=OSO_2Ph, Y=H; 11: X=OH, Y=H; 12: X=OMe, Y=H; 14: X=CHSiMe_3, Y=SiMe_3; 15: X=OH, Y=Cl; 16: X=OAc, Y=Cl; 17: X=OMe, Y=Cl. An important objective of this work is to prepare new polycyclic cage compounds which can be utilized as intermediates for the synthesis of new, substituted tricyclopentanoid natural products (triquinanes) and related systems. Compounds 1-4 were identified as target molecules in this connection.

A thesis submitted to the Faculty of Science, University of the Witwatersrand Johannesburg. In fulfilment of the requirements for the Degree of Doctor of Philosophy. March 2017 / In this PhD thesis, we report for the first time, new methodology for the synthesis of angucycline antibiotic natural products. In particular, for the synthesis of 1,8-dihydroxy-3methyltetraphene-7,12-dione, commonly known as tetrangulol. We also report on the synthesis of 1,10,12-trimethoxy-8-methylbenzo[c]phenanthridine in our quest to synthesise phenanthroviridone from an intermediate product in the synthesis of tetrangulol. The Suzuki-Miyaura coupling reaction between 1,4,5-(trimethoxynaphthalen-2-yl)boronic acid and 2-iodo-3-methoxy-5-methylbenzaldehyde afforded intermediate, 3-methoxy-5methyl-2-(1,4,5-trimethoxynaphthalen-2-yl)benzaldehyde. Conversion of this benzaldehyde into the alkyne, 2-(2-ethynyl-6-methoxy-4-methylphenyl)-1,4,5-trimethoxynaphthalene was accomplished utilizing the Corey-Fuchs reaction. Exposure of the derived acetylene to a catalytic platinum(II)-mediated ring closure yielded the required tetracyclic aromatic product, 1,7,8,12-tetramethoxy-3-methyltetraphene which was converted into tetrangulol. Exposure of the related 3-methoxy-5-methyl-2-(1,4,5-trimethoxynaphthalen-2-yl)benzaldehyde O-phenyl oxime to microwave irradiation in an ionic liquid yielded 1,10,12-trimethoxy-8methylbenzo[c]phenanthridine, instead of the desired natural product phenanthroviridone. We also report on the unexpected synthesis of the benzonaphthopyranone core found in other classes of angucycline antibiotics from oxygen analogs of 2-naphthylbenzyl alcohols when exposed to N-bromosuccinimide. Treatment of (2-(1,4-dimethoxynaphthalen-2yl)phenyl)methanol and related analogues with N-bromosuccinimide under an oxygen atmosphere afforded 12-methoxy-6H-dibenzo[c,h]chromen-6-one, 2-Methoxy-6Hbenzo[c]chromen-6-one and of 6H-benzo[c]chromen-6-one. An investigation into possible mechanisms for this transformation was also conducted. / LG2017

A thesis submitted to the Faculty of Science University of the Witwatersrand Johannesburg In fulfilment of the requirements for the Degree of Doctor of Philosophy June 2015 / The first two chapters of this thesis deals with the synthesis of 6H-benzo[d]-naphtho[ 1,2- b]pyran-6-one motif found in gilvocarcin as well as related aromatic compounds containing the aromatic pyranone moiety. The synthesis was undertaken by employing the Suzuki- Miyaura cross coupling reaction and a novel N-bromosuccinimide induced ring cyclization reaction to afford the pyranone. It was established that the treatment of both [2-(1,4- dimethoxynaphthalen-2-yl)phenyl]methanol and (2',5'-dimethoxy-[1,1'-biphenyl]-2- yl)methanol separately with N-bromosuccinimide results in the unexpected synthesis of a naphthopyranone ring system in the form of 12-methoxy-6H-dibenzo[c,h]chromen-6-one and 2-methoxy-6H-benzo[c]chromen-6-one respectively. Application of the same methodology for the attempted synthesis of related compounds namely, 1-hydroxy-12-methoxy-6Hdibenzo[ c,h]chromen-6-one and 8-fluoro-12-methoxy-6H-dibenzo[c,h]chromen-6-one unfortunately did not generate the desired results. Attempts were made to elucidate the mechanism of this reaction. The most apparent mechanism indicates that Nbromosuccinimide, in the presence of air, oxidizes the benzylic alcohol to an aldehyde which is then converted to an acid bromide allowing for the ring closure with the adjacent aromatic ether to afford the desired pyranone. In Chapter 3 and 4 of this thesis we dealt with the synthesis of benzo[b]phenanthridine-7,12- dione motif, the backbone of biologically important secondary metabolite jadomycin B. Again, a key step involves employing the Suzuki-Miyaura cross coupling reaction. The synthetic methodology also sheds some light on the dynamics of the ring closure of benzylic amines onto naphthoquinones resulting in the synthesis of benzo[i]phenanthridine-11,12- dione, 12-methoxybenzo[i]phenanthridine and 1-hydroxybenzo[i]phenanthridine-11,12-dione. The synthesis of benzo fused phenanthridines has been undertaken in Chapter 5 and 6 by employing Suzuki-Miyaura cross coupling reaction and a potassium t-butoxide and light mediated cyclization reaction as the key steps. The synthesis of 5- phenylbenzo[i]phenanthridine was undertaken successfully but attempts to execute the same methodology to form a compound library of related benzo-fused phenanthridines was unsuccessful. The same methodology employing a Suzuki-Miyura cross coupling reaction and potassium tbutoxide and light mediated cyclization reaction was applied in Chapter 7 and 8 of the thesis directed towards the synthesis of 13H-indolo[3,2-c]acridine and 3-methoxy-13H-indolo[3,2- c]acridine. The successful synthesis of the 13H-indolo[3,2-c]acridine is reported using this methodology.

We report here the development of new and more general synthetic pathways for the preparation of allenyl and alkynyl carbonyls. These highly dense functionalized compounds were utilized as key intermediates for the synthesis of [3.2.1] and [3.3.1] bicyclic framework, the motifs found in many natural products. A convenient method described for the dehydration of ketoesters to generate conjugated and deconjugated alkynyl esters and conjugated allenyl esters. This sequential one-pot method involves the formation of a vinyl triflate monoanion intermediate that leads to the selective formation of alkynes or allenes depending on additives and conditions used. Product outcomes appear to be a function of unique monoand dianion mechanisms which are described. Our design of a Morita-Baylis-Hilman (MBH) reaction to include a fast silyl 1,3- Brook rearrangement has enabled the first ever anion-catalysis. This new reaction makes possible the addition of both aliphatic and aromatic aldehydes to s ilylallenes leading to carbinol allenoates. These new MBH reactions products allow for a fasttracked synthesis of [3.2.1] bisoxa-bicycles which make up the framework of many biologically active natural products including Vitisinol D. The development of cyclic addition of hydrazine nitrogen to unactivated alkynes catalyzed by non-metals is reported. Starting from readily accessible silyl allenyl esters, alkynyl hydrazines are prepared in one step and subsequently undergo unprecedented cyclization reactions in the presence of ammonium and phosphonium catalysts leading to dehydro-azaproline products. These heterocycles were also produced in high enantiomeric excesses using chiral ammonium phase transfer catalysts via a kinetic resolution pathway. / The racemic synthesis of fully functionalized bicyclic core of Vitisinol D was achieved using allenyl ester as a key intermediate. The required electron withdrawing group (EWG) at the position was screened for better addition followed by the compatibility towards successive transformation and, finally, the ease of removal. A reductive aldol method to transform lactone-enol to the desired [3.2.1] bicycle was extensively studied to understand the stereoelectronic requirements for the formation of such bicyclic structures. Due to the necessity of selective protection and deprotection of many phenolic and aliphatic hydroxyls as well as ester groups, orthogonal protecting groups were established accordingly. / by Pradip Maity. / Thesis (Ph.D.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

Orientador: Marcio José Tiera / Banca: Carla Cristina Schmitt Cavalheiro / Banca: Iêda Aparecida Pastre Fertonani / Resumo: O presente trabalho apresenta a síntese, caracterização e estudo da auto-associação em solução aquosa de derivados anfifílicos zwiteriônicos de quitosana com potencial para o transporte e a liberação controlada de fármacos. Derivados anfifílicos foram obtidos a partir de quitosana previamente desacetilada e degradada, que foram submetidos à reação de adição de Michael com o monômero hidróxido de 1-(3-sulfopropil)-2-vinilpiridina (SPP). O derivado hidrofílico obtido foi posteriormente por modificado com o grupo dodecil aldeído (DD) por meio de reação de aminação redutiva. Os graus de substituições (GS) pelos grupos DD e SPP foram determinados utilizando as técnicas de espectroscopia de ressonância magnética nuclear de hidrogênios RMN de 1H, espectroscopia no infravermelho IV e titulação potenciométrica essas técnicas foram utilizadas para caracterizar a quitosana e seus derivados. Os graus de substituição por SPP foram de 36 e 46% e com grupos dodecil variaram de 2 a 10%. A massa molar média foi determinada utilizando cromatografia de permeação em gel (GPC). E o estudo do comportamento associativo em meio aquoso foi realizado utilizando-se a espectroscopia de fluorescência, espectroscopia no UV-Vis, espalhamento de luz dinâmico (DLS) e microscopia eletrônica de transmissão (TEM). Os derivados hidrofílicos permaneceram solúveis em toda a faixa de pH e os derivados anfifílicos demostraram um comportamento similar aos surfactantes convencionais. As concentrações de agregação crítica (CAC), foram determinadas com a sonda fluorescente o pireno, os valores variaram de 0,005 até 0,017 g L-1 foi observado um decréscimo nos valores com o aumento do conteúdo hidrofóbico e pH. Medidas de DLS mostraram que os derivados formam agregados com diâmetros que variam de 100 a 1000 nm e o potencial zeta varia de acordo pH da solução. Imagens de TEM mostraram agregados esféricos de tamanhos variados ... / Abstract: This work presents the synthesis, characterization and self-association study of amphiphilic zwitterionic derivatives of chitosan in aqueous solution as potential drug delivery systems. Amphiphilic derivatives were obtained from deacetylated and degraded chitosan, followed by Michael addition reaction with the monomer 1-(3-sulfopropyl)-2-vinylpyridine hydroxide (SPP). The hydrophilic derivative was further modified with dodecyl groups (DD) by reductive amination reaction. The degrees of substitution (DS) by DD and SPP groups were determined using H1-NMR, and FTIR and potentiometric titration techniques were used to characterize chitosan and its derivatives. The degrees of substitution by SPP were 36 and 46 % and by dodecyl groups varied from 2 to 10%. The average molecular weights were determined using the gel permeation chromatography (GPC). The study of the selfassociation in aqueous solution was performed by using fluorescence spectroscopy, UV-Vis, dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. The hydrophilic derivatives were soluble in all pH range and the amphiphilic derivatives exhibited self-association behavior similar to conventional surfactants. The critical aggregation concentrations, determined from pyrene fluorescence, varied from 0.005 to 0.017 g l-1 and were shown to decrease with both, the increasing hydrophobic content and pH. DLS measurements showed that self-association of the amphiphilic derivatives leads to formation of aggregates having diameters varying from 100 to 1000 nm and the zeta potential varied according with the pH. The TEM images showed spheroidal aggregates of varied sizes in accordance with DLS measurements. Quercetin was used as a model for drug loading study and the results showed that solubilizing capacity increased from 17 to 54% with the hydrophobic content of the ... / Mestre

The main focus of this thesis is to present the structural and photophysical characteristics of the coordination polymers [Ln(C7H3NO4)(C7H4NO4)(H2O)]n (Ln is Pr, Nd, Sm, Eu, and Tb), as well as attempting to synthesize the novel organic linker 4,4'(4,8-Dihydrobenzo[1,2-b:4,5-b']dithiophene-4,8-diyl)dibenzoic acid (BDTDC). Various lanthanide salts were coordinated with 2,3-pyridinecarboxylate (2,3- pydc) via hydrothermal synthesis. ... Progress was made toward the synthesis of a novel metal-organic framework linker BDTDC. Synthesis of the intermediate benzo[1,2-b:4,5-b']dithiophene as well as the determination of the crystal structure, were performed successfully and are reported herein. / by Amanda Lyn Staggeer Ramirez. / Thesis (M.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Thesis (DTech(Chemistry)) --- Cape Technikon, Cape Town, 1996 / A new general synthetic strategy for the synthesis of benzo[c]pyranquinones, with a view to making the route more generally applicable to the synthesis of naturally occurring naphtho[2,3-c]pyranquinones of potential importance as antimicrobial agents, has been developed. This synthetic approach afforded, inter alia, the natural products, is oeleutherin and hongconin (as their racemates) in good overall yield. A new high-yielding synthetic route for the synthesis of 1,5-dimethoxy-4naphthol, 2-allyl-5-methoxy-I,4-naphthoquinone and 3-acetyl-5-methoxy-I,4naphthoquinone, all ofwhich are key intermediates in several laboratory routes to naturally occurring naphtho[2,3-c]pyranquinones, has also been developed. A key-step in their formation is respective methylation, allylation or acetylation of a common intermediate Diels-Alder adduct. A feasible route to a naphtho[2,3-c]pyranone was developed. This model route is envisaged to be generally applicable for the synthesis of higher oxygenated naphtho[2,3-c]pyranones by virtue ofthe nature of the conditions and reagents used in this synthetic route. The target quinones and some of their precursors were evaluated for antimicrobial activity and specificity in vitro. This showed that the benzo[c]pyranquinones have a broader specificity spectrum than their naphtho[2,3-c] or naphtho[2,3-b] analogues.

A 5-membered INOC cycloadduct 84 was employed to prepare alcohol 91, which was transformed into several cyclopent-2-enone derivatives 94-96. / By using intramolecular nitrile oxide-alkene cycloaddition (INOC) as the kep step to construct hydroxylated carbocycles, gabosine F was synthesized for the first time from L-arabinose. Hence, theoretically, gabosine B, which is the enantiomer of gabosine F, can also be synthesized from D-arabinose by the same synthetic strategy. / In this thesis, the background information on the construction of carbocycles from carbohydrates via intramolecular 1,3-dipolar cycloaddition is presented. A review regarding the syntheses of gabosine B and cocaine are also descibed. / Starting with D-ribose, INAC of nitrones 113, 129, and 140, bearing an alpha/beta-unsaturated ester as the dipolarophile was studied. The INAC endo-cycloadduct 141 (cycloheptane) was converted into natural cocaine sucessfully, together with cocaine analogues 162,169,170,173,175, and 177. / The regioselectivity of intramolecular nitrone-alkene cycloaddition (INAC) was studied. The INAC of hept-6-enose nitrone 98, with a 3,4- trans-pentylidene acetal as the only blocking group, afforded endo-cycloadduct 97 (cycloheptane) exclusively. This result concluded that the regiospecific outcome of this INAC reaction is due to the present of the 3,4-trans-pentylidene acetal blocking group. / To investigate the regioselectivity in INAC of hex-5-enose with a 2,3- trans-pentylidene acetal blocking group, nitrones 178 and 195 were prepared from D-mannitol. endo-Cycloadducts (cyclohexanes) were afforded exclusively. / So, King Ho. / Adviser: Kung Ming Tony Shing. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 165-171). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

by Huichang Zhang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 114-130). / Acknowledgment --- p.i / Abstract --- p.ii / Abbreviations --- p.iii / Table of Contents --- p.iv-v / Chapter Chapter I --- Introduction --- p.1 / Chapter I --- The basis of asymmetric catalysis --- p.6 / Chapter II --- Chiral catalyst --- p.8 / Chapter II-I --- Center metal --- p.9 / Chapter II-II --- Chiral ligand --- p.10 / Chapter III --- Structural analysis of effective chiral ligands --- p.13 / Chapter III-I --- Monodentate ligand --- p.15 / Chapter III-II --- Bidentate Ligand --- p.16 / Chapter 1 --- Bidentate phosphine ligand --- p.16 / Chapter 2 --- Bidentate oxygen ligand --- p.17 / Chapter 3 --- Bidentate nitrogen ligand --- p.19 / Chapter 4 --- "Bidentate ligand with N, 0，P, or S donor atom" --- p.21 / Chapter III-III --- Potentially tridentate ligand --- p.22 / Chapter III-IV --- Potentially tetradentate ligand --- p.23 / Chapter IV --- Tentative conclusions on the effect of structural elements --- p.24 / Chapter Chapter II --- "Design, synthesis and resolution of novel chiral pyridylphenols" --- p.27 / Chapter I --- Design of chiral ligand --- p.27 / Chapter II --- Synthesis of chiral ligands --- p.29 / Chapter II-I --- "Synthesis of the chiral N, O-donor ligands" --- p.29 / Chapter 1 --- Synthesis of the chiral ligands 75a-75c --- p.29 / Chapter 2 --- Synthesis of the chiral ligands 93a and 93b --- p.37 / Chapter 3 --- Synthesis of the chiral ligands 97a-97c --- p.41 / Chapter II-II --- "Synthesis of the chiral N, P-donor ligand 98 and N, S-donor ligand 101" --- p.42 / Chapter III --- Resolution of racemates of chiral ligands --- p.44 / Chapter III-I --- Resolution of of the pyridylphenol 75b --- p.44 / Chapter III-II --- Resolution of of the pyridylphenol 93a --- p.48 / Chapter III-III --- Racemization study of 75b and 93a --- p.52 / Chapter 1 --- Racemization test of 75b --- p.52 / Chapter 2 --- Racemization test of 93a --- p.52 / Chapter Chapter III --- Asymmetric addition of diethylzinc to aromatic aldehydes catalyzed by chiral pyridylphenols / Chapter I --- Backgound --- p.53 / Chapter II --- Asmmetric addition of Et2Zn to aldehydes catalyzed by chiral pyridylphenols --- p.61 / Chapter II-I --- Asmmetric addition of Et2Zn to aldehydes catalyzed by (R)-(+)-75b --- p.61 / Chapter 1 --- The influence of the solvent --- p.61 / Chapter 2 --- The influence of the reaction temperature --- p.64 / Chapter 3 --- The influence of the concentration of catalyst --- p.66 / Chapter 4 --- Electronic effect on the enantioselectivity of asymmetric addition of Et2Zn to aromatic aldehydes --- p.67 / Chapter II-II --- Asmmetric addition of Et2Zn to aldehydes catalyzed by (5)-(+)-75b --- p.73 / Chapter II-III --- Asmmetric addition of Et2Zn to aldehydes catalyzed by (R)-(+)-93a --- p.75 / Chapter III --- Conclusions --- p.78 / Chapter Chapter V --- Experimental Section --- p.79 / References --- p.114 / NMR Spectra --- p.131