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This thesis describes the synthesis of novel thiacrown and azacrown ethers based on the 1.7-dioxaspiro[5.5] undecane ring system. Each chapter discusses the research in some detail. Chapter five describes the attempted kinetic resolution of the spiroacetal moiety, to provide enantiopure starting material for the synthesis of non-racemic spiroacetal crown ethers. Three different approaches were investigated. Chapter six summarises the results achieved and discusses possible strategies emanating from these results. / Doctor of Philosophy (PhD)

This study has resulted in a route to the first known NHZ functionalized xylenebased crown ether, 5-amino-2-methoxy-1,3-xylyl-18-crown-5. The route involves preparing 5-azido-2-methoxy-1,3-xylyl-18-crown-5 from 5-bromo-2-methoxy-1,3-xylyl18-crown-5 by reacting it in turn with n-BuLi and tosyl azide. 5-Amino-2-methoxy-1,3xylyl-l8-crown-5 was obtained by reducing 5-azido-2-methoxy-1,3-xylyl-l8-crown-5 with aqueous sodium borohydride in the presence of a phase transfer agent. The 'H NMR spectrum of the amino derivative showed NMR signals at 6 3.4-3.7 (crown CHZ), S 4.0 (benzylic), S 4.47 (methoxy), and 6 6.58 (aromatic) ppm. The integrated areas were consistent with the formula, and they also suggested the NH2 protons were in the crown CH2 area. The IR (KBr pellet) spectrum showed bands at 3408 cm' and 3364 cm' corresponding to the N-H asymmetric and symmetric stretches, respectively. This study has also provided a new procedure for the preparation of 4-bromo-2,6-bis(bromomethyl) anisole, which was the intermediate for 5-bromo-2-methoxy-1,3-xylyl-18-crown-5. It involved reacting 4-bromophenol in turn with 30 % formaldehyde, dimethylsulfate, and HBr in acetic acid. / Department of Chemistry

The purpose of this research was to synthesize a novel crown ether compound that has been designed to fluoresce with greatly enhanced intensities when in the presence of selected alkali metal cations. The novel crown ether compound (cryptand) 12,25-(1,5 - dimethyloxynaphtho)-1,4,7,10,14,17,20,23-octaoxacyclohexacosane (1) was synthesized through 6 steps. The general synthetic route for the preparation of cryptand 1 is given in the proposed synthetic procedure. Reaction of benzaldehyde (23) with glycerol (24) in the presence of concentrated sulfuric acid afforded cis and traps-1,3-O-benzylideneglycerol (25). Cis and trans-2-O-benzyl-1,3-O-benzylideneglycerol (27) was obtained when 1,3O-benzylideneglycerol (25) was treated with benzyl bromide (26) and sodium wire in benzene. Acid-hydrolysis of the 2-O-benzyl-1,3-O-benzylideneglycerol (27) in methanol gave 2-O-benzylglcerol (28). The key starting material is 12,25-bisbenzyloxy1,4,7,10,14,17,20,23-octaoxacyclohexacosane (31), which requires the formation of four carbon-oxygen bonds. 2-O-benzylglcerol (28) was reacted with triethyene glycol ditosylate and sodium hydride in dioxane. This treatment gave the product 12,25-bisbenzyloxy1,4,7,10,14,17,20,23-octaoxacyclohexacosane likely to be (31) along with the 1:1 and a 3:3 crown ether products. The compound likely to be (31) was treated with H2 and a Pd/Ccatalyst and the resulting compound was 12,25-dihydroxy-1,4,7,10,14,17,20,23Octaoxacyclohexacosane (2). Compound likely to be (2) was reacted with 1,5bis(bromomethy)naphthalene and potassium t-butoxide in tetrahydrofuran to give the final cryptand compound 1. The structures of the crown ethers, the products of this reaction, have not yet been unambiguously assigned. / Department of Chemistry

The goal of this research was to synthesize and study new phosphine crown ethers. The first target molecule was 5-phenylphoshinobis(2-hydroxy,1,3-xylyl-18-crown-5). We tried to synthesize this target molecule in six steps. 5-Bromophenol was reacted with formaldehyde, dimethylsulfate, phosphorus tribromide and tetraethylene glycol in the presence of sodium hydride producing the main intermediate molecule, 5-bromo-2-methoxy-1,3-xylyl-l8-crown-5. This molecule was reacted with n-butyllithium and dimethyl phenylphosphinite at the low temperature . NMR evidence indicated that was not obtained.The second target molecule, the oxide of 5-phenylphosphinobis(2-hydroxy-1,3-xylylcrown-5) was synthesized in nine steps. The main intermediate, 5-bromo-2-methoxy-1,3-xylyl-18-crown-5 was reacted with n-butyllithium and dimethyl phenylphosphinite to form the phosphine. This phosphine was oxidized with hydrogen peroxide. The OCH3 bond of this crown ether was cleaved by using LiI in boiling anhydrous pyridine. NMR data indicated the product was formed. / Department of Chemistry

It has been shown that photolysis of 4-azidopyridine N-oxide yields the singlet nitrene, which undergoes intersystem crossing at room temperature to generate triplet 4- nitrenopyridine N-oxide. The room temperature photochemistry is dominated by triplet nitrene chemistry leading to the formation of the azo-dimer. This unusual behavior is a result of selective stabilization of the lowest singlet state of the nitrene by the N-oxide group. In this study, we wish to investigate the effect of complexation of the N-oxide group with a metal cation on the kinetics and reactivity of 4-nitrenopyridine N-oxide and related compounds. It is envisaged that complexation will alter the polarity of the N-oxide bond making it less capable of spin delocalization in the nitrene. Complexation may be achieved through two different methods: complexation with cations in aqueous salt solutions and complexation of cations inside crown ethers. Crown ethers provide useful models due to the selectivity of complexation with different ions based on ring size and slower diffusion of cations away from the N-oxide group. Progress toward the multi-step synthesis of crown ethers containing the 4- azidopyridine N-oxide substructure is described herein. / Department of Chemistry

This study has resulted in a phosphine funetionalized crown ether. synrdiQ-methoxy-5-diphenylphosphino-1.3-cplyl l-24-crown-6, obtained tkmt a live step synthesis. 4-13romophenol was treated in turn with formaldehyde. di methyl sulfate, and phosphorous trihromide. producing 4-bromo-2.6-his(bromomethyl )anisole. The key intermediate. spm-di(2-methoz}-5-bromo-I.3-z( I).l )-24-crown-6. was obtained from treating 4-hromo-3.6-bis(bromomethyl )anisole with diethylenc glycol and potassium thutoyide. The potassium ion apparently provided a template to assist the formation of the product. SLm-di(2-methosp-5-diphenylphosphino- I.3-x lyl )-24-crown-6 was obtained from treating sm-di(2-methos5-5-hromo-I.3-x'kI -24-crown-6 in sequence with n-BuLi and methyldiphern I phosphinite. The nP NMR of the phosphine crown ether showed a single signal at 6 -5.35 ppm. consistent with the formation of a single product.The'1I NMR of the phosphine crown ether in chloroform-d showed signals at6354-3.56 (crown CIF). 3.61 I OCI I;I. 4.44 (benzylic Cl I.6 and 7.25-7.29 (aromatic Ii) ppm.The integrated areas were consistent with the formula. The `C NNIR of the phosphine crown ether in chloroform-d displaced signals at 6 63.1, 68.5. 70.0. 70.1. 128.5 and 128.6 (d). 128.7. 131.8 and 131.9 (d), 132.0. 133.6 and 133.7 (d). 136.1 and 136.4 (d). 137.4 and 137.5 (dl, and 158.4 ppm. The "C signals were consistent with the formula and structure. The br)minated crown ether was characterized with 'I I and ''C NMR. as well as X-ray crystallography and elemental analysis. / Department of Chemistry

Thesis (M.S.)--University of Texas at Dallas, 2008. / Includes vita. Includes bibliographical references (leaves 85-88)