Doctor of Philosophy, Case Western Reserve University, 2005, Chemistry

A new method for cationic cyclization of iron tricarbonyl diene complexes with pendant alkenes and arenes is presented, improving an earlier method developed in the Pearson laboratory, both in terms of economy and reactivity. Previously reported dehydroxylation of diastereomeric alcohols is replaced by regiospecific protonation of a double bond adjacent to the iron tricarbonyl diene moiety (both processes occur with anchimeric assistance from the iron atom). The method was tested in a simple synthetic application: bicyclization of polyene substrates toward octahydrophenanthrene derivatives. Complete diastereoselectivity and adherence to the Stork-Eschenmoser postulate was observed.

Committee: Anthony Pearson (Advisor) Subjects:

Doctor of Philosophy, University of Akron, 2016, Chemistry

99mTc is the most used radionuclide in diagnostic nuclear medicine. Technetium small molecule imaging agents are being used to image almost every tissue in the body, from heart and bones, to the difficult imaging of brain tissue. Though there are many 99mTc complexes currently in use, the search for an ideal technetium radiopharmaceutical is ongoing. Ideal imaging agents must be robust enough to withstand complex biological conditions and ensure clearance from the body, yet selective enough to reach their target tissues for successful scanning. Recent work has shown that compounds based on the fac-99mTc(I)(CO)3+ core exhibit increased stability and resistance to decomposition. The chemistry and pharmacokinetics of these complexes can be safely explored using the non-radioactive, isoelectronic Re(I)(CO)3+ species. Medically useful isotopes of rhenium, 188Re and 186Re, add to the potential applications of this chemistry. In this dissertation we describe the synthesis and metathesis of [Re(CO)3(TAME)]X (where X= Br-, Cl-, NO3-, ClO4-, and PF6-), and it's toxicity in both primary and immortal cell culture lines. The toxicity of the parent molecule, [Re(CO)3(OH2)3]Br, in HeLa-S3 cell culture is explored. The preparation and characterization of a Re(CO)3+-lysozyme adduct is discussed. Additional studies of the efficacy of [Re(CO)3(OH2)3]Br as an X-ray contrast agent and the preparation and partial characterization of an Re(CO)3+-insulin adduct is also described herein.

Committee: Christopher Ziegler Dr. (Advisor); Thomas Leeper Dr. (Committee Member); Sailaja Paruchuri Dr. (Committee Member); Leah Shriver Dr. (Committee Member); Todd Blackledge Dr. (Committee Member) Subjects: Biochemistry; Chemistry; Inorganic Chemistry

BS, Kent State University, 2015, College of Arts and Sciences / Department of Chemistry and Biochemistry

1,3,4-thiadiazole-2-carboxylate thioesters are attractive moieties for inclusion in potentially ferroelectric liquid crystalline materials (possess a strong lateral dipole, small width, and a large bend angle between C2 and C5). The Late-Stage Lawesson's Cyclization strategy has proven extremely effective in preparing these materials. Cyclization of the appropriate 1,4,5-tricarbonyl precursors as the last step in the synthetic pathway has avoided rapid competing decarboxylation reactions, providing high yields and allowing a simple purification process. Three examples of liquid crystalline materials exhibiting wide SmC phases have been prepared.

Committee: Paul Sampson Dr. (Advisor); Alexander Seed Dr. (Advisor) Subjects: Chemical Engineering; Chemistry; Materials Science; Organic Chemistry

BS, Kent State University, 2013, College of Arts and Sciences / Department of Chemistry and Biochemistry

1,3,4-Thiadiazole-2-carboxylate esters are attractive moieties for inclusion in potential ferroelectric liquid crystalline materials (strong later dipole, relatively small bend between C2 and C5, compact size, etc.). However, methods for preparing these materials (of which there are few) have proven difficult in the past due primarily to competition from decarboxylation reactions leading to large amounts of byproducts. Postponing the cyclization of appropriate 1,4,5-tricarbonyl precursors until the last step has proven effective, circumventing demanding experimental conditions and difficult purification processes. Three examples of liquid crystalline materials exhibiting wide SmC phases have been prepared using this method.

Committee: Paul Sampson Dr. (Advisor); Alexander Seed Dr. (Advisor) Subjects: Chemical Engineering; Chemistry; Materials Science

Doctor of Philosophy, Case Western Reserve University, 2008, Chemistry

Dynamic diastereoselectivity during Fe(CO) 3promoted [6 + 2] ene spirocyclization of amide complexes, having a chiral center on the pendant side chain, was investigated to show that the introduction of chirality can dictate the stereochemistry of the cyclization products by strong steric hindrance effect in reaction intermediates. One substrate underwent diastereoselective cyclization to afford two high optical purity products, which might be possible important intermediates for total synthesis of the natural product 18-deoxycytochalasin H. Furthermore, a stepwise second cyclization and a tandem double cyclization mediated by the Fe(CO) 3moiety was investigated. An intramolecular iron tricarbonyl promoted aldehyde-diene coupling reaction was discovered and investigated to provide spirocyclic or bicyclic products. The ability to stereospecifically build new chiral centers, introduce a functionalizable hydroxyl group and avoid isomerization of products significantly expands the scope of our previously reported [6+2] ene type of spirocyclization and tandem double cyclization. An all-carbon double cyclization reaction was also investigated, but it could not proceed to give the anticipated cyclized products due to the difficulty in cyclohexadiene double bond migration before the cyclization step. An alternative strategy was designed and is still under investigation.

Committee: ANTHONY PEARSON (Advisor) Subjects: Chemistry, Organic

Doctor of Philosophy, Case Western Reserve University, 1991, Chemistry

1-carbomethoxy(cyclohepta-1,3-diene)tricarbonyliron 1 and 2-carbomethoxy-(cyclohepta-1,3-diene)tricarbonyliron 2 were prepared in good yield from 2-carbomethoxy-cyclohept-1,3-diene by complexation with pentacarbonyliron or diiron nonacarbonyl. The corresponding dienyl salts 3 and 4 respectively were prepared by hydride abstaction with triphenylmethyl hexafluorophosphate. A range of nucleophiles including dimethyl malonate, nitrile, hydride and thiophenoxide were added to these dienyl salts and some interesting regiochemical results were observed. Addition of dimethyl malonate to both of the dienyl complexes gave a ς-ϖ-allyl complex such as 5 as product. In all previous cases, addition of dimethyl malonate went at the terminus of the dienyl system to give a diene complex. In order to explain this unusual observation 13C NMR studies and extended Huckel calculations were done on some model dienyl complexes to determine charge densities and LUMO coefficients for the carbons of the dienyl system. Also, a classical resolution of the complexes was accomplished via the corresponding caboxylic acid-substituted complex.

Committee: Anthony Pearson (Advisor) Subjects: