Thesis (Ph.D.) - University of St Andrews, March 2009. / Electronic version restricted until 17th March 2010.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 143-147).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1973. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Dissertation--Hamburg, 1925. / Lebenslauf.

With the intention of preparing long chain esters containing a carbocyclic system, methyl linoleate and related esters were subjected to strongly acidic reaction conditions. The major product of the reaction, however, was shown to be a mixture of isomeric 1,4-epoxidea (tetrahydrofurans) and for comparison, a mixture of the cis and trans 9,12-epoxidos was prepared by an unambiguous synthesis. The discovery of those hotorocyclic fatty esters prompted further investigations into their methods of preparation. The cyclodehydration of some trihydroxyacids containing a 1,4-diol system was examined and the mechanism of the reaction elucidated. Those studies led to the formulation of the absolute configurations of the 9,12,13-tri-hydroxystearic acids. Methyl ricinoleate and methyl 9-hydroxyoctadec-cis-12- enoate were found to give different types of product when epexidised, The former yielded the expected 1,2-epoxide, whilst the latter furnished a mixture of hydroxytetrahydrofurans (90%). Since it was evident that the second reaction involved participation by the hydroxyl function, other epoxidation Reactions of various hydroxy, oxo and acetylenic ostors were investigated. The results indicated that oxo and hydroxy functions can interact with a proformed epoxide to yield cyclic products. Finally, various unsubstiuted 1,4-opoxidos were prepared by free radical oxidations of some hydroxyostors. Both load totraacotate and metal oxido-halogon mixtures were used as oxidising agents.

Twelve heterocyclic ring compounds have been prepared and a high resolution Nuclear Magnetic Resonance study of each carried out. In particular, solvent effects and coupling constants have been studied. Some axial and equatorial shifts of methylene protons were found to be reversed compared to the predicted situation, Observed coupling constants have been found to be slightly solvent dependent. Some interesting values of coupling constants prompted a full X-ray crystal analysis of two of the compounds. This has been done, yielding bond lengths, bond angles, configuration around the phosphorus atom and conformation of the heterocyclic ring, all in the solid state. Dihedral angles for P-O-C-H systems have been calculated and an attempt has been made to correlate observed coupling constants with dihedral angles and electronegativity of substituents.

Various rules which have been used to rationalise molecular geometries are discussed. After this the results from MNDO calculations on simple carbenes, ethers and amines are presented, and these were designed to test the hypothesis that in the presence of ligands of low electronegativity lone pairs would not fulfil their stereochemical role assigned to them in the VSEPR model. Following on are MNDO calculations on cyclic molecules: the cyclopentadiene ring is planar in silylcyclopentadiene and non-planar in trimethylsilylcyclopentadiene. The calculations attempt to resolve this and in addition the nature of the fluxional exchange. The intermediates which are formed by diazepinium salts when they are protodebrominated are then discussed in the light of MNDO calculations. Single crystal x-ray work was carried out for four heterocyclic molecules. The compounds reported are: 4-phenyl-3-phenylamino-1,2,4-thiadiazolin-5-one; 5-(N-methylthiocarbamoylimino)-4-phenyl-3-phenylamino-4H-l,2,4-thiadiazoline; N,N-bis[2-(5-t-butyl-3H-1,2-dithiol-3-ylidene)ethylidene]hydrazine and N,N-dimethyl-N-[2-(5-t-butyl-3H-1,2-dithiol-3-ylidene)ethylidene]hydrazine. Details of MNDO calculations which were undertaken on molecules related to the x-ray work are then presented, and in the final chapter a discussion of the heterocyclic crystal structures appears. The first appendix reports the structure of a macrocyclic ligand, the second provides a list of publications and the third appendix is a list of the structure factors, least-squares planes and anisotropic temperature parameters for the crystal structure determinations.

No description available.

The reaction of specially prepared salicylaldehyde benzyl ethers with the activated alkenes, methyl acrylate or acrylonitrile, in the presence of the catalyst, DABCO, has afforded Baylis-Hillman products, which have been subjected to conjugate addition with either piperidine or benzylamine. Hydrogenolysis of these conjugate addition products in the presence of a palladium-on-carbon catalyst has been shown to afford the corresponding 3-substituted coumarins, while treatment of O-benzylated Baylis-Hillman adducts with HCl or HI afforded the corresponding 3-(halomethyl)coumarins directly, in up to 94%. The 3-(halomethyl)coumarins have also been obtained in excellent yields (up to 98%) and even more conveniently, by treating the unprotected Baylis-Hillman products with HCl in a mixture of AcOH and Ac₂O, obtained from tert-butyl acrylate and various salicylaldehydes. The generality of an established route to the synthesis of coumarins via an intramolecular Baylis-Hillman reaction, involving the use of salicylaldehyde acrylate esters in the presence of DABCO, has also been demonstrated. Reactions between the 3-(halomethyl)coumarins and various nitrogen and carbon nucleophiles have been shown to proceed with a high degree of regioselectivity at the exocyclic allylic centre to afford 3-substituted coumarin products. The electronimpact mass spectra of selected coumarin derivatives have been investigated using high-resolution and B/E linked scan data. Fragmentation pathways have been proposed and fragmentation modes associated with different coumarin-containing analogues have been compared. A series of coumarin-containing analogues of ritonavir (a clinically useful HIV-1 protease inhibitor) have been prepared and characterized. The synthetic approach has involved the coupling of coumarin derivatives with a hydroxyethylene dipeptide isostere to afford ritonavir analogues containing coumarin termini. An interactive docking procedure has been used to explore the docking of ritonavir and a coumarincontaining analogue into the enzyme active site.

The reaction of various 2-nitrobenzaldehyde derivatives with methyl vinyl ketone (MVK) in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) has afforded the Baylis-Hillman adducts in moderate to good yield. Dissolution of the catalyst in the solvent before the addition of the aldehyde was observed to improve the yield. Reduction of the Baylis-Hillman adducts was effected by catalytic hydrogenation using a 10% palladium-on- carbon catalyst in ethanol to give quinoline and quinoline-N-oxide derivatives and, in some cases, acyclic reduction products. All products were characterised using NMR and, where appropriate, HRMS methods. Selected quinoline-N-oxides were successfully converted to their corresponding quinoline derivatives using phosphorus tribromide (PBr₃) and DMF as solvent. Conjugate addition of the benzylamine and piperidine nucleophiles to the Baylis-Hillman adducts was also investigated but proved problematic, with one of the substrates undergoing a retro-Baylis-Hillman reaction to afford the aldehyde in ca. 40% yield, but seemingly only traces of the required product. Perkin-type coupling of two 2-methylquinolines with benzaldehyde was successfully effected to afford the desired styrylquinoline derivatives confirming the potential of the Baylis-Hillman approach to the construction of the analogues of known HIV-1 integrase inhibitors. Three ¹³C NMR chemical shift prediction programmes, viz., Chem Window, neural network and HOSE (hierarchically ordered spherical description of environment) methods were applied to selected representative compounds prepared in the project. The results from the three programmes correlated reasonably well with the experimental carbon-13 chemical shift data for each of the selected compounds.