Four main series of novel heterocyclic compounds were successfully syniliesised. Two of these series were found to be post-emergence herbicides with the activities of each being based on a different mode of action. The (pyrazole-4-yl)alkanones are inhibitors of protoporphyrinogen oxidase, an enzyme in chlorophyll biosynthesis, whereas alkyl 3-arylsulfonylamino- 3-methyllhio-2-(pyrimidin-2-ylcarbamoyl)acrylates and pyrimidin-2-yl 3-(2- chlorophenyl)sulfonyl-amino-3-methylthio-2-cyanoacrylamides (collectively termed "vinylogous sulfonylureas") are inhibitors of acetohydroxy acid synthase (AHAS). an enzyme in branched-chain amino acid biosynthesis. Both these enzymes are established targets for current commercial herbicides. Studies of the utility of 2-(l-ethoxyalkylidene)-3-oxoaIkanenitriles (acrylonilriles) in heterocycle synthesis were facilitated by the recent development of a convenient route to these starting materials. Acrytonitriles were reacted with different hydrazines to give (pyrazol-4-yl)alkanones and pyrazole-4-carbonitriles in varying proportions depending on the reaction conditions and the substituents on the reactants. Although distinction between alternative 3- and 5-substituted pyrazoles is a perennial problem in pyrazole synthesis, in this case the products of these reactions were successfully characterised and identified using a range of n.m.r. spectroscopy techniques. Once the herbicidal mode of action of the (pyrazol-4-yl)alkanones had been confirmed, synthesis of a series of analogues allowed the structural elements contributing to biological activity to be identified. The reaction of acrylonitriles with bidetate nucleophiles such as thiourea gave novel pyrimidines. but these compounds were not herbicidal. The vinylogous sulfonylureas were synthesised using established procedures to obtain novel compounds structurally related to the commercial herbicide chlorsulfuron. The biological activity of the vinylogous sulfonylureas was found to be sensitive to apparently minor changes in structure, but x-ray crystallographically-generated structures of an active and an inactive member of the series revealed marked differences in conformation. Some of the vinylogous sulfonylureas were used as synthons for pyrazole and pyrazolopyrimidine derivatives. Although these compounds did not exhibit herbicidal activity, this synthesis provided the basis for some interesting chemistry. Unexpected elimination of the arylsulfonylamino group was observed when a vinylogous sulfonyurea was treated with methyl hydrazine. In order to confirm the identity of the 3-methylthiopyrazole product, model compounds were synthesised using alternative routes. The resulting pairs of 3- and 5-substituted pyrazoles were characterised using n.m.r spectroscopy.

207 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Organic Chemistry, 1981

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

A range of N-H alkynylaziridines were prepared from amphoteric unprotected aziridine aldehydes without protecting-group manipulation. Unprotected alpha -amino allenes can be obtained from these strained propargyl amines via a 9-BBN mediated hydride transfer. Further transformation of alpha -amino allenes to 2,4,6-trisubstituted pyridines was realized. We also developed another class of amphoteric molecules – alpha-boryl aldehydes, equipped with the tetrahedral MIDA boryl group. A wide range of boryl-substituted building blocks or functionalized boronic acid derivatives have been accessed from these bench-stable alpha-borylcarbonyl compounds. Further chemoselective transformations of these alpha-boryl aldehyde derived building blocks have been conducted, where alph-boryl isocyanates, alpha-aminoboronic acids, acylboronates, and borylated heterocycles were achieved through the decarboxylative functionalization of alpha-borylcarboxylic acids.

El treball experimental que ha permès redactar la present Tesi Doctoral ha estat dividit en dues parts. A la primera part es presenten els resultats referents a la síntesi estereocontrolada de noves heteroarilglicines (quinolil i pirazolilglicines) a partir de cetones acetilèniques, substrats quirals que permeten accedir a l'esquelet de diferents heterocicles (quinolines i pirazoles), la posterior obtenció dels corresponents quinolil i pirazolil--aminoalcohols i les diferents metodologies d'oxidació per tal d'accedir a les corresponents quinolil i priazolilglicines objectiu. A la segona part d'aquesta memòria s'ha estudiat, en dissolució, l'habilitat del grup alquilsulfona com a grup sortint eficaç en reaccions d'ipso-substitució nucleofilica. El desenvolupament d'aquesta reacció ha servit de punt de partida per a la creació de llibreries d'heterocicles amb alta diversitat molecular i potencial interès biològic sobre fase sòlida. / These work have been divided in two sections. In the first section, a new and efficient methodology towards the stereocontrolled synthesis of novel -acetylenic ketones containing a masked -amino acid functionality in enantiomerically pure form has been developed. This new chiral building block is the starting material for the synthesis of enantiomerically pure quinolyl and pyrazolylglycines, important structures with potential biological activity and very useful for the synthesis of peptidomimetics. The methods begins from the Garner's aldehyde and takes place through an alkyne derivative via a carbonyl-alkyne homologation reaction. Condensation of the lithium acetylide at low temperatures with different aldehydes yielded the corresponding propargyllic alcohol derivatives in good yields, which under mild oxidative conditions gave the corresponding acetylenic ketones algmost quantitatively.In the second part of this work, the ability of alkylsulfonyl groups as efficient leaving groups in heteroaromatic mucleophilic ipso-substitution reactions has been studied. The rational behind this study has been the possibility of transferring the developed methodology to the solid support and thus to synthesize in a parallel fashion a small library of molecularly diverse heterocycles with potential biological interest. An in solution optimised methodology has been successfully transferred to the solid support and a small library of molecularly diverse benzothiazoles (-excedent heterocylces) was prepared in a parallel fashion in good overall yields and purities of the final products.

Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains xvi, 377 p. : ill. Includes abstract. Includes bibliographical references (p. 120-128).

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 176-193). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves [207]-216).

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 176-193). Also available on the Internet.

Thesis (M. Sc.)--University of Hong Kong, 1964. / Typewritten.