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A methodology for the synthesis of substituted pyridines via Diels-Alder condensation of N-(O-tbutyldimethylsilyloxy)-3-methyl-l-aza-1,3-butadiene (65) and N-(O-tbutyl dimethylsilyloxy)-2-methyl-l-aza-1,3-butadiene (66) with substituted 1,4-benzoquinones was developed.The novel azadienes 65 and 66 were synthesized by direct condensation of N-(Otbutyldimethylsilyloxy) hydroxylamine with methacrolein and methyl vinyl ketone respectively. The azadiene 66 was also prepared by condensation of N-(O-tbutyldimethylsilyloxy) hydroxylamine with 3-bromo-2-butanone followed by dehydrohalogenation of the resulting imine with potassium tbutoxide.The Diels-Alder condensation of 66 with N-phenylmaleimide produced N-phenyl-6methyl-2,3-pyridinedicarboximide (82). The [4+2] cycloaddition of 66 with Nphenylmaleimide, naphthoquinone, 2-acetamido-5-bromo- and 2-acetamido-6-bromo-1,4benzoquinone, 2,6-dichloro-1,4-benzoquinone, 2-bromo- 1,4-benzoquinone resulted in the formation of N-phenyl-5-methyl-2,3-pyridinedicarboximide (83), 3-methyl-lazaanthracene-9,10-dione (87), 6-acetamido-3-methylquinoline-5,8-Dione (90), 7acetamido-3-methylquinoline-5,8-dione (91), 7-chloro-3-methylquinoline-5,8-dione (93), 3-methylquinoline-5,8-dione (95) respectively. Diels-Alder condensation of 2,6-dibromo 1,4-benzoquinone with azadienes 65 and 66 produced some non-isolable tar. Total synthesis of 7-bromolavendamycin methyl ester 33 was also attempted. Although all attempts to obtain the key intermediate, 7-bromo-2-methyl-5,8-quinolinedione (98a), either from the Diels-Alder condensation of 66 or oxidation of 5,7-dibromo-2-methyl-8hydroxy quinoline (99) failed, 98a was synthesized through oxidation of 5-amino-7bromo-2-methyl-8-hydroxyquinoline (104). Selective oxidation of 98a with SeO2 produced 7-bromo-2-formylquinoline-5,8-dione (98b). Pictet-Spengler condensation of 98b with p-methyl trypthophan methyl ester (55), gave the tetrahydrocarboline 106 which was decomposed in refluxing benzene.In a different pathway, 103 was selectively oxidized to 7- bromo-2- form yl -5-ni tro8-hydroxyquinoline (107b). Condensation of this aldehyde with p-methyl tripthophan (55), produced 3-carbomethoxy-4methyl-l-(7-bromo-8-hydroxy-5-nitro-2-quinolinyl)-(3carboline (109a). 3-Carbomethoxy-4-methyl-l-(7-bromo-8-hydroxy-5-amino-2quinolinyl)-p-carboline (109b) was obtained by reduction of 109a. It is expected that 7bromolavendamycin methyl ester 33 to be produced by oxidation of 109b.The structures of the new compounds were confirmed by NMR, IR and mass spectroscopy as well as the elemental analysis. All the spectra are included at the end of this thesis for further reference. / Department of Chemistry

Thesis (Ph. D.)--Virginia Polytechnic Institute, 1955. / Vita. Abstract. Includes bibliographical references (leaves 266-285). Also available via the Internet.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 248-257). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Hong Kong, 1993.

Thesis (M. Phil.)--University of Hong Kong, 1990.

Thesis (M. Phil.)--University of Hong Kong, 1991.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 211-213).

This thesis describes the investigation of the Diels-Alder reaction of the imine (140) with the diene (141) to give four products (142,143,156, 157). At low temperatures the enone (156) is the major product while at ambient temperature the bicyclic compounds (142) and (143) predominate. The reaction is highly solvent dependent, with the best results being obtained in benzene solution. Lewis acids appear to have little effect on the course of the reaction. The reaction of the imine (140) with the TBDMSO diene (159) gives the silyl enol ethers (160) and (161) as well as the above four products. Possible mechanisms are discussed. COOM. OSIM., In order to investigate asymmetric induction the 8- phenylmenthyl derived imine (194) was reacted with the diene (141) under a variety of conditions but no asymmetric induction was seen in the exo adducts, and only a small degree in the endo adducts. The bromination and Baeyer-Villiger oxidation of the ketone (142) were investigated and the resultant lactone (209) was converted into the bromide (258). ISOPROSOPININE A (84) ISOPROSOPININE B (S3) Several methods to prepare a suitable side chain for isoprosopinine A were investigated. The prosopis alkaloids isoprosopinine A (84) and B (85) were prepared by alkylation of the sulphones (252) and (266) with the bromide (258) followed by reductive removal of the N-tosyl and sulphone moieties with sodium amalgam. The imine (274) has been prepared and shown to undergo a Lewis acid catalysed imino-Diels-Alder reaction with the diene (141) to give the adducts (283) and (284). hCH,M=CHCOjM» (2T4) Alternative imines for asymmetric synthesis, such as (299) and (288) have been investigated. Preparation of the sulphinamide imine (299) has proved difficult. Attempts to carry out aqueous Diels-Alder reactions of the silyloxydiene (159) with iminium ions, generated in situ from amines, aldehydes and acids, have proved fruitless.

The chemoselective hydrozirconation reaction of a series of 1-ene-3-yne molecules 51a-d, using the commercially available hydride reagent, Cp₂ZrCl(H) 1, provides an efficient route to the syntheses of 1,3-dienes 55a-d, substituted at the 1-position by the Cp₂ZrCl moiety. Similar chemoselectivity was observed in the hydrozirconation reaction of α, β-unsaturated nitriles, to generate the corresponding 1-azadienyl complexes 68-71. The complexes 55a-d were found to be useful general precursors in the preparation of other heterosubstituted 1,3-dienes. Thus, corresponding tin-, phosphorus-, boron-, selenium-and sulfur-heterosubstituted 1,3-dienes 77a-d, 79a-d, 87a-d, 88a-d and 89a-d were readily prepared in good to excellent yields by a stereoselective transfer reaction from zirconium. The 1-azadienyl complexes also served as useful starting materials in the preparation of selenium-and phosphorus-substituted 1-azadienes. The selenium-substituted 1,3-dienes 88a-d underwent a facile isomerization reaction when exposed to fluorescent light, and when thermolysed in the dark at 80°C in unsealed reactors. Mechanistic studies of this isomerization process suggested that an intermolecular pathway involving free radical intermediates was operable. A comparable photochemical isomerization reaction of the sulfur-substituted 1,3-dienes was also observed. When the cycloaddition reactions of 88a-b and 88d with maleic anhydride were performed in the absence of light at reson able temperatures, good yields of the expected endo-cycloadducts were obtained. However, when the same reactions were repeated in room light or at temperatures in excess of those required for formation of the endo-cycloadducts an, interesting, apparent [l,3]-shift of the phenylselenenyl moiety resulted. The results of a crossover experiment indicated that this rearrangment was intermolecular in nature. The preparation of the trialkylstannyl and phenylselenenyl 2-substituted 1,3-dienes (128 and 129) was achieved via a transmetalation reaction of the Grignard reagent 24. The Diels-Alder reactivity of 1,3-dienes 128 and 129, with a series of electron-deficient dienophiles, was successfully investigated. [Formula Omitted] / Science, Faculty of / Chemistry, Department of / Graduate