Syntheses related to some naturally occurring naphthopyranquinones

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dc.contributor.advisorGiles, R G Fen_ZA
dc.contributor.authorHugo, Victor Ignatiusen_ZA
dc.date.accessioned2016-02-15T07:15:37Z
dc.date.available2016-02-15T07:15:37Z
dc.date.issued1986en_ZA
dc.descriptionBibliography: pages 248-257.en_ZA
dc.description.abstractThe naphtho[2,3-c]pyran ring system occurs not infrequently in Nature as derivatives of the 5,10-quinone. Examples include the eleutherins, the nanaomycins and the protoaphins some of which have been shown to possess antibiotic activity. The synthesis of these natural products requires appropriate regiospecific aromatic oxygenation of 2- acetylnaphthoquinone. Syntheses of 3-acetyl-5-methoxy-1, 4- naphthoquinone and the corresponding 5,7-dimethoxy analogue are described and the use of these in the syntheses of several naturally occurring pyranquinones or their derivatives, has been investigated. In the course of this work, an unusual Fries rearrangement and a novel baseinduced cyclisation were discovered - the latter affording several naphtho[2,3-c]pyrans in high yield. Previous routes to (±)-isoeleutherin and (±)-deoxyquinone A dimethyl ether have been recorded, but they give rise to a mixture of eleutherin and isoeleutherin in the first case, and a mixture of deoxyquinone A dimethyl ether and its cisdimethyl isomer. The synthetic routes to isoeleutherin and deoxyquinone A dimethyl ether developed during this investigation are highly stereoselective. The formation of the dimethyl ethers of quinones A and A', which is also highly stereoselective represents the first reported synthesis of the degradation products of the aphid pigments, protoaphin-fb and protoaphin-s1. The synthesis of 7-methoxyeleutherin is also described. The reaction of trifluoroacetic anhydride with various naphthalene derivatives is described and the potential of some of these acylated naphthalenes to be employed in the syntheses of naphtho[2, 3-c]pyrans and naturally occurring quinones has been investigated.en_ZA
dc.identifier.apacitationHugo, V. I. (1986). <i>Syntheses related to some naturally occurring naphthopyranquinones</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/17036en_ZA
dc.identifier.chicagocitationHugo, Victor Ignatius. <i>"Syntheses related to some naturally occurring naphthopyranquinones."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Chemistry, 1986. http://hdl.handle.net/11427/17036en_ZA
dc.identifier.citationHugo, V. 1986. Syntheses related to some naturally occurring naphthopyranquinones. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Hugo, Victor Ignatius AB - The naphtho[2,3-c]pyran ring system occurs not infrequently in Nature as derivatives of the 5,10-quinone. Examples include the eleutherins, the nanaomycins and the protoaphins some of which have been shown to possess antibiotic activity. The synthesis of these natural products requires appropriate regiospecific aromatic oxygenation of 2- acetylnaphthoquinone. Syntheses of 3-acetyl-5-methoxy-1, 4- naphthoquinone and the corresponding 5,7-dimethoxy analogue are described and the use of these in the syntheses of several naturally occurring pyranquinones or their derivatives, has been investigated. In the course of this work, an unusual Fries rearrangement and a novel baseinduced cyclisation were discovered - the latter affording several naphtho[2,3-c]pyrans in high yield. Previous routes to (±)-isoeleutherin and (±)-deoxyquinone A dimethyl ether have been recorded, but they give rise to a mixture of eleutherin and isoeleutherin in the first case, and a mixture of deoxyquinone A dimethyl ether and its cisdimethyl isomer. The synthetic routes to isoeleutherin and deoxyquinone A dimethyl ether developed during this investigation are highly stereoselective. The formation of the dimethyl ethers of quinones A and A', which is also highly stereoselective represents the first reported synthesis of the degradation products of the aphid pigments, protoaphin-fb and protoaphin-s1. The synthesis of 7-methoxyeleutherin is also described. The reaction of trifluoroacetic anhydride with various naphthalene derivatives is described and the potential of some of these acylated naphthalenes to be employed in the syntheses of naphtho[2, 3-c]pyrans and naturally occurring quinones has been investigated. DA - 1986 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1986 T1 - Syntheses related to some naturally occurring naphthopyranquinones TI - Syntheses related to some naturally occurring naphthopyranquinones UR - http://hdl.handle.net/11427/17036 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17036
dc.identifier.vancouvercitationHugo VI. Syntheses related to some naturally occurring naphthopyranquinones. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Chemistry, 1986 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17036en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemistryen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherOrganic Chemistryen_ZA
dc.titleSyntheses related to some naturally occurring naphthopyranquinonesen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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