Approaches to the synthesis of 9 -member carbon to carbon rings through novel benzofuranyl C-glycosides.
Item
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Title
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Approaches to the synthesis of 9 -member carbon to carbon rings through novel benzofuranyl C-glycosides.
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Identifier
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AAI9405558
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identifier
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9405558
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Creator
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Meleties, Panayiotis C.
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Contributor
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Adviser: Vernon G. S. Box
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Date
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1993
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Language
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English
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Publisher
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City University of New York.
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Subject
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Chemistry, Organic
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Abstract
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The novel non natural 6-C-benzofuranylglycosides were synthesized from 4-bromobenzofuran derivatives and protected carbohydrate lactones. An intramolecular nucleophilic reaction between the benzofuranyl moiety (position 3) and the anomeric carbon will lead to the 9-member C-C ring.;The synthesis of the 4-bromobenzofuran derivatives was achieved either by (3,3) aromatic Claisen rearrangement or by condensation of salicylaldehyde derivatives with {dollar}\alpha{dollar}-haloketones. The 2-acylbenzofuran derivatives were deoxygenated either directly or after reduction and methylation by a novel application of the TMSCI/NaBH{dollar}\sb3{dollar}CN reagent. Bromine-lithium exchange yielded the 4-lithiated benzofuran derivatives, which were used for the synthesis of the 6-C-benzofuranyl glycosides.;Protected derivatives of glucurono-6,3-lactone, and idofurano-6,3-lactone were synthesized and allowed to react with the 4-lithiated benzofuran derivatives to produce the novel 6-C-benzofuranyl glycosides. Reduction and dehydration yielded a pair of diastereomeric 6-endo or exo-C-benzofuranyl- (1,4:3,6) -difuranosides. Deprotection of the difuranosides with the I{dollar}\sb2{dollar}/MeOH reaction led to the mixture of the four possible diastereomeric 1-methoxy-6-C-benzofuranyl- (1,4:3,6) -difurano-{dollar}2 {dollar},5-diols arising from the anomeric center and the scrambling of the stereogenic center at C{dollar}\sb6{dollar}.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
