Carbohydrates in synthesis
<p>The use of carbohydrates as starting materials for organic synthesis is illustrated by the synthesis of several polyhydroxylated piperidine, pyrrolidine, indolizine and pyrrolizidine alkaloids.</p> <p>Nucleophilic displacement by azide ion at C-2 in a D-glucose derivative, with...
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| Format: | Thesis |
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1986
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| _version_ | 1826286467633119232 |
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| author | Smith, P |
| author_facet | Smith, P |
| author_sort | Smith, P |
| collection | OXFORD |
| description | <p>The use of carbohydrates as starting materials for organic synthesis is illustrated by the synthesis of several polyhydroxylated piperidine, pyrrolidine, indolizine and pyrrolizidine alkaloids.</p> <p>Nucleophilic displacement by azide ion at C-2 in a D-glucose derivative, with subsequent intramolecular cyclisation through nitrogen onto the C-6 or C-5 position and functional group manipulation, led to the synthesis of: 1,5-dideoxy-1,5-imino-D-mannitol; 1,2,5-trideoxy-1,5-imino-D-arabinohexitol; 1,5-dideoxy-1,5-imino-D-glucitol; 2-Acetamido-1,5-imino-1,2,5- trideoxy-D-glucitol; 2-Acetamido-1,5-imino-1,2,5-trideoxy-D-mannitol; (2S, 3R, 4R, 5S)-3,4,5-trihydroxypipecolic acid; (2S, 3R, 4R, 5R)-3,4,5- trihydroxypipecolic acid and 2,5-dideoxy-2,5-imino-D-mannitol.</p> <p>Nucleophilic displacement by azide ion at C-3 in a D-glucose derivative, with subsequent intramolecular cyclisation through nitrogen onto the C-6 position, produced the tosylate salt of 3,6-dideoxy-3,6-imino-1,2-0-isopropylidene- ⫏-D-glucofuranose, a highly divergent intermediate, from which the pyrrolidines: 1,4-dideoxy-1,4-imino-L-gulitol, 1,4-dideoxy-1,4-imino-D-lyxitol and (2S, 3S, 4R) - 3,4-dihydroxyproline were prepared directly. Periodate cleavage of the C1-2 bond and a 2-C chain extension from C-2 with subsequent intramolecular cyclisation, produced the pyrrolizidine (IS, 2R, 8R) - 1,2-dihydroxypyrrolizidine. An intramolecular Wadsworth Emmans cyclisation between a lactol at C-1 and a phosphonate, produced by a DCC coupling of the amine with dimethoxyphosphinylacetic acid, led to the formation of the indolizine (1S, 2R, 8S, 8aR) - 1,2,8-trihydroxyoctahydroindolizine.</p> <p>The synthesis of 1,4-dideoxy-1,4-imino-D-lyxitol, was achieved by connection of C1 and C4 of a D-mannose derivative through nitrogen.</p> <p>Methyl 3,5-0-isopropylidene- ⫏-D-xylofuranoside was elaborated to both enantiomers of 1,4-dideoxy-1,4-imino-arabinitol. The _D-enantiomer was produced by introduction of a nitrogen between C-2 and C-5, the L- enantiomer by introduction of a nitrogen between C-1 and C-4.</p> <p>(2R, 3S, 4R) - 3,4-dihydroxyproline was prepared from _D-ribonolactone. The key step of the synthesis was a nucleophilic displacement by azide ion at C-2 in which the stereochemistry was unexpectedly retained.</p> |
| first_indexed | 2024-03-07T01:44:12Z |
| format | Thesis |
| id | oxford-uuid:97dd273b-2577-4556-8889-361f801a826a |
| institution | University of Oxford |
| last_indexed | 2024-03-07T01:44:12Z |
| publishDate | 1986 |
| record_format | dspace |
| spelling | oxford-uuid:97dd273b-2577-4556-8889-361f801a826a2022-03-27T00:03:00ZCarbohydrates in synthesisThesishttp://purl.org/coar/resource_type/c_db06uuid:97dd273b-2577-4556-8889-361f801a826aPolonsky Theses Digitisation Project1986Smith, P<p>The use of carbohydrates as starting materials for organic synthesis is illustrated by the synthesis of several polyhydroxylated piperidine, pyrrolidine, indolizine and pyrrolizidine alkaloids.</p> <p>Nucleophilic displacement by azide ion at C-2 in a D-glucose derivative, with subsequent intramolecular cyclisation through nitrogen onto the C-6 or C-5 position and functional group manipulation, led to the synthesis of: 1,5-dideoxy-1,5-imino-D-mannitol; 1,2,5-trideoxy-1,5-imino-D-arabinohexitol; 1,5-dideoxy-1,5-imino-D-glucitol; 2-Acetamido-1,5-imino-1,2,5- trideoxy-D-glucitol; 2-Acetamido-1,5-imino-1,2,5-trideoxy-D-mannitol; (2S, 3R, 4R, 5S)-3,4,5-trihydroxypipecolic acid; (2S, 3R, 4R, 5R)-3,4,5- trihydroxypipecolic acid and 2,5-dideoxy-2,5-imino-D-mannitol.</p> <p>Nucleophilic displacement by azide ion at C-3 in a D-glucose derivative, with subsequent intramolecular cyclisation through nitrogen onto the C-6 position, produced the tosylate salt of 3,6-dideoxy-3,6-imino-1,2-0-isopropylidene- ⫏-D-glucofuranose, a highly divergent intermediate, from which the pyrrolidines: 1,4-dideoxy-1,4-imino-L-gulitol, 1,4-dideoxy-1,4-imino-D-lyxitol and (2S, 3S, 4R) - 3,4-dihydroxyproline were prepared directly. Periodate cleavage of the C1-2 bond and a 2-C chain extension from C-2 with subsequent intramolecular cyclisation, produced the pyrrolizidine (IS, 2R, 8R) - 1,2-dihydroxypyrrolizidine. An intramolecular Wadsworth Emmans cyclisation between a lactol at C-1 and a phosphonate, produced by a DCC coupling of the amine with dimethoxyphosphinylacetic acid, led to the formation of the indolizine (1S, 2R, 8S, 8aR) - 1,2,8-trihydroxyoctahydroindolizine.</p> <p>The synthesis of 1,4-dideoxy-1,4-imino-D-lyxitol, was achieved by connection of C1 and C4 of a D-mannose derivative through nitrogen.</p> <p>Methyl 3,5-0-isopropylidene- ⫏-D-xylofuranoside was elaborated to both enantiomers of 1,4-dideoxy-1,4-imino-arabinitol. The _D-enantiomer was produced by introduction of a nitrogen between C-2 and C-5, the L- enantiomer by introduction of a nitrogen between C-1 and C-4.</p> <p>(2R, 3S, 4R) - 3,4-dihydroxyproline was prepared from _D-ribonolactone. The key step of the synthesis was a nucleophilic displacement by azide ion at C-2 in which the stereochemistry was unexpectedly retained.</p> |
| spellingShingle | Smith, P Carbohydrates in synthesis |
| title | Carbohydrates in synthesis |
| title_full | Carbohydrates in synthesis |
| title_fullStr | Carbohydrates in synthesis |
| title_full_unstemmed | Carbohydrates in synthesis |
| title_short | Carbohydrates in synthesis |
| title_sort | carbohydrates in synthesis |
| work_keys_str_mv | AT smithp carbohydratesinsynthesis |