Chiral transformations of D-ribose to 2(S)-amino-2-[2,5-dihydro-5(R)-methylfuran-2(R)-yl]ethanoic acid, a diastereomer of the antibiotic (+)-furanomycin
The chain-extended 2-(2,3-O-isopropylidene-β- D -ribofuranosyl)-1,3-diphenylimidazolidine derivative (3a) was prepared by a known sequence from D -ribose. Benzylation of the primary alcohol function of 3a, deprotection of the masked aldehyde, chain extension using a modified Strecker-type synthesis,...
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Veröffentlicht in: | Canadian journal of chemistry 1983-02, Vol.61 (2), p.317-322 |
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Hauptverfasser: | , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | The chain-extended 2-(2,3-O-isopropylidene-β-
D
-ribofuranosyl)-1,3-diphenylimidazolidine derivative (3a) was prepared by a known sequence from
D
-ribose. Benzylation of the primary alcohol function of 3a, deprotection of the masked aldehyde, chain extension using a modified Strecker-type synthesis, and acetylation of the resulting epimeric 2-hydroxyl groups gave the appropriately blocked seven-carbon 3,6-anhydro compounds (
5
a, b). The primary alcohol function was deprotected and then removed by mesylation, iodide replacement, and hydrogenolysis. The 2-hydroxyl group was deprotected, mesylated, and replaced by azide. Methanolysis of the amide and isopropylidene groups gave the α-azido ester diols (
13
a, b). Treatment of
13
a with thiocarbonyldiimidazole followed by the Corey-Winter reaction with trimethylphosphite effected concomitant reduction of the azide function and reductive elimination of the cyclic thionocarbonate group. Saponification of the ester intermediate gave the target α-amino acid, 2(S)-amino-2-[2,5-dihydro-5(R)-methylfuran-2(R)-yl]ethanoic acid (
1
). Comparison of the properties of
1
and (+)-furanomycin confirmed the necessity of revision of stereochemistry for the antibiotic. |
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ISSN: | 0008-4042 1480-3291 |
DOI: | 10.1139/v83-057 |