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
Hauptverfasser: Robins, Morris J, Parker, J. M. Robert
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.
ISSN:0008-4042
1480-3291
DOI:10.1139/v83-057