title: Semisynthetic epsilon-(iso)rhodomycins: a new glycosylation variant and modification reactions.
abstract: Synthesis of 7-O-(3-amino-2,3,6-trideoxy-alpha-L-lyxo-hexopyranosyl)-epsilon-(i so)rhodomycinones 16 and 17, and their 3'-morpholino derivatives are described. Glycosylation (trimethylsilyl triflate, 10:1 dichloro-methane-acetone, -35 degrees) of 1-O-tert-butyldimethylsilyl-2,3-6-trideoxy-4-O-p-nitrobenzoyl-3-trifl uoroacetamido-beta-L-lyxo-hexopyranose (4) with epsilon-rhodomycinone (epsilon-RMN, 5) or epsilon-isorhodomycinone (epsilon-isoRMN, 6) afforded 7-O-alpha-glycosyl-epsilon-RMN (9) and -epsilon-isoRMN (12) in high yield. The glycosyl donors 2,3,6-trideoxy-4-O-p-nitrobenzoyl-3-trifluoroacetamido-L-lyxo++ +-hexopyrano se (2) or its 1-O-trimethylsilylated alpha-anomer 3 were less suitable for the glycosylation of these aglycons. Sapinification of 9 and 12 provided 16 and 17, respectively, which reacted with various 2,2'-oxydiacetaldehydes under conditions of reductive alkylation to give 3'-morpholinyl-epsilon-(iso)rhodomycins.
authors.affiliation: Research Laboratories of Behringwerke, Marburg, F.R.G.
authors.forename: C
authors.initials: C
authors.lastname: Kolar
authors.forename: G
authors.initials: G
authors.lastname: Kneissl
authors.forename: U
authors.initials: U
authors.lastname: Knödler
authors.forename: K
authors.initials: K
authors.lastname: Dehmel
mesh_terms: D018943:Anthracyclines; D000903:Antibiotics, Antineoplastic / Q000138:chemical synthesis* / Q000737:chemistry; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006031:Glycosylation; D008969:Molecular Sequence Data; D015394:Molecular Structure
chemical_list: D018943:Anthracyclines; D000903:Antibiotics, Antineoplastic; C004977:rhodomycin