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Synthesis of Methyl N ‐Acetyl‐4‐amino‐2,4,6‐trideoxy‐3‐ C ‐methyl‐α‐ L ‐rhamnohexopyranoside − Towards Elucidation of the Relative Configuration of Saccharocarcin E Sugar
Author(s) -
Langner Martin,
Laschat Sabine,
Grunenberg Jörg
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200390209
Subject(s) - chemistry , stereochemistry , epimer , hydrolysis , halogenation , sugar , acetylation , organic chemistry , biochemistry , gene
L ‐Olivomycal 8 , obtained from L ‐rhamnose ( 10 ) in six steps, was used as a precursor for the preparation of methyl N ‐acetyl‐4‐amino‐2,4,6‐trideoxy‐3‐ C ‐methyl‐α‐ L ‐rhamnohexopyranoside ( 5b ). The amino group at C‐4 of 5b was introduced by intramolecular nucleophilic displacement of a (trichloromethyl)imidate derived from 8 , yielding the 3,4‐ trans ‐(trichloromethyl)oxazoline 13 with retention of configuration. Compound 13 was further converted into the N ‐acetamide 14 by basic hydrolysis and subsequent acetylation. N ‐Iodosuccinimide‐promoted glycosylation and reductive dehalogenation yielded the target molecule 5b , together with its β epimer 5c (α/β = 85:15). Comparison of the NMR spectroscopic data of 5b with those of saccharocarcin E sugar and several other 4‐amino‐2‐deoxyhexoses revealed similarities between saccharocarcin E sugar and kijanimicin derivative 23 , which suggest the proposed β‐ L ‐ xylo ‐hexopyranose configuration 4d for saccharocarcin E sugar. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)