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Synthesis of the Proposed Structure of Pentahydroxylated Pyrrolizidine Hyacinthacine C 5 and Its C 6 ,C 7 Epimer
Author(s) -
Tamayo Juan A.,
Franco Francisco,
SánchezCantalejo Fernando
Publication year - 2011
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.201101126
Subject(s) - chemistry , pyrrolizidine , pyrrolidine , epimer , absolute configuration , stereochemistry , chemical synthesis , in vitro , biochemistry
The synthesis of two pentahydroxylated pyrrolizidines, hyacinthacine C 5 ( 1 ) and 6,7‐di‐ epi ‐hyacinthacine C 5 ( 12 ), from an orthogonally protected pyrrolidine of 2,5‐dideoxy‐2,5‐imino‐ D ‐mannitol configuration (i.e., 7 ) is described. The analytical and spectroscopic data of synthetic 1 present some differences with those of natural hyacinthacine C 5 that exceed the previously observed variations in similar compounds. On this respect, additional studies on chemical derivatives of synthetic 1 support our initially proposed structure and establish the absolute configuration of putative (+)‐hyacinthacine C 5 as that shown in 1 . These studies lead us to conclude that the natural compound originally labeled as (+)‐hyacinthacine C 5 might be a different isomer.