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Oligonucleosides with a Nucleobase‐Including Backbone. Part 12
Author(s) -
Eppacher Simon,
Bhardwaj Punit Kumar,
Bernet Bruno,
Bravo Gala José Luis,
Knöpfel Thomas,
Vasella Andrea
Publication year - 2004
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200490269
Subject(s) - chemistry , tetramer , sonogashira coupling , trimer , monomer , uridine , iodide , propargyl alcohol , stereochemistry , propargyl , medicinal chemistry , dimer , organic chemistry , palladium , enzyme , rna , biochemistry , polymer , gene , catalysis
In contradistinction to the corresponding Grignard reagent, bis[(trimethylsilyl)ethynyl]zinc reacted with the 5′‐oxoadenosine 3 diastereoselectively to the β ‐ D ‐ allo ‐hept‐6‐ynofuranosyladenine 5 . Lithiation/iodination of the monomeric propargyl alcohol 5 and of the dimeric propargyl alcohol 22 provided the 8‐iodoadenosines 7 and 18 , respectively, considerably shortening the synthesis of the dimeric O ‐silylated 8‐iodoadenosine 25 . The mixed uridine‐ and adenosine‐derived tetramers 21 and 32 were synthesised. The tetramer 21 was prepared by a linear sequence. Sonogashira coupling of 9 and 13 yielded the trimer 16 that was C ‐desilylated to 17 . A second Sonogashira coupling of 17 and 19 yielded the tetramer 21 . Tetramer 32 was prepared in higher yields by a convergent route, coupling the acetylene 29 and the iodide 30 . The uridine‐derived iodides proved more reactive than the adenosine‐derived analogues, and the N 6 ‐unprotected adenosine‐derived alkynes were more reactive than their N 6 ‐benzoylated analogues.