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Oligonucleosides with a Nucleobase‐Including Backbone, Part 2, Synthesis and Structure Determination of Adenosine‐Derived Monomers
Author(s) -
Gunji Hiroki,
Vasella Andrea
Publication year - 2000
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 - 10.1002/1522-2675(20000705)83:7<1331::aid-hlca1331>3.0.co;2-z
Subject(s) - chemistry , silylation , acetylide , substituent , adenosine , deprotonation , monomer , stereochemistry , nucleoside , derivative (finance) , ketone , yield (engineering) , aldehyde , organic chemistry , catalysis , biochemistry , polymer , ion , materials science , financial economics , economics , metallurgy
The synthesis and structure determination of adenosine‐derived monomeric building blocks for new oligonucleosides are described. Addition of Me 3 Si‐acetylide to the aldehyde derived from the known partially protected adenosine 1 led to the epimeric propargylic alcohols 2 and 3 , which were oxidised to the same ketone 4 , while silylation and deprotection led to 7 and 9 ( Scheme 1 ). Introduction of an I substituent at C(8) of the propargylic silyl ethers 10 and 11 was not satisfactory. The protected adenosine 12 was, therefore, transformed in high yield into the 8‐chloro derivative 13 by deprotonation and treatment with PhSO 2 Cl; the iodide 15 was obtained in a similar way ( Scheme 2 ). The 8‐Cl and the 8‐I derivatives 13 and 15 were transformed into the propargylic alcohols 17 , 18 , 25 , and 26 , respectively ( Scheme 3 ). The propargylic derivatives 2 , 10 , 17 , 19 , 23 , 25 , and 27 were correlated, and their (5′ R ) configuration was determined on the basis of NOEs of the anhydro nucleoside 19 ; similarly, correlation of 3 , 11 , 18 , 20 , 24 , 26 , and 28 , and NOE's of 20 evidenced their (5′ S )‐configuration.