
TY  - JOUR
A1  - Noyori, R 
A1  - Uchiyama, M 
A1  - Nobori, T 
A1  - Hirose, M 
A1  - Hayakawa, Y 
T1  - Practical Synthesis of 2'-5'-Linked Oligoadenylates (2-5A Oligomers)
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1992
VL  - 45
IS  - 1
SP  - 205
EP  - 225
KW  - 
UR  - https://doi.org/10.1071/CH9920205 
N2  - A general, facile synthesis of 2'-5'-linked oligonucleotides (2-5A oligomers ) has been achieved based on the second-order regioselective protection of adenosine, one-pot formation of the 2'5' internucleotide linkage, and O-selective phosphorylation of N-unblocked nucleosides. Standard t- butyldimethylsilylation of 5'-O-p-methoxytrityladenosine followed by careful recrystallization from a mixture of triethylamine , methanol, ethyl acetate and ether (4 : 4 : 5 : 100 v/v) gives the 3',5'-di-O-protected adenosine in high yield. Magnesium alkoxide -mediated condensation of the 2'-O-free adenosine with o-chlorophenyl p-nitrophenyl phosphorochloridate followed by 2',3'-di-O-t-butyldimethylsilyladenosine produces the N-free and fully O-protected adenylyl (2'-5')adenosine. The resulting adenylyl dimer, after removal of the 5'-O-trityl protector, is elongated to the protected trimeric compound through a similar reaction sequence. Deprotection of the product furnishes the 2-5A core. Condensation of the 5?-0-detritylated core and bis (2,2,2-trichloroethyl) phosphorochloridite assisted by 2,6-lutidine and subsequent oxidation with aqueous iodine produces, after deblocking, 2-5A 5'-monophosphate (p5'A2'p5'pA2'p5'A). The 2-5A 5'-monophosphate is converted into 2-5A 5'-triphosphate (ppp5'A2'p5'A2'p5'A) by reaction with N,N'-carbonyldiimidazole in the presence of triethylamine followed by tributylammonium diphosphate. This procedure allows ready synthesis of 2-5A oligomers and related compounds on a multigram scale. 
ER  -

