An Improved Method for the Application of the 4-Methoxybenzyl Group to Protect the 2'-Hydroxyl Group in the Ribonucleotide Synthesis by TFA-acidolysis
The cleavage of the 4-methoxybenzyl group from the 2'-OH-position of ribonucleosides by the hydrogenation with different Pd-catalysts as well as trifluoroacetic acid has been studied in detail.During hydrogenation, side reactions at the base residue of cytidine occurred which, however, could be extensively suppressed by PdCl2 catalysis.More practicable results were obtained with trifluoroacetic acid in the presence of cation scavengers, allowing smoothly to convert a series of 2'-methoxybenzyl ribonucleotides to the homogeneous deprotection products.
Losse, G.,Pechstein, Birgit
p. 46 - 54
(2007/10/02)
Synthesis of Ribooligonucleotides Using the 4-Methoxybenzyl Group as a New Protecting Group for the 2'-Hydroxyl Group
The 4-methoxybenzyl group was introduced to protect the 2'-hydroxyl group of uridine, cytidine, and N2-benzoylguanosine by treatment of 2',3'-O-(dibutylstannylene)uridine or NaH-treated nucleosides with 4-methoxybenzyl bromide.The 2'-O-(4-methoxybenzyl)nucleosides can be used as useful starting materials for the synthesis of 3',5'-linked ribooligonucleotides.The 4-methoxybenzyl group was removed rapidly from the ribooligonucleotides by treatment with triphenylmethyl fluoroborate, and the completely deblocked ribooligonucleotides were characterized by enzymatic hydrolysis.