A simple method of the preparation of 2'-O-methyladenosine. Methylation of adenosine with methyl iodide in anhydrous alkaline medium.

J Yano, L S Kan, P O Ts'o

Index: Biochim. Biophys. Acta 629(1) , 178-83, (1980)

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Abstract

A simple and effective method of the methylation on the 2'-O position of adenosine is described. Adenosine is treated with CH3I in an anhydrous alkaline medium at 0 degrees C for 4 h. The major products of this reaction are monomethylated adenosine at either the 2'-O or 3'-O position (total of 64%) and the side products are dimethylated adenosine ((2', 3'-O-dimethyladenosine, 21%, and N6-2'-O-dimethyladenosine, 11%). The ratio of 2'-O- and 3'-O-methyladenosine has been found to be 8 to 1. Therefore, this reaction preferentially favors the synthesis of 2'-O-methyladenosine. The monomethylated adenosine is isolated from reaction mixture by a silica gel column chromatography. Then the pure 2'-O-methyladenosine can be separated by crystallization in ethanol from the mixture of 2'=O and 3'-O-methylated isomers. The overall yield of 2'-O-methyladenosine is 42%.