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%.

中文翻译：

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一种简单的制备2'-O-甲基腺苷的方法。在无水碱性介质中用甲基碘将腺苷甲基化。

描述了一种简单有效的腺苷2'-O位置甲基化方法。在无水碱性介质中于0摄氏度下用CH3I处理腺苷4小时。此反应的主要产物是2'-O或3'-O位置的单甲基化腺苷（占64％），副产物是二甲基化的腺苷（（2'，3'-O-二甲基腺苷，21％，和N6-2'-O-二甲基腺苷（11％）。发现2'-O-和3'-O-甲基腺苷的比例为8：1。因此，该反应优先促进2'-的合成O-甲基腺苷通过硅胶柱色谱法从反应混合物中分离出单甲基化腺苷，然后通过在乙醇中结晶从2'= O和3'的混合物中分离出纯净的2'-O-甲基腺苷 -O-甲基化的异构体。2'-O-甲基腺苷的总产率为42％。