Kuijpers W H, Huskens J, Koole L H, van Boeckel C A
Department of Organic Chemistry, Eindhoven University of Technology, The Netherlands.
Nucleic Acids Res. 1990 Sep 11;18(17):5197-205. doi: 10.1093/nar/18.17.5197.
A new deprotection procedure in the synthesis of (partially) phosphate-methylated oligodeoxynucleotides has been developed, involving treatment of fully protected DNA fragments with methanolic potassium carbonate. It is shown that base deprotection can be accomplished in potassium carbonate/methanol without affecting the methyl phosphotriesters. This methodology enables us to synthesize, both in solution and on a solid support, DNA fragments which are phosphate-methylated at defined positions. The solid phase synthesis, however, turns out to be accompanied by considerable demethylation of the phosphotriesters. It is demonstrated that this demethylation does not occur during the deprotection or work-up procedure. Furthermore, it was found that the latter side-reaction is suppressed when the standard capping procedure with acetic anhydride is included.
已开发出一种用于合成（部分）磷酸甲基化寡脱氧核苷酸的新脱保护方法，该方法包括用碳酸钾甲醇溶液处理完全保护的DNA片段。结果表明，在碳酸钾/甲醇中可以实现碱基脱保护，而不会影响甲基磷酸三酯。这种方法使我们能够在溶液中和在固体支持物上合成在特定位置磷酸甲基化的DNA片段。然而，固相合成结果显示伴有磷酸三酯的大量去甲基化。已证明这种去甲基化在脱保护或后处理过程中不会发生。此外，发现当包括用乙酸酐进行的标准封端步骤时，后一种副反应会受到抑制。
