Embodiments for the synthesis of sensitive oligonucleotides as well as insensitive oligonucleotides are provided. Sulfur-based groups are used for the protection of exo-amino groups of nucleobases, phosphate groups and 2′-OH groups, and as cleavable linker for linking oligonucleotides to a support. Oligonucleotide syntheses are achieved under typical conditions using phosphoramidite chemistry with important modifications. To prevent replacing sulfur-based protecting groups by acyl groups via cap-exchange, special capping agents are used. To retain hydrophobic tag to assist RP HPLC purification, special phosphoramidites are used in the last synthetic cycle. With the sulfur-based groups for protection and linking, oligonucleotide deprotection and cleavage are achieved via oxidation followed by beta-elimination under mild conditions. Therefore, besides for insensitive oligonucleotide synthesis, the embodiments of the invention are capable for the synthesis of oligonucleotide analogs containing sensitive functional groups that cannot survive the harsh conditions used in prior art oligonucleotide synthesis technologies.
本发明提供了用于合成敏感寡核苷酸和不敏感寡核苷酸的实施方案。使用基于
硫的基团来保护核苷酸碱基的exo-
氨基团、
磷酸基团和2′-OH基团,并且作为可裂解的连接剂将寡核苷酸连接到支持物上。寡核苷酸的合成是在典型条件下使用
磷酰亚胺化学进行的,并进行了重要的修改。为了防止通过帽交换将基于
硫的保护基团替换为酰基,使用了特殊的封端剂。为了保留亲脂性标签以协助反相高效
液相色谱(RP HPLC)纯化,在最后的合成周期中使用了特殊的
磷酰亚胺。使用基于
硫的基团进行保护和连接,寡核苷酸的脱保护和裂解是通过氧化随后在温和条件下进行beta-消除实现的。因此,除了用于不敏感寡核苷酸的合成外,本发明的实施方案还能够合成包含在先前的寡核苷酸合成技术中使用的严酷条件下无法存活的敏感功能团的寡核苷酸类似物。