Phosphoramidites of the formula
    where R is a base-labile protecting group, R¹ and R² are individually alkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 8 carbon atoms, or aryl of 6 to 20 carbon atoms or are joined together to form with the nitrogen atom a cyclic structure of 4-7 carbon atoms and 0 to 1 annular chalcogen atoms of atomic number 8 to 16, G is a hydrocarbylene group of 1 to 20 carbon atoms and Z is a hydroxy-protected vicinal diol group bound to G by one of the vicinal diol carbon atoms or a disulfide group and bound to G by one of the sulfur atoms of the disulfide group, with the proviso that G is of at least 4 carbon atoms when Z is said disulfide group are used in conventional automated oligonucleotide synthesis to introduce a functional aldehyde or thiol group on the 5′ end of the oligonucleotide to thereby provide a reactive site on the oligonucleotide that may be used to conjugate the oligonucleotide to molecules that contain a free amino group or an electrophilic center reactive with a thiol group.
                            式中的
磷酰胺
 其中 R 为碱基易败保护基团,R¹ 和 R² 分别为 1 至 6 个碳原子的烷基、3 至 8 个碳原子的环烷基或 6 至 20 个碳原子的芳基,或连接在一起与氮原子形成 4 至 7 个碳原子和 0 至 1 个原子序数为 8 至 16 的环状链烯原子的环状结构、G 是 1 至 20 个碳原子的烃基,Z 是羟基保护的沧海二醇基,通过沧海二醇的一个碳原子或二
硫化物基团与 G 结合,并通过二
硫化物基团的一个
硫原子与 G 结合、在传统的寡核苷酸自动合成中,当 Z 为所述二
硫基时,G 至少有 4 个碳原子,用于在寡核苷酸的 5′端引入功能性醛基或
硫醇基,从而在寡核苷酸上提供一个反应位点,可用于将寡核苷酸与含有游离
氨基或与
硫醇基反应的亲电中心的分子共轭。