N-Protected 2'-O-(o-nitrobenzyl) nucleosides have been used as condensing units with protected nucleoside 3'-phosphates. After formation of the 3'-5'linkage, the 3'-hydroxyl group of the dinucleoside monophosphate was phosphorylated by treatment with ether p-chlorophenyl phosphate plus DCC or p-chlorophenyl phosphoroditriazolide. The dinucleotide was further elongated in the 3'-direction by condensation with the N-and 2'-O-protected nucleosides followed by phosphorylation. Protected C-Gp and C-A-Up were prepared by this procedure. The trimer was used in the synthesis of hexamer C-A-U-A-A-C by condensation with the 3'-O-(o-nitrobenzyl)-containing trimer block. This hexamer corresponds to the bases 35 to 40 of E. coli tRNAMetf, which are located in the anticodon loop. A trimer containing uridine in the middle position has also been synthesized by this method in combination with an extraction procedure for the intermediate to permit rapid isolation.
N-保护的2'-O-(o-
硝基苯基)核苷被用作保护核苷3'-
磷酸的缩合单元。在形成3'-5'连接后,二核苷酸单
磷酸的3'-羟基通过与醚p-
氯苯基
磷酸和
DCC或p-
氯苯基
磷酸二三唑化物反应被
磷酸化。该二核苷酸进一步通过与N和2'-O-保护核苷的缩合进行3'-方向的延伸,随后进行
磷酸化。通过这一程序制备了保护的C-Gp和C-A-Up。该三聚体被用于合成六聚体C-A-U-A-A-C,方法是与含有3'-O-(o-
硝基苯基)的三聚体区块缩合。该六聚体对应于大肠杆菌tRN
AMetf的35到40号碱基,位于反密码子环中。还通过该方法合成了一个中间位置含有
尿苷的三聚体,并结合了中间体的提取程序,以便快速分离。