BACKGROUND & AIMS:
:Oligonucleotides containing 2'-O,4'-C-ethylene nucleic acids (ENA) have been proven highly effective for antisense therapeutics. 2'-O,4'-C-Ethyleneguanosine and its phosphoramidite were previously obtained from 3,5-di-O-benzy1-4-C-(p-tolulenesulfonyloxyethyl)-1,2-di-O-acetyl-α-D-erythropentofuranose by glycosylation, but with limited efficiency. Using 3,5-di-O-benzy1-4-C-(2-t-butyldiphenylsilyloxyethyl)-1,2-di-O-acetyl-α-D-erythropentofuranose as an alternative substrate, we developed several methods to obtain 2'-O,4'-C-ethyleneguanosine derivatives with much higher yields than previously reported. These methods were also applicable for the synthesis of 2'-O,4'-C-ethyleneadenosine and 2'-O,4'-C-ethylene-5-methyluridine derivatives. Moreover, we investigated the thermodynamic benefit of DNA strands containing 2'-O,4'-C-ethyleneguanosines during duplex formation with complementary RNA. Only a single modification by the nucleoside resulted in a 10-fold greater binding constant of the DNA/RNA duplex.
背景与目标:
: 含有2 '-O,4'-C-乙烯核酸 (ENA) 的寡核苷酸已被证明对反义治疗非常有效。2 '-O,4'-C-亚乙基鸟苷及其亚磷酰胺先前是通过糖基化从3,5-二-O-苄基1-4-c-(对甲苯磺酰氧基乙基)-1,2-di-O-acetyl-α-D-erythropentofuranose获得的,但效率有限。使用3,5-二-O-苄基1-4-c-(2-叔丁基二苯基甲硅烷基氧基乙基)-1,2-di-O-acetyl-α-D-erythropentofuranose作为替代底物,我们开发了几种方法来获得2 '-O,4'-C-乙基鸟苷衍生物,其收率远高于以前报道的。这些方法也适用于2 '-O,4'-C-乙烯腺苷和2 '-O,4'-C-ethylene-5-methyluridine衍生物的合成。此外,我们研究了含有2 '-O,4'-C-亚乙基鸟嘌呤的DNA链在互补RNA双链形成过程中的热力学益处。只有核苷的一次修饰才能使DNA/RNA双链体的结合常数提高10倍。