Oligonucleotides Containing 7-Deaza-2′-deoxyxanthosine: Synthesis, Base Protection, and Base-Pair Stability
作者:Frank Seela、Khalil I. Shaikh
DOI:10.1002/hlca.200690251
日期:2006.11
Oligonucleotides incorporating 7-deaza-2′-deoxyxanthosine (3) and 2′-deoxyxanthosine (1) were prepared by solid-phase synthesis using the phosphoramidites 6–9 and 16 which were protected with allyl, diphenylcarbamoyl, or 2-(4-nitrophenyl)ethyl groups. Among the various groups, only the 2-(4-nitrophenyl)ethyl group was applicable to 7-deazaxanthine protection being removed with 1,8-diazabicyclo[5.4
掺入7-脱氮-2'- deoxyxanthosine(寡核苷酸3)和2'-deoxyxanthosine(1使用亚磷酰胺固相合成方法制备)6 - 9和16,其被保护用烯丙基,二苯基氨基甲,或2-(4-硝基苯基)乙基。在各个基团中,仅2-(4-硝基苯基)乙基适用于通过β-消除作用通过1,8-二氮杂双环[5.4.0] undec-7-ene(DBU)除去7-脱氮黄嘌呤的保护,而用Pd 0催化剂对烯丙基残基的脱保护或用氨对二苯基氨基甲酰基的脱保护失败。相反,发现烯丙基是2'-脱氧黄嘌呤(1)。核苷3与四种典型DNA成分以及3-溴-1-(2-脱氧-β -D-赤型-戊呋喃糖基)-1 H-吡唑并[3,4- d ]嘧啶-4的碱基配对对12-mer双链体中的1,6-二胺(4)进行了研究,结果表明7-deaza-2'-deoxyxanthosine(3)具有与2'-deoxyxanthosine(1)相同的