We report the first example of alkylation of underivatized xanthine with chloroacetic acid to yield a separable mixture of N 7- and N 9-(methylenecarboxyl)xanthine and its conversion to a peptide nucleic acid monomer compatible with Fmoc-based oligomerization chemistry. Additionally, we have simultaneously prepared the N 7 - and N 9-PNA monomers of guanine by alkylation of 2-N-isobutyrylguanine which were subsequently separated. Molecular modeling of the nucleobase base triplets indicates that N 7-xanthine and N 7-guanine form isomorphous triplets with adenine and guanine, respectively. We also show that polyamides containing N 7-xanthine are compatible with triple-helix formation.
我们报告了未衍生化
黄嘌呤与
氯乙酸烷基化的首个例子,得到了可分离的N7-和N9-(亚甲基羧基)
黄嘌呤混合物,并将其转化为与基于Fmoc的寡聚
化学兼容的肽核酸单体。此外,我们还通过对2-N-异丁酰
鸟苷进行烷基化,同时制备了N7-和N9-
PNA的
鸟苷单体,并进行了分离。分子建模结果表明,N7-
黄嘌呤和N7-
鸟苷与
腺嘌呤和
鸟苷形成同晶体三联体。我们还表明,含有N7-
黄嘌呤的聚酰胺与三重螺旋的形成是兼容的。