New isoelectronic, non-isosteric phosphonate analogues of nucleoside 5′-phosphates featuring the phosphorus moiety directly attached on the sugar ring in the C4′ position are described. The analogues were synthesised by a nucleosidation reaction from tetrofuranosyl phosphonate synthons and silylated nucleobases. The pyrimidine compounds with erythro and threo configuration in both D- and L-series were prepared, and the structures were assigned by NMR spectroscopy. The results of NMR conformational studies show that all calculated conformers have a maximum pucker in the range typical for nucleosides. In all compounds, the S-type conformer is preferred and is more significant in α-D-threo-compounds. Studies on inhibition of thymidine phosphorylase revealed that one of the prepared phosphonic acids was a competitive inhibitor of the enzyme (Ki = 4 μM).
描述了新的等电子、非同构的磷酸酯类核苷酸5'-磷酸的类似物,其磷酸基直接连接在糖环的C4'位置。这些类似物是通过从四氧杂环磷酸酯合成物和硅化的核碱基进行核苷化反应合成的。制备了具有D-和L-系列中erythro和threo构型的嘧啶化合物,并通过核磁共振谱学确定了它们的结构。核磁共振构象研究的结果显示,所有计算的构象体现出典型的核苷酸范围内的最大皱曲。在所有化合物中,S-型构象体更受青睐,并在α-D-threo-化合物中更为显著。对胸苷磷酸酶抑制的研究表明,所制备的磷酸类化合物之一是该酶的竞争性抑制剂(Ki = 4 μM)。