Hassan Muhammad Murtaza, Yaseen Ayat, Ebead Abdelaziz, Audette Gerald, Lee-Ruff Edward
a Department of Chemistry , York University , Toronto , Ontario , Canada.
b Chemistry , Arish University , El Arish , Egypt.
Nucleosides Nucleotides Nucleic Acids. 2018;37(9):518-531. doi: 10.1080/15257770.2018.1500697. Epub 2018 Sep 6.
A synthesis of cyclobutene nucleoside analogs in which the nucleobase is tethered by a methylene group is described. The coupling of 6-chloropurine with 3-hydroxymethyl-cyclobutanone proceeds via its triflate to give both N-7 and N-9 regioisomers with relative yields corresponding to the calculated charge distribution of the 6-chloropurinyl anion. The stereoselective reduction of the N-alkylated ketones yielded quantitatively one stereoisomer in each case. The structural assignments were based on spectroscopic data and single crystal X-ray diffraction. Attempts to photoexcite the N-7 and N-9 ketones in order to promote ring-expansion did not ensue. Preliminary evidence suggests a photodecarbonylation to cyclopropanes took place.
描述了一种环丁烯核苷类似物的合成方法，其中核碱基通过亚甲基连接。6-氯嘌呤与3-羟甲基环丁酮通过其三氟甲磺酸酯进行偶联，得到N-7和N-9区域异构体，其相对产率与6-氯嘌呤基阴离子的计算电荷分布相对应。在每种情况下，N-烷基化酮的立体选择性还原定量地产生一种立体异构体。结构归属基于光谱数据和单晶X射线衍射。为了促进环扩展而对N-7和N-9酮进行光激发的尝试没有成功。初步证据表明发生了光脱羰反应生成环丙烷。
