Synthesis of acyclic nucleoside analogues based on 1,2,4-triazolo[1,5-a]pyrimidin-7-ones by one-step Vorbrüggen glycosylation
作者:Igor A. Khalymbadzha、Tatyana S. Shestakova、Julia O. Subbotina、Oleg S. Eltsov、Alexandra A. Musikhina、Vladimir L. Rusinov、Oleg N. Chupakhin、Inna L. Karpenko、Maxim V. Jasko、Marina K. Kukhanova、Sergey L. Deev
DOI:10.1016/j.tet.2013.12.051
日期:2014.2
the absence of N,O-bis(trimethylsilyl)acetamide (BSA). Glycosylated products 6a–f and 7a–f underwent reversible isomerization under TMSOTf treatment. The ratio of glycosylated products of the coupling reaction between 4 and 5 was thermodynamically controlled. A similar reaction occurred if ZnCl2 was chosen as a catalyst, although lower yields of the acyclic analogues of nucleosides were observed. The
在三甲基甲硅烷基三氟甲磺酸酯(TMSOTf)存在下,使1,2,4-三唑并[1,5- a ]嘧啶-7-酮4a - i与(2-乙酰氧基乙氧基)乙酸甲酯5反应获得新的阿昔洛韦类似物(Vorbrüggen程序)。化合物4a – f和5之间的耦合分别导致N3-和N4-异构体6和7的混合物。相反,化合物4g – i与5的反应选择性地进行,仅形成N3-异构体。发现比率为6a – f与图7a - ˚F依赖于存在或不存在的Ñ,ö双(三甲基硅烷基)乙酰胺(BSA)。在TMSOTf处理下,糖基化产物6a – f和7a – f经历了可逆异构化。热力学控制4和5之间偶联反应的糖基化产物的比例。如果ZnCl 2发生类似的反应尽管观察到较低的核苷无环类似物产率,但还是选择了“草”作为催化剂。其他嘌呤(腺嘌呤和鸟嘌呤)的糖基化可以通过Vorbrüggen程序的非BSA修饰来实现。