Synthesis of phosphonate derivatives of methylenecyclopropane nucleoside analogues by alkylation–elimination method and unusual opening of cyclopropane ring
作者:Hui-Ping Guan、Yao-Ling Qiu、Mohamad B. Ksebati、Earl R. Kern、Jiri Zemlicka
DOI:10.1016/s0040-4020(02)00589-6
日期:2002.7
were then used for alkylation–elimination of nucleic acid bases (adenine) or precursors (2-amino-6-chloropurine and N4-acetylcytosine). The intermediary Z+E-isomers 22a+23a and 22b+23b were dealkylated with bromo- of iodotrimethylsilane to free phosphonic acids 15a, 16a and phosphonate with an open cyclopropane ring 25 which were separated by ion exchange chromatography on Dowex 1. Phosphonate diesters
描述了通过烷基化-消除法合成亚甲基环丙烷核苷类似物15a - 18a,15b - 18b和15c - 18c的膦酸酯。在一个简化的系列中,甲磺酸19通过与二乙基或二异丙基亚磷酸酯的Michaelis-Becker反应转化为亚甲基环丙烷膦酸酯20a或20b。后者被转化为邻位二溴化物21a和21b,然后用于烷基化-消除核酸碱基(腺嘌呤)或前体(2-氨基-6-氯嘌呤和N 4-乙酰胞嘧啶)。用碘代三甲基硅烷的溴将中间的Z + E异构体22a + 23a和22b + 23b烷基化为游离的膦酸15a,16a,并用开放的环丙烷环25膦酸酯,将其通过Dowex 1上的离子交换色谱法分离。膦酸酯二酯22c通过硅胶色谱分离分离出23a和23c,将它们水解为鸟嘌呤衍生物22d和23d,然后将其脱烷基以得到目标类似物15b,16b。以及在双键26a或26b上加成溴化氢或碘化氢的产物。所述ë + ž异构体22E +