An Efficient Synthesis of 2-Substituted 6-Methylpurine Bases and Nucleosides by Fe- or Pd-Catalyzed Cross-Coupling Reactions of 2,6-Dichloropurines
作者:Michal Hocek、Hana Dvořáková
DOI:10.1021/jo034351i
日期:2003.7.1
Fe-catalyzed cross-coupling reactions of 9-substituted or protected 2,6-dichloropurines with 1 equiv of methylmagnesium chloride gave regioselectively 2-chloro-6-methylpurines in good yields. The same reactions with 3 equiv of methylmagnesium chloride or Pd-catalyzed reactions with trimethylaluminum afforded 2,6-dimethylpurines. The 2-chloro-6-methylpurines underwent another coupling with phenylboronic
铁的9-取代或受保护的2,6-二氯嘌呤与1当量的甲基氯化镁的铁催化交叉偶联反应以良好的产率得到了区域选择性的2-氯-6-甲基嘌呤。与3当量的甲基氯化镁的相同反应或与三甲基铝的Pd催化的反应提供2,6-二甲基嘌呤。将2-氯-6-甲基嘌呤与苯基硼酸再进行偶联,得到6-甲基-2-苯基嘌呤。所有反应均针对Bn和THP保护的嘌呤碱基以及酰基保护的核糖苷和2-脱氧核糖苷进行。脱保护后,获得游离嘌呤碱基和核苷。