Zavialov Ilia A, Dahanukar Vilas H, Nguyen Hoa, Orr Cecilia, Zhang Fucheng, Andrews David R
Department of Synthetic Chemistry, Schering-Plough Research Institute, 1011 Morris Avenue, Union, New Jersey 07083, USA.
Org Lett. 2004 Jun 24;6(13):2237-40. doi: 10.1021/ol049272n.
[reaction: see text] A new and practical method for the synthesis of 1- and 1,3-substituted xanthines is reported. Direct base-promoted condensation of the imidazole precursor 1 with carbamates 2 gives 1-substituted 7-PMB xanthines 7 in good yields. Alkylation of these derivatives or their potassium salts proceeds under mild conditions to give functionalized 1,3-substituted 7-PMB xanthines 9 in good to excellent yields. The obtained 7-PMB-protected derivatives can be readily deprotected to give the parent 1- and 1,3-substituted xanthines.
[反应：见正文] 报道了一种合成1-和1,3-取代黄嘌呤的新实用方法。咪唑前体1与氨基甲酸酯2在碱的直接促进下缩合，以良好的产率得到1-取代的7-PMB黄嘌呤7。这些衍生物或其钾盐的烷基化在温和条件下进行，以良好至优异的产率得到功能化的1,3-取代的7-PMB黄嘌呤9。所得到的7-PMB保护的衍生物可以很容易地脱保护得到母体1-和1,3-取代的黄嘌呤。
