An alternative synthesis of pyrimido[4,5-b]quinoline-4-ones via metal-free amination in water and Vilsmeier–Haack cyclization
作者:Radhey M. Singh、Neha Sharma、Ritush Kumar、Mrityunjaya Asthana、Shraddha Upadhyay
DOI:10.1016/j.tet.2012.10.004
日期:2012.12
Two-step synthesis of pyrimido[4,5-b]quinoline-4-ones is described from 2-chloroquinoline-3-carbonitries via amination and cyclization reactions, respectively. The amination reactions proceeded much faster in water via simple SNAr displacement reactions of chlorine. The cyclization reactions using Vilsmeier reagent at 60 °C gave the best yield of the products. The isolation of starting compound from
从2-氯喹啉-3-碳酸盐通过胺化和环化反应分别描述了嘧啶[4,5 - b ]喹啉-4-酮的两步合成。通过简单的氯的S N Ar置换反应,胺化反应在水中的进行速度大大加快。使用Vilsmeier试剂在60°C下进行环化反应可得到最佳的产物收率。从环化产物与I 2 / K 2 CO 3的反应中分离起始化合物为环化产物的结构提供了进一步的化学证明。提出了合理的环化机理。