Diversity oriented synthesis of fused-ring 1,3-oxazines from carbohydrates as biorenewable feedstocks
作者:Lal Dhar S. Yadav、Vishnu P. Srivastava、Vijai K. Rai、Rajesh Patel
DOI:10.1016/j.tet.2008.02.084
日期:2008.5
Microwave enhanced diversity oriented synthesis (MEDOS) of various N- and O-heterocyclic systems fused with 1,3-oxazine ring is reported. The synthesis represents a new montmorillonite K-10 clay-catalyzed green protocol, which utilizes d-glucose/d-xylose as biorenewable feedstocks. d-Glucose/d-xylose-derived 1,3-oxazin-2-ones(thiones) either directly undergo K-10 clay-catalyzed cyclization to yield pyrano-/furo-1
报道了与1,3-恶嗪环稠合的各种N-和O-杂环系统的微波增强的面向多样性的合成(MEDOS)。该合成代表了一种新的蒙脱石K-10粘土催化的绿色方案,该方案利用d-葡萄糖/ d-木糖作为生物可再生原料。d-葡萄糖/ d-木糖衍生的1,3-恶嗪-2-酮(硫酮)在无溶剂微波辐射下直接经历K-10粘土催化的环化反应,生成吡喃-/呋喃-1,3-恶嗪系统进行Malaprade反应,然后用适当的试剂环化时,可提供一定的条件或得到azolo- / azino-1,3-oxazines。苯肼,羟胺,乙am,苯脲和半(硫代半)脲。