Orthogonal aerobic conversion of N-benzyl amidoximes to 1,2,4-oxadiazoles or quinazolinones
作者:Feng-Lian Zhang、Yi-Feng Wang、Shunsuke Chiba
DOI:10.1039/c3ob41393d
日期:——
Concise synthesis of 1,2,4-oxadiazoles was achieved by heating N-benzyl amidoximes with K3PO4 in DMF at 60 °C under an O2 atmosphere via benzylic C–H oxygenation. On the other hand, aerobic treatment of N-benzyl amidoximes with Cs2CO3 in DMSO at 100 °C could result in oxidative skeletal rearrangement to deliver quinazolinones as a major product. This orthogonal product selectivity could be realized by difference of the reaction temperature as well as selection of the solvents and inorganic bases.
通过在60°C下,在O2气氛中使用K3PO4作为催化剂,将N-苄基脒肟在DMF中加热,实现了1,2,4-噁二唑的简洁合成,这一过程涉及苄基C-H氧合作用。另一方面,在100°C下,使用Cs2CO3作为催化剂,在DMSO中对N-苄基脒脟进行需氧处理,可能导致骨架氧化重排,主要产物为喹唑啉酮。这种正交的产品选择性可以通过反应温度、溶剂和无机碱的选择来实现。