Quinoxalines XIV. Synthesis, 1H, 13C, 15N NMR spectroscopic, and quantum chemical study of 1H-pyrazolo[3,4-b]quinoxalines (flavazoles)
作者:Matthias Heydenreich、Andreas Koch、Gerhard Sarodnick、Erich Kleinpeter
DOI:10.1016/j.tet.2005.01.013
日期:2005.2
their structure is investigated by 1H, 13C, and 15N NMR spectroscopy. The restricted rotation about the partial C, N double bond of the N-acyl derivatives 7–10 is studied by dynamic NMR spectroscopy and the barriers to rotation are determined. In order to assign unequivocally the 15N chemical shifts of N-4 and N-9, in case of 3-substituted flavazoles, exemplary the 1H, 13C, and 15N NMR chemical shifts
报道了通过母体化合物的酰化,烷基化,卤化和氨基甲基化合成一系列1 H-吡唑并[3,4- b ]喹喔啉(黄酮)的结构,并通过1 H,13 C和15研究了它们的结构。N NMR光谱。关于部分C,N的N-酰基衍生物的双键的受限旋转7 - 10是由动态NMR光谱研究,被确定为旋转的障碍。为了明确分配N-4和N-9的15 N化学位移,在3取代的黄酮唑的情况下,示例性地为1 H,13 C和15N个NMR化学位移34,35,和39,也通过理论上量子化学的方法计算〔从头在不同层次的理论(HF / 6-31G *和B3LYP / 6-31G *)的]。