自旋偶合信息一般可通过2D-COSY谱来确定.在COSY谱中,除能判断质子间的自旋耦合关系外,还能确定偶合常数的相对符号.本文用COSY-45谱确定了土槿皮类化合物中具有AMX自旋体系的偶合常数相对符号. 根据COSY基本脉冲序列θ值,可以得到COSY-90或COSY-45谱(θ=90°或45°).对于AMX体系,其一维~1H谱表现为三组四连峰.在COSY-90谱中,有九组峰,每组 Spin coupling information can be generally determined by 2D-COZY spectrum. In COZY spectrum, in addition to being able to determine the spin-coupled relationship between protons, the relative sign of the coupling constant can be determined.In this paper, Derivatives of COXY-90 or COZY-45 (θ = 90 ° or 45 °) can be obtained based on the θ value of COZY basic pulse sequence. For the AMX system, one-dimensional ~ 1H spectrum showed three groups of tetranophora.The COZY-90 spectrum, there are nine groups of peaks, each group