利用质子COSY-45来确定土槿皮酸类衍生物偶合常数的相对符号

Determination of Relative Signs of Scalar Coupling Constants in Pseudolaric Acid Derivatives by~1H COSY-45

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H谱表现为三组四连峰.在COSY-90谱中,有九组峰,每组

The relative Signs of scalar coupling constants in pseudolaric acid B(2)and its derivative 1 were reported using 2D COSY-45.The results obtained in 1 were consistent with that from pseudo-INDOR spectrum.