Total assignment of 13C and 1H spectra of three isomeric triterpenol derivatives by 2D NMR: an investigation of the potential utility of 1H chemical shifts in structural investigations of complex natural products
作者:William F. Reynolds、Stewart McLean、Janusz Poplawski、Raul G. Enriquez、Laura I. Escobar、Ismael Leon
DOI:10.1016/s0040-4020(01)87309-9
日期:1986.1
heteronuclear shift-correlated spectra are used to totally assign 1H spectra for , , and taraxasteryl acetate (). 1H chemical shifts are mainly sensitive to local environment and often show values which are characteristic of a particular environment. Knowledge of 1H chemical shifts and splitting patterns also places useful constraints on assignment of 13C chemical shifts for 13C1Hn units. It is strongly recommended
结果表明,最近提出的间接异核移位相关脉冲序列XCORFE可用于明确分配三种异构体(C 30 H 50 O)三萜醇:taraxasterol(),pseudo-taraxasterol()和lupeol的13 C光谱。()。此序列可提供出色的分辨率和灵敏度,远远超过13 C- 13 C连通性实验所给出的灵敏度。直接异移位相关光谱被用于完全分配1 H光谱为,,和蒲公英甾醇乙酸酯()。1个H化学位移主要对当地环境敏感,并且通常显示特定环境特征的值。的知识1个ħ化学位移和分裂模式也对的分配有用约束13对C化学位移13 Ç 1 ħ Ñ单元。强烈建议天然产物化学家常规使用2D NMR分配复杂有机衍生物的1 H化学位移,以建立1 H光谱数据的数据库。