摘要
应用规范不变原子轨道GIAO法,分别在HF/6-311+G(2d,p)//B3LYP/6-31G(d)和HF/6-311+G(2d,p)//B3LYP/6-31G(d,p)水平上,计算了从卫茅科南蛇藤属植物苦皮藤中分离鉴定出的2,4,6-三甲氧基苯-1-O-D葡萄糖苷(化合物1)的α和β分子构型的1HNMR和13CNMR的化学位移值,并对理论计算值与实验值的误差进行了统计分析,其中β分子构型的计算值与实验值较为接近,结合α和β分子构型的总能量计算值,预测化合物1分子应择型于β构型,即为2,4,6-三甲氧基苯-1-O-β-D葡萄糖苷,这与根据糖的端基质子化学位移和耦合常数实验值(δH=4.81,J=7.3Hz)推断的结论相吻合,进一步说明理论计算的合理性.
The ^1 H and ^13 C-NMR of 2,4,6-trimethoxyphenol-1-O-D-glucopyranoside （ Compound 1 ） isolated from Celastrus angulatus （Celastraceae） was calculated theoretically at the both levels HF/6-311 ＋ G（2d, p）//B3LYP/ 6-31 G（d） and HF/6-311 ＋ G（ 2d, p）//B3 LYP/6-31 G（ d, p） using the GIAO （ gauge-independent atomic orbital） method. Statistical error analysis for theoretically predicted δH and δc values versus those experimentally observed for compound 1 was discussed. The results show that the theoretically predicted δH and δc values of β conformer of compound 1 are more close to the experimentally observed values than ct conformer, and the β conformer of compound 1 is more stable than at conformer according to molecular energy theoretically calculated. So compound 1 is assigned to be 2, 4, 6-trimethoxyphenol-1-O-β-D-glucopyranoside, which is in good consistence with the conclusion deduced by the anomeric proton signal （δH =4.80, J =7.3 Hz） experimentally observed.
基金
ProjectsupportedbyHenanInnovationProjectForUniversityProminentResearchTalents(2004).
