四种姜黄素类似物核磁共振谱的理论研究

Theoretical Study on Nuclear Magnetic Resonance Spectra of the Four Kinds of Curcumin Analogues

在B3LYP/6-31G(d,p)水平下优化了四种姜黄素类似物的几何构型,并通过振动分析验证了其构型稳定性。在B3LYP/6-311G(d,p)水平下计算了该类化合物的核磁共振谱,研究结果表明:四种化合物主体结构共平面性较好,为一较大共轭体系。由于羟基及甲氧基的引入,使Compound-B/C/D中C3,C4以及Compound-A/D中C5均具有较大δ值,Compound-A中C4和C6的δ值相对较小,C3的δ值相对较大。而在羰基与碳碳双键所形成的共轭羰基化合物中,羰基C13的δ值(183ppm)相对于乙醛中的δ值(201ppm)有所减小,C11,15(α碳)的δ值(122ppm)相对减小,而C9,17(β碳)的δ值(145ppm)相对增大。最后,通过线性回归方法,利用相关系数值r研究了1 H NMRδ值的实验和理论计算值的相关性,结果表明相关性较好,实验值和理论值基本吻合。

The structure of four kinds of curcumin analogues was optimized at the level of B3LYP/6-31G（d,p）,under which the stability was verified by means of vibration analysis.Moreover,NMR spectra of curcumin analogues compounds were studied at the level of B3LYP/6-311G（d,p）by GIAO method.The results show that the structure of four kinds of compounds,a larger conjugated system,has good planarity.Because of introducing hydroxyl and methoxy,the compound-B/C/D-C3,C4and compoud-A and compound-D-C5have greaterδvalue.δvalue of compound-A-C4.C6is relatively smaller,andδvalue of C3is relatively larger.In the conjugated carbonyl compounds,compared with the acetaldehydeδvalue（201ppm）,carbonyl C13δvalue（183ppm）decreases relatively,C11,15（α-carbon）δvalue（122ppm）decreases relatively,and C9,17（β-carbon）δvalue（145ppm） increases relatively.Finally,the correlation between experimentalδvalue and theoreticalδvalue of the ^1 H NMR was analyzed through the linear regression method.Results show that they have good correlation,and the experimental values coincide with the theoretical values.