反式-4',7-二羟基异黄酮-4-醇和顺式异黄酮-4-醇构象平衡的实验与密度泛函理论1H NMR研究

Experimental and DFT 1H NMR study of conformational equilibria in trans-4',7-dihydroxyisoflavan-4-ol and trans-isoflavan-4-ol.

作者信息

Pihlaja Kalevi, Tähtinen Petri, Klika Karel D, Jokela Tuija, Salakka Auli, Wähälä Kristiina

机构信息

Structural Chemistry Group, Department of Chemistry, University of Turku, Vatselankatu 2, FIN-20014 Turku, Finland.

出版信息

J Org Chem. 2003 Sep 5;68(18):6864-9. doi: 10.1021/jo0301200.

DOI:10.1021/jo0301200

PMID:12946124

Abstract

The solution-state conformational equilibria of trans-4',7-dihydroxyisoflavan-4-ol (1) and trans-isoflavan-4-ol (2) were assessed based on the temperature dependence of their vicinal coupling constants J(H)(-)(2)(alpha)(,H)(-)(3) and J(H-3,H)(-)(4) in comparison to values calculated with density functional theory (DFT) methods at the B3LYP/cc-pVTZ//B3LYP/6-31G(d,p) level of theory. For each half-chair conformer, several rotamers with respect to the C-4 hydroxyl and C-3 phenyl were calculated and the overall diequatorial-to-diaxial ratio at 298 K was assessed as 66:34 for 1 and 73:27 for 2. The syntheses of 1 and 2 are described.

摘要

基于反式-4',7-二羟基异黄酮-4-醇（1）和顺式异黄酮-4-醇（2）的邻位偶合常数J(H)(-)(2)(α),H)(-)(3)和J(H-3,H)(-)(4)的温度依赖性，并与在B3LYP/cc-pVTZ//B3LYP/6-31G(d,p)理论水平下用密度泛函理论（DFT）方法计算的值进行比较，评估了它们在溶液状态下的构象平衡。对于每个半椅式构象异构体，计算了相对于C-4羟基和C-3苯基的几个旋转异构体，并评估了在298 K时1的全二平伏键与二直立键的比例为66:34，2为73:27。描述了1和2的合成方法。