麦角甾醇及其衍生物的氢化学位移溶剂效应  

Solvent Effects on Proton Chemical Shifts of Ergosterol and Its Derivatives

作　　者：李厚金[1] 林永成[1] 

机构地区：[1]中山大学化学与化学工程学院,广东广州510275

出　　处：《分析测试学报》2004年第3期26-30,共5页Journal of Instrumental Analysis

基　　金：国家863基金项目 (2001AA624010) ;中山大学青年教师科研启动基金资助项目(31110-1131037)

摘　　要：首次研究了麦角甾醇及其衍生物的氢化学位移溶剂效应。发现麦角甾醇和3β,5α,6β_三羟基麦角甾醇分别以CDCl3、CD3COCD3、DMSO_d6为溶剂 ,测 1HNMR谱 ,甾醇中羟基附近的氢有明显的溶剂效应现象。麦角甾醇和3β,5α,6β_三羟基麦角甾醇中19位的甲基虽然和羟基的距离相对比较远 ,但也存在明显的位移改变。当把麦角甾醇羟基乙酰化之后 ,明显的溶剂效应现象消失 ,说明溶剂效应现象跟甾醇羟基有关。不同的溶剂有不同的介电常数 ,和甾醇羟基形成氢键的能力也不同 ,羟基氧的电子云密度不同 ,它能通过空间的相互作用 ,对19位甲基及羟基附近的氢产生不同的屏蔽作用 ,导致了不同的化学位移改变。Solvent effects on proton chemical shifts of ergosterol and its derivatives were investigated.The proton chemical shifts in the 1 H NMR spectra indicate,the protons around the3-hydroxyl groups in ergosˉterol and ergosta-7,22-dien-3β,5α,6β-triol have distinct solvent effects in solvents CDCl 3 ,CD 3 COCD 3 and DMSO-d6.For the H 3 -19methyl groups of the sterols significant shift was also found,even though they are quite apart from the hydroxyl groups.For the acetylated ergosterol,however,the distinct solvent effects were not observed.This implies that the solvent effects are mainly related to the hydroxyl groups of the sterols.The solvents CDCl 3 ,CD 3 COCD 3 and DMSO-d6have different dielectric constantsε,and hence different capabilities to form hydrogen bonds with the hydroxyl groups.The oxygen atom in the hyˉdroxyl group could exert some effect to the protons of the H 3 -19methyl group through their steric interacˉtion as well.Consequently,chemical shift was observed too,but to a less extent than the shift of the proˉton in the hydroxyl group owing to the shielding effect.

关 键 词：麦角甾醇 3β 5α 6β-三羟基麦角甾醇 ^1H NMR 化学位移 溶剂效应 

分 类 号：O657.2[理学—分析化学] O629.21[理学—化学]