HPLC和1HNMR分析确定cis-A-和cis-B-羟甲芬太尼的组成和构型

羟甲芬太尼(1)是一个强效的镇痛剂和高亲和、高选择性的阿片μ受体激动剂。通过HPLC和¹HNMR分析,cis-A-l被确定为由等量的cis-(+)-(3R,4S,2'S)-l和:cis-(—)-(3S,4R,2'R)-1组成的外消旋体,cis-B-l被确定为由等量的cis-(—)-(3R,4S,2'R)-1和cis-(+)-(3S/,4R,2'S)-1组成的外消旋体。     

核磁共振氢谱法鉴别黄连的研究

用 FT- NMR波谱仪测定了 6个不同产地黄连特征总提物的 1 HNMR图谱 ,并对特征信号进行了归属。从特征总提物中分得并鉴定了小檗碱和棕榈碱。分析结果指出 ,每种黄连的 1 HNMR图谱都显示出原小檗碱型生物碱的特征共振峰。黄连伪品无此信号     

(+)-cis-ε-Viniferin的结构确证

用光化学沟通方法确证了从葡萄科植物蘡薁Vitis thunbergii(Vitaceae)中分离得到的( )-cis-ε-viniferin的结构；并纠正了文献核磁共振氢谱(^1H-NMR)数据。     

卡莫司他衍生物的合成

目的 合成一种具有游离伯胺的卡莫司他衍生物.方法 以对羟基苯乙酸为原料,经4步反应得到目标化合物.结果与结论 成功制备了目标产物,所得产物的化学结构经1HNMR、MS确认.     

四氢叶酸辅酶模型及与亲核试剂反应生成物的核磁共振研究

对新合成的四氢叶酸辅酶模型碘化1、2-一二甲基—3—对甲氧苯磺酰基咪唑啉及与亲核试剂反应生成的产物进行了~1HNMR谱的研究,通过化学位移及偶合常数研究探讨其规律性。     

Exchange radioiodination produces inversion at C‐4 of 1‐(4‐deoxy‐4‐iodo‐β‐D‐xylopyranosyl)‐2‐nitroimidazole

The title compound, 3a , when exchange labeled with ¹²⁵I results in three new labeled products. The major labeled product (84.1%) is 1‐(4‐deoxy‐4‐iodo‐β‐L‐arabinopyranosyl)‐2‐nitroimidazole, 3b , that could result from inversion of configuration at C‐4. Exchange labeling carried out under conditions of kinetic control yielded dramatically different product ratios than thermodynamic equilibrium reactions. Confirmation of these results was established by extensive ¹HNMR spectral analyses. A possible mechanism is presented. Copyright © 2002 John Wiley & Sons, Ltd.     

Metabolomics in necrotizing enterocolitis: the state of the art

Introduction: Necrotizing enterocolitis (NEC) is a serious inflammation of the bowel that most often affects premature infants. The exact cause of NEC is still poorly understood but investigators believe that these different factors can play an important role: prematurity and immaturity of the intestine of the preterm newborns, differences in the intestinal bacterial colonization and an abnormal immune response. Since the early symptoms of NEC are often rather non-specific, the diagnosis of NEC can be difficult. Therefore, the search for diagnostic biomarkers for NEC remains warranted. This review focuses on the results of recent metabolomics investigations on NEC, providing important contributions to the understanding of the biochemical process characterizing this disease.

Areas covered: Only a few metabolomics applications of NEC are reported in the literature. The metabolic pathway principally altered in NEC patients is suggested to be linked to the carbohydrates metabolism and the role of gluconate as a predictive marker for this pathology is investigated.

Expert commentary: Biomarkers are crucial as a confident diagnostic tool to make NEC therapy more efficient. Although only a few metabolomics studies have been performed in NEC research, this technique proved to be helpful to understand the pathophysiological mechanisms of this disease.     

抗癌活性络合物[Fe(Ⅱ)- 平阳霉素]的溶液态构型及活化机理研究

平阳霉素（ｐｉｎｇｙａｎｇｍｙｃｉｎ，ＰＹＭ）是以博莱霉素（ｂｌｅｏｍｙｃｉｎ，ＢＬＭ）Ａ５为主要组分的混合物，有独特的抗癌功效，其抗癌指标高于ＢＬＭＡ２，而毒性却低于ＢＬＭＡ２。体外实验表明：ＢＬＭ抗肿瘤的主要机制是直接作用于ＤＮＡ，使ＧｐＣ或Ｇｐ...     

三个新的芳酯基取代单糖的波谱特征

目的:研究新的天然产物芳酯基取代单糖的波谱特征.方法:从光苞紫菊(Notoseris psilolopis Shih)中分离得到三个芳酯基取代单糖化合物,用红外光谱、质谱、核磁共振氢谱与碳谱进行测试.结果:三个新化合物的红外光谱3400 cm-1处有典型的羟基吸收,1730～1724 cm-1有典型的酯基吸收,1600～1400 cm-1有苯环的骨架吸收;质谱上应采用快原子轰击质谱(FAB)、电喷雾质谱(ESI)等软电离技术确定它们的分子量和分子式;由于互变异构体的存在,核磁共振谱有特征较明显的异头氢和异头碳信号.结论:归纳三个新的化合物的波谱特征.     

甙中寡糖链结构测定的核磁共振研究

目的：直接测定甙类药物中寡糖链的结构。方法：新建立的一维ＳＥＭＤＹ,旋转坐标系ＮＯＥ差谱和选择性远程ＤＥＰＴ核磁共振技术相互配合。结果和结论：采用一维ＳＥＭＤＹ技术可以从高度重叠的＾１Ｈ－ＮＭＲ谱中得到糖体的吸收形亚谱,为利用ＮＯＥ与核间距关系确定糖体之间和糖体与甙元之间的连接方式创造了条件。采用旋转坐标系ＮＯＥ差谱技术测定不受分子相关时间的影响,并且可以从高度重叠的＾１Ｈ－ＮＭＲ谱中定量测定ＮＯ