10257-32-6Relevant articles and documents
Reactions of Adenine Nucleosides with Aqueous Alkalies: Kinetic and Mechanism
Lehikoinen, Pertti,Mattinen, Jorma,Loennberg, Harri
, p. 3819 - 3823 (1986)
The hydrolysis of adenosine in aqueous alkali has been studied by liquid chromatography (LC), NMR spectroscopy, and isotopic labeling techniques.The first step of the multistage reaction pathway has been shown to be a nucleophilic attack of hydroxide ion on the C8 atom with concomitant opening of the imidazole ring.The equilibrium mixture of 4-amino-5-formamido-6-(ribosylamino)pyrimidines obtained undergoes three competitive reactions, viz., intramolecular cyclization to adenine nucleosides and N6-ribosyladenines and degradation to nonchromophoric products, most probably via intermediary formation of 4,5-diamino-6-(ribosylamino)pyrimidines.Isomeric N6-ribosyladenines are further hydrolyzed to adenine and D-ribose.The rate constants for the different partial reactions have been determined at various concentrations of hydroxide ion.The mechanisms of individual steps are discussed.Comparative kinetic studies with 2'-deoxy-, 2',3'-O-isopropylidene-, and 5'-O-methyladenosine and 9-β-D-arabinofuranosyladenine and its 5'-O-methyl derivative are interpreted to indicate that the glycon moiety hydroxyl groups do not play any important role in the alkaline cleavage of adenine nucleosides.
New flavonoid glycosides from Xanthium strumarium with their protein tyrosine phosphatase 1B inhibitory activity
Jiang, Pei-Jing,Lu, Mei-Jiao,Xi, Yi-Yuan,Chen, Jun,Zheng, Ju-Jia,Xu, Xiang-Wei
, p. 45 - 51 (2021/01/25)
Two new flavonoid glycosides named 6-hydroxy-3-methoxy-apigenin 7-O-α-?-rhamnopyranoside (1) and 3-hydroxyl-apigenin 8-C-β-?-xylopyranoside (2), along with five known compounds (3-7), were isolated from Xanthium strumarium. Their structures were elucidate
Isolation and structural characterization of four diastereomeric lignan glycosides from Abies holophylla and their neuroprotective activity
Cha, Joon Min,Lee, Tae Hyun,Subedi, Lalita,Ha, Young Jun,Kim, Hye Ryeong,Kim, Sun Yeou,Choi, Sang Un,Kim, Chung Sub
, (2020/12/02)
Diastereomers are a type of a stereoisomer and they are often isolated as a mixture due to their similar physical properties. Through HPLC technique, we isolated four stereoisomeric lignan glycosides, holophyllosides A–D (1–4), from the trunk of Abies holophylla Maxim. which were first isolated as a mixture 25 years ago. The planar structures of 1–4 were characterized by conventional 1D and 2D NMR data analysis and their stereochemistry was determined via empirical comparison of their 13C NMR chemical shifts and 3JH-H coupling constants with the reported values, enzymatic hydrolysis followed by LC-MS analysis, and ECD experiment. Of the four stereoisomers isolated, only compounds 1, 3, and 4 showed moderate neuroprotective activity by inducing NGF secretion in C6 cells whereas 2 did not. This study highlights again the stereochemical importance of molecules in their biological and pharmaceutical application.