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
Arenarosides A-G, Polyhydroxylated Oleanane-Type Saponins from Polycarpaea arenaria and their Cytotoxic and Antiangiogenic Activities
Nguyen, Nham-Linh,Vo, Thanh-Hoa,Lin, Yu-Chi,Liaw, Chia-Ching,Lu, Mei-Kuang,Cheng, Jing-Jy,Chen, Mei-Chuan,Kuo, Yao-Haur
, p. 259 - 267 (2021/02/06)
Seven new polyhydroxylated oleanane-type triterpene saponins, arenarosides A-G (1-7), together with four known compounds, were isolated from an ethanol extract of the aerial parts of the Vietnamese plant Polycarpaea arenaria. The chemical structures of the newly isolated oleanane saponins were elucidated on the basis of spectroscopic and spectrometric analysis, especially 2D NMR and HRMS. Biological evaluation revealed that 3, 4, 6, and 7 showed moderate activities against four human cancer cell lines (A549, HTC116, PC3, and RT112) with IC50 values of 6.0-9.9 μM, and 3, 4, 5, and 7 also displayed promising antiangiogenesis effects with IC50 values 5 μM in the test system used. Among the isolates, arenaroside D (4) exhibited the most potent inhibitory effects, not only in cancer cell proliferation but also in angiogenic activities. Preliminary SAR studies revealed that the presence of an acetyl group at C-22 in oleanane-type triterpene saponins increases these bioactivities.