Ribonucleoside Complexes Research Articles

Non-covalent complexes of nucleosides and nucleobases with β-cyclodextrin: a study by fast atom bombardment mass spectrometry and collision-induced dissociation

Naturally occurring nucleosides and nucleobases form inclusion complexes with β-cyclodextrin. These host-guest complexes could be detected by fast atom bombardment mass spectrometry. The collision-induced dissociation spectra of the protonated complexes showed mainly ions related to the guest molecules. However, deoxyribonucleoside complexes also exhibited facile elimination of the sugar moiety, whereas this fragmentation was absent in ribonucleoside complexes. The deprotonated inclusion complexes underwent collision-induced dissociation to give mainly the deprotonated host molecule. It appears, therefore, that the protonated complexes have protonated guests inside the cavity of the neutral host and the deprotonated complexes have neutral guests in the cavity of the deprotonated host.

Non‐covalent complexes of nucleosides and nucleobases with β-cyclodextrin: a study by fast atom bombardment mass spectrometry and collision‐induced dissociation

Naturally occurring nucleosides and nucleobases form inclusion complexes with β-cyclodextrin. These host–guest complexes could be detected by fast atom bombardment mass spectrometry. The collision-induced dissociation spectra of the protonated complexes showed mainly ions related to the guest molecules. However, deoxyribonucleoside complexes also exhibited facile elimination of the sugar moiety, whereas this fragmentation was absent in ribonucleoside complexes. The deprotonated inclusion complexes underwent collision-induced dissociation to give mainly the deprotonated host molecule. It appears, therefore, that the protonated complexes have protonated guests inside the cavity of the neutral host and the deprotonated complexes have neutral guests in the cavity of the deprotonated host. © 1998 John Wiley & Sons, Ltd.

A New Class of Pentacoordinate Ribonuclease Inhibitors: Synthesis, Characterization, and Inhibition Studies of Ribonucleoside and Anhydropentofuranose Oxorhenium(V) Complexes

This article describes the synthesis, characterization, and kinetic studies of a new class of stable ribonuclease (RNase) inhibitors. Herein the first synthesis of oxorhenium(V) complexes of diaminonucleosides and diaminoaldopentofuranoses is reported. Stability studies have shown that the complexes are stable between pH 3 and 13 at temperatures of 25−80 °C for 24 h with no occurrence of ligand exchange or epimerization at the ReO core. Kinetic studies show that both the syn (1a) and anti (1b) diastereoisomers of oxorhenium(V) complexes of 9-(2‘,3‘-diamino-2‘,3‘-dideoxy-β-d-ribofuranosyl)adenine (13) are excellent inhibitors of the purine specific ribonuclease, RNase U2. Dixon and Lineweaver−Burke analyses suggest that the inhibition is competitive, with inhibitory constants (Kis) of 15 and 93 μM, respectively. These complexes are of equivalent inhibitory potency to previously reported nucleoside vanadium alkoxide inhibitors with the added advantage of being completely stable in aqueous solution. The oxor...