Quantitative estimation of interaction between carbohydrates and concanavalin A by surface plasmon resonance biosensor

We measured the affinity of more than 20 sugars with concanavalin A (ConA) by an optical biosensor (surface plasmon resonance sensor) using asialofetuin (ASF) as an immobilized binding partner of ConA. We determined kinetic parameters of the effects of sugars on the dissociation of ConA from ASF quantitatively, and the structural requirements of the functional groups of sugars for binding with ConA. We found that the affinity of ConA for sugars is dependent on its conformation induced by interaction with the binding partner. In addition, the results showed that optical biosensor system is well mimics the interaction of ConA with sugars in biomembrane.     

One-pot synthesis of N-acyl-substituted sulfamides from chlorosulfonyl isocyanate via the Burgess-type intermediates

The title N-alkoxycarbonyl- or N-aryloxycarbonyl-substituted sulfamides were synthesised in one-pot in efficient yields from chlorosulfonyl isocyanate (CSI), alcohols and aqueous (or dry) amines via the corresponding water-resistant intermediates, carboxysulfamoylammonium salts (Burgess-type reagents), which were generated in situ by the deactivation of the corresponding water-sensitive N-(chlorosulfonyl)carbamates with tertiary amines.     

Binuclear 1,2,4,5-tetraimino-3,6-diketocyclohexane bis[bis(bipyridine)ruthenium(II)] redox series

The reaction of the [Ru(bpy)2(MeOH)2]2+ cation (bpy = 2,2'-bipyridine) with 1,2,4,5-tetraaminobenzene in the presence of trace water and oxygen yields the cation [(bpy)2Ru(1,2,4,5-tetraimino-3,5-diketocyclohexane)Ru(bpy)2]4+. This binuclear species undergoes ligand-based reductions, giving the 3+ and 2+ charged species. The X-ray structure, electrochemistry, ZINDO calculations, and NMR, ESR, UV/vis, and IR spectra were analyzed where possible, giving an electronic model of the binuclear species and some of its redox products. The X-ray structure reveals the [(bpy)2Ru] fragments symmetrically disposed across the 1,2,4,5-tetraimino-3,5-diketocyclohexane bridge in a molecule with Cs symmetry.